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Tinnitus and musical hallucinosis: The same but more
... However, in the vast majority of cases, musical ear syndrome is associated with hearing impairments and other neurological and psychiatric disorders, and so can be said to have an underlying cause [2,3]. Although the condition is sometimes termed musical hallucinations, it is not a symptom of psychosis and is not associated with schizophrenia [4,5]. There is an existing body of literature indicating a connection between MH and several mental health factors such as psychiatric disorders [6], aging [7], and hearing impairment [8]. ...
... There is very little published research on brain activity during MH. There have also been related studies on the differences between brains creating standard hallucinations and brains of those that do not have hallucinations [5,19]. These studies have also considered the differences between the brain during standard hallucinations and the brain on days when hallucination do not occur [5,20,21]. ...
... There have also been related studies on the differences between brains creating standard hallucinations and brains of those that do not have hallucinations [5,19]. These studies have also considered the differences between the brain during standard hallucinations and the brain on days when hallucination do not occur [5,20,21]. These have not focused on, or found to be significant, a single cortical area, indicating that a single area of the brain cannot be credited with creating all hallucinations or MH. ...
Patient: Male, 62-year-old
Final Diagnosis: Hearing impairment
Symptoms: Hallucinations • hearing impairment
Medication: —
Clinical Procedure: —
Specialty: Audiology
Objective
Unknown etiology
Background
Hearing music that has no source is known as musical ear syndrome, also known as musical hallucinations (MH), and is often associated with hearing impairment. This report is of a 62-year-old man with a 20-year history of unilateral hearing loss and continuous MH. We investigated the neural basis of MH in a subject without any known neurological or psychiatric disorders.
Case Report
A 62-year-old man had a history of 20 years of symptomatic mild hearing loss accompanied with continuous MH in the form of multiple tones. The MH were unilateral in the left side and much more likely to be experienced as externally located and uncontrollable. He underwent structural and functional magnetic resonance imaging (fMRI). Results indicated increased activity and reduced cortical thickness in multiple cortical areas, such as the prefrontal cortex (PFC) and temporal and limbic regions, indicating complex processing and involvement.
Conclusions
The neurological findings indicate differentiated or multiple-area involvement in MH. These morpho-functional changes may represent a neural reorganization causing MH to arise. The altered or activated regions are all related to the processing of emotions and the processing of episodic memory, which has been seen in the MH of schizophrenic patients. This report also highlights that patients with hearing loss may present with continuous MH, and that these patients should not be assumed to have delusions or psychosis, but should be investigated for underlying auditory abnormalities and treated appropriately.
... Thalamocortical dysrhythmia (TCD) has been proposed as a pathological neurophysiological state that underlies a myriad of neurological disorders such as movement disorders, epilepsy, depression, tinnitus, and neuropathic pain (57). In order to define a neural signature of phantom percept and differentiate the underlying electrophysiological activity of simple and complex auditory phantom perceptions found in tinnitus and musical hallucinations, respectively, Vanneste et al. (58) performed source localized EEG studies on these phenomena in healthy chronic hallucinators. This study tested the theory of auditory deafferentation commonly described in these phantom auditory percepts, in which oscillatory alpha activity decreases and theta band activity increases, resulting in surrounding gamma activity known as the "edge effect" (57,58). ...
... In order to define a neural signature of phantom percept and differentiate the underlying electrophysiological activity of simple and complex auditory phantom perceptions found in tinnitus and musical hallucinations, respectively, Vanneste et al. (58) performed source localized EEG studies on these phenomena in healthy chronic hallucinators. This study tested the theory of auditory deafferentation commonly described in these phantom auditory percepts, in which oscillatory alpha activity decreases and theta band activity increases, resulting in surrounding gamma activity known as the "edge effect" (57,58). The findings suggest that while tinnitus and musical hallucinations share a common neural substrate defined by thalamocortical dysrhythmia, including increased beta activity in the ACC, the complex phantoms of musical hallucinations are associated with activation of brain regions linked to music and language processing. ...
... The findings suggest that while tinnitus and musical hallucinations share a common neural substrate defined by thalamocortical dysrhythmia, including increased beta activity in the ACC, the complex phantoms of musical hallucinations are associated with activation of brain regions linked to music and language processing. In this case, TCD is defined as abnormally persistent coupled theta-gamma dysrhythmia relayed to the auditory cortex in deafferented thalamic nuclei, binding auditory events into one phantom auditory percept (58). Both neuropathic pain and tinnitus may occur in the deafferented thalamic nuclei and exhibit similar characteristics of TCD. ...
The anterior cingulate cortex (ACC) has been extensively implicated in the functional brain network underlying chronic pain. Electrical stimulation of the ACC has been proposed as a therapy for refractory chronic pain, although, mechanisms of therapeutic action are still unclear. As stimulation of the ACC has been reported to produce many different behavioral and perceptual responses, this region likely plays a varied role in sensory and emotional integration as well as modulating internally generated perceptual states. In this case series, we report the emergence of subjective musical hallucinations (MH) after electrical stimulation of the ACC in two patients with refractory chronic pain. In an N-of-1 analysis from one patient, we identified neural activity (local field potentials) that distinguish MH from both the non-MH condition and during a task involving music listening. Music hallucinations were associated with reduced alpha band activity and increased gamma band activity in the ACC. Listening to similar music was associated with different changes in ACC alpha and gamma power, extending prior results that internally generated perceptual phenomena are supported by circuits in the ACC. We discuss these findings in the context of phantom perceptual phenomena and posit a framework whereby chronic pain may be interpreted as a persistent internally generated percept.
... Consequently, the amount of spontaneous activity detected along the auditory pathways of the brain increases. This spontaneous activity is then misinterpreted as an external auditory stimulus and form the source of the AH (De Ridder et al., 2014;Linszen, Brouwer, Heringa, & Sommer, 2016;Vanneste, Song, & De Ridder, 2013). Spontaneous brain activity might not only cause the occurrence of deafferentation hallucinations, but could also be involved in the specific phenomenology and complexity of the experience, depending on the location and extent of activity. ...
... To our knowledge only one study (Vanneste et al., 2013) investigated brain activity of hearing-impaired patients with complex musical hallucinations and compared that to hearing-impaired patients with tinnitus in two groups of 10 patients. Similar to our results they differentiated musical hallucinations from tinnitus based on temporal lobe activity. ...
... Based on the deafferentation theory, we would have expected to find a continuum from normal hearing via simple AH towards complex AH, with increasing levels of spontaneous activity either along the auditory pathway or in areas of higher order auditory processing AH (De Ridder et al., 2014;Linszen et al., 2016;Vanneste et al., 2013). Indeed, the main difference between controls and hearing-impaired patients reflects higher order processes of auditory perception which could resemble more general mechanisms of hallucinations. ...
Auditory hallucinations, the perception of a sound without a corresponding source, are common in people with hearing impairment. Two forms can be distinguished: simple (i.e., tinnitus) and complex hallucinations (speech and music). Little is known about the precise mechanisms underlying these types of hallucinations. Here we tested the assumption that spontaneous activity in the auditory pathways, following deafferentation, underlies these hallucinations and is related to their phenomenology. By extracting (fractional) Amplitude of Low Frequency Fluctuation ([f]ALFF) scores from resting state fMRI of 18 hearing impaired patients with complex hallucinations (voices or music), 18 hearing impaired patients with simple hallucinations (tinnitus or murmuring), and 20 controls with normal hearing, we investigated differences in spontaneous brain activity between these groups. Spontaneous activity in the anterior and posterior cingulate cortex of hearing-impaired groups was significantly higher than in the controls. The group with complex hallucinations showed elevated activity in the bilateral temporal cortex including Wernicke's area, while spontaneous activity of the group with simple hallucinations was mainly located in the cerebellum. These results suggest a decrease in error monitoring in both hearing-impaired groups. Spontaneous activity of language-related areas only in complex hallucinations suggests that the manifestation of the spontaneous activity represents the phenomenology of the hallucination. The link between cerebellar activity and simple hallucinations, such as tinnitus, is new and may have consequences for treatment.
... The most relevant etiological factors for musical hallucinations are brain injuries, epilepsy, psychiatric disorders, and the use of illicit substances or medicines [6]. Recent insights into the neurophysiology of musical hallucinations, as well as the application of Bayesian prediction models, provide a window on these complex phenomena, and allow us to catch a glimpse of their pathophysiology [7,8]. ...
... However, there are also cases where there is a clear and unambiguous relationship. In the present review, we critically appraise this type of literature on epilepsy and musical hallucinations, and place our findings in the context of models of magnetoencephalography (MEG) changes of (de-)synchronisation [7,8,14]. In addition, we borrow from the field of network science in relation to tinnitus to generate further hypotheses about the pathophysiology of epilepsy-induced musical hallucinations, and investigate whether these mechanisms can be generalised to other types of musical hallucination. ...
... Vanneste et al. [8] studied EEG changes in ten women (with a mean age of 66 years) with continuous musical hallucinations since more than a year, and compared them with ten patients with tinnitus, with similar laterality, loudness, distress level, and hearing loss, and ten healthy control subjects. For the theta-and alpha1-frequency band, a significant increase of power was seen in right auditory cortex in patients with either tinnitus or musical hallucinations. ...
Musical hallucinations are poorly understood phenomena. Their relation with epilepsy was first described over a century ago, but never systematically explored. We, therefore, reviewed the literature, and assessed all descriptions of musical hallucinations attributed to epileptic activity. Our search yielded 191 articles, which together describe 983 unique patients, with 24 detailed descriptions of musical hallucinations related to epilepsy. We also describe six of our own patients. Based on the phenomenological descriptions and neurophysiological data, we distinguish four subgroups of epilepsy-related musical hallucination, comprising auras/ictal, inter-ictal and post-ictal phenomena, and phenomena related to brain stimulation. The case descriptions suggest that musical hallucinations in epilepsy can be conceptualised as lying on a continuum with other auditory hallucinations, including verbal auditory hallucinations, and—notably—tinnitus. To account for the underlying mechanism we propose a Bayesian model involving top-down and bottom-up prediction errors within the auditory network that incorporates findings from EEG and MEG studies. An analysis of phenomenological characteristics, pharmacological triggers, and treatment effects suggests wider ramifications for understanding musical hallucinations. We, therefore, conclude that musical hallucinations in epilepsy open a window to understanding these phenomena in a variety of conditions.
... The review called for further RCTs of tDCS and studies involving variations to the stimulation protocol. Many RCTs of tDCS have subsequently been conducted [101,102,149,163,172], which report it to be safe but with little or no effect on tinnitus. ...
... There are few studies investigating tACS. One randomised study concluded there are no effects on tinnitus [172]. ...
... Most people find that it does not affect them in any way. Some people find it moderately annoying, while others finding it very troublesome [172,189]. ...
... Na pochodzenie szumów usznych na skutek nieprawidłowego działania różnych ośrodków korowych wskazują też prace Vanneste i wsp. [23]. Badacze ci, prowadząc badania na pacjentach słyszących uporczywą muzykę w uszach lub w głowie (złożony sygnał szumów), zaobserwowali bowiem zwiększoną aktywację prawego dolnego zakrętu czołowego (prawostronny odpowiednik ośrodka Broca) i prawego górnego zakrętu skroniowego, który jest prawdopodobnie powiązany z muzyką [23]. ...
... [23]. Badacze ci, prowadząc badania na pacjentach słyszących uporczywą muzykę w uszach lub w głowie (złożony sygnał szumów), zaobserwowali bowiem zwiększoną aktywację prawego dolnego zakrętu czołowego (prawostronny odpowiednik ośrodka Broca) i prawego górnego zakrętu skroniowego, który jest prawdopodobnie powiązany z muzyką [23]. W innych badaniach stwierdzono, że u pacjentów, którzy mogą świadomie modulować szumy przez ruch głowy, szyi czy zaciśnięcie zębów, obserwuje się wzmożoną aktywność kory słuchowej tylko po stronie lewej (pole 21 i 41 Brodmana) [12]. ...
Tinnitus jest percepcją dźwięku bez zewnętrznego źródła stymulacji akustycznej. Większość osób habituuje fantomowe dźwięki, jednakże około 1–2% ludzi odczuwa szumy uszne jako bardzo dokuczliwe, pogarszające jakość ich życia. Z uwagi na fakt, że szumy są często związane z niedosłuchem pochodzenia ślimakowego, źródła ich generacji upatrywano w ślimaku. Dzięki współczesnym metodom neuroobrazowania możliwa stała się identyfikacja regionów w ośrodkowym układzie nerwowym związanych z szumami. Deprywacja słuchowa powoduje wzrost neuronalnej aktywności, jej synchronizację, zmiany w tonotopowej organizacji centralnych ośrodków słuchowych oraz zmiany poza układem słuchowym odpowiedzialne za powstawanie szumów. Celem artykułu jest przedstawienie hipotez na temat różnych patomechanizmów powstawania szumów usznych.
... The majority of patients presenting with tinnitus have hearing loss measurable with conventional pure tone audiometry (Langguth et al., 2017;Moller, 2007b;Norena et al., 2002). And even in tinnitus patients with normal standard pure tone audiometry there may be some form of hearing loss (Barnea et al., 1990;Frosch, 2016;Stouffer and Tyler, 1990;Vanneste et al., 2013;Weisz et al., 2006). ...
... Whereas musical hallucinosis is usually encountered in people with severe hearing loss, verbal hallucinations are typical for psychosis, as encountered in schizophrenia (Griffiths, 2000;Vanneste et al., 2013). Thus, a preliminary definition could be that "tinnitus is the conscious awareness of a constant or intermittent sound that has no intrinsic meaning and for which there is no identifiable corresponding external sound source." ...
... The majority of patients presenting with tinnitus have hearing loss measurable with conventional pure tone audiometry (Langguth et al., 2017;Moller, 2007b;Norena et al., 2002). And even in tinnitus patients with normal standard pure tone audiometry there may be some form of hearing loss (Barnea et al., 1990;Frosch, 2016;Stouffer and Tyler, 1990;Vanneste et al., 2013;Weisz et al., 2006). ...
... Whereas musical hallucinosis is usually encountered in people with severe hearing loss, verbal hallucinations are typical for psychosis, as encountered in schizophrenia (Griffiths, 2000;Vanneste et al., 2013). Thus, a preliminary definition could be that "tinnitus is the conscious awareness of a constant or intermittent sound that has no intrinsic meaning and for which there is no identifiable corresponding external sound source." ...
As for hypertension, chronic pain, epilepsy and other disorders with particular symptoms, a commonly accepted and unambiguous definition provides a common ground for researchers and clinicians to study and treat the problem. The WHO's ICD11 definition only mentions tinnitus as a nonspecific symptom of a hearing disorder, but not as a clinical entity in its own right, and the American Psychiatric Association's DSM-V doesn't mention tinnitus at all. Here we propose that the tinnitus without and with associated suffering should be differentiated by distinct terms: "Tinnitus" for the former and "Tinnitus Disorder" for the latter. The proposed definition then becomes "Tinnitus is the conscious awareness of a tonal or composite noise for which there is no identifiable corresponding external acoustic source, which becomes Tinnitus Disorder "when associated with emotional distress, cognitive dysfunction, and/or autonomic arousal, leading to behavioural changes and functional disability.". In other words "Tinnitus" describes the auditory or sensory component, whereas "Tinnitus Disorder" reflects the auditory component and the associated suffering. Whereas acute tinnitus may be a symptom secondary to a trauma or disease, chronic tinnitus may be considered a primary disorder in its own right. If adopted, this will advance the recognition of tinnitus disorder as a primary health condition in its own right. The capacity to measure the incidence, prevalence, and impact will help in identification of human, financial, and educational needs required to address acute tinnitus as a symptom but chronic tinnitus as a disorder.
... The majority of patients presenting with tinnitus have hearing loss measurable with conventional pure tone audiometry (Langguth et al., 2017;Moller, 2007b;Norena et al., 2002). And even in tinnitus patients with normal standard pure tone audiometry there may be some form of hearing loss (Barnea et al., 1990;Frosch, 2016;Stouffer and Tyler, 1990;Vanneste et al., 2013;Weisz et al., 2006). ...
... Whereas musical hallucinosis is usually encountered in people with severe hearing loss, verbal hallucinations are typical for psychosis, as encountered in schizophrenia (Griffiths, 2000;Vanneste et al., 2013). Thus, a preliminary definition could be that "tinnitus is the conscious awareness of a constant or intermittent sound that has no intrinsic meaning and for which there is no identifiable corresponding external sound source." ...
As for hypertension, chronic pain, epilepsy and other disorders with particular symptoms, a commonly accepted and unambiguous definition provides a common ground for researchers and clinicians to study and treat the problem. The WHO's ICD11 definition only mentions tinnitus as a nonspecific symptom of a hearing disorder, but not as a clinical entity in its own right, and the American Psychiatric Association's DSM-V doesn't mention tinnitus at all.
Here we propose that the tinnitus without and with associated suffering should be differentiated by distinct terms: “Tinnitus” for the former and “Tinnitus Disorder” for the latter. The proposed definition then becomes “Tinnitus is the conscious awareness of a tonal or composite noise for which there is no identifiable corresponding external acoustic source, which becomes Tinnitus Disorder “when associated with emotional distress, cognitive dysfunction, and/or autonomic arousal, leading to behavioural changes and functional disability.”. In other words “Tinnitus” describes the auditory or sensory component, whereas “Tinnitus Disorder” reflects the auditory component and the associated suffering. Whereas acute tinnitus may be a symptom secondary to a trauma or disease, chronic tinnitus may be considered a primary disorder in its own right.
If adopted, this will advance the recognition of tinnitus disorder as a primary health condition in its own right. The capacity to measure the incidence, prevalence, and impact will help in identification of human, financial, and educational needs required to address acute tinnitus as a symptom but chronic tinnitus as a disorder.
... To assess the severity of a perceived tinnitus handicap severity and tinnitus-related distress severity the standardized Persian version of the Tinnitus Handicap Inventory (THI) [38] and Tinnitus Questionnaire (TQ) [39] were presented to the participants with tinnitus. Tinnitus handicap was clustered into five categories include slight (0-16), mild (18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36), moderate (38)(39)(40)(41)(42)(43)(44)(45)(46)(47)(48)(49)(50)(51)(52)(53)(54)(55)(56), severe (58)(59)(60)(61)(62)(63)(64)(65)(66)(67)(68)(69)(70)(71)(72)(73)(74)(75)(76), and catastrophic (78-100) [40]. In the present study, one participant was characterized with slight, two with mild, six with moderate, and one with the severe handicap. ...
... Neuroimaging evidence suggests that tinnitus and musical hallucination reveal similar central cortex activity, with an increase in theta-gamma response during EEG measurement. Whereas both tinnitus and musical hallucinosis are often correlated to sound deprivation, they have similar neural substrate differing only in the complexity, as musical hallucination relating to areas associated with higher-level semantic and melodic sound processing [71,72]. Accordingly, tinnitus might be considered as a simple form of hallucinations [73]. ...
Tinnitus is defined as the auditory phantom perception in the absence of any objective external sound source. In this paper, we used the resting-state electroencephalography (EEG) data to reconstruct the neural sources based on the unit-noise-gain linearly constrained minimum-variance (LCMV) beamformer and applied the effective connectivity analysis on the reconstructed sources to examine the directional neuronal interactions between brain regions in tinnitus patients compared to the healthy controls. We found significantly disrupted patterns of effective connectivity in several brain areas including the frontal, temporal, and occipital cortices as well as the caudate nucleus. Particularly, significant aberrant causal couplings were observed in the orbitofrontal cortex, inferior frontal gyrus_triangular, and parahippocampal region that could potentially illustrate the auditory information retrieval, perception, and evaluation of the phantom sound in the brain of tinnitus patients. Furthermore, topological alterations of the brain network were investigated using graph theoretical analysis. Our findings demonstrated significantly decreased both global integration and segregation of the brain network in tinnitus patients accompanied by the topological shift of tinnitus network to a more random structure in the high-frequency bands. These findings were consistent with the hypothesis of the brain network deviation from small-worldness topology accompanied by reduced global integration in brain-related disorders.
... However, gain was not always regarded positively; obtaining a new device, and the associated difficulties of its management, were mentioned by several participants as hurdles to continuing their audiological rehabilitation. Additionally, some participants gained an array of unwanted auditory inputs, either emitted from their hearing device (e.g., a cochlear implant would misinterpret some environmental noises as speech sounds) or via phantom auditory perceptions (i.e., the perception of sound without external auditory input; Vanneste et al., 2013). When auditory perception is compromised, either through hearing loss or hearing devices, it is possible that interpretation and comprehension of sounds can be influenced by psychological symptoms. ...
... Several participants also reported complex phantom auditory perceptions, where sounds had semantic quality, for example, trucks, music, and voices. It may be beneficial for audiologists to differentiate types of phantom auditory perceptions, not only because some participants reported anxiety, discomfort, or frustration in response to these sounds but also because there are differences in their underlying psychopathology and mechanisms (Fischer et al., 2004;Hemming & Merrill, 2015;Rocha et al., 2015;Vanneste et al., 2013). No studies to date have investigated perceptual misinterpretation with hearing devices, but several case studies and cohort studies have identified complex phantom auditory perceptions (variously termed musical or auditory hallucinations or pseudohallucinations) in acquired hearing loss (Balan et al. 1996;Bernard & Quante, 2011;Brunner & Amedee, 2015). ...
Purpose
There is a well-established relationship between hearing loss and psychological symptoms. To ensure audiological rehabilitation is provided appropriately for older adults with comorbid psychological symptoms, a greater understanding of their preferences and experiences is needed. This study sought to understand experiences of hearing loss and audiological rehabilitation from the perspective of older adults with comorbid psychological symptoms (e.g., depression, anxiety, psychosis).
Design
A qualitative study using in-depth semistructured interviews was conducted with older adults who had attended audiological rehabilitation within the last year and scored above established cutoffs on measures of depression, anxiety, and psychosis. A thematic analysis generated themes that related to participants' experiences of hearing loss and audiological rehabilitation.
Results
Participants included 14 older adults (eight men and six women) with an average age of 70.5 years (SD = 4.45, range: 64–80) who received hearing aids or a cochlear implant. Three major themes emerged from the analysis of participant interviews. “The cumulative impact of hearing loss and psychological symptoms” theme describes the two-way, additive relationship between hearing ability and psychological symptoms. “The experience of loss throughout hearing loss and audiological rehabilitation” captures subjective losses, the impact they have, and how participants cope with them. In contrast, “The experience of gain throughout hearing loss and audiological rehabilitation” describes the participants' reported gains, their related impacts, and coping strategies.
Conclusions
The experiences of participants revealed that the presence of comorbid psychological symptoms can influence the experience of hearing loss and audiological rehabilitation. These findings have implications for how audiological rehabilitation is provided to ensure optimal outcomes for adults with hearing loss and comorbid psychological symptoms.
Supplemental Material
https://doi.org/10.23641/asha.12985955
... The centro-parietal (CPz), parietal (Pz), and parieto-occipital (POz) electrodes were chosen to obtain N400 latencies based on the difference in the wave between congruent and incongruent signals [3]. Spectral power (event-related spectral perturbation, ERSP) was also computed during the time of interest (N400) at alpha (8)(9)(10)(11)(12), beta (14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24), and gamma (25-29.5 Hz) frequency bands. ERSP measures the average time course of relative changes in the EEG amplitude spectrum induced by a set of similar events [20]. ...
... To identify any potential differences across listening conditions, non-parametric statistical analyses for each contrast using multiple voxel-by-voxel comparisons to obtain a logarithm of the F-ratio were performed. The significance of the log F-ratio is a threshold (p< 0.05) based on a random test with 5,000 permutations [22]. Other statistical analyses were performed using the SPSS software and built-in functions provided by Matlab (R2014a, Mathworks, Natick, MA, USA). ...
Background and objectives:
In distracting listening conditions, individuals need to pay extra attention to selectively listen to the target sounds. To investigate the amount of listening effort required in reverberating and noisy backgrounds, a semantic mismatch was examined.
Subjects and methods:
Electroencephalography was performed in 18 voluntary healthy participants using a 64-channel system to obtain N400 latencies. They were asked to listen to sounds and see letters in 2 reverberated×2 noisy paradigms (i.e., Q-0 ms, Q-2000 ms, 3 dB-0 ms, and 3 dB-2000 ms). With auditory-visual pairings, the participants were required to answer whether the auditory primes and letter targets did or did not match.
Results:
Q-0 ms revealed the shortest N400 latency, whereas the latency was significantly increased at 3 dB-2000 ms. Further, Q-2000 ms showed approximately a 47 ms delayed latency compared to 3 dB-0 ms. Interestingly, the presence of reverberation significantly increased N400 latencies. Under the distracting conditions, both noise and reverberation involved stronger frontal activation.
Conclusions:
The current distracting listening conditions could interrupt the semantic mismatch processing in the brain. The presence of reverberation, specifically a 2000 ms delay, necessitates additional mental effort, as evidenced in the delayed N400 latency and the involvement of the frontal sources in this study.
... These types of auditory hallucinations are thought to arise by a similar mechanism of increased excitation in the auditory cortex on a background of hearing impairment and may follow a lesion anywhere along the auditory pathway, from the inner ear to the brain [17,18]. They are related in pathogenesis to tinnitus, but their complex and semantic nature may indicate involvement of additional cortical areas, such as those involved in language and memory [19]. Her hearing loss is likely attributable to presbycusis, although some degree of cortical hearing loss cannot be ruled out given evidence on her CT scan of parietotemporal atrophy encompassing the superior temporal gyrus, the location of the primary auditory cortex. ...
... Her hearing loss is likely attributable to presbycusis, although some degree of cortical hearing loss cannot be ruled out given evidence on her CT scan of parietotemporal atrophy encompassing the superior temporal gyrus, the location of the primary auditory cortex. This and other cortical areas have been implicated in the functional neurological basis of musical hallucinations based on functional magnetic resonance imaging (fMRI) and other neuroimaging studies [18][19][20]. We suspect her clinical picture illustrates a case of classic CBS in parallel with musical hallucinosis; while sharing a similar underlying mechanism, they likely arose independently of each other from pathology in different sensory pathways. ...
Charles Bonnet syndrome (CBS) refers to the experience of visual hallucinations in the context of visual impairment. The underlying pathology may be localized anywhere along the visual pathway from the eye itself to visual cortical centers. It is sometimes compared to phantom limb syndrome; both involve decreased sensory input, as in loss of a limb or declining vision, resulting in overactivity in areas of the brain controlling sensory perception. Definitive diagnostic criteria are still lacking and may vary by discipline. However, the following features are generally agreed upon: visual hallucinations, impaired vision, and intact cognition and insight. Psychiatric symptoms, cognitive decline, and hallucinations of other sensory modalities are often excluded, although this remains an area of debate. Certain non-classic cases of CBS have inspired the designation of atypical CBS, which encompasses a wide spectrum of sensory experiences and associated symptoms. Auditory hallucinations in the hearing-impaired, a well-described phenomenon thought to have a similar pathogenesis, share with CBS the important risk factor of increased age. In patients experiencing both types of hallucinations with deterioration in both sensory domains, the distinction between a CBS variant and two independent processes may not be straightforward. In addition to the ongoing diagnostic dilemma posed by multimodal hallucinations, these phenomena tend to be underreported by patients likely due to concern that they will be diagnosed with mental illness. Although many patients with this condition are indifferent to it, some suffer distress from their hallucinations and would benefit from recognition, reassurance, and in some cases correction of the underlying cause or pharmacologic treatment. Here we present the case of an elderly woman with a history of macular degeneration and chronic hearing loss who experienced complex auditory and visual hallucinations surrounding an episode of severe anxiety. We postulate that her anxiety acted as a precipitant to her hallucinatory experiences and may partially explain their abrupt onset in the absence of other clear pathologic processes. This case serves to reinforce CBS as a possible etiology of visual hallucinations in the elderly population, while also generating discussion of how to classify her particular set of symptoms.
... Na pochodzenie szumów usznych na skutek nieprawidłowego działania różnych ośrodków korowych wskazują też prace Vanneste i wsp. [23]. Badacze ci, prowadząc badania na pacjentach słyszących uporczywą muzykę w uszach lub w głowie (złożony sygnał szumów), zaobserwowali bowiem zwiększoną aktywację prawego dolnego zakrętu czołowego (prawostronny odpowiednik ośrodka Broca) i prawego górnego zakrętu skroniowego, który jest prawdopodobnie powiązany z muzyką [23]. ...
... [23]. Badacze ci, prowadząc badania na pacjentach słyszących uporczywą muzykę w uszach lub w głowie (złożony sygnał szumów), zaobserwowali bowiem zwiększoną aktywację prawego dolnego zakrętu czołowego (prawostronny odpowiednik ośrodka Broca) i prawego górnego zakrętu skroniowego, który jest prawdopodobnie powiązany z muzyką [23]. W innych badaniach stwierdzono, że u pacjentów, którzy mogą świadomie modulować szumy przez ruch głowy, szyi czy zaciśnięcie zębów, obserwuje się wzmożoną aktywność kory słuchowej tylko po stronie lewej (pole 21 i 41 Brodmana) [12]. ...
Streszczenie Tinnitus jest percepcją dźwięku bez zewnętrznego źródła stymulacji akustycznej. Większość osób habituuje fantomowe dźwię-ki, jednakże około 1-2% ludzi odczuwa szumy uszne jako bardzo dokuczliwe, pogarszające jakość ich życia. Z uwagi na fakt, że szumy są często związane z niedosłuchem pochodzenia ślimakowego, źródła ich generacji upatrywano w ślimaku. Dzię-ki współczesnym metodom neuroobrazowania możliwa stała się identyfikacja regionów w ośrodkowym układzie nerwowym związanych z szumami. Deprywacja słuchowa powoduje wzrost neuronalnej aktywności, jej synchronizację, zmiany w tono-topowej organizacji centralnych ośrodków słuchowych oraz zmiany poza układem słuchowym odpowiedzialne za powstawa-nie szumów. Celem artykułu jest przedstawienie hipotez na temat różnych patomechanizmów powstawania szumów usznych. Abstract Tinnitus is a phantom perception of sound in the absence of external acoustic stimuli. Many people are able to habituate to the phantom sounds, 1-2% people worldwide however, perceive tinnitus as annoying, worsening their quality of life. Because tinnitus is often associated with the cochlear hearing loss, it was traditionally believed to originate in the cochlea. Studies using modern neuroimaging methods have shown changes in the brain activity of tinnitus patients. Increased neuronal firing rate, enhanced neuronal synchrony and changes in the tonotopic organization of the primary auditory cortex in tinnitus have been interpreted as the brain response to auditory input deprivation occurring in both auditory and non-auditory areas. The purpose of this paper is to provide information on different pathological mechanisms underlying tinnitus perception. Wstęp Subiektywne szumy uszne (tinnitus) są percepcją dźwięku bez obecności zewnętrznego źródła stymulacji akustycz-nej. Mogą występować pod postacią różnych fantomo-wych dźwięków, przypominających najczęściej dzwonie-nie, pisk, gwizd, szum, brzęczenie czy cykanie świerszcza. Mogą być odczuwane jedno-lub obustronnie, a także sły-szane w środku głowy. Szumy subiektywne są słyszane tylko przez osobę, która ich doświadcza. Występują sto-sunkowo często. Istnieją również szumy uszne obiektyw-ne, będące w sensie fizycznym rzeczywistym dźwiękiem, który da się zarejestrować. Szumy obiektywne są bardzo rzadkie. Powstają wskutek zaburzonego przepływu krwi w naczyniach lub toniczno-klonicznych skurczów mięśni w obrębie ucha środkowego lub podniebienia miękkiego. Badania przeprowadzone przez Instytut Fizjologii i Pa-tologii Słuchu (IFPS) pokazały, że około 20% dorosłych Polaków doświadcza szumów usznych trwających dłu-żej niż 5 minut, a około 5% zauważa u siebie stałe szu-my uszne [1]. Szacuje się, że w Polsce co dziesiąta osoba między 55 a 64 rokiem życia i co piąta po 75 roku życia cierpi na szumy uszne [2]. Na podstawie raportów ro-dziców dzieci uczestniczących w badaniach przeprowa-dzonych przez IFPS stwierdzono, że 12,9% dzieci sied-mioletnich i 16,6% dzieci dwunastoletnich doświadcza szumów usznych. Z badań tych wynika, że wśród 12-let-nich dzieci odczuwających szumy uszne obserwuje się wielomówność, nerwowość, obniżoną koncentrację; na-tomiast u młodszych, 6-latków, krzykliwość i nadmierną ruchliwość. Łatwe rozpraszanie się, izolowanie występuje zarówno u 6-latków, jak i u 12-latków [3].
... They are thought to result from aberrant neural activity in the auditory cortex and related pathways. Functional imaging shows that brain areas involved in music perception, such as the auditory cortex, are activated during these hallucinations [5]. ...
Musical hallucinations (MH) represent a rare and complex auditory phenomenon where individuals perceive music without external stimuli. This case study explores auditory Charles Bonnet syndrome (ACBS) in a 51-year-old male with a history of bilateral sensorineural hearing loss. The patient reported hearing recognizable prayer chants, initially perceived as external sounds from a nearby temple. Over time, these hallucinations persisted and interfered with his daily activities, prompting medical consultation. Despite the absence of psychiatric illness, the patient was diagnosed with ACBS and treated with risperidone, an atypical antipsychotic. The intervention led to a significant reduction in the frequency and intensity of the hallucinations, alongside improved sleep and concentration. The patient also experienced a recurrence of symptoms upon discontinuation of the medication, highlighting the importance of adherence to treatment. This case underscores the need for awareness and understanding of non-psychotic auditory hallucinations in individuals with hearing impairments. The pathophysiology of MH is not fully understood but is believed to involve abnormal activity in the auditory associative cortices due to sensory deprivation. Treatment approaches often include both pharmacological and non-pharmacological strategies, such as optimizing hearing with aids and providing psychoeducation. This study contributes to the limited literature on ACBS and emphasizes the efficacy of antipsychotics in managing MH. Further research is essential to explore the underlying mechanisms and to develop comprehensive management plans for patients experiencing these distressing auditory phenomena. The findings advocate for a multidisciplinary approach to treatment, integrating audiological and psychiatric care to improve patient outcomes.
... They consisted of frames of popular Italian songs and religious Christmas melodies (i.e., "Vecchio Scarpone", "Tu scendi dalle stelle" or "Astro del ciel") which represented A.P.'s musical background. A.P. was aware that what she perceived was independent of any external sound source; for this reason, we should speak of hallucinosis rather than hallucinations, but, for simplicity, we'll continue to refer to this phenomenon as MHs (Cavaliere et al., 2018;Vanneste et al., 2013). Furthermore, when A.P. was engaged in a task or conversation, her hallucinations would decrease in volume and then increased again as soon as she was left alone. ...
We reported a case of a 62-year-old female patient affected by musical hallucinations (MHs) as a transient symptom after an ischemic stroke in the right middle cerebral artery. CT scan showed widespread cortical and subcortical hypodensity associated with moderate hemorrhage involving the lentiform nucleus, insular cortex, and caudate nucleus. The patient had no history of psychiatric disorders, hearing defects, or epilepsy. MHs appeared one week after the stroke and spontaneously vanished 10 days after their onset. From our perspective, the early activation of MHs after unilateral brain injury, and their timing of resolution, can be explained according to the “interhemispheric imbalance theory”. According to this theory, in the minutes or weeks following the onset of a focal cerebrovascular event, a series of changes in global brain connectivity occur leading to a temporary imbalance in interhemispheric excitation.
... In the absence of an auditory input, the brain exhibits hypersensitivity analogous to denervation hypersensitivity, leading to the emergence of patterned sounds [44]. One study suggested that MHs and tinnitus share a common brain substrate, although their underlying mechanisms differ [77]. ...
b>Introduction: Musical hallucinations (MHs) is a heterogeneous phenomenon. Multiple case reports and series have improved our understanding of this complex phenomenon. This systematic review aims to assess the available evidence regarding MHs.
Methods: PubMed and ProQuest databases were searched for articles published between 2005 and 2022. The keywords used for the search were “music,” “musical,” “hallucinations,” and “hallucinosis.”
Results: The search identified 421 articles; however, only 67 were selected. A total of 77 patients were selected from case reports and series. We identified 50 articles with single cases, four articles with two cases, four articles with three cases, and one article with six cases. Eight additional articles that provided information regarding the prevalence of MHs were included in the review.
Conclusions: MHs are common among older individuals, women, and hearing-impaired individuals. The etiologies include psychiatric, neurological, hearing impairments, and substances. Content of MHs is typically familiar songs/music. No randomized controlled studies are available for determining the treatment for MHs.
... They showed that taVNS in tinnitus patients' modulated tone evoked synchronicity in the beta-and gamma-band (Hyvärinen et al., 2015). Hypersynchronous activity in the auditory beta range has also been observed in patients suffering from tinnitus and auditory hallucinations (Vanneste et al., 2013).Yet, it is imperative to notify that these results have to be interpreted with caution as highlighted in detail by two recent reviews (Stegeman et al., 2021;Yakunina and Nam, 2021). Both, studies that used taVNS alone as well as studies that used taVNS in combination with ST, have severe methodological flaws. ...
Transcutaneous auricular vagus nerve stimulation (taVNS), as a non-invasive brain stimulation technique may influence the locus coeruleus-norepinephrine system (LC-NE system) via modulation of the Vagus Nerve (VN) which projects to the LC. Few human studies exist examining the effects of taVNS on the LC-NE system and studies to date assessing the ability of taVNS to target the LC yield heterogeneous results. The aim of this review is to present an overview of the current challenges in assessing effects of taVNS on LC function and how translational approaches spanning animal and human research can help in this regard. A particular emphasis of the review discusses how the effects of taVNS may be influenced by changes in structure and function of the LC-NE system across the human lifespan and in disease.
... In this study, we investigate the changes in the 1/f slope of the power spectrum and discuss these findings in the light of the proposed tinnitus mechanisms. As tinnitus is a simple phantom percept similar to phantom pain (De Ridder et al., 2011a;Hullfish et al., 2019;Mohan and Vanneste, 2017;Vanneste et al., 2013) with comorbidities such as depression and anxiety, we expect spectra shifts toward a white noise based on auditory input deprivation. It has further been suggested that in a 1/f relationship, perturbations that occur at slow frequencies (i.e., theta) cause a cascade of energy disposition at beta and gamma frequencies as widespread slow oscillations modulate faster local events (Buzsaki and Draguhn, 2004). ...
Electrophysiological tinnitus research, such as EEG studies, typically investigates the irregularities in separate frequency bands. These frequency bands are coupled, such that the higher oscillation frequencies are nested (phase–amplitude coupled) on the lower frequencies, resulting in a 1/f power spectrum. The changes in the 1/f slope of the power spectrum in tinnitus patients are unexplored. Deviations from the 1/f pattern also reflect a change toward a more lattice (steeper slope) or random network (flatter slope) and relate to the amount of information in a network. In this study, we investigate the 1/f slope in the resting-state EEGs of tinnitus patients and relate these findings to proposed tinnitus mechanisms. Our data show that tinnitus is characterized by a slope that is flattened in comparison to the control group and that the tinnitus loudness percept correlates the steepness of the slope of the power spectrum in resting-state EEG signals for the left auditory cortex and left parahippocampus. The steepness of the slope is predominantly related to an increase in theta activity and its minor increase in gamma activity, suggesting that the slope is deviating toward white noise. These results should motivate further research into this hitherto elusive form of brain activity that resides behind the mask of the universal 1/f power spectrum observed across nature.
... Esto ocurre ya que las capacidades para recordar mejoran sustancialmente cuando existe de por medio la evocación de emociones o situaciones afectivas que causan la activación neuronal de diversas áreas del cerebro 49 . Las personas con discapacidades auditivas, suelen sufrir de alucinaciones musicales, ya que el cerebro, crea percepciones de estímulos auditivos inexistentes, susceptibles a correlacionarse con estímulos anteriores, memorizarse o tomar un carácter afectivo; facilitando así una construcción necesaria para la visión general del mundo 50 . ...
RESUMEN La música juega un papel importante sobre el desarrollo de diferentes actividades cerebrales; como lo son la comunicación, interacción, memoria, emoción, razona-miento; así como la actividad sensorial y motora. Sin dejar de lado la regulación sobre efectos periféricos como metabolismo y percepción del dolor. Los estímulos musicales pueden ser utilizados como herramienta en la práctica médica por el fuerte impacto que puede llegar a tener en el individuo, gracias a los efectos que tiene sobre la corteza auditiva y la extensa conexión de esta con otras regiones del cerebro. Estos estímulos musicales son una herramienta de gran utilidad en diversos campos, como la medicina, psicología y neurología. La musicoterapia por su labor multifacética y múltiples ventajas, se perfila de manera significativa como una disciplina que apotra recursos muy accesibles y útiles en la práctica clínica. ABSTRACT Music plays an important role on the development of different brain activities; such as communication, interaction, memory, emotion, reasoning; also sensory and motor activity. While regulation of peripheral side effects such as metabolism and pain perception. Musical stimuli could be used as a tool, in medical practice by the strong impact that can have on the person, because of the effects that have music, on the auditory cortex and extensive connection of this with other brain regions. These melodies are a very useful tool in various fields such as medicine, psychology and neurology. Music therapy for its multifaceted character and many advantages, will become a highly accessible and useful tool in clinical practice
... and elderly populations (30%) [2,3]. Tinnitus is commonly described as a ringing, buzzing, cricket-like, hissing, whistling, or humming sound or as a combination of these sounds [4]. ...
This study was aimed at delineating and comparing differences in clinical characteristics and brain activity between patients with low- and high-frequency tinnitus (LFT and HFT, respectively) using high-density electroencephalography (EEG). This study enrolled 3217 patients with subjective tinnitus who were divided into LFT ( frequency < 4000 Hz) and HFT (≥4000 Hz) groups. Data regarding medical history, Tinnitus Handicap Inventory, tinnitus matching, and hearing threshold were collected from all patients. Twenty tinnitus patients and 20 volunteers were subjected to 256-channel EEG, and neurophysiological differences were evaluated using standardized low-resolution brain electromagnetic tomography (sLORETA) source-localized EEG recordings. Significant differences in sex ( p < 0.001 ), age ( p = 0.022 ), laterality ( p < 0.001 ), intensity ( p < 0.001 ), tinnitus type ( p < 0.001 ), persistent tinnitus ( p = 0.04 ), average threshold ( p < 0.001 ), and hearing loss ( p = 0.028 ) were observed between LFT and HFT groups. The tinnitus pitch only appeared to be correlated with the threshold of the worst hearing loss in the HFT group. Compared with the controls, the LFT group exhibited increased gamma power ( p < 0.05 ), predominantly in the posterior cingulate cortex (PCC, BA31), whereas the HFT group had significantly decreased alpha1 power ( p < 0.05 ) in the angular gyrus (BA39) and auditory association cortex (BA22). Higher gamma linear connectivity between right BA39 and right BA41 was observed in the HFT group relative to controls ( t = 3.637 , p = 0.027 ). Significant changes associated with increased gamma in the LFT group and decreased alpha1 in the HFT group indicate that tinnitus pitch is crucial for matching between the tinnitus and control groups. Differences of band frequency energy in brain activity levels may contribute to the clinical characteristics and internal tinnitus “spectrum” differences.
... L'hallucinose se réfère à des troubles perceptifs de type hallucinations qui sont critiqués par le patient. Les critères phénoménologiques d'une hallucinose sont : 1. la présence de fausses perceptions sensorielles (visuelles, auditives ou somesthésiques), comme, par exemple, des acouphènes (Vanneste et al., 2013) ; 2. le fait que le patient reste conscient que ce qu'il voit, entend ou ressent n'est pas réel ; 3. l'absence d'état confusionnel. ...
Suspicion d’hallucinose pédonculaire en l’absence de lésion du mésencéphale. Problématique des hallucinations bimodales dans un contexte vasculaire.
... Suggested areas associated with auditory deafferentation include, but are not limited to auditory pathways [40,41], basal ganglia [40,43,44] and frontal areas [19,40,42,43]. In an empirical study contrasting the brain activity of hearing-impaired patients with complex auditory hallucinations, tinnitus patients, and healthy controls, Vanneste et al. [45] suggested that tinnitus and auditory hallucinations in hearing-impaired patients share similar activity patterns. Differences between the two groups seemed to be related to brain activity in areas of higher order functions, such as music and language processing, indicating a relationship between the content of the hallucination and brain activity. ...
Purpose of review:
The association between hallucinations and sensory loss, especially vision- and hearing-impairment, has been firmly established over the past years. The deafferentation theory, a decrease of the threshold for activation in the brain and the consequential imbalance between excitatory and inhibitory brain networks, is hypothesized to underly this relationship. Here we review the studies investigating this theory with a focus on the most recent literature to better understand the contribution of sensory loss to hallucinations.
Recent findings:
A large cross-sectional study has recently confirmed the relationship between auditory impairment and deafferentation. However, the underlying mechanisms of deafferentation are still under debate, with hyperexcitability and deviations in bottom-up and top-down processes being the most likely explanations. Social isolation following sensory impairment increases the risk for hallucinations. Better knowledge and awareness about the contribution of deafferentation and loneliness would benefit diagnosis and treatment of hallucinations.
Summary:
Studies imply activity in higher order areas, corresponding to the functional mapping of sensory system, and a general state of higher excitability as neurobiological explanation. Auditory deafferentation, tinnitus and other auditory hallucinations, likely lie on a continuum. Social isolation mediates psychotic symptoms in sensory-impaired individuals. Currently, there is no standard treatment for deafferentation hallucinations.
... Tinnitus is the phantom perception of sound (Henry, Dennis et al. 2005, Moller 2006, Kaltenbach 2011, De Ridder, Vanneste et al. 2014. It is understood to arise as a result of neuroplastic changes across several overlapping brain networks in response to changes in auditory sensitivity (Schecklmann, Landgrebe et al. 2011, Vanneste, Van de Heyning et al. 2011, Schecklmann, Lehner et al. 2013, Vanneste, Song et al. 2013, Husain and Schmidt 2014. ...
Background:
This study was conducted to investigate the short-term behavioral and neurophysiological effects of MDMA (3,4-methylenedioxymethamphetamine) on tinnitus perception.
Methods:
A double-blind randomized controlled cross-over design. Part 1. Behavioural measures of tinnitus following 30 mg MDMA or placebo administration (N = 5 participants) and Part 2. Behavioral measures of tinnitus and correlations between pairs of apriori regions of interest (ROI) using resting-state functional magnetic resonance imaging (rs-fMRI) before and after 70 mg of MDMA or placebo (N = 8 participants).
Results:
The results to MDMA were similar to placebo. For the 70 mg dose there was a significant reduction after 4 hours in annoyance and ignore ratings. RsMRI showed decreased connectivity compared to placebo administration between the left hippocampal, right hippocampal, left amygdala and right amygdala regions, and between the right posterior parahippocampal cortex and the left amygdala after two hours of 70 mg MDMA administration. Increased connectivity compared to placebo administration was found post MDMA between the right post-central gyrus and right posterior and superior temporal gyrus, and between the thalamus and frontoparietal network.
Conclusions:
Following 70 mg of MDMA two tinnitus rating scales significantly improved. There was, however, a placebo effect. Compared to placebo the rsMRI following the MDMA showed reductions in connectivity between the amygdala, hippocampus and parahippocampal gyrus. There is sufficient proof of concept to support future investigation of MDMA as a treatment for tinnitus.
... In patients, hf-tRNS has been successfully applied for reducing pain in multiple sclerosis 12 and for decreasing motor cortex excitability in Parkinson's disease 13 , as well as for reducing depressive symptoms 14 and improving negative symptoms in schizophrenia 15 . Both lf-tRNS and hf-tRNS have shown promising results in reducing tinnitus intensity and distress [16][17][18] . Last but not least, hf-tRNS has shown an advantage over other electrical stimulation techniques in boosting perceptual and motor learning [19][20][21][22][23][24][25][26] . ...
Transcranial random noise stimulation (tRNS) is a recent neuromodulation protocol. The high-frequency band (hf-tRNS) has shown to be the most effective in enhancing neural excitability. The frequency band of hf-tRNS typically spans from 100 to 640 Hz. Here we asked whether both the lower and the higher half of the high-frequency band are needed for increasing neural excitability. Three frequency ranges (100–400 Hz, 400–700 Hz, 100–700 Hz) and Sham conditions were delivered for 10 minutes at an intensity of 1.5 mA over the primary motor cortex (M1). Single-pulse transcranial magnetic stimulation (TMS) was delivered over the same area at baseline, 0, 10, 20, 30, 45 and 60 minutes after stimulation, while motor evoked potentials (MEPs) were recorded to evaluate changes in cortical excitability. Only the full-band condition (100–700 Hz) was able to modulate excitability by enhancing MEPs at 10 and 20 minutes after stimulation: neither the higher nor the lower sub-range of the high-frequency band significantly modulated cortical excitability. These results show that the efficacy of tRNS is strictly related to the width of the selected frequency range.
... The significance threshold of the log F ratio was based on a permutation test with 5000 permutations. 62 Statistical analyses were performed using the SPSS software (ver. 22.0; IBM Corp., Armonk, New York, USA) and built-in functions provided by Matlab (R2014a, Mathworks). ...
Objectives
Despite no observable external sound present, a perceived feeling of a recurrent unpleasant sound is a main complaint in the patients with chronic tinnitus. This phantom perception of sound is considered as the auditory equivalent of phantom limb pain, and altered excitability may be involved in its underlying pathology. Tinnitus-related hyper-excitation is suppressed by inhibitory repetitive transcranial magnetic stimulation (rTMS). However, the neural mechanism underlying the treatment is not fully understood, and quantifying the suppression induced by rTMS has yet to be considered.
Methods
We evaluated the effect of rTMS on the cortical inhibition status following single-site stimulation over the auditory temporal cortex (T group) or dual-site stimulation over the auditory temporal and the frontal regions (TF group). These effects were also compared with outcomes following sham stimulation (S group). Subjective response was recorded using tinnitus-related handicap index (THI), and changes in the cortical inhibition status were assessed using an auditory paired-pulse suppression index (PPSI).
Results
TF group showed the greatest benefit from the treatment evidenced in the reduced PPSI and THI scores. T and S groups did not benefit much. TF group overlapped mostly with the responder group, indicating improvement in both subjective THI and objective PPSI measurements.
Conclusion
Our results suggest that rTMS is a beneficial therapeutic treatment for chronic tinnitus patients and the dual-site treatment was the most effective in terms of both tinnitus complaint and quantitative indices. Thus, subjective reports and electrophysiological signatures may be complementary for the diagnosis/prognosis of tinnitus.
... Because they had sufficient auditory experience involving the affected ear before losing their hearing, they do have those perceptual priors and thus do have a basis to infer tinnitus. Notably, these observations in tinnitus apply equally well to complex auditory phantoms such as musical hallucinosis (Kumar et al., 2014;Vanneste et al., 2013) as well as to phantoms in other sensory domains, e.g. Charles Bonnet syndrome; see (Mohan and Vanneste, 2017) for a detailed review. ...
More than 150 years have passed since Helmholtz first described perception as a process of unconscious inference about the causes of sensations. His ideas have since inspired a wealth of literature investigating the mechanisms underlying these inferences. In recent years, much of this work has converged on the notion that the brain is a hierarchical generative model of its environment that predicts sensations and updates itself based on prediction errors. Here, we build a case for modeling tinnitus from this perspective, i.e. predictive coding. We emphasize two key claims: (1) acute tinnitus reflects an increase in sensory precision in related frequency channels and (2) chronic tinnitus reflects a change in the brain’s default prediction. We further discuss specific neural biomarkers that would constitute evidence for or against these claims. Finally, we explore the implications of our model for clinical intervention strategies. We conclude that predictive coding offers the basis for a unifying theory of cognitive neuroscience, which we demonstrate with several examples linking tinnitus to other lines of brain research.
... In order for effective aural communication to occur, a listener must selectively attend to the relevant acoustic signal in a noisy environment in order to from a coherent auditory stream, a task normal listeners perform effortlessly (Lee et al., 2008). The involvement of the SN has been implicated in tinnitus, as increased activity in the SN and enhanced insula-auditory cortex couplings might be associated with tinnitus percept and continuous awareness (Vanneste et al., 2013). Listeners with SNHL have great difficulty filtering out irrelevant acoustic information resulting in impaired auditory processing, diminished attention and an inability to use memory and cognition to fill in missing information in an auditory stream. ...
Sensorineural hearing loss (SNHL), sometimes accompanied with tinnitus, is associated with dysfunctions within and outside the classical auditory pathway. The salience network, which is anchored in bilateral anterior insula and dorsal anterior cingulate cortex, has been implicated in sensory integration. Partial auditory deprivation could alter the characteristics of the salience network and other related brain areas, thereby contributing to hearing impairments-induced neuropsychiatric symptoms. To test this hypothesis, we performed fMRI scanning and neuropsychological tests on 32 subjects with long-term bilateral hearing impairment and 30 well-matched Controls. Non-directional functional connectivity and directional Granger causality analysis were used to identify aberrant spatial and temporal patterns of connections targeting bilateral anterior insula and dorsal anterior cingulate cortex. We found that the left anterior insula showed decreased connectivity with right precentral gyrus and superior frontal gyrus. The connections between the dorsal anterior cingulate cortex and middle frontal gyrus, superior parietal gyrus and supplementary motor area (SMA) were also reduced. Relative to Controls, SNHL patients showed abnormal effective connectivity of the salience network, including inferior temporal gyrus, cerebellum lobule VI, lobule VIII, precentral gyrus, middle frontal gyrus and SMA. Furthermore, correlation analysis demonstrated that some of these atypical connectivity measures were correlated with performance of neuropsychiatric tests. These findings suggest that the inefficient modulation of the salience network might contribute to the neural basis of SNHL and tinnitus, as well as associated cognition and emotion deficits.
... Simple phantoms such as tinnitus (i.e., simple auditory phantom perception) are among the most common, chronically affecting one in five adults (Elgoyhen et al., 2015). Phantom perception as a broader category, however, describes phenomena that vary starkly in complexity (Vanneste, Song, & De Ridder, 2013) and can occur in any sensory domain (Mohan & Vanneste, 2017). Despite this, there is a mounting body of evidence that phantoms nevertheless have much in common. ...
In the present study, we use resting state fMRI to investigate whether nucleus accumbens (NAc) and extended frontostriatal networks are involved in the pathology of auditory phantom perception, i.e., tinnitus, through a study of functional connectivity. We hypothesize that resting state functional connectivity involving NAc will be increased relative to what is observed in healthy subjects and that this connectivity will correlate with clinical measures of tinnitus such as percept loudness, duration of symptoms, etc. We show that a large sample of patients with chronic tinnitus (n = 90) features extensive functional connectivity involving NAc that is largely absent in healthy subjects (n = 94). We further show that connectivity involving NAc correlates significantly with tinnitus percept loudness and the duration of tinnitus symptoms, even after controlling for the effects of age and hearing loss. The loudness correlation, which involves NAc and parahippocampal cortex, is consistent with existing literature identifying the parahippocampus as a tinnitus generator. Our results further suggest that frontostriatal connectivity may predict the transition from acute to chronic tinnitus, analogous to what is seen in the pain literature. We discuss these ideas and suggest fruitful avenues for future research.
... The consciousness about the self-generation of auditory contents distinguishes hallucinations from hallucinosis, which implies the self-attribution of perceived stimuli. In the present case it would be more correct referring to musical hallucinosis phenomenon, rather than musical hallucinations, according to Vanneste et al. (2013). ...
The aim of the study is to investigate morphofunctional circuits underlying musical hallucinations (MH) in a 72-years old female that underwent a simultaneous 18fluoredeoxyglucose positron emission tomography (PET) and advanced magnetic resonance (MR) exam. This represents a particular case of MH occurred in an healthy subject, not displaying neurological or psychopathological disorders, and studied simultaneously with a multimodal approach. For the resting-state fMRI analysis a seed to seed approach was chosen. For the task-based fMRI, 4 different auditory stimuli were presented. Imaging findings were compared with data obtained by ten healthy controls matched for age and sex. Neuropsychological evaluation and questionnaires investigating depression and anxiety were also administered. PET findings showed hypermetabolism of: superior temporal gyri, anterior cingulate, left orbital frontal, and medial temporal cortices. Structural MRI did not show macroscopical lesions except for gliotic spots along the uncinate fascicle pathways with an increased cortical thickness for the right orbitofrontal cortex (p = 0.003). DTI showed increased fractional anisotropy values in the left uncinate fascicle, when compared to controls (p = 0.04). Resting-state fMRI showed increased functional connectivity between the left inferior frontal gyrus and the left temporal fusiform cortex (p = 0.01). Task-based fMRI confirmed PET findings showing an increased activation of the superior temporal gyrus in all the auditory tasks except for the monotone stimulus, with a significant activation of the left orbital frontal cortex only during the song in foreign language, object of MH. Results on cognitive test did not show cognitive impairment, excepting for the performance on Frontal Assessment Battery where the patient fails in the cognitive domains of conceptualization, sensitive to interference, and inhibitory control. The subject did not show depressive or anxiety symptoms. Summarizing, multimodal imaging analyses in the MH case showed a microstructural alteration of the left uncinate fascicle paralleled by an increased metabolism and functional connectivity of cortical regions that receive left uncinate projections (orbital frontal cortex, and medial temporal cortex). This alteration of fronto-hyppocampal circuits could be responsible of retrieval of known songs even in the absence of real stimuli.
... This paper will only 43 consider subjective tinnitus that will herein be referred to 44 simply as tinnitus. 45 Tinnitus is apparent in a wide and diverse range of people 46 and it is therefore important to focus on the similarities that 47 unite the tinnitus cohort. Over 90% of people with tinnitus 48 have observable hearing loss [2]. ...
Tinnitus is a problem that affects a diverse range of people. One common trait amongst tinnitus sufferers is the presence of hearing loss, which is apparent in over 90% of the cohort. It is postulated that the remainder of tinnitus sufferers have hidden hearing loss in the form of cochlear synaptopathy. The loss of hearing sensation is thought to cause a reduction in the bottom-up excitatory signals of the auditory pathway leading to a change in the frequency of thalamocortical oscillations known as Thalamocortical Dysrhythmia (TCD). The downward shift in oscillatory behaviour, characteristic of TCD, has been recorded experimentally but the underlying mechanisms responsible for TCD in tinnitus subjects cannot be directly observed. This paper investigates these underlying mechanisms by creating a biologically faithful model of the auditory periphery and thalamocortical network, called the central auditory processing (CAP) model. The proposed model replicates tinnitus related activity in the presence of hearing loss and hidden hearing loss in the form of cochlear synaptopathy. The results of this work show that both bottom-up and top-down changes are required in the auditory system for tinnitus related hyperactivity to coexist with TCD, contrary to the theoretical model for TCD. The CAP model provides a novel modelling approach to account for tinnitus related activity with and without hearing loss. Moreover, the results provide additional clarity to the understanding of TCD and tinnitus and provide direction for future approaches to treating tinnitus.
... For example, Kindler et al. (2011) found microstate D of the EEG to be significantly shorter in periods of hallucination when compared to non-hallucinating patients. As tinnitus and auditory hallucination share similar central cortex activity, with an increase in theta-gamma response during EEG measurement (Vanneste et al., 2013), and the generation of tinnitus involves several brain regions and multiple neural networks, the microstate analysis may be a powerful method to explore the neurophysiological mechanism of tinnitus over the whole brain. Therefore, the present study set out to explore alteration in EEG microstates in tinnitus patients with normal persons as controls. ...
Given the importance of central reorganization and tinnitus, we undertook the current study to investigate changes to electroencephalogram (EEG) microstates and their association with the clinical symptoms in tinnitus. High-density (128 channel) EEG was used to explore changes in microstate features in 15 subjects with subjective tinnitus and 17 age-matched controls. Correlations between microstate parameters and subjective tinnitus symptoms were also analyzed. An increased presence of class A microstate and decreased presence of class D microstate were found in coverage and lifespan of microstate parameters in the tinnitus patients. Syntax analysis also demonstrated an aberrant pattern of activity, with reduced transitions from class D to class B in tinnitus patients. Moreover, a significant positive correlation of tinnitus loudness with increased lifespan of microstate class C was found. Significant differences in temporal characteristics and syntax of the EEG microstate classes were found at rest between tinnitus patients and the healthy subjects. Our study indicates that EEG microstates may provide a possible valuable method to study large-scale brain networks, which may in turn be beneficial to investigation of the neurophysiological mechanisms behind tinnitus.
... The presence of tinnitus is positively associated with auditory hallucinations, even after correction for the severity of hearing impairment. Previous studies have suggested that in patients with hearing impairment, simple auditory hallucinations (such as tinnitus) and complex auditory hallucinations (such as music or voices) may represent different phenomena within the same spectrum, and may share etiological mechanisms, such as deafferentation (Vanneste et al. 2013;Mccarthy-Jones et al. 2014;Linszen et al. 2016). Although our findings do not directly prove the existence of such a spectrum, it deserves further study. ...
Background
Similar to visual hallucinations in visually impaired patients, auditory hallucinations are often suggested to occur in adults with hearing impairment. However, research on this association is limited. This observational, cross-sectional study tested whether auditory hallucinations are associated with hearing impairment, by assessing their prevalence in an adult population with various degrees of objectified hearing impairment.
Methods
Hallucination presence was determined in 1007 subjects aged 18–92, who were referred for audiometric testing to the Department of ENT-Audiology, University Medical Center Utrecht, the Netherlands. The presence and severity of hearing impairment were calculated using mean air conduction thresholds from the most recent pure tone audiometry.
Results
Out of 829 participants with hearing impairment, 16.2% ( n = 134) had experienced auditory hallucinations in the past 4 weeks; significantly more than the non-impaired group [5.8%; n = 10/173; p < 0.001, odds ratio 3.2 (95% confidence interval 1.6–6.2)]. Prevalence of auditory hallucinations significantly increased with categorized severity of impairment, with rates up to 24% in the most profoundly impaired group ( p < 0.001). The corrected odds of hallucination presence increased 1.02 times for each dB of impairment in the best ear. Auditory hallucinations mostly consisted of voices (51%), music (36%), and doorbells or telephones (24%).
Conclusions
Our findings reveal that auditory hallucinations are common among patients with hearing impairment, and increase with impairment severity. Although more research on potential confounding factors is necessary, clinicians should be aware of this phenomenon, by inquiring after hallucinations in hearing-impaired patients and, conversely, assessing hearing impairment in patients with auditory hallucinations, since it may be a treatable factor.
... T innitus is the perception of sound in the absence of sound in the environment (Henry et al, 2005;Moller, 2006, p. 254;Kaltenbach, 2011;De Ridder et al, 2014c). The precise mechanisms giving rise to tinnitus perception and distress are still not fully known, although it is now understood to be generated predominantly as a result of peripheral lesions in the auditory system triggering cortical neuroplasticity changes or inadequate noise reduction in central processing pathways (Rauschecker et al, 2010;Kaltenbach, 2011;Vanneste et al, 2013;De Ridder et al, 2014b). It is important to note that tinnitus is not a disease in itself but a presenting symptom in various underlying diseases and pathologies (Vernon and Schleuning, 1978;Vernon and Meikle, 2000;Lockwood et al, 2002;Chan, 2009;Holmes and Padgham, 2011). ...
Background:
The precise mechanisms underlying tinnitus perception and distress are still not fully understood. A recent proposition is that auditory prediction errors and related memory representations may play a role in driving tinnitus perception. It is of interest to further explore this.
Purpose:
To obtain a comprehensive narrative synthesis of current research in relation to auditory prediction and its potential role in tinnitus perception and severity.
Research design:
A narrative review methodological framework was followed.
Data collection and analysis:
The key words Prediction Auditory, Memory Prediction Auditory, Tinnitus AND Memory, Tinnitus AND Prediction in Article Title, Abstract, and Keywords were extensively searched on four databases: PubMed, Scopus, SpringerLink, and PsychINFO. All study types were selected from 2000-2016 (end of 2016) and had the following exclusion criteria applied: minimum age of participants <18, nonhuman participants, and article not available in English. Reference lists of articles were reviewed to identify any further relevant studies. Articles were short listed based on title relevance.
Study sample:
After reading the abstracts and with consensus made between coauthors, a total of 114 studies were selected for charting data.
Results:
The hierarchical predictive coding model based on the Bayesian brain hypothesis, attentional modulation and top-down feedback serves as the fundamental framework in current literature for how auditory prediction may occur. Predictions are integral to speech and music processing, as well as in sequential processing and identification of auditory objects during auditory streaming. Although deviant responses are observable from middle latency time ranges, the mismatch negativity (MMN) waveform is the most commonly studied electrophysiological index of auditory irregularity detection. However, limitations may apply when interpreting findings because of the debatable origin of the MMN and its restricted ability to model real-life, more complex auditory phenomenon. Cortical oscillatory band activity may act as neurophysiological substrates for auditory prediction. Tinnitus has been modeled as an auditory object which may demonstrate incomplete processing during auditory scene analysis resulting in tinnitus salience and therefore difficulty in habituation. Within the electrophysiological domain, there is currently mixed evidence regarding oscillatory band changes in tinnitus.
Conclusions:
There are theoretical proposals for a relationship between prediction error and tinnitus but few published empirical studies.
... Hz), and gamma (30.5-44 Hz) (Song et al., 2013a(Song et al., ,b, 2014(Song et al., , 2015aVanneste et al., 2013;Kim et al., 2015Kim et al., , 2016. This software implements the lead field of Fuchs et al. (2002) that was derived from standard electrode positions realigned to a standard Montreal Neurological Institute (MNI)-152 head in combination with a boundary element method derived from the same standard anatomy (Jurcak et al., 2007). ...
The mechanism of tinnitus suppression after cochlear implantation (CI) in single-sided deafness (SSD) is not fully understood. In this regard, by comparing pre- and post-CI quantitative electroencephalography (qEEG), we explored cortical changes relevant to tinnitus improvement. In SSD patients who underwent CI, qEEG data were collected: (1) before CI, (2) 6 months post-operatively with CI-on, and (3) 30 min after CI-off and source-localized cortical activity/functional connectivity analyses were performed. Compared to the pre-operative baseline, the CI-on condition demonstrated significantly decreased activity in the right auditory- and orbitofrontal cortices (OFC) for the delta frequency band as well as decreased connectivity between the auditory cortex/posterior cingulate cortex for the delta/beta2 bands. Meanwhile, compared to the CI-off condition, the CI-on condition displayed decreased activity in the right auditory cortices/OFC for the delta band, and in bilateral auditory cortices, left inferior frontal cortex/OFC for the gamma band. However, qEEG analyses showed no significant differences between the CI-off and baseline conditions. CI induced overall decreased cortical activity and functional connectivity. However, judging from no differences between the CI-off and baseline conditions, CI-induced cortical activity and functional connectivity changes are not by cortical plastic changes, but by dynamic peripheral reafferentation.
... Auditory phantoms are the perception of simple or complex sounds in the absence of external auditory input (Jastreboff, 1990;Vanneste et al., 2013). Simple auditory phantoms such as the intermittent or continuous perception of a ringing, buzzing, or hissing sound are collectively called tinnitus (Jastreboff, 1990;Møller et al., 2010). ...
It is suggested that the brain undergoes plastic changes in order to adapt to changing environmental needs. Sensory deprivation results in decreased input to the brain leading to adaptive or maladaptive changes. Although several theories hypothesize the mechanism of these adaptive and maladaptive changes, the course of action taken by the brain heavily depends on the age of incidence of damage. The growing body of literature on the topic proposes that maladaptive changes in the brain are instrumental in creating phantom percepts, defined as the perception of a sensory experience in the absence of a physical stimulus. The current article reviews the mechanisms of adaptive and maladaptive plasticity in the brain in congenital, early, and late-onset sensory deprivation in conjunction with the phantom percepts in the different sensory domains. We propose that the mechanisms of adaptive and maladaptive plasticity fall under a universal construct of updating hierarchical Bayesian prediction errors. This theory of the Bayesian brain hypothesizes that the brain constantly compares its internal milieu with changing environmental cues and either adjusts its predictions or discards the change, depending on the novelty or salience of the external stimulus. We propose that adaptive plasticity reflects both successful bottom-up compensation and top-down updating of the model while maladaptive plasticity reflects failure in one or both mechanisms, resulting in a constant prediction-error. Finally, we hypothesize that phantom percepts are generated by the brain as a solution to this prediction error and are thus a manifestation of unsuccessful adaptation to sensory deprivation.
Tinnitus is a very common oto-neurological disorder of the perception of sound when no sound is present. To improve understanding of the scope, strengths and weaknesses of New Zealand tinnitus research, a critical scoping review was undertaken. The aim was to help develop priorities for future research. A review of the literature was undertaken using a 6-stage scoping review framework of Scopus and Pub Med were searched in May 2023 with the combination of following key word [Tinnitus] and country of affiliation [New Zealand]. The search of PubMed resulted in 198 articles and that of Scopus 337 articles. After initial consideration of title relevance to the study (165 from PubMed and 196 from Scopus) removal of duplicates and after reading the articles and adding from references, 208 studies were chosen for charting of data. Nine themes were identified and described: A. Epidemiology; B. Models; C. Studies in animals; D. Mechanisms; E. Assessment and prognosis; F. Pharmacotherapy; G. Neuromodulation; H. Sensory therapies; I. Clinical practice. An urgent priority for future tinnitus research in NZ must be to address the absence of cultural and ethnic diversity in participants and consideration of traditional knowledge.
There is strong and growing evidence for ‘Bayesian’ accounts of brain function, such as predictive coding, in which perception depends upon internally generated models of the sensorium, which are updated and refined based on sensory input.
Bayesian perception involves both automatic stimulus-based perceptual inference and active time-based inference that underwrites the active sampling of predicted sensory stimuli.
Predictions in perceptual inference are associated with beta band activity, the precision of predictions with alpha activity and prediction errors with gamma oscillatory activity in sensory cortex, where prediction errors are propagated to other brain areas. Predictions in active inference are associated with theta activity, precision with delta and prediction errors with gamma activity in hippocampus and other cortical areas.
Activity in these frequency bands, in auditory and other cortical areas, has been linked to tinnitus, but not yet specifically to Bayesian processes in this context.
Different pathophysiological models have been proposed to explain the emergence of tinnitus, two of which are based on Bayesian processes. One account postulates that tinnitus is the result of memory-based prior beliefs about sounds, which are mobilised in compensation for the absence of evidence from sensory input. This model is based on active inference. Alternatively, spontaneous activity in the ascending auditory pathway (a ‘tinnitus precursor’) is usually ignored as noise, which conflicts with the default prediction of ‘no sound’, and chronic tinnitus occurs when this activity gains sufficient ‘precision’ to influence perceptual inference.
Stress may influence perceptual inference in various ways, favouring the initial emergence of tinnitus and/or its perpetuation.
In both accounts, incorporation of the tinnitus percept into default predictions leads to chronification of the condition.
Anatomical and electrophysiological data in tinnitus research are compatible with a Bayesian brain model, but are largely circumstantial and also compatible with alternative formulations.
Tinnitus is a phantom perception, analogous to hallucinations, visual snow, or some forms of chronic pain. These phantom perceptions can be associated with affective, cognitive, and behavioural symptoms, which are largely defining the related distress and the functional disability.
Accordingly, it has recently been proposed that tinnitus without and with suffering (or distress) should be differentiated by distinct terms: “tinnitus” for the former and “tinnitus disorder” for the latter. “Tinnitus” was defined as ‘the conscious awareness of a tonal and/or noise sound for which there is no identifiable corresponding external acoustic source’. By contrast, “tinnitus disorder” was defined as ‘tinnitus plus tinnitus-associated suffering with or without functional disability.’ Tinnitus was further differentiated in objective and subjective, pulsatile and non-pulsatile, constant and intermittent, or acute and chronic.
Whereas tinnitus is a simple or elementary form of auditory phantom perception, musical hallucinosis and verbal hallucinations are more complex auditory phantom phenomena not only limited to sound perception, but also containing semantic content. Whereas verbal hallucinations are a typical feature of a psychiatric condition (i.e. psychosis or schizophrenia), musical hallucinosis commonly results from severe auditory deprivation, deafferentation, or deafness without altered consciousness.
Hallucinations can also occur in other sensory modalities—visual, olfactory, gustatory, tactile, proprioceptive, vestibular, nociceptive, thermoceptive, and chronoceptive. Hallucinations can be associated with sensory deprivation, drug use (particularly deliriants), sleep deprivation, psychosis, neurological disorders, and delirium tremens.
Background:
Tinnitus is a bothersome condition associated with various symptoms. However, the mechanisms of tinnitus are still uncertain, and a standardized assessment of the diagnostic criteria for tinnitus is required. We aimed to reach a consensus on diagnosing tinnitus with professional experts by conducting a Delphi study with systematic review of the literature.
Methods:
Twenty-six experts in managing tinnitus in Korea were recruited, and a two-round modified Delphi study was performed online. The experts evaluated the level of agreement of potential criteria for tinnitus using a scale of 1-9. After the survey, a consensus meeting was held to establish agreement on the results obtained from the Delphi process. Consensus was defined when over 70% of the participants scored 7-9 (agreement) and fewer than 15% scored 1-3 (disagreement). To analyze the responses of the Delphi survey, the content validity ratio and Kendall's coefficient of concordance were evaluated.
Results:
Consensus was reached for 22 of the 38 statements. For the definition of tinnitus, 10 out of 17 statements reached consensus, with three statements achieving complete agreement including; 1) Tinnitus is a conscious perception of an auditory sensation in the absence of a corresponding external stimulus, 2) Tinnitus can affect one's quality of life, and 3) Tinnitus can be associated with hearing disorders including sensorineural hearing loss, vestibular schwannoma, Meniere's disease, otosclerosis, and others. For the classification of tinnitus, 11 out of 18 statements reached consensus. The participants highly agreed with statements such as; 1) Vascular origin is expected in pulse-synchronous tinnitus, and 2) Tinnitus can be divided into acute or chronic tinnitus. Among three statements on the diagnostic tests for tinnitus only Statement 3, "There are no reliable biomarkers for sensory or emotional factors of tinnitus." reached consensus. All participants agreed to perform pure-tone audiometry and tinnitus questionnaires, including the Tinnitus Handicap Inventory and Tinnitus Questionnaire.
Conclusion:
We used a modified Delphi method to establish a consensus-based definition, a classification, and diagnostic tests for tinnitus. The expert panel reached agreement for several statements, with a high level of consensus. This may provide practical information for clinicians in managing tinnitus.
The species of Orinus (Poaceae) are important alpine plants with a variety of phenotypic traits and potential usages in molecular breeding toward drought-tolerant forage crops. However, the genetic basis of evolutionary adaption and diversification in the genus is still unclear. In the present study, we obtained transcriptomes for the two most divergent species, O. thoroldii and O. kokonoricus, using the Illumina platform and de novo assembly. In total, we generated 23,029 and 24,086 unigenes with N50 values of 1188 and 1203 for O. thoroldii and O. kokonoricus respectively, and identified 19,005 pairs of putative orthologs between the two species of Orinus. For these orthologs, estimations of non-synonymous/synonymous substitution rate ratios indicated that 568 pairs may be under strongly positive selection (Ka/Ks > 1), and Gene Ontogeny (GO) enrichment analysis revealed that significantly enriched pathways were in DNA repair and resistance to abiotic stress. Meanwhile, the divergence times of species between O. thoroldii and O. kokonoricus occurred 3.2 million years ago (Mya), and the recent evolutionary branch is an allotetraploid species, Cleistogenes songorica. We also detected a Ks peak of ∼0.60 for Orinus. Additionally, we identified 188 pairs of differentially expressed genes (DEGs) between the two species of Orinus, which were significantly enrich in stress resistance and lateral root development. Thus, we considered that the species diversification and evolutionary adaption of this genus was initiated by environmental selection, followed by phenotypic differentiation, finally leading to niche separation in the Qinghai-Tibet Plateau.
Tinnitus is hypothesised to be a predictive coding problem. Previous research indicates lower sensitivity to prediction errors (PEs) in tinnitus patients while processing auditory deviants corresponding to tinnitus-specific stimuli. However, based on research with patients with hallucinations and no psychosis we hypothesise tinnitus patients may be more sensitive to PEs produced by auditory stimuli that are not related to tinnitus characteristics. Specifically in patients with minimal to no hearing loss, we hypothesise a more top-down subtype of tinnitus that may be driven by maladaptive changes in an auditory predictive coding network. To test this, we use an auditory oddball paradigm with omission of global and local deviants, a measure that is previously shown to empirically characterise hierarchical prediction errors (PEs).
We observe: (1) increased predictions characterised by increased pre-stimulus response and increased alpha connectivity between the parahippocampus, dorsal anterior cingulate cortex and parahippocampus, pregenual anterior cingulate cortex and posterior cingulate cortex; (2) increased PEs characterised by increased P300 amplitude and gamma activity and increased theta connectivity between auditory cortices, parahippocampus and dorsal anterior cingulate cortex in the tinnitus group; (3) increased overall feed-forward connectivity in theta from the auditory cortex and parahippocampus to the dorsal anterior cingulate cortex; (4) correlations of pre-stimulus theta activity to tinnitus loudness and alpha activity to tinnitus distress. These results provide empirical evidence of maladaptive changes in a hierarchical predictive coding network in a subgroup of tinnitus patients with minimal to no hearing loss. The changes in pre-stimulus activity and connectivity to non-tinnitus specific stimuli suggest that tinnitus patients not only produce strong predictions about upcoming stimuli but also may be predisposed to stimulus a-specific PEs in the auditory domain. Correlations with tinnitus-related characteristics may be a biomarker for maladaptive changes in auditory predictive coding.
The mechanisms underlying sound’s effect on tinnitus perception are unclear. Tinnitus activity appears to conflict with perceptual expectations of “real” sound, resulting in it being a salient signal. Attention diverted towards tinnitus during the later stages of object processing potentially disrupts high-order auditory streaming, and its uncertain nature results in negative psychological responses. This study investigated the benefits and neurophysiological basis of passive perceptual training and informational counseling to recategorize phantom perception as a more real auditory object. Specifically, it examined underlying psychoacoustic correlates of tinnitus and the neural activities associated with tinnitus auditory streaming and how malleable these are to change with targeted intervention. Eighteen participants (8 females, 10 males, mean age = 61.6 years) completed the study. The study consisted of 2 parts: (1) An acute exposure over 30 min to a sound that matched the person’s tinnitus (Tinnitus Avatar) that was cross-faded to a selected nature sound (Cicadas, Fan, Water Sound/Rain, Birds, Water and Bird). (2) A chronic exposure for 3 months to the same “morphed” sound. A brain-inspired spiking neural network (SNN) architecture was used to model and compare differences between electroencephalography (EEG) patterns recorded prior to morphing sound presentation, during, after (3-month), and post-follow-up. Results showed that the tinnitus avatar generated was a good match to an individual’s tinnitus as rated on likeness scales and was not rated as unpleasant. The five environmental sounds selected for this study were also rated as being appropriate matches to individuals’ tinnitus and largely pleasant to listen to. There was a significant reduction in the Tinnitus Functional Index score and subscales of intrusiveness of the tinnitus signal and ability to concentrate with the tinnitus trial end compared to baseline. There was a significant decrease in how strong the tinnitus signal was rated as well as ratings of how easy it was to ignore the tinnitus signal on severity rating scales. Qualitative analysis found that the environmental sound interacted with the tinnitus in a positive way, but participants did not experience change in severity, however, characteristics of tinnitus, including pitch and uniformity of sound, were reported to change. The results indicate the feasibility of the computational SNN method and preliminary evidence that the sound exposure may change activation of neural tinnitus networks and greater bilateral hemispheric involvement as the sound morphs over time into natural environmental sound; particularly relating to attention and discriminatory judgments (dorsal attention network, precentral gyrus, ventral anterior network). This is the first study that attempts to recategorize tinnitus using passive auditory training to a sound that morphs from resembling the person’s tinnitus to a natural sound. These findings will be used to design future-controlled trials to elucidate whether the approach used differs in effect and mechanism from conventional Broadband Noise (BBN) sound therapy.
Tinnitus, the perception of sound in the absence of a physical sound in the environment, is highly heterogeneous. It varies in its etiology, characteristics, and impact on an individual's life. The sound is commonly described as "ringing," "buzzing," "crickets," "hissing," "humming." Tinnitus can be acute or chronic, mild or disabling. It can be perceived unilaterally or, more commonly, bilaterally. The sound and its location differ from person to person and fluctuate in the same individual over a certain period of time. This heterogeneity in characterization has important implications for research and clinical practice. Identifying patterns in how tinnitus sounds and its relationship to hearing may aid in identifying different forms of tinnitus and revealing their underlying mechanisms. However, the subjective nature of characterizing tinnitus makes it difficult to reliably define and measure. This chapter will focus on reviewing the psychoacoustic assessment of tinnitus, its relationship to cognitive and behavioral aspects of tinnitus, and its neuropathophysiology. In particular, it will describe the heterogeneity of tinnitus and tinnitus matching, and how individual variability in measures may be used to guide treatment and as a prognostic factor.
Objectives:
The aim of this study was to determine whether auditory streaming (segregation of incoming sounds into separate sound sources) and the ability to anticipate future auditory events are affected in tinnitus sufferers compared with nontinnitus controls with matched levels of hearing. It was hypothesized that tinnitus would result in abnormal electroencephalography responses to tone deviants and tone omissions compared to controls for frequencies near the pitch of tinnitus, and this should correspond with increased levels of cortical γ and θ oscillatory rhythms.
Design:
Sixteen individuals with tinnitus (10 men and 6 women; age, 53.44; SD, 12.92 years) and 14 control participants (8 men and 6 women; age, 50.25; SD, 18.54 years) took part in the study. A modified version of the ABA streaming paradigm, with repeating triplet pattern of two frequencies (A and B) presented as A-B-A, was used to examine deviant-related prediction error. Omission-related prediction errors were examined using a modified version of a tone-omission paradigm. Regions of interest were frontocentral, left frontal, right frontal, and temporal lobes.
Results:
A larger N1c waveform was elicited in the absence of any tone deviation within the left primary auditory cortex of tinnitus participants. No differences were present between groups for omissions. The only difference in oscillatory band activity between the two groups in this study was in response to tones 7 semitones different from tinnitus pitch, with significantly lower β-2 band activity present for the tinnitus group, correlating most with activity within the right inferior occipital gyrus.
Conclusions:
The findings from this study imply that cortical-level auditory stream segregation is altered among individuals with tinnitus.
As the COMT polymorphism is especially prominent in the prefrontal cortex and has been associated with auditory gating, we hypothesize that tinnitus patients with this polymorphism have altered activity in the ventromedial prefrontal/anterior cingulate areas that modulates the tinnitus percept. To test this, we recruited a total of 40 tinnitus subjects and 20 healthy controls for an EEG study. A comparison between tinnitus subjects and healthy controls and their frequency of being Val/Val genotype or Met carriers (including Val/Met and Met/Met genotype) shows no significant effect, suggesting that the distributions for the tinnitus and healthy groups are similar. Our results show that an interaction between the amount of hearing loss and the COMT Val158Met polymorphism can increase susceptibility to the clinical manifestation of tinnitus. We further demonstrate that the parahippocampus becomes involved in tinnitus in patients with hearing loss that are Met carriers. In these patients, the parahippocampus sends more tinnitus information to the pregenual anterior cingulate cortex and auditory cortex that is specifically related with increased loudness. At the same time, the pregenual anterior cingulate cortex, which normally functions as a gatekeeper, is not cancelling this auditory information, ultimately leading to increased tinnitus loudness.
An automated coordinate-based system to retrieve brain labels from the 1988 Talairach Atlas, called the Talairach Daemon (TD), was previously introduced [Lancaster et al., 1997]. In the present study, the TD system and its 3-D database of labels for the 1988 Talairach atlas were tested for labeling of functional activation foci. TD system labels were compared with author-designated labels of activation coordinates from over 250 published functional brain-mapping studies and with manual atlas-derived labels from an expert group using a subset of these activation coordinates. Automated labeling by the TD system compared well with authors' labels, with a 70% or greater label match averaged over all locations. Author-label matching improved to greater than 90% within a search range of +/-5 mm for most sites. An adaptive grey matter (GM) range-search utility was evaluated using individual activations from the M1 mouth region (30 subjects, 52 sites). It provided an 87% label match to Brodmann area labels (BA 4 & BA 6) within a search range of +/-5 mm. Using the adaptive GM range search, the TD system's overall match with authors' labels (90%) was better than that of the expert group (80%). When used in concert with authors' deeper knowledge of an experiment, the TD system provides consistent and comprehensive labels for brain activation foci. Additional suggested applications of the TD system include interactive labeling, anatomical grouping of activation foci, lesion-deficit analysis, and neuroanatomy education. (C) 2000 Wiley-Liss, Inc.
The objective was to examine functional connectivity linked to the auditory system in patients with bothersome tinnitus. Activity was low frequency (< 0.1 Hz), spontaneous blood oxygenation level-dependent (BOLD) responses at rest. The question was whether the experience of chronic bothersome tinnitus induced changes in synaptic efficacy between co-activated components. Functional connectivity for seed regions in auditory, visual, attention, and control networks was computed across all 2 mm(3) brain volumes in 17 patients with moderate-severe bothersome tinnitus (Tinnitus Handicap Index: average 53.5 ± 3.6 (range 38-76)) and 17 age-matched controls.
In bothersome tinnitus, negative correlations reciprocally characterized functional connectivity between auditory and occipital/visual cortex. Negative correlations indicate that when BOLD response magnitudes increased in auditory or visual cortex they decreased in the linked visual or auditory cortex, suggesting reciprocally phase reversed activity between functionally connected locations in tinnitus. Both groups showed similar connectivity with positive correlations within the auditory network. Connectivity for primary visual cortex in tinnitus included extensive negative correlations in the ventral attention temporoparietal junction and in the inferior frontal gyrus and rostral insula - executive control network components. Rostral insula and inferior frontal gyrus connectivity in tinnitus also showed greater negative correlations in occipital cortex.
These results imply that in bothersome tinnitus there is dissociation between activity in auditory cortex and visual, attention and control networks. The reciprocal negative correlations in connectivity between these networks might be maladaptive or reflect adaptations to reduce phantom noise salience and conflict with attention to non-auditory tasks.
Auditory verbal hallucinations (AVHs), the perception of voices in the absence of auditory stimuli, are common and distressing symptoms reported by 50%-80% of patients with schizophrenia. However, the results in a number of imaging and electrophysiological studies on the origins of AVH are not consistent, and the underlying pathophysiology remains unclear. The authors enrolled a group of schizophrenia patients and normal-control subjects, age 18-45 years. Two patient groups participated in the study; 1) a group of 8 patients with drug-resistant spontaneous AVHs; and 2) a group of 7 patients whose AVHs were successfully controlled with neuroleptic medication; along with 16 normal-control subjects. The entire sample had EEG recording done, with the AVH group told to press a button when they experienced a hallucination, and the other two groups randomly told when to press the button. In the AVH group, hallucinations were longer in the "eyes-closed" than "eyes-open" condition. There was spreading phase-coupling in the AVH group, intra- and inter-hemispherically, at left and right frontal and temporal areas, under both eyes-closed and eyes-open condition, during the experience of AVH. There was a statistically significant increase of α-band frequency-specific synchrony maximum values in the AVH group. AVHs are considered to be complex features, and, as such, they reflect abnormal functional connectivity in multiple related regions in both intra- and inter-hemispherical brain sites, primarily defined by phase-integration.
Spontaneous magnetoencephalographic activity was recorded in awake, healthy human controls and in patients suffering from neurogenic pain, tinnitus, Parkinson's disease, or depression. Compared with controls, patients showed increased low-frequency theta rhythmicity, in conjunction with a widespread and marked increase of coherence among high- and low-frequency oscillations. These data indicate the presence of a thalamocortical dysrhythmia, which we propose is responsible for all the above mentioned conditions. This coherent theta activity, the result of a resonant interaction between thalamus and cortex, is due to the generation of low-threshold calcium spike bursts by thalamic cells. The presence of these bursts is directly related to thalamic cell hyperpolarization, brought about by either excess inhibition or disfacilitation. The emergence of positive clinical symptoms is viewed as resulting from ectopic gamma-band activation, which we refer to as the "edge effect." This effect is observable as increased coherence between low- and high-frequency oscillations, probably resulting from inhibitory asymmetry between high- and low-frequency thalamocortical modules at the cortical level.
Tinnitus is an auditory phantom percept with a tone, hissing, or buzzing sound in the absence of any objective physical sound source. Persons with tinnitus engage in a number of health behaviors to manage tinnitus. This can go from prescription medication, masking devices, behavioral training techniques to cortical implants. Potentially less adaptive methods of coping with tinnitus, such as the use of alcohol, are poorly studied. The purpose of this study was to further explore the neurobiological mechanism of tinnitus improvement by the use of alcohol. We observed differences in the alpha, beta and gamma frequency band when comparing resting-state EEG before and after alcohol intake. More precisely increased synchronized alpha1 activity was found in the posterior cingulate cortex and decreased synchronized alpha2 activity was demonstrated in orbitofrontal cortex, ventrolateral prefrontal cortex and subcallosal anterior cingulate cortex after alcohol intake. Increased synchronized activity was found in a region between the pregenual and dorsal anterior cingulate cortex and the left insula for beta and decreased activity in the precuneus after alcohol intake. For the gamma frequency band decreased synchronized activity in the precuneus and the posterior cingulate cortex was demonstrated after alcohol intake. Region of interest analyses in auditory cortices and parahippocampal area revealed however no differences in the different frequency bands before and after alcohol consumption.
Phantom perception refers to the conscious awareness of a percept in the absence of an external stimulus. On the basis of basic neuroscience on perception and clinical research in phantom pain and phantom sound, we propose a working model for their origin. Sensory deafferentation results in high-frequency, gamma band, synchronized neuronal activity in the sensory cortex. This activity becomes a conscious percept only if it is connected to larger coactivated "(self-)awareness" and "salience" brain networks. Through the involvement of learning mechanisms, the phantom percept becomes associated to distress, which in turn is reflected by a simultaneously coactivated nonspecific distress network consisting of the anterior cingulate cortex, anterior insula, and amygdala. Memory mechanisms play a role in the persistence of the awareness of the phantom percept, as well as in the reinforcement of the associated distress. Thus, different dynamic overlapping brain networks should be considered as targets for the treatment of this disorder.
Tinnitus is considered an auditory phantom percept analogous to phantom pain. Thalamocortical dysrhythmia has been proposed as a possible pathophysiological mechanism for both tinnitus and pain. Thalamocortical dysrhythmia refers to a persistent pathological resting state theta-gamma coupling that is spatially localized at an area where normally alpha oscillations predominate. Auditory cortex stimulation via implanted electrodes has been developed to treat tinnitus, targeting an area of activation on functional MR imaging elicited by tinnitus-matched sound presentation. The authors describe a case in which clinical improvement was correlated with changes in intracranial recordings. Maximal tinnitus suppression was obtained by current delivery exactly at the blood oxygen level-dependent activation hotspot, which colocalizes with increased gamma and theta activity, in contrast to the other electrode poles, which demonstrated a normal alpha peak. These spectral changes normalized when stimulation induced tinnitus suppression, both on electrode and source-localized electroencephalography recordings. These data suggest that thetagamma coupling as proposed by the thalamocortical dysrhythmia model might be causally related to a conscious auditory phantom percept.
Tinnitus is an auditory sensation characterized by the perception of sound or noise in the absence of any external sound source. Based on neurobiological research, it is generally accepted that most forms of tinnitus are attributable to maladaptive plasticity due to damage to auditory system. Changes have been observed in auditory structures such as the inferior colliculus, the thalamus and the auditory cortex as well as in non-auditory brain areas. However, the observed changes show great variability, hence lacking a conclusive picture. One of the reasons might be the selection of inhomogeneous groups in data analysis.
The aim of the present study was to delineate the differences between the neural networks involved in narrow band noise and pure tone tinnitus conducting LORETA based source analysis of resting state EEG.
Results demonstrated that narrow band noise tinnitus patients differ from pure tone tinnitus patients in the lateral frontopolar (BA 10), PCC and the parahippocampal area for delta, beta and gamma frequency bands, respectively. The parahippocampal-PCC current density differences might be load dependent, as noise-like tinnitus constitutes multiple frequencies in contrast to pure tone tinnitus. The lateral frontopolar differences might be related to pitch specific memory retrieval.
Activation in a network of language-related regions has been reported during auditory verbal hallucinations. It remains unclear, however, how this activation is triggered. Identifying brain regions that show significant signal changes preceding auditory hallucinations might reveal the origin of these hallucinations.
Twenty-four patients with a psychotic disorder indicated the presence of auditory verbal hallucinations during 3-Tesla functional magnetic resonance imaging by squeezing a handheld balloon. A one-sample t test was performed to reveal groupwise activation during hallucinations. To enable analysis of brain activation 6 to 0 seconds preceding hallucinations, a tailored 'selective averaging' method, without any a priori assumptions concerning the hemodynamic response profile, was performed. To control for motor-related activation, 15 healthy comparison subjects squeezed a balloon at matched time intervals.
Groupwise analysis during auditory verbal hallucinations revealed brain activation in bilateral (right more than left) language-related regions and bilateral motor regions. Prominent deactivation preceding these hallucinations was observed in the left parahippocampal gyrus. In addition, significant deactivation preceding hallucinations was found in the left superior temporal, right inferior frontal, and left middle frontal gyri as well as in the right insula and left cerebellum. No significant signal changes were revealed prior to the matched balloon squeezing among the comparison subjects.
Auditory verbal hallucinations in patients with a psychotic disorder are consistently preceded by deactivation of the parahippocampal gyrus. The parahippocampus has been hypothesized to play a central role in memory recollection, sending information from the hippocampus to the association areas. Dysfunction of this region could trigger inadequate activation of right language areas during auditory hallucinations.
Recent studies have shown that ongoing activity fluctuations influence trial-by-trial perception of identical stimuli. Some brain systems seem to bias toward better perceptual performance and others toward worse. We tested whether these observations generalize to another as of yet unassessed sensory modality, audition, and a nonspatial but memory-dependent paradigm. In a sparse event-related functional magnetic resonance imaging design, we investigated detection of auditory near-threshold stimuli as a function of prestimulus baseline activity in early auditory cortex as well as several distributed networks that were defined on the basis of resting state functional connectivity. In accord with previous studies, hits were associated with higher prestimulus activity in related early sensory cortex as well as in a system comprising anterior insula, anterior cingulate, and thalamus, which other studies have related to processing salience and maintaining task set. In contrast to previous studies, however, higher prestimulus activity in the so-called dorsal attention system of frontal and parietal cortex biased toward misses, whereas higher activity in the so-called default mode network that includes posterior cingulate and precuneus biased toward hits. These results contradict a simple dichotomic view on the function of these two latter brain systems where higher ongoing activity in the dorsal attention network would facilitate perceptual performance, and higher activity in the default mode network would deteriorate perceptual performance. Instead, we show that the way in which ongoing activity fluctuations impact on perception depends on the specific sensory (i.e., nonspatial) and cognitive (i.e., mnemonic) context that is relevant.
Classical theories of sensory processing view the brain as a passive, stimulus-driven device. By contrast, more recent approaches emphasize the constructive nature of perception, viewing it as an active and highly selective process. Indeed, there is ample evidence that the processing of stimuli is controlled by top-down influences that strongly shape the intrinsic dynamics of thalamocortical networks and constantly create predictions about forthcoming sensory events. We discuss recent experiments indicating that such predictions might be embodied in the temporal structure of both stimulus-evoked and ongoing activity, and that synchronous oscillations are particularly important in this process. Coherence among subthreshold membrane potential fluctuations could be exploited to express selective functional relationships during states of expectancy or attention, and these dynamic patterns could allow the grouping and selection of distributed neuronal responses for further processing.
Distortion of the sense of reality, actualized in delusions and hallucinations, is the key feature of psychosis but the underlying neuronal correlates remain largely unknown. We studied 11 highly functioning subjects with schizophrenia or schizoaffective disorder while they rated the reality of auditory verbal hallucinations (AVH) during functional magnetic resonance imaging (fMRI). The subjective reality of AVH correlated strongly and specifically with the hallucination-related activation strength of the inferior frontal gyri (IFG), including the Broca's language region. Furthermore, how real the hallucination that subjects experienced was depended on the hallucination-related coupling between the IFG, the ventral striatum, the auditory cortex, the right posterior temporal lobe, and the cingulate cortex. Our findings suggest that the subjective reality of AVH is related to motor mechanisms of speech comprehension, with contributions from sensory and salience-detection-related brain regions as well as circuitries related to self-monitoring and the experience of agency.
Advances in cognitive neuroscience offer us new ways to understand the symptoms of mental illness by uniting basic neurochemical and neurophysiological observations with the conscious experiences that characterize these symptoms. Cognitive theories about the positive symptoms of schizophrenia--hallucinations and delusions--have tended to treat perception and belief formation as distinct processes. However, recent advances in computational neuroscience have led us to consider the unusual perceptual experiences of patients and their sometimes bizarre beliefs as part of the same core abnormality--a disturbance in error-dependent updating of inferences and beliefs about the world. We suggest that it is possible to understand these symptoms in terms of a disturbed hierarchical Bayesian framework, without recourse to separate considerations of experience and belief.
The pathophysiology of auditory verbal hallucinations (AVH) is largely unknown. Several functional imaging studies have measured cerebral activation during these hallucinations, but sample sizes were relatively small (one to eight subjects) and findings inconsistent. In this study cerebral activation was measured using fMRI in 24 psychotic patients while they experienced AVH in the scanner and, in another session, while they silently generated words. All patients were right handed and diagnosed with schizophrenia, schizo-affective disorder or psychotic disorder not otherwise specified. Group analysis for AVH revealed activation in the right homologue of Broca's area, bilateral insula, bilateral supramarginal gyri and right superior temporal gyrus. Broca's area and left superior temporal gyrus were not activated. Group analysis for word generation in these patients yielded activation in Broca's and Wernicke's areas and to a lesser degree their right-sided homologues, bilateral insula and anterior cingulate gyri. Lateralization of activity during AVH was not correlated with language lateralization, but rather with the degree to which the content of the hallucinations had a negative emotional valence. The main difference between cerebral activity during AVH and activity during normal inner speech appears to be the lateralization. The predominant engagement of the right inferior frontal area during AVH may be related to the typical low semantic complexity and negative emotional content.
Epidemiological studies suggest that auditory verbal hallucinations (AVH) occur in approximately 10%-15% of the general population, of whom only a small proportion has a clinically relevant psychotic disorder. It is unclear whether these hallucinations occur as an isolated phenomenon or if AVH in nonclinical individuals are part of a more general susceptibility to schizophrenia. For this study, 103 healthy individuals with frequent AVH were compared with 60 controls matched for sex, age, and education. All participants were examined by a psychiatrist using standardized diagnostic interviews and questionnaires. The individuals with AVH did not have clinically defined delusions, disorganization, or negative or catatonic symptoms, nor did they meet criteria for cluster A personality disorder. However, their global level of functioning was lower than in the controls and there was a pronounced increase on all subclusters of the Schizotypal Personality Questionnaire (SPQ) and the Peters Delusion Inventory, indicating a general increased schizotypal and delusional tendency in the hallucinating subjects. History of childhood trauma and family history of axis I disorders were also more prevalent in these individuals. We showed that higher SPQ scores, lower education, and higher family loading for psychiatric disorders, but not presence of AVH, were associated with lower global functioning. Our data suggest that AVH in otherwise healthy individuals are not an isolated phenomenon but part of a general vulnerability for schizophrenia.
This paper introduces the use of magnetic field tomography (MFT), a noninvasive technique based on distributed source analysis of magnetoencephalography data, which makes possible the three-dimensional reconstruction of dynamic brain activity in humans. MFT has a temporal resolution better than 1 msec and a spatial accuracy of 2-5 mm at the cortical level, which deteriorates to 1-3 cm at depths of 6 cm or more. MFT is used here to visualize the origin of a spatiotemporally organized pattern of coherent 40-Hz electrical activity. This coherence, initially observed during auditory input, was proposed to be generated by recurrent corticothalamic oscillation. In support of this hypothesis, we illustrate well-defined 40-Hz coherence between cortical-subcortical sites with a time shift that is consistent with thalamocortical conduction times. Studies on Alzheimer patients indicate that, while a similar activity pattern is present, the cortical component is reduced in these subjects.
Phantom auditory perception--tinnitus--is a symptom of many pathologies. Although there are a number of theories postulating certain mechanisms of its generation, none have been proven yet. This paper analyses the phenomenon of tinnitus from the point of view of general neurophysiology. Existing theories and their extrapolation are presented, together with some new potential mechanisms of tinnitus generation, encompassing the involvement of calcium and calcium channels in cochlear function, with implications for malfunction and aging of the auditory and vestibular systems. It is hypothesized that most tinnitus results from the perception of abnormal activity, defined as activity which cannot be induced by any combination of external sounds. Moreover, it is hypothesized that signal recognition and classification circuits, working on holographic or neuronal network-like representation, are involved in the perception of tinnitus and are subject to plastic modification. Furthermore, it is proposed that all levels of the nervous system, to varying degrees, are involved in tinnitus manifestation. These concepts are used to unravel the inexplicable, unique features of tinnitus and its masking. Some clinical implications of these theories are suggested.
In monkeys, bilateral damage to the medial temporal region produces severe memory impairment. This lesion, which includes the hippocampal formation, amygdala, and adjacent cortex, including the parahippocampal gyrus (the H+A+ lesion), appears to constitute an animal model of human medial temporal lobe amnesia. Reexamination of histological material from previously studied monkeys with H+A+ lesions indicated that the perirhinal cortex had also sustained significant damage. Furthermore, recent neuroanatomical studies show that the perirhinal cortex and the closely associated parahippocampal cortex provide the major source of cortical input to the hippocampal formation. Based on these 2 findings, we evaluated the severity of memory impairment in a group of monkeys that received bilateral lesions limited to the perirhinal cortex and parahippocampal gyrus (the PRPH lesion). The performance of the PRPH group was compared with that of monkeys with H+A+ lesions, who had been studied previously, and with a group of normal monkeys. Monkeys with PRPH lesions were severely impaired on 3 amnesia-sensitive tasks: delayed nonmatching to sample, object retention, and 8-pair concurrent discrimination. On pattern discrimination, a task analogous to ones that amnesic patients perform well, monkeys in the PRPH group performed normally. Overall, monkeys with PRPH lesions were as impaired or more impaired than the comparison group of monkeys with H+A+ lesions. These and other recent findings (Zola-Morgan et al., 1989b) suggest that the severe memory impairment in monkeys and humans associated with bilateral medial temporal lesions results from damage to the hippocampal formation and adjacent, anatomically related cortex, not from conjoint hippocampus-amygdala damage.
Network oscillations are postulated to be instrumental for synchronizing the activity of anatomically distributed populations of neurons. Results from recent studies on the physiology of cortical interneurons suggest that through their interconnectivity, they can maintain large-scale oscillations at various frequencies (4-12 Hz, 40-100 Hz and 200 Hz). We suggest that networks of inhibitory interneurons within the forebrain impose co-ordinated oscillatory 'contexts' for the 'content' carried by networks of principal cells. These oscillating inhibitory networks may provide the precise temporal structure necessary for ensembles of neurons to perform specific functions, including sensory binding and memory formation.
Spontaneous oscillatory electrical activity at a frequency near 40 Hz in the human brain and its reset by sensory stimulation have been proposed to be related to cognitive processing and to the temporal binding of sensory stimuli. These experiments were designed to test this hypothesis and to determine specifically whether the minimal interval required to identify separate auditory stimuli correlates with the reset of the 40-Hz magnetic signal. Auditory clicks were presented at varying times, while magnetic activity was recorded from awake human subjects. Experimental and modeling results indicate a stimulus-interval-dependent response with a critical interval of 12-15 ms. At shorter intervals only one 40-Hz response, to the first stimulus, was observed. With longer intervals, a second 40-Hz wave abruptly appeared, which coincided with the subject's perception of a second distinct auditory stimulus. These results indicate that oscillatory activity near 40 Hz represents a neurophysiological correlate to the temporal processing of auditory stimuli. It also supports the view that 40-Hz activity not only relates to primary sensory processing, but also could reflect the temporal binding underlying cognition.
Cortical activity and perception are not driven by the external stimulus alone; rather sensory information has to be integrated with various other internal constraints such as expectations, recent memories, planned actions, etc. The question is how large scale integration over many remote and size-varying processes might be performed by the brain. We have conducted a series of EEG recordings during processes thought to involve neuronal assemblies of varying complexity. While local synchronization during visual processing evolved in the gamma frequency range, synchronization between neighboring temporal and parietal cortex during multimodal semantic processing evolved in a lower, the beta1 (12-18 Hz) frequency range, and long range fronto-parietal interactions during working memory retention and mental imagery evolved in the theta and alpha (4-8 Hz, 8-12 Hz) frequency range. Thus, a relationship seems to exist between the extent of functional integration and the synchronization-frequency. In particular, long-range interactions in the alpha and theta ranges seem specifically involved in processing of internal mental context, i.e. for top-down processing. We propose that large scale integration is performed by synchronization among neurons and neuronal assemblies evolving in different frequency ranges.
We studied eight normal subjects in an fMRI experiment where they listened to natural speech sentences and to matched simple or complex speech envelope noises. Neither of the noises (simple or complex) were understood initially, but after the corresponding natural speech sentences had been heard, comprehension was close to perfect for the complex but still absent for the simple speech envelope noises. This setting thus involved identical stimuli that were understood or not and permitted to identify (i) a neural substrate of speech comprehension unconfounded by stimulus acoustic properties (common to natural speech and complex noises), (ii) putative correlates of auditory search for phonetic cues in noisy stimuli (common to simple and complex noises once the matching natural speech had been heard) and (iii) the cortical regions where speech comprehension and auditory search interact. We found correlates of speech comprehension in bilateral medial (BA21) and inferior (BA38 and BA38/21) temporal regions, whereas acoustic feature processing occurred in more dorsal temporal regions. The left posterior superior temporal cortex (Wernicke’s area) responded to the acoustic complexity of the stimuli but was additionally sensitive to auditory search and speech comprehension. Attention was associated with recruitment of the dorsal part of Broca’s area (BA44) and interaction of auditory attention and comprehension occurred in bilateral insulae, the anterior cingulate and the right medial frontal cortex. In combination, these results delineate a neuroanatomical framework for the functional components at work during natural speech processing, i.e. when comprehension results from concurrent acoustic processing and effortful auditory search.
Objective: To define the spatial, temporal, and functional characteristics of induced gamma (>30 Hz) activity during functional activation of the left superior temporal gyrus.Methods: Electrocorticographic (ECoG) recordings were made in 4 clinical subjects during auditory tone and phoneme discrimination tasks, and event-related changes in the ECoG band power were calculated. The topography and temporal sequence of event-related power changes in different gamma bands were contrasted with those of auditory evoked potentials (AEPs), and with those of event-related power changes in the alpha band (8–12 Hz).Results: Auditory stimuli induced a broadband power augmentation that included 40 Hz, as well as higher (80–100 Hz) gamma frequencies. The topography of gamma augmentation was similar, but not identical, to that of the AEP, and was more focused than that of alpha power suppression. Its temporal onset coincided with the N100, but outlasted it. Phonemes produced greater gamma augmentation than tones, while a similar difference was not observed in the N100.Conclusions: Auditory perception induces ECoG gamma activity not only at 40 Hz, but also in higher gamma frequencies. This activity appears to be an index of cortical activation that reflects task-specific processing in the human auditory cortex more closely than the AEP or alpha power suppression.
Cortical projections to subdivisions of the cingulate cortex in the rhesus monkey were analyzed with horseradish peroxidase and tritiated amino acid tracers. These projections were evaluated in terms of an expanded cytoarchitectural scheme in which areas 24 and 23 were divided into three ventrodorsal parts, i.e., areas 24a–c and 23a–c.
Most cortical input to area 25 originated in the frontal lobe in lateral areas 46 and 9 and orbitofrontal areas 11 and 14. Area 25 also received afferents from cingulate areas 24b, 24c, and 23b, from rostral auditory association areas TS2 and TS3, from the subiculum and CA1 sector of the hippocampus, and from the lateral and accessory basal nuclei of the amygdala (LB and AB, respectively).
Areas 24a and 24b received afferents from areas 25 and 23b of cingulate cortex, but most were from frontal and temporal cortices. These included the following areas: frontal areas 9, 11, 12, 13, and 46; temporal polar area TG as well as LB and AB; superior temporal sulcus area TPO; agranular insular cortex; posterior parahippocampal cortex including areas TF, TL, and TH and the subiculum. Autoradiographic cases indicated that area 24c received input from the insula, parietal areas PG and PGm, area TG of the temporal pole, and frontal areas 12 and 46, Additionally, caudal area 24 was the recipient of area PG input but not amygdalar afferents. It was also the primary site of areas TF, TL, and TH projections.
The following projections were observed both to and within posterior cingulate cortex. Area 29a–c received inputs from area 46 of the frontal lobe and the subiculum and in turn it projected to area 30. Area 30 had afferents from the posterior parietal cortex (area Opt) and temporal area TF. Areas 23a and 23b received inputs mainly from frontal areas 46, 9, 11, and 14, parietal areas Opt and PGm, area TPO of superior temporal cortex, and areas TH, TL, and TF. Anterior cingulate areas 24a and 24b and posterior areas 29d and 30 projected to area 23. Finally, a rostromedial part of visual association area 19 also projected to area 23.
The origin and termination of these connections were expressed in a number of different laminar patterns. Most corticocortical connections arose in layer III and to a lesser extent layer V, while others, e.g., those from the cortex of the superior temporal sulcus, had an equal density of cells in both layers III and V. In one instance projections to area 24 arose almost entirely from layer V of areas TH, TL, and TF. Furthermore, although most projections terminated in layers I–III of cingulate cortex, those of the amygdala to rostral area 24 terminated in deep layer I and layer II while area Opt projections to area 23 terminated mainly in layers I, II, and IV.
Four classes of cortical connections have been characterized and each may play a role in the sensorimotor functions of cingulate cortex. These include connections with sensory association and multimodal areas, projections to and from premotor area 24c, subicular termination in areas 25, 24, and 29, and intracingulate connections that may transmit sensory input to areas 24 and 23 into area 24c.
Many theories of perception are anchored in the central notion that the brain continuously updates an internal model of the world to infer the probable causes of sensory events. In this framework, the brain needs not only to predict the causes of sensory input, but also when they are most likely to happen. In this article, we review the neurophysiological bases of sensory predictions of "what' (predictive coding) and 'when' (predictive timing), with an emphasis on low-level oscillatory mechanisms. We argue that neural rhythms offer distinct and adapted computational solutions to predicting 'what' is going to happen in the sensory environment and 'when'.
Phantom perceptions arise almost universally in people who sustain sensory deafferentation, and in multiple sensory domains. The question arises 'why' the brain creates these false percepts in the absence of an external stimulus? The model proposed answers this question by stating that our brain works in a Bayesian way, and that its main function is to reduce environmental uncertainty, based on the free-energy principle, which has been proposed as a universal principle governing adaptive brain function and structure. The Bayesian brain can be conceptualized as a probability machine that constantly makes predictions about the world and then updates them based on what it receives from the senses. The free-energy principle states that the brain must minimize its Shannonian free-energy, i.e. must reduce by the process of perception its uncertainty (its prediction errors) about its environment. As completely predictable stimuli do not reduce uncertainty, they are not worthwhile of conscious processing. Unpredictable things on the other hand are not to be ignored, because it is crucial to experience them to update our understanding of the environment. Deafferentation leads to topographically restricted prediction errors based on temporal or spatial incongruity. This leads to an increase in topographically restricted uncertainty, which should be adaptively addressed by plastic repair mechanisms in the respective sensory cortex or via (para)hippocampal involvement. Neuroanatomically, filling in as a compensation for missing information also activates the anterior cingulate and insula, areas also involved in salience, stress and essential for stimulus detection. Associated with sensory cortex hyperactivity and decreased inhibition or map plasticity this will result in the perception of the false information created by the deafferented sensory areas, as a way to reduce increased topographically restricted uncertainty associated with the deafferentation. In conclusion, the Bayesian updating of knowledge via active sensory exploration of the environment, driven by the Shannonian free-energy principle, provides an explanation for the generation of phantom percepts, as a way to reduce uncertainty, to make sense of the world.
The brain uses context and prior knowledge to repair degraded sensory inputs and improve perception. For example, listeners hear speech continuing uninterrupted through brief noises, even if the speech signal is artificially removed from the noisy epochs. In a functional MRI study, we show that this temporal filling-in process is based on two dissociable neural mechanisms: the subjective experience of illusory continuity, and the sensory repair mechanisms that support it. Areas mediating illusory continuity include the left posterior angular gyrus (AG) and superior temporal sulcus (STS) and the right STS. Unconscious sensory repair occurs in Broca's area, bilateral anterior insula, and pre-supplementary motor area. The left AG/STS and all the repair regions show evidence for word-level template matching and communicate more when fewer acoustic cues are available. These results support a two-path process where the brain creates coherent perceptual objects by applying prior knowledge and filling-in corrupted sensory information.
Multimodal objects and events activate many sensory cortical areas simultaneously. This is possibly reflected in reciprocal modulations of neuronal activity, even at the level of primary cortical areas. However, the synaptic character of these interareal interactions, and their impact on synaptic and behavioral sensory responses are unclear. Here, we found that activation of auditory cortex by a noise burst drove local GABAergic inhibition on supragranular pyramids of the mouse primary visual cortex, via cortico-cortical connections. This inhibition was generated by sound-driven excitation of a limited number of cells in infragranular visual cortical neurons. Consequently, visually driven synaptic and spike responses were reduced upon bimodal stimulation. Also, acoustic stimulation suppressed conditioned behavioral responses to a dim flash, an effect that was prevented by acute blockade of GABAergic transmission in visual cortex. Thus, auditory cortex activation by salient stimuli degrades potentially distracting sensory processing in visual cortex by recruiting local, translaminar, inhibitory circuits.
Synchronization of gamma oscillations among brain regions is relevant for dynamically organizing communication among neurons to support cognitive and perceptual processing, including attention orienting. Recent research has demonstrated that inter-regional synchronization in the gamma-band is modulated by theta rhythms during cortical processing. It has been proposed that such cross-frequency dynamics underlie the integration of local processes into large-scale functional networks. To investigate the potential role of theta-gamma mechanisms during auditory attention control, we localized activated regions using EEG beamformer analysis, and calculated inter-regional gamma-band synchronization between activated regions as well as modulation of inter-regional gamma-band synchronization by the phase of cortical theta rhythms. Abundant synchronization of gamma-band oscillations among regions comprising the auditory attention control network was observed. This inter-regional gamma synchronization was modulated by theta phase. These results provide further evidence implicating inter-regional gamma-band synchronization, and theta-gamma interactions, in task-dependent communication among cortical regions, and provide the first evidence that such mechanisms are relevant for auditory attention control.
Tinnitus is described as an auditory perception in the absence of any external sound source. Tinnitus loudness has been correlated to sustained high frequency gamma-band activity in auditory cortex. It remains unknown whether unilateral tinnitus is always generated in the left auditory cortex, irrespective of the side on which the tinnitus is perceived, or in the contralateral auditory cortex. In order to solve this enigma source localized electroencephalographic (EEG) recordings of a homogenous group of unilateral left and right-sided tinnitus patients presenting with noise-like tinnitus was analyzed. Based on a region of interest analysis, the most important result of this study is that tinnitus lateralization depended on the gamma-band activity of the contralateral parahippocampal area. As for the auditory cortex no differences were found between left-sided and right-sided tinnitus patients. However, in comparison to a control group both left and right-sided tinnitus patients had an increased gamma-band activity in both the left and right primary and secondary auditory cortex. Thus whereas in tinnitus the primary and secondary auditory cortices of both sides are characterized by increased gamma-band activity, the side on which the tinnitus is perceived relates to gamma-band activity in the contralateral parahippocampal area.
Tinnitus is characterized by an ongoing conscious perception of a sound in the absence of any external sound source. Chronic tinnitus is notoriously characterized by its resistance to treatment. In the present study the objective was to verify whether the neural generators and/or the neural tinnitus network, evaluated through EEG recordings, change over time as previously suggested by MEG. We therefore analyzed the source-localized EEG recordings of a very homogenous group of left-sided narrow-band noise tinnitus patients. Results indicate that the generators involved in tinnitus of recent onset seem to change over time with increased activity in several brain areas [auditory cortex, supplementary motor area and dorsal anterior cingulate cortex (dACC) plus insula], associated with a decrease in connectivity between the different auditory and nonauditory brain structures. An exception to this general connectivity decrease is an increase in gamma-band connectivity between the left primary and secondary auditory cortex and the left insula, and also between the auditory cortices and the right dorsal lateral prefrontal cortex. These networks are both connected to the left parahippocampal area. Thus acute and chronic tinnitus are related to differential activity and connectivity in a network comprising the auditory cortices, insula, dACC and premotor cortex.
Bifrontal transcranial direct current stimulation (tDCS), with the anodal electrode overlying the right and the cathodal electrode overlying the left dorsolateral prefrontal cortex, has been shown to suppress tinnitus significantly in 30% of patients. The source localized resting-state electrical activity is recorded before and after bifrontal tDCS in patients who respond to tDCS to unravel the mechanism by which tDCS suppresses tinnitus. The present electroencephalography study (N = 12) provides support for the ability of bifrontal tDCS to suppress tinnitus intensity and tinnitus-related distress by modulation of the pregenual anterior cingulate cortex, parahippocampal area and right primary auditory cortex in resting-state spontaneous brain activity. These findings provide direct support for tDCS having an impact not only directly on the underlying dorsolateral prefrontal cortex but also indirectly on functionally connected brain areas relevant for tinnitus distress and tinnitus intensity, respectively.
Remembering past events - or episodic retrieval - consists of several components. There is evidence that mental imagery plays an important role in retrieval and that the brain regions supporting imagery overlap with those supporting retrieval. An open issue is to what extent these regions support successful vs. unsuccessful imagery and retrieval processes. Previous studies that examined regional overlap between imagery and retrieval used uncontrolled memory conditions, such as autobiographical memory tasks, that cannot distinguish between successful and unsuccessful retrieval. A second issue is that fMRI studies that compared imagery and retrieval have used modality-aspecific cues that are likely to activate auditory and visual processing regions simultaneously. Thus, it is not clear to what extent identified brain regions support modality-specific or modality-independent imagery and retrieval processes. In the current fMRI study, we addressed this issue by comparing imagery to retrieval under controlled memory conditions in both auditory and visual modalities. We also obtained subjective measures of imagery quality allowing us to dissociate regions contributing to successful vs. unsuccessful imagery. Results indicated that auditory and visual regions contribute both to imagery and retrieval in a modality-specific fashion. In addition, we identified four sets of brain regions with distinct patterns of activity that contributed to imagery and retrieval in a modality-independent fashion. The first set of regions, including hippocampus, posterior cingulate cortex, medial prefrontal cortex and angular gyrus, showed a pattern common to imagery/retrieval and consistent with successful performance regardless of task. The second set of regions, including dorsal precuneus, anterior cingulate and dorsolateral prefrontal cortex, also showed a pattern common to imagery and retrieval, but consistent with unsuccessful performance during both tasks. Third, left ventrolateral prefrontal cortex showed an interaction between task and performance and was associated with successful imagery but unsuccessful retrieval. Finally, the fourth set of regions, including ventral precuneus, midcingulate cortex and supramarginal gyrus, showed the opposite interaction, supporting unsuccessful imagery, but successful retrieval performance. Results are discussed in relation to reconstructive, attentional, semantic memory, and working memory processes. This is the first study to separate the neural correlates of successful and unsuccessful performance for both imagery and retrieval and for both auditory and visual modalities.
Present study investigates the combination of Deanxit and clonazepam (Rivotril) intake for relief of tinnitus complaints, respecting a double-blind placebo-controlled approach for Deanxit in a crossover setup.
Although several pharmacologic treatments--including antidepressants, prostaglandins, and aminobutyric acid (GABA)-active drugs--were already presented as promising in tinnitus treatment, no drug has yet been approved by the Food and Drug Administration and European Medicine Agency for the treatment of tinnitus.
Patients were randomly assigned to patient group A or patient group B in a double-blind way. Patient group A first received 3 weeks of Deanxit, followed by 1 week of washout and 3 weeks of placebo. Treatment was given in opposite order to subjects from Patient group B.All patients received a daily treatment consisting of clonazepam 1 mg once daily, starting on Day 1.
Significant tinnitus reduction was seen after intake of the combination clonazepam-Deanxit, whereas no differences in tinnitus could be demonstrated after the administration of clonazepam-placebo. This was true for all patients according to the following parameters: time patients are annoyed by the tinnitus (p = 0.026) and the visual analogue scale for tinnitus annoyance (p = 0.024).
Although tinnitus reduction was recorded as modest, this article provides valuable data demonstrating a placebo-controlled tinnitus reduction after clonazepam and Deanxit intake.
Tinnitus can be considered an auditory phantom percept, in which patients hear an internal sound in the absence of any external sound source, mimicking tonal memory. Tinnitus however can be perceived exclusively uni- or bilaterally.
The neurophysiological differences were investigated between unilateral and bilateral tinnitus using LORETA source localized resting state EEG recordings.
The difference between unilateral and bilateral tinnitus is reflected by high frequency activity (beta and gamma) in the superior prefrontal gurus, right parahippocampus, right angular gyrus and right auditory cortex. Unilateral tinnitus is characterized by contralateral beta2 in the superior prefrontal gyrus in comparison to bilateral tinnitus, but gamma in comparison to non-tinnitus subjects. Bilateral tinnitus has delta activity in the ventrolateral prefrontal cortex in comparison to unilateral tinnitus, and bilateral beta1 in comparison to non-tinnitus subjects. Bilateral tinnitus is also characterized by bilateral frontopolar beta1 activity.
Unilateral and bilateral tinnitus can be differentiated based on their resting state oscillation patterns: beta3 and gamma-band activity in the superior premotor cortex, parahippocampal area and angular gyrus seem to form the core of a spatial localization network involved in tinnitus.
These differences should be taken into account when evaluating functional neuroimaging data relating to tinnitus.
In this review, we consider the potential functional role of beta-band oscillations, which at present is not yet well understood. We discuss evidence from recent studies on top-down mechanisms involved in cognitive processing, on the motor system and on the pathophysiology of movement disorders that suggest a unifying hypothesis: beta-band activity seems related to the maintenance of the current sensorimotor or cognitive state. We hypothesize that beta oscillations and/or coupling in the beta-band are expressed more strongly if the maintenance of the status quo is intended or predicted, than if a change is expected. Moreover, we suggest that pathological enhancement of beta-band activity is likely to result in an abnormal persistence of the status quo and a deterioration of flexible behavioural and cognitive control.
Hallucinations can be auditory, visual, tactile, gustatory, or olfactory, and can be caused by psychiatric (such as schizophrenia and depression), neurological (such as cerebrovascular accidents, neoplasia, and infection), or endocrine and metabolic disorders. Musical hallucinations related to neurological disorders are rare. The authors present a case of a patient with a right insular glioma who developed transient musical hallucinations after microsurgical resection of the tumor. (DOI: 10.3171/2009.12.FOCUSFOCUS09243)
Phase-shift treatment is a new tinnitus therapy that aims at sound cancelling. This technique is based on a theory advocating that the induction of a sound wave with a 180 degrees phase-shift compared to the sound experienced by the patient could result in sound cancelling, likely by negation of the cortical perception of tinnitus or residual inhibition, which can be partial or complete. The aim of our study is to compare the effect of phase-shifting generated by the tinnitus phase-out device between pure tone tinnitus patients (PTP) and narrow band noise tinnitus patients (NBNP). In present comparative study, we explore the effects of phase-shifting during 6 weeks of phase-out therapy in PTP and NBNP. Thirty-five tinnitus patients were included in the study. Twenty-one patients had pure tone tinnitus and 14 patients had narrow band noise tinnitus. The effects on tinnitus were assessed using three separate visual analogue scales (VAS), the tinnitus questionnaire, the hyperacusis questionnaire, the Beck depression inventory, a categorical scale and audiometric measurements. While no differences in VAS were seen after therapy in NBNP, tinnitus increase could be demonstrated in PTP. This increase could be demonstrated for tinnitus loudness (p = 0.002) and tinnitus annoyance (p = 0.014). In conclusion, implementation of phase-shifting did not lead to significant sound cancelling. Our results are discussed and compared to previous studies investigating the effects of phase-out in tinnitus patients.
A painful experience is modified by processes like habituation/antinociception or sensitization. Altered habituation may be one characteristic of chronic pain syndromes. In the present study we sought to investigate the functional magnetic resonance imaging (fMRI) blood oxygen level dependent (BOLD) correlate of rapid habituation to pain using simultaneous single trial electrodermal activity (EDA)/fMRI measurements. A total of N=32 healthy subjects have been investigated. Subjects received painful laser stimulation of the left hand. The fMRI BOLD response was measured simultaneously with continuous EDA recordings. Single trial EDA responses to laser stimulation habituated over time with substantial subject-to-subject differences in the degree and speed of habituation. fMRI BOLD habituation was assessed by contrasting the first half of the experiment against the second half and was found in primary and secondary somatosensory cortices, the insula and the anterior cingulate cortex (ACC). We hypothesized that single trial EDA habituation would reflect BOLD habituation which was investigated separately in subjects with 'faster' (N=15) and 'slower' (N=14) EDA habituation. Significant habituation of the BOLD signal was only found in subjects with 'faster' EDA habituation that was accompanied by a signal increase in the rostral ACC and the periaqueductal grey. Furthermore, subjects with faster EDA habituation provided lower pain ratings. Therefore the EDA habituation profile to painful stimulation may constitute a pain-related (endo)phenotype and may be an informative additional endpoint measure in fMR-imaging of pain, especially when people suffering from chronic pain states in which pain processing is often altered are studied.
Musical hallucination is the subjective experience of hearing music, or aspects of music, when none is being played, and as such is a disorder of the processing of complex sounds.
To determine the extent to which the otological system is responsible for musical hallucination, and to evaluate approaches to clinical management.
A review of all studies and literature reviews pertaining to musical hallucination, supplemented by inclusion of informative case reports.
A systematic search of multiple databases carried out on 22nd March 2009 was complemented by referral to the reference lists of included manuscripts.
Although not always troublesome in itself, musical hallucination can be a marker of underlying pathology in the ear or brain, or indicate obsessive-compulsive traits or social isolation, and is likely to be clinically underreported. Associations have been reported with hearing loss, female gender, social isolation and being over 60 years of age, although it is rare even in this group, and these may well not be independent risk factors. Robust comparative analysis of these factors with controls has yet to be undertaken. Underlying causes include neurovascular pathology, psychiatric disorders and opioid medications, however these are absent in the majority of cases.
This review supports the proposal that the otological system plays a role in the pathogenesis of musical hallucination. Hearing impairment may act as an initiating factor, and the primary dysfunction is overactivity of auditory association cortex, although an impairment of higher-level inhibition does also seem necessary. Once underlying sinister causes have been excluded, first line treatment should be explanation of the condition and optimisation of hearing. Medications have a role only in selected patient groups.
Tinnitus is the perception of sound in the absence of any external auditory stimulus. Based on previous research we have proposed a framework which postulates that the reduction of ongoing inhibitory alpha activity in tinnitus subjects favors a synchronization of neurons in the gamma frequency range while in a resting state. In the present work we are validating the existence of an inverse relationship between auditory gamma and alpha activity in tinnitus and control subjects using Magnetoencephalography. Tinnitus subjects exhibited a significantly steeper slope of the regression line compared to controls, presumably because a greater number of subjects concurrently exhibited low alpha and high gamma power. Therefore, the role of the alpha-gamma pattern is discussed regarding its possible implication for the generation of tinnitus.
Dimensions of psychological complaints due to chronic and disabling tinnitus were investigated by means of the Tinnitus Questionnaire (TQ), administered to a sample of 138 tinnitus sufferers who had been admitted to a psychosomatic hospital. Factor analysis revealed that tinnitus-related patterns of emotional and cognitive distress, intrusiveness, auditory perceptual difficulties, sleep disturbances, and somatic complaints can be differentiated. Cognitive distortions and inappropriate attitudes towards the tinnitus and it's personal consequences were found to be highly intercorrelated forming a subgroup within a broader and more general distress factor. The stability of the factor solution obtained was examined by systematically varying the number of factors to be extracted. Based on the results of this method, scales are proposed for the questionnaire which can be used in clinical and scientific work to specifically assess major areas of tinnitus-related distress and their degree of severity. Implications for a further evaluation of the instrument are discussed.
The interconnections of the auditory cortex with the parahippocampal and cingulate cortices were studied in the cat. Injections of the anterograde and retrograde tracer WGA-HRP were performed, in different cats (n = 9), in electrophysiologically identified auditory cortical fields. Injections in the posterior zone of the auditory cortex (PAF or at the PAF/AI border) labeled neurons and axonal terminal fields in the cingulate gyrus, mainly in the ventral bank of the splenial sulcus (a region that can be considered as an extension of the cytoarchitectonic area Cg), and posteriorly in the retrosplenial area. Labeling was also present in area 35 of the perirhinal cortex, but it was sparser than in the cingulate gyrus. Following WGA-HRP injection in AII, no labeling was found in the cingulate gyrus, but a few neurons and terminals were labeled in area 35. In contrast, no or very sparse labeling was observed in the cingulate and perirhinal cortices after WGA-HRP injections in the anterior zone of the auditory cortex (AI or AAF). A WGA-HRP injection in the cingulate gyrus labeled neurons in the posterior zone of the auditory cortex, between the posterior ectosylvian and the posterior suprasylvian sulci, but none was found more anteriorly in regions corresponding to AI, AAF and AII. The present data indicate the existence of preferential interconnections between the posterior auditory cortex and the limbic system (cingulate and parahippocampal cortices). This specialization of posterior auditory cortical areas can be related to previous observations indicating that the anterior and posterior regions of the auditory cortex differ from each other by their response properties to sounds and their pattern of connectivity with the auditory thalamus and the claustrum.
Human amnesics are severely impaired in learning arbitrary associations between word pairs. This report examines the role of the hippocampal system in an analog of paired-associate learning developed for rats. Subjects with selective damage to the parahippocampal region and controls were tested on an odor-guided paired-associate task. Normal rats readily learned to distinguish paired associates from various mispairings of the same odors, whereas most animals with parahippocampal damage failed to learn. Lesioned animals were, however, able to acquire correct responses to stimulus pairs for which an association between odors was not required. These findings extend the usefulness of olfactory learning as a model for studies of higher order learning capacity in rodents and indicate that in rats, as in humans, hippocampal areas are critical for learning arbitrary nonspatial relationships between stimuli.
The analysis of functional mapping experiments in positron emission tomography and fMRI involves the formation and assessment of images of statistics. Existing methods are predominantly parametric, requiring a multitude of assumptions and relying on various approximations. In contrast to the parametric approaches, this chapter presents a nonparametric procedure that is intuitive, flexible, and exact, given minimal assumptions regarding the mechanisms generating the data. These randomization and permutation tests are simple extensions of widely accepted univariate exact nonparametric statistical procedures to the multiple comparison problem of assessing a statistic image. These methods can consider any voxel statistic, including “pseudo” t-statistic images computed with smoothed variance estimates. For t-statistic images of low degrees of freedom, this appears to give the nonparametric methods greatly improved power over their conservative parametric counterparts. This suggests the use of nonparametric methods with “pseudo” statistics for analyzing low degree-of-freedom statistic images, such as those from single-subject analyses. Further, the guaranteed validity and flexibility of the nonparametric method make it attractive in situations where parametric methods are unavailable or the requisite assumptions or approximations untenable.