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Publications (142)
The pulse waveform and current direction contribute to the specific effects of transcranial magnetic stimulation (TMS). For single pulse TMS these factors have been shown to influence, for example, motor threshold and recruitment curve, motor-evoked potential latency and silent period duration detected by motor cortex stimulation, and phosphene thr...
Persistent stuttering is a prevalent neurodevelopmental speech disorder, which presents with involuntary speech blocks, sound and syllable repetitions, and sound prolongations. Affected individuals often struggle with negative feelings, elevated anxiety, and low self-esteem. Neuroimaging studies frequently link persistent stuttering with cortical a...
Objective
The neurophysiological dynamics of the occurrence of a stuttering event are largely unknown. This sensor-level EEG study investigated whether already the intention to speak alters the formation of the speech production network in stuttering.
Methods
We studied alpha (8-13 Hz), low beta (15-25 Hz) and high beta (25-30 Hz) power modulation...
Introduction: High frequency repetitive transcranial magnetic stimulation applied to the motor cortex causes an increase in the amplitude of motor evoked potentials (MEPs) that persists after stimulation. Here, we focus on the aftereffects generated by high frequency controllable pulse TMS (cTMS) with different directions, intensities, and pulse du...
Fluency-shaping enhances the speech fluency of persons who stutter, yet underlying conditions and neuroplasticity-related mechanisms are largely unknown. While speech production-related brain activity in stuttering is well studied, it is unclear whether therapy repairs networks of altered sensorimotor integration, imprecise neural timing and sequen...
Introduction. After-effects induced by repetitive transcranial magnetic stimulation (rTMS) at the primary motor cortex (M1) are usually indexed by the amplitude of the motor evoked potential (MEP). They depend on various parameters, in particular on the temporal pattern. Quadripulse stimulation (QPS; high-frequency train of four pulses delivered ev...
Purpose
Childhood onset speech fluency disorder (stuttering) is possibly related to dopaminergic dysfunction. Mesencephalic hyperechogenicity (ME) detected by transcranial ultrasound (TCS) might be seen as an indirect marker of dopaminergic dysfunction. We here determined whether adults who stutter since childhood (AWS) show ME.
Methods
We perform...
Recent studies have identified two distinct cortical representations of voice control in humans, the ventral and the dorsal laryngeal motor cortex. Strikingly, while persistent developmental stuttering has been linked to a white matter deficit in the ventral laryngeal motor cortex, intensive fluency shaping intervention modulated the functional con...
Recent studies have identified two distinct cortical representations of voice control in humans, the ventral and the dorsal laryngeal motor cortex. Strikingly, while persistent developmental stuttering has been linked to a white matter deficit in the ventral laryngeal motor cortex, intensive fluency shaping intervention modulated the functional con...
Developmental stuttering is a fluency disorder with anomalies in the neural speech motor system. Fluent speech requires multifunctional network formations. Currently, it is unclear which functional domain is targeted by speech fluency interventions. Here, we tested the impact of fluency-shaping on resting-state fMRI connectivity of the speech plann...
Originary neurogenic, non-syndromatic stuttering has been linked to a dysfunctional sensorimotor system. Studies have demonstrated that adults who stutter (AWS) perform poorly at speech and finger motor tasks and learning (e.g., Smits-Bandstra et al., 2006b; Namasivayam and van Lieshout, 2008). The high relapse rate after stuttering treatment could...
Whether fluent-sounding utterances of adults who stutter (AWS) are normally articulated is unclear. We asked 15 AWS and 17 matched adults who do not stutter (ANS) to utter the pseudoword “natscheitideut” 15 times in a 3 T MRI scanner while recording real-time MRI videos at 55 frames per per second in a mid-sagittal plane. All stuttered or otherwise...
Persistent developmental stuttering (PDS) disrupts speech fluency in about 1% of adults. Although many models of speech production assume an intact sensory feedback from the speech organs to the brain, very little is actually known about the integrity of their sensory representation in PDS. Here, we studied somatosensory evoked potentials (SEPs) in...
Persistent developmental stuttering (PDS) is a speech fluency disorder characterized by intermittent involuntary breakdowns of speech motor control, possibly related to motor cortex excitability. Whether motor cortex dysfunction extends into hand representations is unclear. We here studied task-dependent modulations of hand motor cortex excitabilit...
Introduction: High frequency repetitive transcranial magnetic stimulation induces excitation when applied to the motor cortex, as measured by increased amplitudes of motor evoked potentials (MEPs) after the intervention. Different pulse widths induce different effects, likely by primarily stimulating distinct segments of neurons due to the differen...
Introduction:
Motor evoked potentials (MEP) in response to anteroposterior transcranial (AP) magnetic stimulation (TMS) are sensitive to the TMS pulse shape. We are now able to isolate distinct pulse properties, such as pulse width and directionality and evaluate them individually. Different pulse shapes induce different effects, likely by stimula...
Objectives
Persistent developmental stuttering is a speech fluency disorder defined by its symptoms, where the underlying neurophysiological causes remain uncertain. This study examined the underlying neurophysiological mechanisms of the speech planning process, using facilitation in the motor cortex during speech preparation as an analogue.
Metho...
Individual stuttering demographics–Group was used for the main analyses.
Percentage of stuttering was used for the supplementary analyses.
(DOCX)
Model Summary for Experiment 2 –Additional statistical information pertaining to Table 3 in the text.
(DOCX)
Appendix (to Table 6)–Specific statistical analysis of the comparison between experiments 1 and 3.
The constant (M = 0.617, SED = 0.133, p < .001) and pre-speech interval (M = 2.295, SED = 0.356, p < .001) were significantly smaller than in the first experiment, while group (M = -0.302, SED = 0.126, p = .0167) and the group-interval interaction (M...
Model Summary for Experiment 3 –Additional statistical information pertaining to Table 4 in the text.
(DOCX)
Model Summary for Experiment 2 –Additional statistical information pertaining to Table 8 in the text.
(DOCX)
Appendix (to Table 10A–10D)–Significance of reaction time with pulse condition and trial.
As a side note, one significant value was unexpected–the correlation between State and Trial in the first experiment. This implies that there were more late stimulation states in the later trials, on average. However, due to the random order of presentation an...
Model Summary for Experiment 1 –Additional statistical information pertaining to Table 2 in the text.
(DOCX)
Model Summary for Experiment 1 –Additional statistical information pertaining to Table 7 in the text.
(DOCX)
Model Summary for Experiment 3 –Additional statistical information pertaining to Table 9 in the text.
(DOCX)
Appendix (to Table 5)–Specific statistical analysis of the comparison between experiments 1 and 2.
The constant (M = 0.711, SED = 0.117, p < .001), pre-speech interval (M = 0.980, SED = 0.306, p < .01) and group (M = -0.305, SED = 0.113, p < .01) were all lower than in the immediate condition, even after Bonferroni correction (sig. p < 0.0125). The...
Introduction
Repetitive transcranial magnetic stimulation (rTMS) has been found to be a promising non-invasive therapeutic tool for a variety of neuropsychiatric conditions. Variable pulse shapes can now be generated with a controllable pulse stimulator TMS (cTMS). We looked into two main characteristics of the pulse: the pulse width and the pulse...
Introduction
Persistent developmental stuttering (PDS) disrupts speech fluency in about 1% of adults, predominantly males. Its etiology remains unclear.
PDS shares clinical characteristics with focal, task specific dystonias. Both disorders are associated with excessive activity in muscles not needed to perform a desired movement. Both disorders ar...
Background:
Biphasic pulses produced by most commercially available TMS machines have a cosine waveform, which makes it difficult to study the interaction between the two phases of stimulation.
Objective:
We used a controllable pulse TMS (cTMS) device delivering quasi-rectangular pulse outputs to investigate whether monophasic are more effective...
Persistent developmental stuttering is associated with basal ganglia dysfunction or dopamine dysregulation. Here, we studied whole-brain functional connectivity to test how basal ganglia structures coordinate and reorganize sensorimotor brain networks in stuttering. To this end, adults who stutter and fluent speakers (control participants) performe...
A neuronal sign of persistent developmental stuttering is the magnified coactivation of right frontal brain regions during speech production. Whether and how stuttering severity relates to the connection strength of these hyperactive right frontal areas to other brain areas is an open question. Scrutinizing such brain-behaviour and structure-functi...
Different aspects of motor behaviour may engage distinct interneuron circuits in the human motor cortex. If so, the behavioural effects of repetitive transcranial magnetic stimulation (rTMS) protocols may critically depend on the specific circuit stimulated. We used TMS of the hand area to activate two distinct synaptic inputs to corticospinal neur...
Objectives
This study examined underlying neurophysiological mechanisms of developmental stuttering – facilitation in the motor cortex during speech preparation served as analogue to the speech planning process.
Methods
Transcranial Magnetic Stimulation pulses induced Motor Evoked Potentials (MEPs), recorded from the tongue. 18 Adults Who Stutter...
Introduction
Repetitive transcranial magnetic stimulation (rTMS) has been found to be a promising noninvasive therapeutic tool for a variety of neuropsychiatric conditions. Variable pulse shapes can now be generated with a controllable pulse stimulator TMS (cTMS). We looked into two main characteristics of the pulse: the pulse width and the pulse d...
Background: Approximately 1% of children and adolescents, 0.2% of women, and 0.8% of men suffer from stuttering, and lesser numbers from cluttering. Persistent speech fluency disorders often cause lifelong problems in communi- cation and social participation.
Methods: In an interdisciplinary, evidence and consensus based clinical practice guideline...
Purpose: Neuroimaging studies in persistent developmental stuttering repeatedly report altered basal ganglia functions. Together with thalamus and cerebellum, these structures mediate sensorimotor functions and thus represent a plausible link between stuttering and neuroanatomy. However, stuttering is a complex, multifactorial disorder. Besides sen...
Developmental Stuttering (DS) is a disruption of the rhythm of speech, and affected people may be unable to execute fluent voluntary speech. There are still questions about the exact causes of DS. Evidence suggests there are differences in the structure and functioning of motor systems used for preparing, executing, and controlling motor acts, espe...
Was passiert im Kopf, wenn die Wörter stecken bleiben? Stottern kann mit hohem Leidensdruck verbunden sein. Neue Studien, gestützt auf moderne neurophysiologische und MRT-Untersuchungen, tragen dazu bei, die Ursachen im Gehirn grundlegend zu verstehen, den Verlauf der Störung exakter vorherzusagen und die Stottertherapie zu verbessern.
Background:
Transcranial magnetic stimulation (TMS) with different current directions can activate different sets of neurons. Current direction can also affect the results of repetitive TMS.
Objective:
To test the influence of uni-directional intermittent theta burst stimulation (iTBS) using different current directions, namely posteroanterior (...
Die neurogenen Sprach- und Sprechstörungen Aphasien und Dysarthrien führen bei den Patienten zu einem hohen Leidensdruck. Häufig werden im diagnostischen Prozess Fehlinterpretationen von Störungscharakteristika und Schweregrad getroffen, die zu einer falschen Verordnung von Therapieart, -methode und -frequenz führen können. Für die korrekte Diagnos...
Different aspects of motor behaviour may engage distinct interneuron circuits in the human motor cortex. If so, the behavioural effects of repetitive transcranial magnetic stimulation (rTMS) protocols may critically depend on the specific circuit stimulated. We used TMS of the hand area to activate two distinct synaptic inputs to corticospinal neur...
Area 44 is a cytoarchitectonically distinct portion of Broca's region. Parallel and overlapping large-scale networks couple with this region thereby orchestrating heterogeneous language, cognitive and motor functions. In the context of stuttering, area 44 frequently comes into focus because structural and physiological irregularities affect develop...
Anticipation of stuttering events in persistent developmental stuttering is a frequent but inadequately measured phenomenon that is of both theoretical and clinical importance. Here, we describe the development and preliminary testing of a German version of the Premonitory Awareness in Stuttering Scale (PAiS): a 12-item questionnaire assessing imme...
Background:
Paired-pulse protocols have played a pivotal role in neuroscience research using transcranial magnetic stimulation (TMS). Stimulus parameters have been optimized over the years. More recently, pulse width (PW) has been introduced to this field as a new parameter, which may further fine-tune paired-pulse protocols. The relationship betw...
The objective of this study was to investigate the significance of pulse configurations and current direction for corticospinal activation using transcranial magnetic stimulation (TMS). In 11 healthy subjects (8 female), a motor map for the motor evoked potentials (MEPs) recorded from the first dorsal interosseus (FDI), abductor digiti minimi (ADM)...
Ziel der Studie: Stottern ist eine häufige Redeflussstörung, die als Kontrollverlust der Sprechmuskulatur erlebt wird. Studien jüngerer Zeit vertiefen unser Wissen über die neurophysiologischen Grundlagen dieses Kontrollverlustes.
Methodik: Nach einer Übersicht zu Phänomenologie, Epidemiologie und strukturell sowie funktionell bildgebenden Daten fü...
Background:
Deep brain stimulation is increasingly used in the treatment of advanced Parkinson's disease. While its short-term effectiveness is well documented, there are only few reports on long-term outcomes, and the need to repeatedly reprogram the stimulator is seldom reported.
Case presentation:
We present a 74-year-old man with gait impair...
Screenings for preschool stuttering exist only for children with a suspicion of stuttering or with risk factors. A universal screening, however, might be advisable within regular medical checkups or screenings for developmental language abnormalities as performed routinely by local pediatricians or in kindergartens. The benefit criteria for such a...
The precise excitability regulation of neuronal circuits in the primary motor cortex is central to the successful and fluent production of speech. Our question was whether the involuntary execution of undesirable movements, e.g. stuttering, is linked to an insufficient excitability tuning of neural populations in the orofacial region of the primary...
Question: In a companion poster (Sommer et al.) we show that iTBS with a monophasic anterior-posterior (AP) current pulse, which differs from conventional TBS applied with biphasic pulses (Huang et al. 2005), produces
reliable suppression of corticospinal excitability. Here we test the effect of applying cTBS with the same monophasic pulses. Method...
Question: Does the current direction influence the effect of intermittent theta burst stimulation (iTBS) on human motor cortex excitability? Methods: We stimulated the dominant hand representation of the motor cortex in 15 healthy subjects, using “unidirectional biphasic” pulses with an M-ratio (i.e, degree of monophasicity) of 0.2, generated by a...
Introduction
Persistent developmental stuttering (PDS) is a speech fluency disorder that affects 1% of the population, predominantly males. Its etiology is unclear and likely multifactoral, with contributions from intrinsic factors pertaining to brain anatomy and neurophysiology, particularly abnormal right-hemispheric lateralization of blood flow...
Learning as measured by eyeblink classical conditioning is preserved in patients with idiopathic Parkinson's disease, but severely affected in patients with progressive supranuclear palsy. We here sought to clarify whether procedural learning is impaired in multiple system atrophy (MSA), and whether it may be helpful for the differentiation of park...
Our knowledge about the mechanisms of human motor cortex facilitation induced by repetitive transcranial magnetic stimulation (rTMS) is still incomplete. Here we used pharmacological conditioning with carbamazepine, dextrometorphan, lorazepam and placebo to elucidate the type of plasticity underlying this facilitation, and to probe if mechanisms re...
Background:
Directional sensitivity is relevant for the excitability threshold of the human primary motor cortex, but its importance for externally induced plasticity is unknown.
Objective:
To study the influence of current direction on two paradigms inducing neuroplasticity by repetitive transcranial magnetic stimulation (rTMS).
Methods:
We s...
In individuals who stutter (IWS), speech fluency can be enhanced by altered auditory feedback, although it has adverse effects in control speakers. This indicates abnormalities in the auditory feedback loop in stuttering. Current motor control theories on stuttering propose an impaired processing of internal forward models that might be related to...
This article introduces the difference between biphasic and monophasic transcranial magnetic stimulation (TMS). Waveform and current direction determine the effectiveness of TMS in humans. The alternating use of mono and biphasic pulses as conditioning or test pulse has so far not been possible. Since pulses of different waveform or orientation can...
In adults who do not stutter (AWNS), the control of hand movement timing is assumed to be lateralized to the left dorsolateral premotor cortex (PMd). In adults who stutter (AWS), the network of speech motor control is abnormally shifted to the right hemisphere. Motor impairments in AWS are not restricted to speech, but extend to non-speech orofacia...
We sought to elucidate the influence of centrally active drugs on interhemispheric inhibition (IHI) between primary motor cortices in healthy humans.
We therefore studied IHI before and 2h after intake of a single oral dose of carbamazepine, dextrometorphane, lorazepam, or placebo and compared it with the well known results for short-interval intra...
We aimed at detecting neurophysiological changes, in the primary motor tongue representation in adults with persistent stuttering.
Using transcranial magnetic stimulation in 12 patients and 14 controls, we examined motor threshold, motor-evoked potential (MEP) input-output curve, short-term intracortical inhibition (SICI) and intracortical facilita...
The intensity of transcranial magnetic stimulation (TMS) is typically adjusted by changing the amplitude of the induced electrical field, while its duration is fixed. Here we examined the influence of two different pulse durations on several physiological parameters of primary motor cortex excitability obtained using single pulse TMS.
A Magstim Bis...
This study aimed to assess thermal and mechanical perception and pain thresholds in primary idiopathic restless legs syndrome and secondary restless legs syndrome associated with small fibre neuropathy. Twenty-one patients (age: 53.4 + or - 8.4, n = 3, male) with primary restless legs syndrome and 13 patients (age: 63.0 + or - 8.2, n = 1, male) wit...
Stimulation frequency has been considered the most important factor in conventional repetitive transcranial magnetic stimulation (rTMS) for determining the direction of after effects on corticospinal excitability. Here, we examined the functional relevance of breaks during high-frequency subthreshold rTMS for the induction of facilitatory after eff...
To acquire information about the physical properties and physiological effects of the H-coil.
We used a robotized system to measure the electric field (E-field) generated by a H-coil prototype and compared it with a standard figure-of-eight coil. To explore the physiological properties of the coils, input/output curves were recorded for the right a...
The previous decade has shed light on the neuro-anatomical correlates of persistent developmental stuttering (PDS). Initially, PET and more recently, functional MRI, were used to examine brain function in PDS. Diffusion Tensor Imaging (DTI) enables us to explore particularly the white matter in vivo. Previous DTI studies provided evidence for a dis...
Imaging studies suggest a right hemispheric (pre)motor overactivity in patients with persistent developmental stuttering (PDS). The interhemispheric inhibition (IHI) studied with transcranial magnetic stimulation is an established measure of the interplay between right and left motor areas. We assessed IHI in 15 young male adults with PDS and 15 ag...
We briefly summarized several new stimulation techniques. There are many new methods of human brain stimulation, including modification of already known methods and brand-new methods. In this article, we focused on theta burst stimulation (TBS), repetitive monophasic pulse stimulation, paired- and quadri-pulse stimulation, transcranial alternating...
Focal single-session repetitive transcranial magnetic stimulation (rTMS) of the primary motor cortex has been claimed to be capable of improving motor function in Parkinson's disease.
The authors sought to determine which type of rTMS protocol holds the highest potential for future therapeutic application.
Twenty-two patients with Parkinson's disea...
Comparative assessment of best conventional with best theta burst repetitive transcranial magnetic stimulation (rTMS) protocols on human motor cortex excitability.
Stimulation of dominant hand abductor digiti minimi muscle representation of motor cortex in nine healthy right-handed subjects utilising two different MagPro stimulators to generate TMS...
Objective: Comparative assessment of best conventional with best theta burst repetitive transcranial magnetic stimulation (rTMS) protocols on human motor cortex excitability.
Methods: Stimulation of dominant hand abductor digiti minimi muscle representation of motor cortex in 9 healthy right handed subjects utilising two different MagPro stimulato...
Experiments in animal models suggest that neuronal plasticity can be enhanced by dopaminergic receptor activation. The present study tested whether stimulation-induced plasticity of human motor cortex after low-frequency repetitive transcranial magnetic stimulation (rTMS) could be potentiated by a single oral dose of the combined D1/D2 receptor ago...
