Thomas Hummel

Thomas Hummel
Technische Universität Dresden | TUD · Faculty of Medicine Carl Gustav Carus

Prof. Dr. med.

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1,241
Publications
223,418
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Article
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Purpose Olfactory adaptation is a peripheral (at the epithelium level) or a central (at the brain level) mechanism resulting from repeated or prolonged odorous exposure that can induce a perceptual decrease. The aim of this study was to assess whether a peripheral adaptation occurs when an odor is repeated ten times. Moreover, the specificity of the peripheral adaptation to the nature of the odorant was investigated. Methods Four odorants (eugenol, manzanate, ISO E Super and phenylethanol) were presented using precisely controlled air-dilution olfactometry. They differed in terms of their physicochemical properties. Electrophysiological recordings were made at the level of the olfactory mucosa, the so-called electro-olfactogram (EOG). Thirty-five right-handed participants were recruited. Results Sixty-nine percent of the participants presented at least one EOG, whatever the odor condition. The EOG amplitude did not significantly decrease over 10 repeated exposures to any odorant. The intensity ratings tended to decrease over stimulations for manzanate, PEA, and eugenol. No correlation was found between the mean EOG amplitudes and the mean intensity ratings. However, the presence of EOG amplitude decreases over stimulations for few subjects suggests that peripheral adaptation might exist. Conclusion Overall, our results did not establish a clear peripheral adaptation measured with EOG but indicate the eventuality of such an effect.
Article
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Introduction Chronic rhinosinusitis with nasal polyps (CRSwNP) often leads to impaired olfactory function and reduced quality of life. When conservative treatments such as nasal irrigation and topical steroids fail, functional endoscopic sinus surgery (FESS) is often necessary, because it improves symptoms and enhances quality of life. Materials and methods A total of 88 patients was included in this prospective study. All subjects underwent an extensive examination both presurgically and 4 months after operations including nasal endoscopy and psychophysical olfactory testing (Sniffin’ Sticks). Moreover, disease-specific quality of life was assessed and presurgical CT scans were rated regarding the opacification of the paranasal sinuses. Results Presurgically psychophysical tests showed an overall olfactory dysfunction. Olfactory test results (TDI score) correlated with endoscopic (Lund–Kennedy and Lildtholdt score) and CT scores (Lund–Mackay and TOCS scores). Four months after surgery olfactory function was enhanced and quality of life significantly showed an overall improvement. However, the outcome was dependent on the extent of presurgical olfactory function: olfaction and quality of life improved most pronounced in anosmics compared to hyposmic and especially normosmic patients. Conclusions This study confirmed that FESS in CRSwNP leads to a significant improvement of both olfaction and disease-specific quality of life. Moreover, preoperative psychophysical assessment of the extent of olfactory dysfunction can help to objectively assess possible risks and expected benefits of the surgery in terms of olfaction and quality of life.
Article
Full-text available
Background: Categorization of individuals as normosmic, hyposmic, or anosmic from test results of odor threshold, discrimination and identification may provide a limited view of the sense of smell. The purpose of this study was to expand the clinical diagnostic repertoire by including additional tests. Methods: A random cohort of n = 135 individuals (83 women and 52 men, aged 21 to 94 years) was tested for odor threshold, discrimination, and identification, plus a distance test, in which the odor of peanut butter is perceived, a sorting task of odor dilutions for phenylethyl alcohol and eugenol, a discrimination test for odorant enantiomers, a lateralization test with eucalyptol, a threshold assessment after 10 minutes of exposure to phenylethyl alcohol, and a questionnaire on the importance of olfaction. Unsupervised methods were used to detect structure in the olfaction-related data, followed by supervised feature selection methods from statistics and machine learning to identify relevant variables. Results: The structure in the olfac-tion-related data divided the cohort into two distinct clusters with n = 80 and 55 subjects. Odor threshold, discrimination, and identification did not play a relevant role for cluster assignment, which, on the other hand, depended on performance in the two odor dilution sorting tasks, from which cluster assignment was possible with median 100-fold cross-validated balanced accuracy of 77 – 88 %. Conclusions: The addition of an odor sorting task with the two proposed odor dilutions to the odor test battery expands the phenotype of olfaction and fits seamlessly into the sensory focus of standard test batteries.
Article
Full-text available
Purpose The aim of the study was to investigate whether olfactory fluctuations (OF) are pronounced in patients with sinonasal olfactory dysfunction (OD). Methods The retrospective investigation included patients aged 18 years or older, who consulted a tertiary referral center for olfactory loss. Patients with normal smell function were excluded. Patients answered a structured questionnaire about their olfactory symptoms, with specific questions related to the presence of OF and its average frequency, amplitude, duration, time since most recent OF, and associated symptoms of self-reported OF. Patients also underwent clinical evaluation including a structured medical history and physical examination including nasal endoscopy. In addition, we assessed orthonasal olfactory function using Sniffin’ Sticks, and gustatory function using “taste sprays”. Results Participants included 131 men and 205 women ( n = 336), aged 18 to 86 years (mean 50, SD 16). Patient-reported fluctuations occurred most frequently in sinonasal (38%), idiopathic (29%), and postviral (29%) OD. Amplitude of OF was highest in postviral OD ( p = 0.009). Average frequency, duration, and the time since the most recent fluctuation were not significantly different between groups (all p ’s > 0.42). Odor discrimination ( p = 0.002) and identification ( p = 0.017) scores were higher among those individuals with OF. Conclusion Amplitude of OF may help distinguish postviral from other causes of OD, especially in patients presenting with equivocal symptoms of sinonasal disease.
Article
Full-text available
Zusammenfassung Das vorliegende Konsensuspapier bietet in Ergänzung zur AWMF-S1-Leitlinie eine Übersicht über die verschiedenen klinischen Aspekte von Long COVID im Kindes- und Jugendalter. Es wurde von Vertreter:innen aus 19 Fachgesellschaften des DGKJ-Konvents und kooperierenden Fachgesellschaften erstellt und bietet Expertenempfehlungen für die Praxis auf Grundlage der bisherigen, noch geringen studienbasierten Evidenz zu Long COVID im Kindes- und Jugendalter. Es enthält Screeningfragen zu Long COVID sowie einen Vorschlag zur strukturierten, standardisierten pädiatrischen Anamnese und zur diagnostischen Evaluation bei V. a. Long COVID . Dazu werden ein zeit- und ressourcensparender Erfassungsbogen, der die Komplexität des Krankheitsbildes berücksichtigt, über die Internetseiten der DGKJ und DGPI zur Verfügung gestellt und weitere Fragebögen zur Abklärung von spezifischen neurokognitiven und/oder psychischen Störungen sowie post-exertioneller Malaise (PEM) und myalgischer Enzephalomyelitis/chronischem Fatigue-Syndrom (ME/CFS) benannt. Anhand der jeweiligen anamnestisch und klinisch ermittelten Hauptsymptome werden ein gestuftes, diagnostisches Vorgehen und eine multidisziplinäre Betreuung empfohlen.
Additional affiliations
January 1998 - present
Universitätsklinikum Carl Gustav Carus Dresden
Position
  • University Clinic Dresden
May 1996 - December 1997
University of Pennsylvania
Position
  • Smell & Taste Center, Philadelphia
April 1992 - March 1993
University of Iowa
Position
  • Department of Pharmacology, University of Iowa

Publications

Publications (1,241)
Article
The molecules that elicit taste sensation are perceived by interacting with the taste receptors located in the taste buds. Enzymes involved in the detoxification processes are found in saliva as well as in type II cells, where taste receptors, including bitter taste receptors, are located. These enzymes are known to interact with a large panel of m...
Article
Full-text available
Purpose Olfactory adaptation is a peripheral (at the epithelium level) or a central (at the brain level) mechanism resulting from repeated or prolonged odorous exposure that can induce a perceptual decrease. The aim of this study was to assess whether a peripheral adaptation occurs when an odor is repeated ten times. Moreover, the specificity of th...
Article
Full-text available
Background: Categorization of individuals as normosmic, hyposmic, or anosmic from test results of odor threshold, discrimination and identification may provide a limited view of the sense of smell. The purpose of this study was to expand the clinical diagnostic repertoire by including additional tests. Methods: A random cohort of n = 135 individual...
Article
Full-text available
Introduction Chronic rhinosinusitis with nasal polyps (CRSwNP) often leads to impaired olfactory function and reduced quality of life. When conservative treatments such as nasal irrigation and topical steroids fail, functional endoscopic sinus surgery (FESS) is often necessary, because it improves symptoms and enhances quality of life. Materials a...
Article
Loss of olfaction is one of the symptoms most commonly reported by patients with coronavirus disease 2019 (COVID-19). Although the spontaneous recovery rate is high, recent studies have shown that up to 7% of patients remain anosmic for more than 12 months after the onset of infection, leaving millions of people worldwide suffering from severe olfa...
Article
Background: The olfactory system is affected early in Alzheimer's disease and olfactory loss can already be observed in patients with mild cognitive impairment (MCI). Olfactory training is effective for improving olfactory and cognitive function by stimulating the olfactory pathway, but its effect on patients with MCI remains unclear. Objective:...
Article
Full-text available
Purpose The aim of the study was to investigate whether olfactory fluctuations (OF) are pronounced in patients with sinonasal olfactory dysfunction (OD). Methods The retrospective investigation included patients aged 18 years or older, who consulted a tertiary referral center for olfactory loss. Patients with normal smell function were excluded. P...
Article
The sense of smell is important as a warning system, in social communication and in guiding food intake. Impairment is common, and cases are increasing following COVID‐19. Olfactory dysfunction may lead to decreased quality of life. There are several established ways to assess olfaction including the “Sniffin’ Sticks” which are a validated test for...
Article
There is no licensed treatment for refractory chronic cough; off-label therapies have limited efficacy and can produce adverse effects. Excessive adenosine triphosphate signaling via P2X3 receptors is implicated in refractory chronic cough, and selective P2X3 receptor antagonists such as eliapixant (BAY 1817080) are under investigation. The objecti...
Article
Full-text available
Zusammenfassung Das vorliegende Konsensuspapier bietet in Ergänzung zur AWMF-S1-Leitlinie eine Übersicht über die verschiedenen klinischen Aspekte von Long COVID im Kindes- und Jugendalter. Es wurde von Vertreter:innen aus 19 Fachgesellschaften des DGKJ-Konvents und kooperierenden Fachgesellschaften erstellt und bietet Expertenempfehlungen für die...
Article
Full-text available
Olfactory dysfunction is common in COVID-19, and sudden-onset dysosmia is an early marker for wild-type SARS-CoV-2 infection. Over 10,000 mutations of SARS-CoV-2 have been registered, with variants of concern (VOC) under particular scrutiny. We report a telemedicine-based, multicentre, prospective cohort study with quantitative olfaction testing co...
Article
Full-text available
Background Orthonasal and retronasal olfaction are intimately connected. Still, they exhibit differences. The present study aimed to compare orthonasal and retronasal olfaction at both suprathreshold and threshold levels in a healthy population considering age. Material and Methods A total of 171 participants with subjective normal olfactory funct...
Article
This manuscript aims to provide an overview of the etiology and diagnosis of olfactory and gustatory disorders. Not only are they common with about 5% of the population affected, but olfactory and gustatory disorders have recently gained attention in light of the rising SARS-CoV‑2 pandemic: sudden loss of smell and/or taste is regarded as one of th...
Article
Introduction: COVID-19 can be associated with a variety of longer-lasting impairments that can have a significant impact on patients' quality of life (QoL). While this is well described in the literature for limitations in lung capacity or permanent headaches, there is little research on the impact of olfactory dysfunction in the context of COVID-...
Article
Full-text available
Olfactory loss is associated with symptoms of depression. The present study, conducted on a large cohort of mostly dysosmic patients, aimed to investigate whether improvement in olfactory performance would correspond with a decrease in depression severity. In 171 participants (157 dysosmic), we assessed olfactory function and severity of depression...
Article
Full-text available
Background Key to curtailing the COVID-19 pandemic are wide-scale screening strategies. An ideal screen is one that would not rely on transporting, distributing, and collecting physical specimens. Given the olfactory impairment associated with COVID-19, we developed a perceptual measure of olfaction that relies on smelling household odorants and ra...
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Full-text available
Introduction Taste perception is affected by trigeminal stimuli, i.e., capsaicin. This has been studied at suprathreshold concentrations. However, little is known about taste perception at threshold level in the presence of low concentration of capsaicin. The aim of the study was to explore whether taste sensitivity for sweet, sour, salt, bitter, a...
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Full-text available
Introduction The Sniffin’ Sticks threshold test is widely used to assess olfactory threshold due to its high reliability and validity. Nevertheless, this test procedure is quite long with an average duration of 10 to 20 min. In study designs that require multiple olfactory threshold tests on short intervals, this could exhaust participants. To coun...
Article
Background: The literature regarding clinical olfaction, olfactory loss, and olfactory dysfunction has expanded rapidly over the past two decades, with an exponential rise in the past year. There is substantial variability in the quality of this literature and a need to consolidate and critically review the evidence. It is with that aim that we ha...
Article
Olfactory epithelium (OE) is capable of lifelong regeneration due to presence of basal progenitor cells that respond to injury or neuronal loss with increased activity. However, this capability diminishes with advancing age and a decrease in odor perception in older individuals is well established. To characterize changes associated with age in the...
Article
Objective Olfactory preference emerges very early in life, and the sense of smell in children rapidly develops until the second decade of life. It is still unclear whether hedonic perception of odors is shared in children inhabiting different regions of the globe. Methods Five-hundred ten healthy children (N = 510; ngirls = 256; nboys = 254) aged...
Article
Aim: Neuronal hypersensitisation due to ATP-dependent P2X3 receptor signalling plays a significant role in several disorders including chronic cough and endometriosis. This first-in-human study of eliapixant (BAY 1817080) investigated the tolerability, safety and pharmacokinetics (PK) of single doses of eliapixant, including the effect of food and...
Article
Full-text available
People suffering from congenital anosmia show normal brain architecture although they do not have functional sense of smell. Some studies in this regard point to the changes in secondary olfactory cortex, orbitofrontal cortex (OFC), in terms of gray matter volume increase. However, diffusion tensor imaging has not been explored so far. We included...
Article
Full-text available
Olfactory and gustatory disorders are prominent symptoms of acute COVID-19. Although both senses recover in many patients within weeks to months, persistency has been described in up to 60%. However up to now most reports on the course of chemosensitive disorders after COVID-19 are not based on psychophysical testing but only on subjective patients...
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Full-text available
The aim of this study was to investigate whether COVID-associated olfactory impairment differs from olfactory disorders due to other upper respiratory tract infections. We investigated the frequency of a SARS-CoV-2 infection among subjects presenting with a subjective olfactory impairment to a corona outpatient clinic between October 2020 and March...
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Purpose Septoplasty is one of the most frequently performed operations in patients with septal deviation of the nose. The aim of this surgical intervention is to reduce nasal obstruction and to achieve a physiological nasal breathing. The nasal cycle plays a crucial role in this. The aim of this study was to investigate nasal breathing and the nasa...
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Background Late-life depression (LLD) is a risk factor for cognitive decline in older adults, and odor identification (OI) deficits are an early indicator of cognitive decline with LLD. However, neuropsychiatric symptoms (NPSs) are common in LLD and are associated with OI deficits. In subjects with LLD, when OI deficits forecast cognitive decline,...
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Full-text available
Introduction Smell disorders are common in the general population and occur e.g., after infections, trauma or idiopathically Treatment strategies for smell loss range from surgery, medication to olfactory training, depending on the pathology, but they are limited This study examined the effect of acupuncture on olfactory function. Methods Sixty pa...
Article
Background Odor identification (OI) impairment increases the risk of Alzheimer's disease and brain abnormalities in patients with late-life depression (LLD). However, it remains unclear whether abnormal functional connectivity (FC) of olfactory regions is involved in the relationship between OI impairment and dementia risk in LLD patients. The curr...
Article
The COVID-19 pandemic has raised awareness on olfactory dysfunction, although loss of smell has been found commonly present in the general population even before COVID-19. Chronic rhinosinusitis (CRS) is a common upper airway chronic inflammatory disease, being also one of the most common causes of olfactory dysfunction. CRS can be classified in di...
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Full-text available
Purpose Loss of smell decreases the quality of life and contributes to the failure in recognizing hazardous substances. Given the relevance of olfaction in daily life, it is important to recognize an undiagnosed olfactory dysfunction to prevent these possible complications. Up to now, the prevalence of smell disorders in Italy is unknown due to a l...
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Full-text available
Purpose The lack of epidemiological data on the proportion of olfactory dysfunction (OD) using comprehensive olfactory assessment in healthy adults in Scandinavia motivated to the present study which aimed to explore the proportion of OD in voluntary healthy Norwegian adults, assessed by Sniffin’ Sticks, and its correlation to self-reported olfacto...
Article
Background: Chronic rhinosinusitis (CRS) is typically accompanied by impairment of olfaction. Despite of this, until today the efficacy of endonasal sinus surgery (ESS) in terms of olfactory function is still unclear. So far it is known that patients with nasal polyps are most likely to experience post-operative recovery. Within the present study...
Article
Objective: Habitual spicy food consumption leads to altered perception of capsaicin. Little is known about the neural morphological correlates of habitual spicy food intake and related trigeminal perceptions. In this study, we used voxel-based morphometry to identify brain regions where regional gray matter volume (GMV) correlates to spicy food con...
Article
Background: This study aimed to examine whether omega-3 supplementation would support olfactory recovery among postviral olfactory dysfunction patients. Methodology: Patients with postviral olfactory dysfunction were included in this non-blinded, prospective pilot study. Structured medical history was taken from the patients, including the follo...
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Full-text available
Purpose To investigate the clinical utility of q-Powders—a retronasal identification screening test. Methods A total of 156 subjects (92 females, mean age: 54.5 years ± 17.3 years) completed a 3-item q-Powders retronasal identification test and a 16-items Sniffin’ Sticks orthonasal identification test. We analyzed whether the q-Powders test could...
Article
Full-text available
Objective: Gustatory function during COVID-19 is self-reported by around 50% of patients. However, only few studies assessed gustation using psychophysical testing during the acute infection. The objective of this study is to test gustatory function on threshold tests in the very first days of COVID-19. Methods: Psychophysical testing consisted...
Article
Olfaction plays an important role in social interaction. This study examined the influence of chemosensory and cognitive abilities on conscious odor sniffing behaviors in humans. Participants (N = 349) were surveyed using a questionnaire for the frequency of behaviors in terms of odor exploration from intrinsic and external sources. Chemosensory fu...
Article
Objectives: Food neophobia is a rejection or avoidance of novel food products. Despite the adaptive importance of this behavior, it exerts a negative influence on dietary habits and preferences. Sensory sensitivity relates to food neophobia and among specific sensory modalities, olfaction seems to be an obvious candidate for a correlate of this be...
Article
Full-text available
The olfactory bulb (OB) plays a key role in the processing of olfactory information. A large body of research has shown that OB volumes correlate with olfactory function, which provides diagnostic and prognostic information in olfactory dysfunction. Still, the potential value of the OB shape remains unclear. Based on our clinical experience we hypo...
Article
This manuscript aims to provide an overview of the etiology and diagnosis of olfactory and gustatory disorders. Not only are they common with about 5% of the population affected, but olfactory and gustatory disorders have recently gained attention in light of the rising SARS-CoV‑2 pandemic: sudden loss of smell and/or taste is regarded as one of th...
Article
Full-text available
Background: Odor identification dysfunction is an early predictor of the development of Alzheimer's disease (AD), but neuropsychiatric symptoms (NPS), which are common in AD and mild cognitive impairment (MCI), are also associated with odor identification dysfunction. Whether NPS affect the specificity of using odor identification dysfunction to pr...
Article
While the correlation between self-reported olfactory function and psychophysical tests has been extensively analyzed, showing poor agreement between the 2 types of evaluation, no robust data exist concerning the gustatory function. To establish whether psychophysical tests confirm a self-reported alteration of taste, we assessed a series of patien...
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Full-text available
Purpose The olfactory system can be successfully rehabilitated with regular, intermittent stimulation during multiple daily exposures to selected sets of odors, i.e., olfactory training (OT). OT has been repeatedly shown to be an effective tool of olfactory performance enhancement. Recent advancements in studies on OT suggest that its beneficial ef...
Article
Full-text available
Brain structural features of healthy individuals are associated with olfactory functions. However, due to the pathophysiological differences, congenital and acquired anosmia may exhibit different structural characteristics. A systematic review was undertaken to compare brain structural features between patients with congenital and acquired anosmia....
Article
Olfaction is functional at birth and newborns use their sense of smell to navigate their environment. Yet, certain chemosensory abilities are subject to experience and develop with age. It has been argued that odor discrimination is a key ability enabling organisms to capture and distinguish odors occurring in the environment to further identify th...
Article
Background Detailed examination of cognitive deficits in patients with mild cognitive impairment (MCI) yields substantial diagnostic and prognostic value, specifically with respect to memory. Magnitude and characteristics of subjective cognitive deficits, however, often receive less attention in this population at risk for developing dementia. Met...
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Full-text available
This study aimed to determine whether anesthesia would affect olfactory function. Patients who were admitted for surgical intervention that did not include the nasal cavity and paranasal sinuses were included in this prospective cohort study. Structured medical history was taken from the patients, including the following: age, sex, smoking history,...
Article
Background Odor identification (OI) dysfunction is an early marker of Alzheimer’s disease (AD), but it remains unclear how olfactory-related regions change from stages of subjective cognitive decline (SCD) and mild cognitive impairment (MCI) to AD dementia. Methods Two hundred and sixty-nine subjects were recruited in the present study. The olfact...
Article
Background: The olfactory system is affected very early in Alzheimer's disease and olfactory loss can already be observed in patients with mild cognitive impairment (MCI), an early stage of AD. Objective: The aim of this randomized, prospective, controlled, blinded study was to evaluate whether olfactory training (OT) may have an effect on olfac...
Article
Full-text available
Background: Very few studies have investigated whether unilateral choanal atresia is associated with permanent olfactory deficits. Objective: This study aimed to evaluate the olfactory performance of patients with unilateral choanal atresia postsurgically. Methods: Three patients with unilateral atresia were examined in terms of olfactory perf...
Article
Full-text available
Loss of sense of smell is a well-known non-motor symptom of Parkinson’s disease (PD). Here, we present insight into the association between PD advancement and equivalents of smell loss in olfactory-eloquent brain areas, such as the posterior cortex and orbitofrontal cortex. Twelve PD patients in different Hoehn and Yahr stages and 12 healthy normos...
Article
Full-text available
Because it is associated with central nervous changes, and olfactory dys-function has been reported with increased prevalence among persons with diabetes , this study addressed the question of whether the risk of developing diabetes in the next 10 years is reflected in olfactory symptoms. In a cross-sectional study, in 164 individuals seeking medic...
Article
Among those many individuals who experience a reduced odor sensitivity (hyposmia/anosmia) some individuals also have disorders that lead to odor distortion, such as parosmia (i.e., distorted odor with a known source), or odor phantoms (i.e., odor sensation without an odor source). We surveyed a large population with at least one olfactory disorder...