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Mastinu M, Grzeschuchna LS, Mignot C, Guducu C, Bogdanov V, Hummel T. Time-frequency analysis of gustatory event related potentials (gERP) in taste disorders. Sci Rep 2024; 14:2512. [PMID: 38291123 PMCID: PMC10827706 DOI: 10.1038/s41598-024-52986-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 01/25/2024] [Indexed: 02/01/2024] Open
Abstract
In taste disorders, the key to a correct diagnosis and an adequate treatment is an objective assessment. Compared to psychophysical tests, EEG-derived gustatory event-related potentials (gERP) could be used as a less biased measure. However, the responses identified using conventional time-domain averaging show a low signal-to-noise ratio. This study included 44 patients with dysgeusia and 59 healthy participants, who underwent a comprehensive clinical examination of gustatory function. gERPs were recorded in response to stimulation with two concentrations of salty solutions, which were applied with a high precision gustometer. Group differences were examined using gERP analyzed in the canonical time domain and with Time-Frequency Analyses (TFA). Dysgeusic patients showed significantly lower scores for gustatory chemical and electrical stimuli. gERPs failed to show significant differences in amplitudes or latencies between groups. However, TFA showed that gustatory activations were characterized by a stronger power in controls than in patients in the low frequencies (0.1-4 Hz), and a higher desynchronization in the alpha-band (8-12 Hz). Hence, gERPs reflect the altered taste sensation in patients with dysgeusia. TFA appears to enhance the signal-to-noise ratio commonly present when using conventional time-domain averaging, and might be of assistance for the diagnosis of dysgeusia.
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Affiliation(s)
- Mariano Mastinu
- Department of Otorhinolaryngology, Smell & Taste Clinic, Technische Universität Dresden, Dresden, Germany.
| | - Lisa Sophie Grzeschuchna
- Department of Otorhinolaryngology, Smell & Taste Clinic, Technische Universität Dresden, Dresden, Germany
| | - Coralie Mignot
- Department of Otorhinolaryngology, Smell & Taste Clinic, Technische Universität Dresden, Dresden, Germany
| | - Cagdas Guducu
- Department of Otorhinolaryngology, Smell & Taste Clinic, Technische Universität Dresden, Dresden, Germany
- Dokuz Eylül University Faculty of Medicine Department of Biophysics, 35320, Balçova, Izmir, Turkey
| | - Vasyl Bogdanov
- Department of Otorhinolaryngology, Smell & Taste Clinic, Technische Universität Dresden, Dresden, Germany
| | - Thomas Hummel
- Department of Otorhinolaryngology, Smell & Taste Clinic, Technische Universität Dresden, Dresden, Germany
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Hummel T, Power Guerra N, Gunder N, Hähner A, Menzel S. Olfactory Function and Olfactory Disorders. Laryngorhinootologie 2023; 102:S67-S92. [PMID: 37130532 PMCID: PMC10184680 DOI: 10.1055/a-1957-3267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The sense of smell is important. This became especially clear to patients with infection-related olfactory loss during the SARS-CoV-2 pandemic. We react, for example, to the body odors of other humans. The sense of smell warns us of danger, and it allows us to perceive flavors when eating and drinking. In essence, this means quality of life. Therefore, anosmia must be taken seriously. Although olfactory receptor neurons are characterized by regenerative capacity, anosmia is relatively common with about 5 % of anosmic people in the general population. Olfactory disorders are classified according to their causes (e. g., infections of the upper respiratory tract, traumatic brain injury, chronic rhinosinusitis, age) with the resulting different therapeutic options and prognoses. Thorough history taking is therefore important. A wide variety of tools are available for diagnosis, ranging from short screening tests and detailed multidimensional test procedures to electrophysiological and imaging methods. Thus, quantitative olfactory disorders are easily assessable and traceable. For qualitative olfactory disorders such as parosmia, however, no objectifying diagnostic procedures are currently available. Therapeutic options for olfactory disorders are limited. Nevertheless, there are effective options consisting of olfactory training as well as various additive drug therapies. The consultation and the competent discussion with the patients are of major importance.
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Affiliation(s)
- T Hummel
- Interdisziplinäres Zentrum Riechen und Schmecken, HNO Klinik, TU Dresden
| | - N Power Guerra
- Rudolf-Zenker-Institut für Experimentelle Chirurgie, Medizinische Universität Rostock, Rostock
| | - N Gunder
- Universitäts-HNO Klinik Dresden, Dresden
| | - A Hähner
- Interdisziplinäres Zentrum Riechen und Schmecken, HNO Klinik, TU Dresden
| | - S Menzel
- Interdisziplinäres Zentrum Riechen und Schmecken, HNO Klinik, TU Dresden
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Tarfa R, Yu SE, Ahmed OH, Moore JA, Bruña R, Velasquez N, Poplawsky AJ, Coffman BA, Lee SE. Neuromapping olfactory stimulation using magnetoencephalography - visualizing smell, a proof-of-concept study. FRONTIERS IN ALLERGY 2023; 3:1019265. [PMID: 36698377 PMCID: PMC9869273 DOI: 10.3389/falgy.2022.1019265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Accepted: 12/14/2022] [Indexed: 01/12/2023] Open
Abstract
Importance Currently, clinical assessment of olfaction is largely reliant on subjective methods that require patient participation. The objective method for measuring olfaction, using electroencephalogram (EEG) readings, can be supplemented with the improved temporal resolution of magnetoencephalography (MEG) for olfactory measurement that can delineate cortical and peripheral olfactory loss. MEG provides high temporal and spatial resolution which can enhance our understanding of central olfactory processing compared to using EEG alone. Objective To determine the feasibility of building an in-house portable olfactory stimulator paired with electrophysiological neuroimaging technique with MEG to assess olfaction in the clinical setting. Design setting and participants This proof-of-concept study utilized a paired MEG-olfactometer paradigm to assess olfaction in three normosmic participants. We used a two-channel olfactory stimulator to deliver odorants according to a programmed stimulus-rest paradigm. Two synthetic odorants: 2% phenethyl alcohol (rose) and 0.5% amyl acetate (banana) were delivered in increasing increments of time followed by periods of rest. Cortical activity was measured via a 306-channel MEG system. Main outcomes and measures Primary outcome measure was the relative spectral power for each frequency band, which was contrasted between rest and olfactory stimulation. Results Compared to rest, olfactory stimulation produced a 40% increase in relative alpha power within the olfactory cortex bilaterally with both odorants. A 25%-30% increase in relative alpha power occurred in the left orbitofrontal cortex and precentral gyrus with phenethyl alcohol stimulation but not amyl acetate. Conclusion and relevance In this proof-of-concept study, we demonstrate the feasibility of olfactory measurement via an olfactometer-MEG paradigm. We found that odorant-specific cortical signatures can be identified using this paradigm, setting the basis for further investigation of this system as a prognostic tool for olfactory loss.
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Affiliation(s)
- Rahilla Tarfa
- University of Pittsburgh School of Medicine, Pittsburgh, PA, United States,Department of Otolaryngology – Head and Neck Surgery, University of Pittsburgh Medical Center (UPMC), Pittsburgh, PA, United States
| | - Sophie E. Yu
- Department of Otolaryngology – Head & Neck Surgery, Harvard Medical School, Boston, MA, United States
| | - Omar H. Ahmed
- Penn Medicine Becker ENT & Allergy, Robbinsville, NJ, United States
| | - John A. Moore
- Department of Otolaryngology – Head and Neck Surgery, University of Pittsburgh Medical Center (UPMC), Pittsburgh, PA, United States
| | - Ricardo Bruña
- Department of Radiology, Universidad Complutense de Madrid (UCM), IdISSC, Madrid, Spain
| | - Nathalia Velasquez
- Department of Otolaryngology, Cleveland Clinic Florida, Weston, FL, United States
| | - Alexander J. Poplawsky
- Center for Neuroscience, McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Brian A. Coffman
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, United States
| | - Stella E. Lee
- Division of Otolaryngology – Head & Neck Surgery, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, United States,Correspondence: Stella E. Lee
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Guo Y, Wu D, Sun Z, Yao L, Liu J, Wei Y. Prognostic value of olfactory evoked potentials in patients with post-infectious olfactory dysfunction. Eur Arch Otorhinolaryngol 2021; 278:3839-3846. [PMID: 33644842 DOI: 10.1007/s00405-021-06683-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 02/04/2021] [Indexed: 11/29/2022]
Abstract
PURPOSE Prognostic assessment of patients with post-infectious olfactory dysfunction (PIOD) poses a challenge for clinicians. While there have been some studies on the prognostic factors of PIOD focusing on demographic factors, the aim of this study was to investigate whether event-related potentials (ERPs) could be used as a new predictor of olfactory recovery in PIOD. METHODS This was a retrospective study involving patients who underwent olfactory examinations using Sniffin' Sticks test before treatment and after 1 year of follow-up. The responder group was defined by an increase of threshold-discrimination-identification (TDI) score of ≥ 6 points. All patients underwent ERP examination and the amplitude and latency of each wave of ERPs were recorded before treatment. RESULTS A total of 61 patients (age 47.50 ± 11.04 years, 27 males) were analyzed. The presence of olfactory ERPs (oERPs) was greater in the responder group than in the non-responder group (P = 0.007), while that of trigeminal ERPs (tERPs) did not differ between the two groups (P = 0.346). Logistic-regression analyses showed that factors associated with improvement of subjective olfactory function were duration (OR, 1.604; 95% CI, 1.062-2.423; P = 0.025), initial threshold (odds ratio [OR], 0.043; 95% confidence interval [CI], 0.004-0.439; P = 0.008), and latency of N1 in oERPs (OR, 1.007; 95% CI, 1.001-1.013; P = 0.021). CONCLUSION Our study shows that duration of OD, initial threshold, and latency of N1 in oERPs were associated with olfactory improvement in PIOD patients, which may provide guidance for clinicians.
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Affiliation(s)
- Yichen Guo
- Department of Otolaryngology, Smell and Taste Center, Beijing Anzhen Hospital, Capital Medical University, Anzhen Road 2, Chaoyang District, Beijing, 100029, China
| | - Dawei Wu
- Department of Otolaryngology, Smell and Taste Center, Beijing Anzhen Hospital, Capital Medical University, Anzhen Road 2, Chaoyang District, Beijing, 100029, China
| | - Zhifu Sun
- Department of Otolaryngology, Smell and Taste Center, Beijing Anzhen Hospital, Capital Medical University, Anzhen Road 2, Chaoyang District, Beijing, 100029, China
| | - Linyin Yao
- Department of Otolaryngology, Smell and Taste Center, Beijing Anzhen Hospital, Capital Medical University, Anzhen Road 2, Chaoyang District, Beijing, 100029, China
| | - Jia Liu
- Department of Otolaryngology, Smell and Taste Center, Beijing Anzhen Hospital, Capital Medical University, Anzhen Road 2, Chaoyang District, Beijing, 100029, China
| | - Yongxiang Wei
- Department of Otolaryngology, Smell and Taste Center, Beijing Anzhen Hospital, Capital Medical University, Anzhen Road 2, Chaoyang District, Beijing, 100029, China. .,Department of Otorhinolaryngology Head and Neck Surgery, Capital Institute of Pediatrics, Beijing, China.
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Charbel Issa P, Reuter P, Kühlewein L, Birtel J, Gliem M, Tropitzsch A, Whitcroft KL, Bolz HJ, Ishihara K, MacLaren RE, Downes SM, Oishi A, Zrenner E, Kohl S, Hummel T. Olfactory Dysfunction in Patients With CNGB1-Associated Retinitis Pigmentosa. JAMA Ophthalmol 2019; 136:761-769. [PMID: 29800053 DOI: 10.1001/jamaophthalmol.2018.1621] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Importance Co-occurrence of retinitis pigmentosa (RP) and olfactory dysfunction may have a common genetic cause. Objective To report olfactory function and the retinal phenotype in patients with biallelic mutations in CNGB1, a gene coding for a signal transduction channel subunit expressed in rod photoreceptors and olfactory sensory neurons. Design, Setting, and Participants This case series was conducted from August 2015 through July 2017. The setting was a multicenter study involving 4 tertiary referral centers for inherited retinal dystrophies. Participants were 9 patients with CNGB1-associated RP. Main Outcomes and Measures Results of olfactory testing, ocular phenotyping, and molecular genetic testing using targeted next-generation sequencing. Results Nine patients were included in the study, 3 of whom were female. Their ages ranged between 34 and 79 years. All patients had an early onset of night blindness but were usually not diagnosed as having RP before the fourth decade because of slow retinal degeneration. Retinal features were characteristic of a rod-cone dystrophy. Olfactory testing revealed reduced or absent olfactory function, with all except one patient scoring in the lowest quartile in relation to age-related norms. Brain magnetic resonance imaging and electroencephalography measurements in response to olfactory stimulation were available for 1 patient and revealed no visible olfactory bulbs and reduced responses to odor, respectively. Molecular genetic testing identified 5 novel (c.1312C>T, c.2210G>A, c.2492+1G>A, c.2763C>G, and c.3044_3050delGGAAATC) and 5 previously reported mutations in CNGB1. Conclusions and Relevance Mutations in CNGB1 may cause an autosomal recessive RP-olfactory dysfunction syndrome characterized by a slow progression of retinal degeneration and variable anosmia or hyposmia.
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Affiliation(s)
- Peter Charbel Issa
- Oxford Eye Hospital, Oxford University Hospitals National Health Service (NHS) Foundation Trust, Oxford, United Kingdom.,Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.,Department of Ophthalmology, University of Bonn, Bonn, Germany
| | - Peggy Reuter
- Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Laura Kühlewein
- Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Johannes Birtel
- Department of Ophthalmology, University of Bonn, Bonn, Germany
| | - Martin Gliem
- Oxford Eye Hospital, Oxford University Hospitals National Health Service (NHS) Foundation Trust, Oxford, United Kingdom.,Department of Ophthalmology, University of Bonn, Bonn, Germany
| | - Anke Tropitzsch
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Tübingen, Tübingen, Germany
| | - Katherine L Whitcroft
- University College London (UCL) Ear Institute and Royal National Throat, Nose and Ear Hospital, London, United Kingdom.,Centre for the Study of the Senses, Institute of Philosophy, School of Advanced Study, University of London, London, United Kingdom.,Smell and Taste Clinic, Department of Otorhinolaryngology-Head and Neck Surgery, Technische Universität Dresden, Dresden, Germany
| | - Hanno J Bolz
- Bioscientia Center for Human Genetics, Ingelheim, Germany.,Institute of Human Genetics, University Hospital of Cologne, Cologne, Germany
| | - Kenji Ishihara
- Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Robert E MacLaren
- Oxford Eye Hospital, Oxford University Hospitals National Health Service (NHS) Foundation Trust, Oxford, United Kingdom.,Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Susan M Downes
- Oxford Eye Hospital, Oxford University Hospitals National Health Service (NHS) Foundation Trust, Oxford, United Kingdom.,Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Akio Oishi
- Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Eberhart Zrenner
- Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Susanne Kohl
- Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Thomas Hummel
- Smell and Taste Clinic, Department of Otorhinolaryngology-Head and Neck Surgery, Technische Universität Dresden, Dresden, Germany
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Sirous M, Sinning N, Schneider TR, Friese U, Lorenz J, Engel AK. Chemosensory Event-Related Potentials in Response to Nasal Propylene Glycol Stimulation. Front Hum Neurosci 2019; 13:99. [PMID: 30949040 PMCID: PMC6435593 DOI: 10.3389/fnhum.2019.00099] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 03/04/2019] [Indexed: 11/13/2022] Open
Abstract
Propylene glycol, also denoted as 1.2 propanediol (C3H8O2), often serves as a solvent for dilution of olfactory stimuli. It is supposed to serve as a neutral substance and has been used in many behavioral and electrophysiological studies to dilute pure olfactory stimuli. However, the effect of propylene glycol on perception and on neuronal responses has hitherto never been studied. In this study we tested by means of a threshold test, whether a nasal propylene glycol stimulation is recognizable by humans. Participants were able to recognize propylene glycol at a threshold of 42% concentration and reported a slight cooling effect. In addition to the threshold test, we recorded electroencephalography (EEG) during nasal propylene glycol stimulation to study the neuronal processing of the stimulus. We used a flow olfactometer and stimulated 15 volunteers with three different concentrations of propylene glycol (40 trials each) and water as a control condition (40 trials). To evaluate the neuronal response, we analyzed the event-related potentials (ERPs) and power modulations. The task of the volunteers was to identify a change (olfactory, thermal, or tactile) in the continuous air flow generated by the flow olfactometer. The analysis of the ERPs showed that propylene glycol generates a clear P2 component, which was also visible in the frequency domain as an evoked power response in the theta-band. The source analysis of the P2 revealed a widespread involvement of brain regions, including the postcentral gyrus, the insula and adjacent operculum, the thalamus, and the cerebellum. Thus, it is possible that trigeminal stimulation can at least partly account for sensations and brain responses elicited by propylene glycol. Based on these results, we conclude that the use of high propylene glycol concentrations to dilute fragrances complicates the interpretation of presumed purely olfactory effects.
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Affiliation(s)
- Mohammad Sirous
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Nico Sinning
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Till R Schneider
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Uwe Friese
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Faculty of Life Science, MSH Medical School Hamburg, Hamburg, Germany
| | - Jürgen Lorenz
- Faculty of Life Science, Laboratory of Human Biology and Physiology, Applied Science University, Hamburg, Germany
| | - Andreas K Engel
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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Liu J, Pinto JM, Yang L, Yao L, Miao X, Wei Y. Evaluation of idiopathic olfactory loss with chemosensory event-related potentials and magnetic resonance imaging. Int Forum Allergy Rhinol 2018; 8:1315-1322. [PMID: 29782071 PMCID: PMC6282607 DOI: 10.1002/alr.22144] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2017] [Revised: 04/08/2018] [Accepted: 04/27/2018] [Indexed: 11/08/2022]
Abstract
Background Idiopathic olfactory loss (IOL) accounts for a sizable fraction of olfactory dysfunction, but very little is known about its etiology and electrophysiological changes in the olfactory pathway. Methods We analyzed the physiology of IOL using chemosensory event‐related potentials (ERPs) (olfactory and trigeminal: oERP and tERP) and olfactory pathway magnetic resonance imaging (MRI) measured in adult patients with IOL and healthy controls. Subjective olfactory function was measured by Toyota and Takagi (T&T) olfactometry and Sniffin’ Sticks (SS). Results Olfactory function was worse in patients with IOL compared to controls (T&T, p < 0.001; SS, p < 0.001). oERPs could be evoked in 17 IOL patients. Signals in these patients showed lower amplitude in the N1 and P2 waves than controls (p < 0.05 for both), but there were no difference in latency between the 2 groups (p > 0.05). tERP were detected in all patients and controls; there were no differences in latency and nor amplitude between the 2 groups (p > 0.05). The olfactory bulb (OB) volume was significantly smaller in the IOL group than controls (p < 0.001), but there was no difference in the olfactory sulcus depth between groups (p > 0.05). Better olfactory function was associated with increasing magnitude of N1 amplitude in oERPs (p < 0.05) and increasing OB volume (p < 0.05). Conclusion IOL patients show neurophysiologic deficits and some anatomic differences compared to healthy controls.
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Affiliation(s)
- Jia Liu
- Department of Otolaryngology-Head and Neck Surgery, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Jayant M Pinto
- Section of Otolaryngology-Head and Neck Surgery, Department of Surgery, The University of Chicago, Chicago, IL
| | - Ling Yang
- Central Laboratory, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Linyin Yao
- Department of Otolaryngology-Head and Neck Surgery, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Xutao Miao
- Department of Otorhinolaryngology, Beijing United Family Healthcare, Beijing, China
| | - Yongxiang Wei
- Department of Otolaryngology-Head and Neck Surgery, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
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Schriever VA, Han P, Weise S, Hösel F, Pellegrino R, Hummel T. Time frequency analysis of olfactory induced EEG-power change. PLoS One 2017; 12:e0185596. [PMID: 29016623 PMCID: PMC5634540 DOI: 10.1371/journal.pone.0185596] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2017] [Accepted: 09/17/2017] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVES The objective of the present study was to investigate the usefulness of time-frequency analysis (TFA) of olfactory-induced EEG change with a low-cost, portable olfactometer in the clinical investigation of smell function. MATERIALS & METHODS A total of 78 volunteers participated. The study was composed of three parts where olfactory stimuli were presented using a custom-built olfactometer. Part I was designed to optimize the stimulus as well as the recording conditions. In part II EEG-power changes after olfactory/trigeminal stimulation were compared between healthy participants and patients with olfactory impairment. In Part III the test-retest reliability of the method was evaluated in healthy subjects. RESULTS Part I indicated that the most effective paradigm for stimulus presentation was cued stimulus, with an interstimulus interval of 18-20s at a stimulus duration of 1000ms with each stimulus quality presented 60 times in blocks of 20 stimuli each. In Part II we found that central processing of olfactory stimuli analyzed by TFA differed significantly between healthy controls and patients even when controlling for age. It was possible to reliably distinguish patients with olfactory impairment from healthy individuals at a high degree of accuracy (healthy controls vs anosmic patients: sensitivity 75%; specificity 89%). In addition we could show a good test-retest reliability of TFA of chemosensory induced EEG-power changes in Part III. CONCLUSIONS Central processing of olfactory stimuli analyzed by TFA reliably distinguishes patients with olfactory impairment from healthy individuals at a high degree of accuracy. Importantly this can be achieved with a simple olfactometer.
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Affiliation(s)
- Valentin Alexander Schriever
- Smell & Taste Clinic, Department of Otorhinolaryngology, Technical University of Dresden, Dresden, Germany
- Abteilung Neuropädiatrie Medizinische Fakultät Carl Gustav Carus, Technische Universität, Dresden, Germany
| | - Pengfei Han
- Smell & Taste Clinic, Department of Otorhinolaryngology, Technical University of Dresden, Dresden, Germany
| | - Stefanie Weise
- Smell & Taste Clinic, Department of Otorhinolaryngology, Technical University of Dresden, Dresden, Germany
| | - Franziska Hösel
- Smell & Taste Clinic, Department of Otorhinolaryngology, Technical University of Dresden, Dresden, Germany
| | - Robert Pellegrino
- Smell & Taste Clinic, Department of Otorhinolaryngology, Technical University of Dresden, Dresden, Germany
| | - Thomas Hummel
- Smell & Taste Clinic, Department of Otorhinolaryngology, Technical University of Dresden, Dresden, Germany
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