DOCSLIB.ORG

Electrocochleography

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Electrocochleography J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.39.6.586 on 1 June 1976. Downloaded from Journal ofNeurology, Neurosurgery, andPsychiatry, 1976, 39, 586-592 Neurological applications of surface-recorded electrocochleography A. R. D. THORNTON AND C. H. HAWKES From the Audiology Group, Institute of Sound and Vibration Research, University of Southampton, and the Wessex Neurological Centre, Southampton General Hospital, Southampton SYNOPSIS A new outpatient technique, involving the recording of auditory-evoked responses from scalp electrodes, is described. Responses are obtained from the cochlea, cochlear nerve, and auditory brain stem nuclei. The effects of various disorders on these responses are illustrated and the procedure is assessed as a diagnostic technique. Electrocochleography is a technique that involves sensory potential, generated within the cochlea,Protected by copyright. the recording of small amplitude (<0.5 ,uV), which follows the time-history of the stimulus short latency (< 10 ms) auditory evoked pressure wave. The second response is the responses using time-domain averaging tech- cochlear nerve gross action potential (N1). niques to extract these small responses from the In 1967 Sohmer and Feinmesser reported the larger amplitude electrical activity caused by recording of the cochlear nerve response and a the ongoing electroencephalogram (EEG) and series of later responses using disc electrodes spontaneous myogenic potentials. The method placed on the skin surface. Figure 1 shows the most generally used is the transtympanic set of five neurogenic responses (N1 to NO) approach described by Ruben (1967) and by recorded from a normal subject. Lev and Sohmer Portmann and Aran (1971). This involves (1972) investigated the generating sites of these passing a needle electrode through the tympanum responses in the cat by a comparison of record- to make contact with the bony promontory. ings obtained from intracranial and from surface Two responses may be obtained from this electrodes. They concluded that the N1 response recording site. The first is the end-organ potential is generated at the cochlear nerve, N2 at the http://jnnp.bmj.com/ or cochlear microphonic (CM). This is a cochlear nucleus, N3 at the superior olive, and Pi P2 P3 P4 PS on September 25, 2021 by guest. I v \V , A-I I N1 N2 N3 N4 N5 FIG. 1 Cochlear nerve and brain stem evoked responses from a normal subject. The trailing edge of the inset pulse marks the time of acoustic stimulation. Normal responses: X axis- 15 ms/div. Y axis-32 n V/div. (Accepted 10 March 1976.) 586 J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.39.6.586 on 1 June 1976. Downloaded from Neurological app.ications ofsurface-recorded electrocochleography 587 N4 and N5 at the inferior colliculus. Similar NORMATIVE DATA Normative data were obtained response complexes, recorded from humans, from six normal subjects who were tested four times have been described by Coles and Thornton at each of four stimulus levels. The response Terkildsen et al. (1973), and by Picton measurement parameters have been studied in detail (1973), (Thornton, 1975b) and it was concluded that, for et al. (1974). The possible application of these clinical purposes, the data are best represented by measures in the assessment of peripheral and the peak-to-peak amplitude, taken from a negative central neurological disorders has been described peak to the succeeding positive peak, and by the earlier (Thornton, 1975a). Here the neurological, latencies of the negative peaks. The statistical radiological, and audiological findings are properties of these response measures have also been compared with electrocochleographic results evaluated by Thornton (1975c), who showed that the in order to evaluate the use of this technique. normal values at each stimulus level may be ex- Four selected cases will be used to illustrate the pressed as a graph of response amplitude by latency findings. as shown in Fig. 2. Each ellipse corresponds to one of the responses N, to N5 and is centred on the mean METHOD values of amplitude and latency obtained from the The details of electrode derivation, test facilities, and normal subjects for that response. The ellipse itself experimental technique have been described earlier represents an equal probability contour that (Thornton, 1975b). Briefly, the patient lies on a bed corresponds to one standard deviation of latency in an electromagnetically screened anechoic room. on the horizontal axis and one standard deviation Silver-chlorided EEG disc electrodes are used and of amplitude on the vertical axis. Such a presentation the signals from the active electrodes at each mastoid provides a convenient format in which to assess the Protected by copyright. process are amplified, passed to the adjacent control values obtained from patients and to detect abnormal room, filtered, and fed to the analogue-to-digital changes in latency and in amplitude. Approximately converters of a PDP-12 computer. The computer 90 % of the results from normal subjects should lie carries out the averaging of 2000 stimulus presenta- within 1+ standard deviations from the mean value. tions in two channels with a 30 ms window. The It is realized that this small number of subjects averaged data are stored on digital magnetic tape will not provide definitive norms and, when the for subsequent retrieval and analysis. Click stimuli final details of the optimum recording parameters are presented via earphones or loudspeakers at a rate have been determined, larger numbers will be of 10/second and the test session lasts for about tested. However, these data do provide a preliminary 30 minutes. The patients are not sedated but are diagnostic baseline and allow an initial evaluation instructed to relax as much as possible. of this technique to be made. http://jnnp.bmj.com/ 500- 400-4cc- ,u 300- -v 0 0 on September 25, 2021 by guest. E 200- 100- 0 0 0 05 10 5 20 25 30 3-5 40 45 5*0 55 6-o0I 6-5 7-07 7-575 Latency (ms) FIG. 2 Normal values ofamplitude and latency shown as standard deviation ellipses for 80 dB sensation level. F J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.39.6.586 on 1 June 1976. Downloaded from 588 A. R. D. Thornton and C. H. Hawkes RESULTS ventriculogram showed symmetrical enlargement of the lateral and third ventricles; the aqueduct and CASE 1 DIAGNOSIS: CONGENITAL END-ORGAN DEAF- the fourth ventricle were displaced to the left and NEss A nine year old girl presented because of there was a slight forward shift of the aqueduct. At longstanding right-sided deafness and a six month history of rotary vertigo. Clinical examination operation a typical acoustic neuroma was found on the right side, expanding backwards into the cere- revealed a severe perceptive deafness in the right ear bellar hemisphere. but no other abnormality. Audiometrically there Electrocochleography was performed before was no measurable hearing in the affected ear. operation and the cochlear microphonic results are Electronystamography showed a first degree shown in Fig. 4. There are no appreciable nystagmus to the left and caloric testing revealed differences absent vestibular function on the right side. A diagnosis of right-sided end-organ dysfunction was made. The cochlear microphonic results, shown in Fig. 3, support this viewpoint. Binaural stimulation was used and the CM from the left side shows a reasonable reproduction of the stimulus waveform, whereas no similar response is visible in the record obtained simultaneously from the right side. L eft - ILeft / A Protected by copyright. .X. B FIG. 4 Cochlear microphonic responses obtained - I I I 1 i/ i i simultaneously from both sides from the patient with an acoustic neurofibroma. X axis: 90 ks/div. Y axis: 39 n V/div. in the amplitude or in the waveshape between the simultaneously recorded responses from the left and right sides. This implies that there remain some http://jnnp.bmj.com/ functional hair-cells and that the vascular supply to the cochlea is intact. The neurogenic responses, obtained with binaural stimulation and simultaneous FIG. 3 Cochlear microphonic (CM) responses from recording from left and right sides, are shown in the patient with end-organ hearing loss (AG2806). Fig. 5. The responses on the left side are all within Trace A: CM from the right affected side. Trace B: normal limits, as are the responses N2 to N5 (coch- lear nucleus to inferior colliculus) from the right. CM simultaneously recorded from the left unaffected on September 25, 2021 by guest. side. Trace C: Pressure waveform of the acoustic The right side N1 (cochlear nerve) response has a stimulus. Y axis: 20 n V/div. X axis: 58 ,ts/div. significantly smaller amplitude than normal. Thus, the cochlear microphonic measurements indicate normal end-organ function and the brain stem responses give normal values, leaving only the CASE 2 DIAGNOSIS: ACOUSTIC NEUROMA A fifty- abnormal cochlear nerve response, which implies four year old lady was admitted with a two month a lesion at this level. history of progressive headache, ataxia, dysarthria, and right-sided deafness. Neurological examination revealed papilloedema, nystagmus, severe perceptive CASE 3 DIAGNOSIS: PONTINE GLIOMA A seven year deafness on the right side, and truncal ataxia. A old boy was admitted with a six week history of J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.39.6.586 on 1 June 1976. Downloaded from Neutrological applications ofsurface-recorded electrocochleography59589 5cx9 4CO0 ra 300X- 0~ 0 0.5 1.0 15 2-0 2-5 3-0 3-5 4-0 4.5 5.0 5.5 60o 6.5 7-0 7-5 Latency (ins) FIG. 5 Cochlear nerve and brain stem response values from each side from the patient with a right side acoustic neurofibroma.
Load more

Recommended publications
  • Capturing Activity Along the Auditory Nerve
    Into the deep – Capturing activity along the auditory nerve Masterarbeit An der Naturwissenschaftlichen Fakultät der Paris-Lodron-Universität Salzburg im Sommersemester 2018 Eingereicht von Fabian Schmidt Matrikelnummer: 1222361 Gutachter Univ.-Prof. Dr. Nathan Weisz Fachbereich Psychologie INTO THE DEEP 2 Abstract Early auditory evoked potentials occur within the first ten milliseconds after acoustic stimulation. The recording of these potentials usually consists of five to seven vertex positive waves, with Wave I & II being related to activity in the auditory nerve and the cochlear nucleus. The most common used methods of measuring these electrical signals spreading through the auditory pathway are Electrocochleography (ECochG) and the Auditory Brainstem Response (ABR). As the recorded signals are typically weak in amplitude, averaging over a lot of trials, elicited by simple stimuli such as clicks or tone bursts, is required to obtain a reliable response. The large amount of repetitive trials presents a challenge to researchers trying to investigate auditory nerve activity during a more natural stimulation (e.g. listening to running speech). The present study shows, that by combining ECochG, ABR and magnetoencephalography (MEG) using a forward/backward encoding modelling approach, a “pipeline” to the auditory nerve can be built. Results suggest that activity presumably generated by the auditory nerve, can be captured in the MEG. Furthermore, it was shown that early auditory evoked potentials can be reconstructed and used to create a prediction model for the activity along the auditory pathway. This opens the gates to further investigate auditory nerve activity under more natural circumstances (e.g. listening to running speech). keywords: auditory nerve; auditory pathway; cochlear nucleus; early auditory evoked potentials; electrocochleography; magnetoencephalography; auditory brainstem response INTO THE DEEP 3 Zusammenfassung Frühe auditorische evozierte Potentiale ereignen sich in den ersten zehn Millisekunden nach einem akustischen Reiz.
    [Show full text]
  • Simultaneous Extratympanic Electrocochleography and Auditory Brainstem Responses Revisited Carlos Minaya, Samuel R
    Audiology Research 2015; volume 5:105 Simultaneous extratympanic electrocochleography and auditory brainstem responses revisited Carlos Minaya, Samuel R. Atcherson Department of Audiology and Speech Pathology, University of Arkansas for Medical Sciences and University of Arkansas at Little Rock, AR, USA Broadband clicks at a fixed level of 85 dB nHL were presented with Abstract alternating polarity at stimulus rates of 9.3, 11.3, and 15.3/s. Different stimulation rates were explored to identify the most efficient rate The purpose of this study was to revisit the two-channel, simultane- without sacrificing time or waveform morphology. Results revealed ous click-evoked extratympanic electrocochleography and auditory larger ECoG AP than ABR Wave I, as expected, and no significant dif- brainstem response (ECoG/ABR) recording technique for clinical use ference across stimulation rate and no interaction effect. in normal hearing participants. Recording the compound action poten- Extratympanic electrode placement takes little additional clinic time tial (AP) of the ECoG simultaneously with ABR may be useful when and may improve the neurodiagnostic utility of the ABR. Wave I of the ABR is small or diminished in patients with sensorineur- al or retrocochlear disorder and minimizes overall test time. In con- trast to some previous studies that used the extratympanic electrode both as non-inverting electrode for the ECoG and inverting electrode Introduction only for ABR, this study maintained separate recording channel montages unique to conventional click-evoked ECoG and ABR recordings. That Electrocochleography (ECoG or ECochG) and auditory brainstem is, the ABR was recorded using a vertical channel (Cz to ipsilateral ear- responses (ABR or BAER) are well-established auditory evoked poten- lobe), while the ECoG with custom extratympanic electrode was tial tests useduse for the assessment of a variety of auditory conditions.
    [Show full text]
  • Use of an Extra-Tympanic Membrane Electrode to Record Cochlear Microphonics with Click, Tone Burst and Chirp Stimuli
    Article Use of an Extra-Tympanic Membrane Electrode to Record Cochlear Microphonics with Click, Tone Burst and Chirp Stimuli Laura M. Coraci and Andy J. Beynon * Vestibular & Auditory EP Lab—Department Otorhinolaryngology, Radboud University Medical Center, Ph. Van Leijdenlaan 15, 6525EX Nijmegen, The Netherlands; [email protected] * Correspondence: [email protected] Abstract: This study determined electrocochleography (ECochG) parameter settings to obtain cochlear microphonics (CM) with less invasive flexible extra-tympanic membrane electrodes. In 24 adult normal-hearing subjects, CMs were elicited by presenting click stimuli at 100 dBnHL, tone bursts (2 kHz) and broadband (BB) CE-chirps® LS (Interacoustics, Middelfart, Denmark), both at 80 dBnHL. Different high-pass filters (HPFs) (3.3 Hz and 100 Hz, respectively) were used to investi- gate response quality of the CM. CMs were successfully obtained in 92–100% with click-, 75–83% with 2 kHz tone burst- and 58–63% with CE-chirp®-LS stimuli. Click stimuli elicited significantly larger CM amplitudes compared to 2 kHz tone bursts and BB CE-chirp® LS (Interacoustics, Middelfart, Denmark). No significant differences were found between the two different high-pass filter (HPF) settings. The present study shows that it is possible to obtain clear CMs with the flexible extra- tympanic membrane electrodes using click stimuli. In contrast to 2 kHz tone bursts and CE-chirp® (Interacoustics, Middelfart, Denmark) LS, clicks show a significantly higher success rate and are the preferred stimuli to confirm the presence or absence of CMs. Citation: Coraci, L.M.; Beynon, A.J. Keywords: electrocochleography; cochlear microphonic; tympanic membrane electrode; auditory Use of an Extra-Tympanic Membrane evoked potentials Electrode to Record Cochlear Microphonics with Click, Tone Burst and Chirp Stimuli.
    [Show full text]
  • Clinical Evaluation of a New Electrocochleography Recording Electrode
    Aud Vestib Res (2020);29(2):93-100. DOI: 10.18502/avr.v29i2.2790 RESEARCH ARTICLE Clinical evaluation of a new electrocochleography recording electrode Mostafa Eyvazi1, Akram Pourbakht1, Seyyed Jalal Sameni1*, Mohammad Kamali2,3 1- Department of Audiology, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran 2- Rehabilitation Research Center, Iran University of Medical Sciences, Tehran, Iran 3- Department of Basic Sciences, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran Received: 16 Jan 2020, Revised: 28 Feb 2020, Accepted: 11 Mar 2020, Published: 15 Apr 2020 Abstract Background and Aim: Electrocochleography TIP-trode. The mean SP/AP ratio between two is one of the most practically used tests in app- types of electrodes was statistically significant roaching Meniere's disease (MD). To record reli- differences in normal subjects (p = 0.027) and in able response components, the type of applied MD group (p = 0.009). electrode is of particular importance. The TIP- Conclusion: We demonstrated that the utili- trode is an appropriate electrode due to its user- zation of the Gutter electrode in ECochG assess- friendliness. Gutter electrode can be used in ments was considerably effective and beneficial. more than 100 subject. This study aimed to com- It can significantly reduce expenses and be app- pare the results of the Electrocochleography lied in clinical settings. It’s also recommended (ECochG) test responses using TIP-trode and the that 47.22% mean SP/AP amplitude ratio to be Gutter electrode. considered as upper limit of normality by using Methods: This cross-sectional study was perfor- the Gutter electrode.
    [Show full text]
  • A Speed Trap on the Auditory Pathway Investigation of Early Auditory Evoked Brainstem Activity
    A Speed Trap on the Auditory Pathway Investigation of early auditory evoked brainstem activity Masterarbeit zur Erlangung des Mastergrades MSc. an der Naturwissenschaftlichen Fakultät der Paris-Lodron Universität Salzburg eingereicht von Florian Geyer Gutachter: Univ.-Prof. Dr. Nathan Weisz Fachbereich: Psychologie Salzburg, November 2018 A Speed Trap on the Auditory Pathway – Investigation of early auditory evoked brainstem activity Abstract In the first 10 ms after acoustic stimulation afferent information “travels” through the auditory pathway. Starting in cochlear nerve these early auditory evoked activity proceeds through the brainstem and parts of the thalamus into the auditory cortex. Early auditory evoked activity usually consists of five to seven positive vertex potentials and can be measured via Electrocochleography or ABR. Those wave peaks can be defined and correlated to their source in the auditory pathway, e.g. wave V is located in the inferior colliculi of the brainstem and is known to elicit a high peak in ABR. Clinicians use early auditory evoked potentials as diagnosis tool for audiological diseases. However, analysis is mostly done visually. This can be challenging. We introduce an approach to get information about the individual wave-region correlation. This has translational potential to clinical applications (e.g. optimization of early auditory evoked activity as a diagnosis tool by facilitating wave detection) and neuroscientific research (e.g. investigation of attentional modulation of early auditory evoked activity). We measured early auditory evoked activity of 18 healthy participants as response to a 30 hz click stimulation at 60 db SPL with magnetic ABR, electrical ABR, ECochG and MEG. We then used Backward Decoding Model to extract a spatial filter from MEG with reference to ABR.
    [Show full text]
  • ABR Testing ECOG Testing
    Adult & Pediatric Otolaryngology • Head & Neck Surgery • Sinus & Nasal Surgery • Facial Plastic Surgery • Otologic Surgery Auditory Brainstem Response (ABR) and Electrocochleography (ECOG) Testing ABR Testing What is ABR Testing? The Auditory Brainstem Response Test evaluates the auditory nerve pathways from the inner ear to the brainstem. How is the test performed? This diagnostic test obtains auditory information without requiring the active participation of the patient. Very small sensor s (surface electrode tabs) are placed on the forehead and small foam electrodes are also placed just inside the ear canal to present sounds into the ear. The testing begins when click sounds are intro- duced to the ears. The sounds may vary in intensity and tone but should never be uncomfortable. The nerve responses that are picked up by the electrodes and passed on to sophisticated equipment are measured and analyzed by the audiologist. It is painless and non-invasive. The patient is reclined in a comfortable chair. F or best results, the patient is asked to close their eyes, relax, and remain as still as possible. The patient can feel free to fall asleep. Why do I need an ABR? The ABR test can be administered to provide an objective estimate of hearing sensitivity and/or evaluate various neural disorders in the auditory pathways. ABR testing may be performed in cases of asymmetric hearing loss, unilateral tinnitus, sudden hearing loss, or other auditory conditions. What do I need to do before the test? The only requirements for testing are that the patient’s ear canals must be relatively free of wax.
    [Show full text]
  • Utilizing Electrocochleography As a Microphone for Fully Implantable Cochlear Implants William Jason Riggs, Meghan M
    www.nature.com/scientificreports OPEN Utilizing Electrocochleography as a Microphone for Fully Implantable Cochlear Implants William Jason Riggs, Meghan M. Hiss, Jefrey Skidmore, Varun V. Varadarajan, Jameson K. Mattingly, Aaron C. Moberly & Oliver F. Adunka* Current cochlear implants (CIs) are semi-implantable devices with an externally worn sound processor that hosts the microphone and sound processor. A fully implantable device, however, would ultimately be desirable as it would be of great beneft to recipients. While some prototypes have been designed and used in a few select cases, one main stumbling block is the sound input. Specifcally, subdermal implantable microphone technology has been poised with physiologic issues such as sound distortion and signal attenuation under the skin. Here we propose an alternative method that utilizes a physiologic response composed of an electrical feld generated by the sensory cells of the inner ear to serve as a sound source microphone for fully implantable hearing technology such as CIs. Electrophysiological results obtained from 14 participants (adult and pediatric) document the feasibility of capturing speech properties within the electrocochleography (ECochG) response. Degradation of formant properties of the stimuli /da/ and /ba/ are evaluated across various degrees of hearing loss. Preliminary results suggest proof-of-concept of using the ECochG response as a microphone is feasible to capture vital properties of speech. However, further signal processing refnement is needed in addition to utilization of an intracochlear recording location to likely improve signal fdelity. To date, it is estimated that as many as 466 million individuals worldwide have hearing loss as defned as an aver- age hearing level of ≥35 dB HL by pure-tone audiometry1.
    [Show full text]
  • An Evaluation of Electrocochleography As a Diagnostic Tool for Ménière's Disease
    An Evaluation of Electrocochleography as a Diagnostic Tool for Ménière’s Disease _____________________________________________________________________ A thesis submitted in partial fulfilment of the requirements for the Degree of Master of Audiology in the Department of Communication Disorders at the University of Canterbury By Catherine J. Kalin ____________________________________________________________________ University of Canterbury 2010 ii Acknowledgments _____________________________________________________________________ This master’s thesis could not have been completed without the help and support of many people. I would like to express my gratitude to my two primary supervisors, Dr. Emily Lin and Professor Jeremy Hornibrook, who not only served as my supervisors but also encouraged and challenged me throughout my masters study program. Their passion for research was an inspiration to me, and I would like to thank them both sincerely for the guidance and support they have given me over the past year. I would also like to thank my co-supervisor, Dr Greg O’Beirne, for his help and support with my academic writing. I gratefully acknowledge John Gourley and the audiology staff at Christchurch Hospital who have been involved with electrocochleography recordings over the last 15 years. I would like to thank Angela Harrison at Christchurch Hospital and Glynis Whittaker at the private practice of Mr Hornibrook for the retrieval of the data files. I also wish to thank all the research participants for their contributions in this study. I sincerely thank you all for allowing me to have access to your medical files. Finally, I would like to acknowledge the loving support of my friends and family. To my fellow postgraduate students, I am most grateful for your ongoing support, encouragement and company.
    [Show full text]
  • Electrocochleography in Guinea Pigs
    Global Journal of Otolaryngology ISSN 2474-7556 Review Article Glob J Otolaryngol Volume 15 Issue 5 - May 2018 Copyright © All rights are reserved by Negin Salehi DOI: 10.19080/GJO.2018.15.555923 Electrocochleography in Guinea Pigs Negin Salehi*1 and Farzaneh Zamiri Abdollahi2 1Phd student of audiology, Iran University of Medical Science, Iran 2Phd of audiology, Tehran University of Medical Sciences, Iran Submission: April 28, 2018; Published: May 31, 2018 *Corresponding author: Negin Salehi, Phd student of audiology, Iran University of Medical Science, Iran Tel: ; Email: Abstract Electrocochleography is the best electrophysiological measurement for cochlear condition investigation in guinea pig models. In this applications. article, we will review new issues in recording electrocochleography in guinea pigs in two parts including measurement parameters and clinical Keywords: Electrocochleography; Guinea Pig; The cochlea Abbreviations: EcohG: Electrocochleography; CAP: Compound Action Potential; CM: Cochlear Microphonics; SP: Summating Potential; AP: Action Potential; SGNs: Spiral Ganglion Neurons; FFT: Fast Fourier transformation; DC: Direct Current Introduction experiments on auditory system, such as dissection hardness system disorders models via EcochG. This article will review Due to tremendous difficulties associated with human applications of EcochG in guinea pigs. due to stiff temporal bone, animal models are the best choice the most important measurement parameters as well as clinical The goals of recording EcochG in Guinea pigs that range of small mammals like cat, chinchilla, guinea pig, for studies on the cochlear physiology. Researchers have shown One of the main applications of recording EcochG in guinea rat, and mouse, are appropriate options for providing insight pigs is better understanding physiology of the auditory system, into the human cochlear physiology.
    [Show full text]
  • Auditory Cortical Generators of the Frequency Following Response Are
    bioRxiv preprint doi: https://doi.org/10.1101/633834; this version posted May 9, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. 1 Auditory cortical generators of the Frequency Following Response are 2 modulated by intermodal attention 3 Running Title: Auditory cortex underlies attentional modulations of FFR 4 5 Thomas Hartmann1)2) & Nathan Weisz1)2) 6 1. Center of Cognitive Neuroscience, University of Salzburg, Salzburg, Austria 7 2. Department of Psychology, University of Salzburg, Salzburg, Austria 8 9 correspondence: 10 Dr. Thomas Hartmann 11 Paris-Lodron Universität Salzburg 12 Division of Physiological Psychology 13 Hellbrunnerstraße 34 14 5020 Salzburg 15 Austria 16 Phone: +43 (0)662 80445109 17 Fax: +43 (0) 662 / 8044 - 5126 18 E-mail: [email protected] 1 bioRxiv preprint doi: https://doi.org/10.1101/633834; this version posted May 9, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. 19 Abstract 20 The vast efferent connectivity of the auditory system suggests that subcortical 21 (thalamic and brainstem) auditory regions should also be sensitive to top-down processes 22 such as selective attention. In electrophysiology, the Frequency Following Response (FFR) 23 to simple speech stimuli has been used extensively to study these subcortical areas.
    [Show full text]
  • Neural and Receptor Cochlear Potentials Obtained by Transtympanic Electrocochleography in Auditory Neuropathy Q
    Clinical Neurophysiology 119 (2008) 1028–1041 www.elsevier.com/locate/clinph Neural and receptor cochlear potentials obtained by transtympanic electrocochleography in auditory neuropathy q Rosamaria Santarelli a,*, Arnold Starr b, Henry J. Michalewski b, Edoardo Arslan a a Department of Medical and Surgical Specialities, Service of Audiology and Phoniatrics, University of Padua, Via Giustiniani 2, I-35128 Padua, Italy b Department of Neurology, University of California, Irvine, CA, USA Accepted 26 January 2008 Abstract Objective: Transtympanic electrocochleography (ECochG) was recorded bilaterally in children and adults with auditory neuropathy (AN) to evaluate receptor and neural generators. Methods: Test stimuli were clicks from 60 to 120 dB p.e. SPL. Measures obtained from eight AN subjects were compared to 16 normally hearing children. Results: Receptor cochlear microphonics (CMs) in AN were of normal or enhanced amplitude. Neural compound action potentials (CAPs) and receptor summating potentials (SPs) were identified in five AN ears. ECochG potentials in those ears without CAPs were of negative polarity and of normal or prolonged duration. We used adaptation to rapid stimulus rates to distinguish whether the gen- erators of the negative potentials were of neural or receptor origin. Adaptation in controls resulted in amplitude reduction of CAP twice that of SP without affecting the duration of ECochG potentials. In seven AN ears without CAP and with prolonged negative potential, adaptation was accompanied by reduction of both amplitude and duration of the negative potential to control values consistent with neural generation. In four ears without CAP and with normal duration potentials, adaptation was without effect consistent with receptor generation.
    [Show full text]
  • Study Protocol
    INTRA- AND POST-OPERATIVE MEASURES OF AUDITORY FUNCTION STUDY PROTOCOL THURSDAY, APRIL 19, 2018 Table of Contents Background and Objectives of the Study ................................................................................................ 2 Cochlear Implantation ............................................................................................................................... 2 Performance and Candidacy ................................................................................................................... 2 Electrocochleography ................................................................................................................................ 3 Real-Time ECochG monitoring............................................................................................................... 3 Objectives……………………………………………………………………………………………………………….3 Significance .................................................................................................................................................... 4 Study Design ...................................................................................................................................................... 4 Hypotheses ......................................................................................................................................................... 5 Participants ........................................................................................................................................................ 5
    [Show full text]