Dataset Information

Comparisons of auditory brainstem response and sound level tolerance in tinnitus ears and non-tinnitus ears in unilateral tinnitus patients with normal audiograms.

ABSTRACT: Recently, "hidden hearing loss" with cochlear synaptopathy has been suggested as a potential pathophysiology of tinnitus in individuals with a normal hearing threshold. Several studies have demonstrated that subjects with tinnitus and normal audiograms show significantly reduced auditory brainstem response (ABR) wave I amplitudes compared with control subjects, but normal wave V amplitudes, suggesting increased central auditory gain. We aimed to reconfirm the "hidden hearing loss" theory through a within-subject comparison of wave I and wave V amplitudes and uncomfortable loudness level (UCL), which might be decreased with increased central gain, in tinnitus ears (TEs) and non-tinnitus ears (NTEs).Human subjects included 43 unilateral tinnitus patients (19 males, 24 females) with normal and symmetric hearing thresholds and 18 control subjects with normal audiograms. The amplitudes of wave I and V from the peak to the following trough were measured twice at 90 dB nHL and we separately assessed UCLs at 500 Hz and 3000 Hz pure tones in each TE and NTE.The within-subject comparison between TEs and NTEs showed no significant differences in wave I and wave V amplitude, or wave V/I ratio in both the male and female groups. Individual data revealed increased V/I amplitude ratios > mean + 2 SD in 3 TEs, but not in any control ears. We found no significant differences in UCL at 500 Hz or 3000 Hz between the TEs and NTEs, but the UCLs of both TEs and NTEs were lower than those of the control ears.Our ABR data do not represent meaningful evidence supporting the hypothesis of cochlear synaptopathy with increased central gain in tinnitus subjects with normal audiograms. However, reduced sound level tolerance in both TEs and NTEs might reflect increased central gain consequent on hidden synaptopathy that was subsequently balanced between the ears by lateral olivocochlear efferents.

SUBMITTER: Shim HJ

PROVIDER: S-EPMC5734686 | biostudies-other | 2017

REPOSITORIES: biostudies-other

ACCESS DATA

Publications

Comparisons of auditory brainstem response and sound level tolerance in tinnitus ears and non-tinnitus ears in unilateral tinnitus patients with normal audiograms.

Shim Hyun Joon HJ An Yong-Hwi YH Kim Dong Hyun DH Yoon Ji Eun JE Yoon Ji Hyang JH

PloS one 20171218 12

<h4>Objective</h4>Recently, "hidden hearing loss" with cochlear synaptopathy has been suggested as a potential pathophysiology of tinnitus in individuals with a normal hearing threshold. Several studies have demonstrated that subjects with tinnitus and normal audiograms show significantly reduced auditory brainstem response (ABR) wave I amplitudes compared with control subjects, but normal wave V amplitudes, suggesting increased central auditory gain. We aimed to reconfirm the "hidden hearing lo ...[more]

PMID: 29253030

Similar Datasets

Project description:IntroductionTinnitus may have a very severe impact on the quality of life. Unfortunately, for many patients, a satisfactory treatment modality is lacking. The auditory brainstem implant (ABI) was originally indicated for hearing restoration in patients with non-functional cochlear nerves, for example, in neurofibromatosis type II. In analogy to a cochlear implant (CI), it has been demonstrated that an ABI may reduce tinnitus as a beneficial side effect. For tinnitus treatment, an ABI may have an advantage over a CI, as cochlear implantation can harm inner ear structures due to its invasiveness, while an ABI is presumed to not damage anatomical structures. This is the first study to implant an ABI to investigate its effect on intractable tinnitus.Methods and analysisIn this pilot study, 10 adults having incapacitating unilateral intractable tinnitus and ipsilateral severe hearing loss will have an ABI implanted. The ABI is switched on 6 weeks after implantation, followed by several fitting sessions aimed at finding an optimal stimulation strategy. The primary outcome will be the change in Tinnitus Functioning Index. Secondary outcomes will be tinnitus burden and quality of life (using Tinnitus Handicap Inventory and Hospital Anxiety and Depression Scale questionnaires), tinnitus characteristics (using Visual Analogue Scale, a tinnitus analysis), safety, audiometric and vestibular function. The end point is set at 1 year after implantation. Follow-up will continue until 5 years after implantation.Ethics and disseminationThe protocol was reviewed and approved by the Institutional Review Board of the University Medical Centre Groningen, The Netherlands (METc 2015/479). The trial is registered at www.clinicialtrials.gov and will be updated if amendments are made. Results of this study will be disseminated in peer-reviewed journals and at scientific conferences.Trial registration numberNCT02630589.Trial statusInclusion of first patient in November 2017. Data collection is in progress. Trial is open for further inclusion. The trial ends at 5 years after inclusion of the last patient.

Project description:To determine whether suprathreshold measures of auditory function, such as distortion-product otoacoustic emissions (DPOAEs) and auditory brainstem responses (ABRs), are correlated with noise exposure history in normal-hearing human ears. Recent data from animal studies have revealed significant deafferentation of auditory nerve fibers after full recovery from temporary noise-induced hearing loss. Furthermore, these data report smaller ABR wave I amplitudes in noise-exposed animal ears when compared with non-noise-exposed control animals or prenoise exposure amplitudes in the same animal. It is unknown whether a similar phenomenon exists in the normal-hearing, noise-exposed human ear.Thirty normal-hearing human subjects with a range of noise exposure backgrounds (NEBs) participated in this study. NEB was quantified by the use of a noise exposure questionnaire that extensively queried loud sound exposure during the previous 12 months. DPOAEs were collected at three f2s (1, 2, and 4 kHz) over a range of L2s. DPOAE stimulus level began at 80 dB forward-pressure level and decreased in 10 dB steps. Two-channel ABRs were collected in response to click stimuli and 4 kHz tone bursts; one channel used an ipsilateral mastoid electrode and the other an ipsilateral tympanic membrane electrode. ABR stimulus level began at 90 dB nHL and was decreased in 10 dB steps. Amplitudes of waves I and V of the ABR were analyzed.A statistically significant relationship between ABR wave I amplitude and NEB was found for clicked-evoked ABRs recorded at a stimulus level of 90 dB nHL using a mastoid recording electrode. For this condition, ABR wave I amplitudes decreased as a function of NEB. Similar systematic trends were present for ABRs collected in response to clicks and 4 kHz tone bursts at additional suprathreshold stimulation levels (?70 dB nHL). The relationship weakened and disappeared with decreases in stimulation level (?60 dB nHL). Similar patterns were present for ABRs collected using a tympanic membrane electrode. However, these relationships were not statistically significant and were weaker and more variable than those collected using a mastoid electrode. In contrast to the findings for ABR wave I, wave V amplitude was not significantly related to NEB. Furthermore, there was no evidence of a systematic relationship between suprathreshold DPOAEs and NEB.A systematic trend of smaller ABR wave I amplitudes was found in normal-hearing human ears with greater amounts of voluntary NEB in response to suprathreshold clicks and 4 kHz tone bursts. These findings are consistent with the data from previous work completed in animals, where the reduction in suprathreshold responses was a result of deafferentation of high-threshold/low-spontaneous rate auditory nerve fibers. These data suggest that a similar mechanism might be operating in human ears after exposure to high sound levels. However, evidence of this damage is only apparent when examining suprathreshold wave I amplitude of the ABR. In contrast, suprathreshold DPOAE level was not significantly related to NEB. This was expected, given noise-induced auditory damage findings in animal ears did not extend to the outer hair cells, the generator for the DPOAE response.

Project description:OBJECTIVES:To determine whether auditory brainstem response (ABR) wave I amplitude is associated with measures of auditory perception in young people with normal distortion product otoacoustic emissions (DPOAEs) and varying levels of noise exposure history. DESIGN:Tinnitus, loudness tolerance, and speech perception ability were measured in 31 young military Veterans and 43 non-Veterans (19 to 35 years of age) with normal pure-tone thresholds and DPOAEs. Speech perception was evaluated in quiet using Northwestern University Auditory Test (NU-6) word lists and in background noise using the words in noise (WIN) test. Loudness discomfort levels were measured using 1-, 3-, 4-, and 6-kHz pulsed pure tones. DPOAEs and ABRs were collected in each participant to assess outer hair cell and auditory nerve function. RESULTS:The probability of reporting tinnitus in this sample increased by a factor of 2.0 per 0.1 µV decrease in ABR wave I amplitude (95% Bayesian confidence interval, 1.1 to 5.0) for males and by a factor of 2.2 (95% confidence interval, 1.0 to 6.4) for females after adjusting for sex and DPOAE levels. Similar results were obtained in an alternate model adjusted for pure-tone thresholds in addition to sex and DPOAE levels. No apparent relationship was found between wave I amplitude and either loudness tolerance or speech perception in quiet or noise. CONCLUSIONS:Reduced ABR wave I amplitude was associated with an increased risk of tinnitus, even after adjusting for DPOAEs and sex. In contrast, wave III and V amplitudes had little effect on tinnitus risk. This suggests that changes in peripheral input at the level of the inner hair cell or auditory nerve may lead to increases in central gain that give rise to the perception of tinnitus. Although the extent of synaptopathy in the study participants cannot be measured directly, these findings are consistent with the prediction that tinnitus may be a perceptual consequence of cochlear synaptopathy.

Dataset Information

Comparisons of auditory brainstem response and sound level tolerance in tinnitus ears and non-tinnitus ears in unilateral tinnitus patients with normal audiograms.

Publications

Comparisons of auditory brainstem response and sound level tolerance in tinnitus ears and non-tinnitus ears in unilateral tinnitus patients with normal audiograms.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure