Outcome measures of brainwave entrainment using delta wave stimulation in individuals with tinnitus having normal hearing sensitivity.

OBJECTIVE: The current study aimed to evaluate the efficacy of delta frequency binaural beats stimulation in treatment of individuals with tinnitus having normal hearing sensitivity. METHOD: Twenty-four individuals who reported bothersome tinnitus in the presence of clinically normal hearing were grouped into two (I and II). The group was provided with delta frequency binaural beats and II was provided with white noise stimulation (both of 20 min duration) for 30 days. Post 30 days, the re-assessment of tinnitus handicap, depression, anxiety, and quality of life parameters were performed and compared with that of pre-treatment scores. RESULTS: A considerable reduction of tinnitus handicap scores, depression and anxiety levels were observed for both the groups, except for the quality-of-life parameters. However, few of the participants showed limited or negligible improvement post-treatment. On comparison of reduction of scores observed across the groups, there was a higher reduction of scores observed for group I when compared to group II. CONCLUSION: The current study was an initial attempt to study the efficacy of binaural beats in treatment of individuals with tinnitus having normal hearing. Apart from a few individuals, the delta wave stimulation acted as a helpful tool in improving tinnitus borne distress symptoms in such patients with normal hearing. The results of the present study put forward the scope of adapting binaural beats stimulation for the treatment of individuals presenting with tinnitus having normal hearing sensitivity. This technique could be adopted into clinical practice after extensive research involving an extended treatment duration on a larger population.

Validation of LittleEARS questionnaire in Hindi language.

Background: Subjective measures of auditory development are equally important as objective measures to obtain a realistic image of the hearing status in infants and toddlers. Objectives: The objectives of the current study were to translate and validate the LittleEARS questionnaire into the Hindi language, to calculate its psychometric properties and establish a regression curve of the scores obtained as a function of age, to calculate the inter-test and test retest reliability of the same. The secondary objectives were to compare the scores obtained by the normal hearing children and those with hearing impairment and to plot a regression curve of total scores obtained by the hearing-impaired children as a function of the duration of auditory training attended since their first fit of the device. Materials and methods: The procedures involved conventional translation, reverse translation, and content validation before administering the questionnaire. The translated version was administered to parents of 59 children with normal hearing and 41 children with hearing impairment. Results: The finalized version had good reliability and efficient internal consistency with a Cronbach alpha value of 0.96. The mean scores obtained by the normal hearing children showed a progressive pattern as a function of age. Conclusion: The LittleEARS questionnaire has been successfully translated and validated into the Hindi language with excellent validity and reliability and can be used for screening and early identification of hearing impairment and in evaluating the outcome of audiological treatment approaches.

Effects of Maturation and Chronological Aging on Auditory Spatial Processing: A Cross-Sectional Study Across Life Span.

OBJECTIVE: The primary aim of the research was to document spatial acuity changes across the life span using a battery of psychoacoustical and perceptual tests. The secondary aim was to identify the optimal metric for measuring spatial processing changes across the life span (ages 10-70 years). DESIGN AND STUDY SAMPLE: A cross-sectional study comprising 115 participants with clinically normal hearing was conducted. Purposive sampling was adopted to recruit participants in the study, who were divided into six groups based on their chronological age. METHOD: Temporal, intensity, spectral, and composite correlates of spatial acuity were assessed using psychoacoustic measures and perceptual questionnaires. The temporal (interaural time difference [ITD]) and intensity correlates (interaural level difference [ILD]) of spatial perception were obtained using a MATLAB (v 2020a), whereas the composite correlate (virtual auditory space identification scores [VASIs]) and perceptual ratings of spatial processing were measured using Paradigm software and speech spatial and qualities in Kannada (SSQ-K). RESULTS: Results across all tests (multivariate analyses variance: 6 age groups × 4 tests, followed by post hoc tests) consistently demonstrate poor ITD and ILD thresholds and overall lower spatial accuracy (VASI, SSQ-K) with increasing age. Discriminant function analyses (DFAs) revealed that VASI had a higher predictive power in capturing age-related changes in auditory spatial processing. The group segregation on spatial performance in DFA became evident after 50 years. CONCLUSION: This study provides evidence of gradual change in all three correlates of spatial processing, with statistically demonstrable deficits appearing from fourth decade of life on VASI and fifth decade of life on binaural processing.

Assessment of Hidden Hearing Loss in Individuals Exposed to Occupational Noise Using Cochlear, Neural, Temporal Functions and Quality of Life Measures.

The present study aims to identify the objective tests that can identify hidden hearing loss in a group of individuals exposed to occupational noise, which is not otherwise evident as a clinically relevant permanent threshold shift. A standard group comparison design was used to study the hidden auditory effect of occupational noise on traffic police officers. A total of 50 participants (n = 25 exposed to occupational noise; n = 25 non-occupational noise-exposed) were included in the study. The test battery comprised of behavioral tests (hearing thresholds from 250 to 16,000 Hz), fine structure Distortion product otoacoustic emissions (DPOAE's) as physiological measure, Click and CE-chirp® evoked auditory brain stem response (ABR) as electrophysiological, and Gap detection test (GDT) and Temporal modulation transfer function (TMTF) as psychophysical measures. Among the measures evaluated, extended high-frequency audiometry, fine structure DPOAE amplitude, CE-chirp® ABR, GDT, and TMTF showed a significant difference (p < 0.05) between the traffic police individuals exposed to occupational noise and the controls. However, routine audiometry and click-evoked ABR did not show any significant differences. The high-frequency audiometric thresholds, fine structure DPOAEs, CE-chirp® evoked ABR, GDT and TMTF have been shown to be affected in individuals exposed to occupational noise. This finding indicates a hidden hearing loss in the study group. Hence, this study paves the way for early identification and intervention of noise-induced hearing loss by including these measures along with routine test protocol in susceptible individuals.

Musical Training and Its Association With Age-Related Changes in Binaural, Temporal, and Spatial Processing.

OBJECTIVE: This article aimed to assess the relationship between musical training and age-related changes in binaural, temporal, and spatial processing abilities. DESIGN: A standard group comparison study was conducted involving both musicians and nonmusicians. The effect of musical training was assessed using a battery of psychoacoustical tests (interaural time and level difference thresholds: ITD & ILD, binaural gap detection threshold, and virtual auditory space identification test) and subjective ratings (Spatial-Hearing subsection of Speech, Spatial, and Quality of Hearing scale in Kannada). STUDY SAMPLE: A total of 60 participants, between 41 and 70 years, were divided into three groups of 20 each, based on their age (41-50, 51-60, and 61-70 years). Each of these three groups was subdivided into two, one comprising 10 musicians (vocalists practicing South-Indian classical music) and the other comprising 10 nonmusicians. RESULTS: Multivariate analyses of variance revealed that musicians performed significantly better (p < .001) than nonmusicians in all the tests. Analyses of variance showed that whereas age had no effect (p > .05) on performance in any of the tests in musicians, age affected the performance of nonmusicians significantly in terms of ITD (p = .02) and ILD (p = .01) thresholds. CONCLUSION: Musical training appears to have the potential to slow down age-related decline in binaural, temporal, and spatial processing.

Speech ABR Findings in Auto Rickshaw Drivers Exposed to Occupational Noise.

Most of the persons with noise exposure will have clinically normal hearing threshold while experiencing reduced speech comprehension. The motive of this study is to assess the impact of occupational noise on the encoding of speech stimuli in the auditory system in the auto-rickshaw drivers and compare the auditory brainstem responses (ABR) using speech stimuli with that of controls. The study was done in experimental design, where speech evoked ABR was measured in 21 auto-drivers who were continuously exposed to higher levels of occupational noise, and they were compared to the results of 37 individuals who were not exposed to noise. Speech ABR was administered in both the groups and the absolute latencies and amplitudes of the peaks V, A, C, D, E, F and O were compared. The results revealed that there is a statistically significant difference (p < 0.05) in the latency of peak V (F(1,32) = 6.13, p < 0.05, η p 2 = 0.12) and peak A (F(1,32) = 4.03, p < 0.05, η p 2 = 0.08) between the control and experimental group. Similarly, there was a statistically significant difference seen in the amplitude of peak D (F(1,32) = 6.38, p < 0.05, η p 2 = 0.12) and peak F (F(1,32) = 7.97, p < 0.05, η p 2 = 0.15). Acknowledging how the speech signals are coded in the brainstem may aid in the timely detection and intervention of hearing-related issues, even in individuals having normal hearing acuity. The results indicate that there is damage at the level of the brainstem which will lead to poor speech understanding in those who are exposed to occupational noise. These indicators are present even before routine audiometry indicates a hearing loss.

Effects of Aging Versus Noise Exposure on Auditory System in Individuals With Normal Audiometric Thresholds.

BACKGROUND: The study aims at investigating the effect of aging and noise exposure on the auditory system using auditory brainstem responses (ABRs), distortion product otoacoustic emissions (DPOAEs), and contralateral suppression of OAEs (CSOAEs). The objective was to compare DPOAEs, CSOAEs, and ABR in aged and noise-exposed individuals with the normal, to find an indicator for early diagnosis of auditory damage. METHODS: Sixty adult male participants were divided into 3 groups. Group 1 included individuals not exposed to occupational noise and group 3 included individuals exposed to occupational noise who were <35 years of age. Group 2 consisted of individuals with an age range of 45-65 years without any occupational noise exposure. DPOAE fine structure was studied at 8 points per octave at different F2 frequencies. Transient evoked otoacoustic emissions (TEOAEs) were measured with and without contralateral broad band noise (BBN) at 30 dB SL (CSOAEs). ABR was recorded using click stimuli at different levels, from 90 dB nHL down to 50 dB nHL. The absolute amplitude and peak latencies for peaks I, III, and V; and the wave V/I amplitude ratio were analyzed. RESULTS: In CSOAEs, group 1 showed greater contralateral suppression when compared to group 2 and group 3. The amplitude of ABR wave I and the wave V/I ratio showed a significant difference between the 3 groups, and there was a reduction in amplitude of wave I for groups 2 and 3. CONCLUSION: The findings indicate that the functioning of the auditory system is affected by occupational noise exposure and aging. CSOAEs, ABR wave I amplitude, and wave V/I amplitude ratio serve as reliable markers in the identification of hidden hearing loss.

Perception of speech stress in children with hearing impairment.

PURPOSE: The study aimed to test effect of training on the perception of speech stress in children with severe to profound hearing impairment. The first objective was to compare the speech stress perception scores of children with hearing impairment and language age-matched children with normal hearing sensitivity after short term prosody training and the second objective was to correlate between the speech stress perception scores and the language age of the children with hearing impairment. METHOD: Thirty children with normal hearing (CWNH) in the age range of 3-7 years and thirty children with hearing impairment (CWHI) who had a language age of 3-7 years participated in the study. The authors formulated 24 concrete Malayalam sentences and their picture cognate pairs (stressed and unstressed) for each sentence. The stressed and unstressed version for each sentence was audio recorded separately.The study was carried out in two phases; phase 1 included the training on acoustic cues of speech stress followed by testing in phase 2. Both the phases were attended by all the participants. RESULTS: There was a significant difference between the CWNH and CWHI wherein, children with hearing impairment had lower speech stress perception scores. However, improvements in speech stress perception were observed in children with hearing impairment after the training phase. Also, a positive correlation between the language age and the perception of speech stress scores in CWHI was found indicating that as the language age increased there was an increase in the speech stress perception scores. CONCLUSION: The pre and post training speech stress perception scores were significantly different, with higher scores on the post-training test, indicating that the short term speech stress training for the children with hearing impairment was beneficial. The positive strong correlation between stress perception scores and language age shows that, prosody perception and language learning facilitate each other. Thereby, the conventional speech-language and auditory training should expand and include prosody training from an early age for children with hearing impairment.

Perception of vocal emotional prosody in children with hearing impairment.

PURPOSE: The study aimed at testing the effect of supra segmental training on vocal emotional prosody perception of children with hearing impairment. The objectives of the study were to compare the perception of vocal emotional prosody (happy, sad, and neutral) in children with hearing impairment with and without a short-term prosody training and to draw correlations between the vocal emotional prosody perception scores and the subject factors - chronological age, age of hearing aid fitting, duration of the intensive intervention (speech, language and auditory training without breaks more than 30 days) and language age in children with hearing impairment. METHOD: Thirty children with hearing impairment in the age range of 4.1-9.2 years with a language age of 3-7 years participated in the study. The authors formulated 24 concrete Malayalam sentences and their picture representations and these were recorded under three emotional variations (happy, sad, and neutral). Using random sampling, the thirty participants were divided into the control group (CWHI) and the experimental (CWHIt) group. The study was carried out in two phases; phase 1 (training) attended by only the experimental group and phase 2 (testing) attended by both the groups. RESULTS: There was a significant difference between CWHI and CWHIt in the happy, sad, and neutral vocal emotional prosody conditions. Chronological age, duration of speech-language-auditory training, and language age showed a positive correlation with the vocal emotional prosody perception scores; and no correlation was found between the age of fitting of hearing aids and the emotion perception scores. CONCLUSION: The results of the study points out that with adequate prosody training, the children with hearing impairment using benefiting hearing aids could improve their vocal emotional prosody perception. Owing to the role of prosody perception in speech & language, social and cognitive development, the supra segmental training should be made an integral part of the assessment and management intervention strategies.

Narrow-band chirp and tone burst auditory brainstem response as an early indicator of synaptopathy in industrial workers exposed to occupational noise.

This study aims at characterizing and comparing the findings of auditory brainstem response (ABR) using narrow-band chirp (NB-chirp) and tone burst (TB) for both latency and amplitude parameters among those exposed to occupational noise and to determine which among the two serves as a better indicator of noise-induced cochlear neuropathy. Forty adult males in the age range of 20-35 years were considered, wherein 20 of them were exposed to noise > 80 dB (A) for 8 hours per day constituting Noise-exposed group; and Control group consisted of 20 individuals without occupational noise exposure. ABR was recorded using NB-chirp and TB for four frequencies at 80 dB nHL through Etymotic Research - 3A (ER-3A) Insert phones using Interacoustics Eclipse EP-25 in individuals with and without noise exposure. MANOVA was performed to compare between TB ABR and NB-chirp ABR between the two groups. Statistical analysis revealed a notable difference for NB-chirp comparisons between the two groups at three frequencies: 500 Hz, F(1, 38) = 10.6; 1000 Hz, F(1, 38) = 7.91; and 2000 Hz, F(1, 38) = 6.64. Whereas, the difference was evident at only 500 Hz: F(1, 38) = 4.98 in case of TB ABR. However, there was no significant difference seen at any of the frequencies for amplitude parameters in both TB and NB-chirp ABR. Latency of wave V using NB-chirp was considered to be a better indicator compared to TB, acting as a better clinical tool in early identification, diagnosis, and monitoring of noise induced hearing loss (NIHL).

Development of equally intelligible Telugu sentence-lists to test speech recognition in noise.

OBJECTIVE: To develop sentence lists in the Telugu language for the assessment of speech recognition threshold (SRT) in the presence of background noise through identification of the mean signal-to-noise ratio required to attain a 50% sentence recognition score (SRTn). DESIGN: This study was conducted in three phases. The first phase involved the selection and recording of Telugu sentences. In the second phase, 20 lists, each consisting of 10 sentences with equal intelligibility, were formulated using a numerical optimisation procedure. In the third phase, the SRTn of the developed lists was estimated using adaptive procedures on individuals with normal hearing. STUDY SAMPLE: A total of 68 native Telugu speakers with normal hearing participated in the study. Of these, 18 (including the speakers) performed on various subjective measures in first phase, 20 performed on sentence/word recognition in noise for second phase and 30 participated in the list equivalency procedures in third phase. RESULTS: In all, 15 lists of comparable difficulty were formulated as test material. The mean SRTn across these lists corresponded to -2.74 (SD = 0.21). CONCLUSIONS: The developed sentence lists provided a valid and reliable tool to measure SRTn in Telugu native speakers.

Auditory brainstem response and late latency response in individuals with tinnitus having normal hearing.

Tinnitus is a commonly encountered complaint in routine audiology practice. The pathophysiology and exact generation site of tinnitus is not precisely established. Auditory brainstem response (ABR) and late latency response (LLR) findings in individuals with tinnitus show mixed results in the literature. Majority of studies have focused on individuals having tinnitus with peripheral hearing loss. The present study explores ABR and LLR characteristics among tinnitus patients with normal audiometric presentation; with no direct indication of any cochlear lesion. This study aims at characterizing the ABR and LLR findings in individuals with tinnitus having normal audiometric presentation. ABR and LLR waveform characteristics were recorded and compared between participants with tinnitus (Group 1) and those without tinnitus (Group 2). The ABR analysis indicated no significant differences in latency and amplitude between Groups 1 and 2. However, patients with tinnitus showed abnormally reduced absolute amplitudes of peaks I and V. LLR analysis indicated no significant differences in latency and amplitude between Groups 1 and 2 except enhanced amplitude of P1. The reduced amplitude of peaks I and V along with normal absolute latencies of peaks I, III and V indicate that the origin of tinnitus is possibly due to reduced excitation of auditory nerve fibres arising from a peripheral hearing loss beyond 8 kHz. The P1 amplitude enhancement could be attributed to mechanism explaining central gain model; which suggests that central auditory structures recalibrates the mean firing rate, considering the reduced output from sensory structures, generating neural noise perceived as tinnitus.

Auditory brainstem responses for click and CE-chirp stimuli in individuals with and without occupational noise exposure.

INTRODUCTION: Encoding of CE-chirp and click stimuli in auditory system was studied using auditory brainstem responses (ABRs) among individuals with and without noise exposure. MATERIALS AND METHODS: The study consisted of two groups. Group 1 (experimental group) consisted of 20 (40 ears) individuals exposed to occupational noise with hearing thresholds within 25 dB HL. They were further divided into three subgroups based on duration of noise exposure (0-5 years of exposure-T1, 5-10 years of exposure-T2, and >10 years of exposure-T3). Group 2 (control group) consisted of 20 individuals (40 ears). Absolute latency and amplitude of waves I, III, and V were compared between the two groups for both click and CE-chirp stimuli. T1, T2, and T3 groups were compared for the same parameters to see the effect of noise exposure duration on CE-chirp and click ABR. RESULT: In Click ABR, while both the parameters for wave III were significantly poorer for the experimental group, wave V showed a significant decline in terms of amplitude only. There was no significant difference obtained for any of the parameters for wave I. In CE-Chirp ABR, the latencies for all three waves were significantly prolonged in the experimental group. However, there was a significant decrease in terms of amplitude in only wave V for the same group. DISCUSSION: Compared to click evoked ABR, CE-Chirp ABR was found to be more sensitive in comparison of latency parameters in individuals with occupational noise exposure. Monitoring of early pathological changes at the brainstem level can be studied effectively by using CE-Chirp stimulus in comparison to click stimulus. CONCLUSION: This study indicates that ABR's obtained with CE-chirp stimuli serves as an effective tool to identify the early pathological changes due to occupational noise exposure when compared to click evoked ABR.

Coexistence of tinnitus and hyperacusis in individuals with auditory dys-synchrony: A single case study.

Certain clinical pathologies affecting the ear and hearing mechanism may co-exist. It is necessary to probe in detail into such conditions so that the pathophysiology is well understood. This research paper through a single case study tries to explain the probable pathophysiology behind coexistence of three different clinical conditions namely auditory dys-synchrony, hyperacusis and tinnitus. These conditions are common in the clinics, but the coexistence of all the three is rare and demands explanation beyond what is available in the literature. The assumed model highlights involvement of the outer hair cell's motor function in the cochlea along with the auditory central gain mechanism to explain possible pathophysiology behind coexistence of the three conditions. This model will provide insight into the probable link between the contribution of peripheral and central structures of hearing in generating tinnitus and hyperacusis in individuals having auditory dys-synchrony.

Influence of Native and Non-Native Multitalker Babble on Speech Recognition in Noise.

The aim of the study was to assess speech recognition in noise using multitalker babble of native and non-native language at two different signal to noise ratios. The speech recognition in noise was assessed on 60 participants (18 to 30 years) with normal hearing sensitivity, having Malayalam and Kannada as their native language. For this purpose, 6 and 10 multitalker babble were generated in Kannada and Malayalam language. Speech recognition was assessed for native listeners of both the languages in the presence of native and non-native multitalker babble. Results showed that the speech recognition in noise was significantly higher for 0 dB signal to noise ratio (SNR) compared to -3 dB SNR for both the languages. Performance of Kannada Listeners was significantly higher in the presence of native (Kannada) babble compared to non-native babble (Malayalam). However, this was not same with the Malayalam listeners wherein they performed equally well with native (Malayalam) as well as non-native babble (Kannada). The results of the present study highlight the importance of using native multitalker babble for Kannada listeners in lieu of non-native babble and, considering the importance of each SNR for estimating speech recognition in noise scores. Further research is needed to assess speech recognition in Malayalam listeners in the presence of other non-native backgrounds of various types.