Coding of consonant-vowel transition in children with central auditory processing disorder: an electrophysiological study.

INTRODUCTION: Acoustic change complex (ACC) is an important tool to investigate the encoding of the acoustic property of speech signals in various populations. However, there is a limited number of research papers that have explored the usefulness of ACC as a tool to study the neural encoding of consonant-vowel (CV) transition in children with central auditory processing disorder (CAPD). Thus, the present study aims to investigate the utility of ACC as an objective tool to study the neural representation of consonant-vowel (CV) transition in children with CAPD. METHODS: Twenty children diagnosed having CAPD and 20 normal counterparts in the age range of 8-14 years were the participants. The ACC was acquired using naturally produced CV syllable /sa/ with a duration of 380 ms. RESULTS: Latency of N1' and P2' was found to be prolonged in children with CAPD compared to normal counterparts, whereas the amplitude of N1' and P2' did not show any significant difference. Scalp topography showed significantly different activation patterns for children with and without CAPD. CONCLUSION: Prolonged latencies of ACC indicated poor encoding of CV transition in children with CAPD. The difference in scalp topography might be because of the involvement of additional brain areas for the neural discrimination task in children with CAPD.

Neural representation of consonant-vowel transition in individuals with cochlear hearing loss and auditory neuropathy spectrum disorder.

PURPOSE: Acoustic change complex (ACC) is an evoked potential recorded in response to subtle change(s) in the continuing stimuli. It is assumed that poor speech perception can be due to poor encoding of consonant-vowel (CV) transition in cochlear hearing loss (CHL) and auditory neuropathy spectrum disorder (ANSD). The present study aims to investigate the use of ACC as an objective tool to study neural representation of CV transition in individuals with ANSD, CHL, and normal hearing (NH). METHODS: The study consisted of three groups of population (NH, ANSD, and CHL) in the age range of 18-40 years. ACC was recorded for naturally produced CV stimulus /sa/ of 380 ms in duration, which consists consonant (150 ms) and vowel (230 ms) using Biologic Navigator pro 7.2.1. RESULTS: The result showed significantly prolonged latencies of ACC in individuals with ANSD compared to NH. The current study also showed significantly prolonged latency and significantly lower peak-to-peak amplitude in individuals with ANSD compared to CHL. The interesting finding of the present study was significantly better peak-to-peak amplitude for CHL compared to NH. Whereas, there was no significant difference between NH and CHL for latencies measures. CONCLUSION: Poor neural synchronization in individuals with ANSD could be the reason of poor neural representation of CV transition in present study. The outcome of the present study showed poor neural representation of CV transition in individuals with ANSD compared to CHL and NH. Current study also showed better encoding of CV transition in individuals with CHL compared to ANSD.

Speech evoked auditory brainstem response and gap detection threshold in middle-aged individual.

This study aimed at characterizing the gap detection threshold (GDT) and speech evoked ABR (SABR) in younger and middle-aged individuals. Two groups of subjects were participated in the study which includes 15 young adults in the age range of 15-25 years and 15 middle-aged individuals in the age range of 40-60 years. SABR with stimulus/da/of 40 ms and GDT were investigated on both groups. For SABR, Mann-Whitney U test revealed that ageing has significantly adverse effect on the encoding of F1 and F2 at brainstem level. However, no significant effect of ageing (till middle age) on the encoding of F0 was observed in present study. Mann-Whitney U test also showed significant longer latency of wave V in middle-aged individuals compared to younger adults. Furthermore, GDT was significantly better in younger adults compared to middle-aged individuals according to Mann-Whitney U test. This study also revealed no significant correlation between GDT and F0, F1, F2 for younger as well as middle-aged individuals. The findings of this study showed poor encoding of certain aspects of speech at brainstem level in middle-aged individuals compared to younger adults. This study also revealed deterioration of auditory processes in middle-aged individuals.

Cortical and subcortical processing of short duration speech stimuli in trained rock musicians: a pilot study.

Most trained musicians are actively involved in rigorous practice from several years to achieve a high level of proficiency. Therefore, musicians are best group to research changes or modification in brain structures and functions across several information processing systems. This study aimed to investigate cortical and subcortical processing of short duration speech stimuli in trained rock musicians and non-musicians. Two groups of participant (experimental and control groups) in the age range of 18-25 years were selected for the study. Experimental group includes 15 rock musicians who had minimum professional training of 5 years of rock music, and each member had to be a regular performer of rock music for at least 15 h a week. Further age-matched 15 participants who were not having any formal training of any music served as non-musicians, in the control group. The speech-evoked ABR (S-ABR) and speech-evoked ALLR (S-LLR) with short duration speech 'synthetic /da/' was elicited in both groups. Different measures were analyzed for S-ABR and S-LLR. For S-ABR, MANOVA revealed significant main effect of groups on latencies of wave V, wave A, and amplitude of wave V/A slope. Similarly, Kruskal-Wallis test showed significantly higher F 0 amplitude in rock musicians compared with non-musicians. For S-LLR, MANOVA showed statistically significant differences observed for latencies of wave P2 and N2 and amplitude measures of P2-N2 amplitude. This study indicated better neural processing of short duration speech stimuli at subcortical as well as cortical level among rock musicians when compared with non-musicians.

Acoustic Change Complex as a Neurophysiological Tool to Assess Auditory Discrimination Skill: A Review.

Introduction Acoustic change complex (ACC) is a type of event-related potential evoked in response to subtle change(s) in the continuing stimuli. In the presence of a growing number of investigations on ACC, there is a need to review the various methodologies, findings, clinical utilities, and conclusions of different studies by authors who have studied ACC. Objective The present review article is focused on the literature related to the utility of ACC as a tool to assess the auditory discrimination skill in different populations. Data Synthesis Various database providers, such as Medline, Pubmed, Google, and Google Scholar, were searched for any ACC-related reference. A total of 102 research papers were initially obtained using descriptors such as acoustic change complex , clinical utility of ACC , ACC in children , ACC in cochlear implant users , and ACC in hearing loss . The titles, authors, and year of publication were examined, and the duplicates were eliminated. A total of 31 research papers were found on ACC and were incorporated in the present review. The findings of these 31 articles were reviewed and have been reported in the present article. Conclusion The present review showed the utility of ACC as an objective tool to support various subjective tests in audiology.

Is Early Cochlear Implantation Leads to Better Speech and Language Outcomes?

A cochlear implant is an electronic sensory system that converts mechanical energy into coded electrical signals that directly activate the auditory nerve fibers. Present review article investigates the findings of previous research papers which have assessed speech and language outcome in children who underwent early cochlear implantation. Several databases, including PubMed, Google, Google Scholar, and Medline, were investigated for research papers on the speech and language outcomes of children who had early-life implants. According to previous research, early detection and intervention of hearing loss are critical for the growth of speech and language skills. The effect of early detection of hearing loss and early cochlear implantation on a child's overall speech-language and auditory growth is highlighted in this article.

Feasibility of objective assessment of difference limen for intensity using acoustic change complex in children with central auditory processing disorder.

INTRODUCTION: Acoustic change complex (ACC) shows brain's ability to discriminate between acoustic features in an ongoing stimulus. It is this nature of ACC that has generated interest in studying the usefulness of ACC as an objective tool for evaluating difference limens for various stimulus parameters. The present study therefore aimed at investigating the utility of ACC as an objective measure of difference limen for intensity (DLI) in normal hearing children with and without (C)APD. METHODS: Fifteen children with (C)APD and 15 normal hearing children in whom (C)APD was ruled out (comparison group) in the age range of 8-12 years underwent ACC for 6 intensity differences (+1, +3, +4, +5, +10 & +20 dB) and a standard stimulus using a 1000 Hz stimulus. RESULTS: Behavioral DLI (DLIb) as well as DLI found using ACC (DLIo) were both significantly larger in children with (C)APD than the comparison group (p < 0.05). Further, there was a significantly strong positive correlation between DLIb and DLIo (p < 0.001]. CONCLUSION: Outcome of the study provides evidence for the clinical use of ACC as an objective tool for examining DLI in children with (C)APD.

Utility of Acoustic Change Complex as an Objective Tool to Evaluate Difference Limen for Intensity in Cochlear Hearing Loss and Auditory Neuropathy Spectrum Disorder.

Purpose This study aimed to investigate usefulness of acoustic change complex (ACC) as an objective measure of difference limen for intensity (DLI) in auditory neuropathy spectrum disorders (ANSD) and cochlear hearing loss (CHL). Method The study used a multiple static group comparison research design. Twenty normal-hearing individuals (NH), 19 individuals with ANSD, and 23 individuals with CHL underwent DLI measurement using behavioral (psychoacoustic) techniques and ACC. For eliciting ACC, a 500-ms, 1,000-Hz pure tone was presented at 80 dB SPL. Additionally, six variants of this stimulus with intensity increments of 1, 3, 4, 5, 10, and 20 dB starting 250 ms after stimulus onset were used to elicit the ACC. Results The lowest intensity change that produced replicable and clearly identifiable ACC was referred as objective DLI. In comparison to NH and CHL, the behavioral as well as the objective DLI were significantly larger (poorer) in ANSD (p < .05). Significantly strong positive correlation existed between DLI obtained using behavioral and objective measures (p < .05). Conclusions ACC could be a useful objective tool to measure DLI in the clinical population, provided the individuals of the clinical population fulfill the prerequisite of the presence of Auditory Long Latency Responses. Supplemental Material https://doi.org/10.23641/asha.12560132.

Acoustic Change Complex as a Neurophysiological Tool to Assess Auditory Discrimination Skill: A Review

Abstract Introduction Acoustic change complex (ACC) is a type of event-related potential evoked in response to subtle change(s) in the continuing stimuli. In the presence of a growing number of investigations on ACC, there is a need to review the various methodologies, findings, clinical utilities, and conclusions of different studies by authors who have studied ACC. Objectives The present review article is focused on the literature related to the utility of ACC as a tool to assess the auditory discrimination skill in different populations. Data Synthesis Various database providers, such as Medline, Pubmed, Google, and Google Scholar, were searched for any ACC-related reference. A total of 102 research papers were initially obtained using descriptors such as acoustic change complex, clinical utility of ACC, ACC in children, ACC in cochlear implant users, and ACC in hearing loss. The titles, authors, and year of publication were examined, and the duplicates were eliminated. A total of 31 research papers were found on ACC and were incorporated in the present review. The findings of these 31 articles were reviewed and have been reported in the present article. Conclusions The present review showed the utility of ACC as an objective tool to support various subjective tests in audiology.

Speech-Evoked Auditory Brainstem Response in Individuals with Diabetes Mellitus Type 2.

OBJECTIVE: Diabetes is the most common glucose level dependent metabolic disorder and studies have shown that hearing impairment can be a long-term subclinical complication. Studies to investigate auditory system involvement in diabetes has focused majorly on the auditory brainstem response (ABR), otoacoustic emission, and basic audiological measures. Hence in the current study, we used speech-evoked ABR (S-ABR) as a tool to see the effect of diabetes on both a transient and sustained response of the auditory brainstem to a conventionally used consonant-vowel (CV) stimuli /da/. MATERIALS AND METHODS: This preliminary investigation was done on 22 individuals in the age range of 40-55 years. 11 individuals were diabetics for a minimum period of five years. The S-ABR was recorded for all the participants with speech stimuli /da/ of 40 ms duration. Latency analysis of the waves V, A, D, E, F, and O were carried out. The statistical analysis included descriptive measures, paired t tests, and MANOVA. RESULTS: The findings of the current study suggest that middle-aged individuals with diabetes have a significant deficiency in auditory processing at the brainstem level. Both transient (wave V (p=0.00), A (p=0.00), and O (p=0.00)) and sustained responses (wave D (p=0.001), E (p=0.00), and F (p=0.00)) of the S-ABR were found to be affected in diabetic individuals compared to age-matched non-diabetic individuals. CONCLUSION: Considering diabetes is a common metabolic disorder in the middle-aged Indian population, the findings of the present study can have significant clinical implication.

Parental Expectation from Children with Cochlear Implants in Indian Context: a Questionnaire Based Study.

Introduction Parental support is important in the habilitation/rehabilitation of children using cochlear implant devices. Hence, it is important for families to know the realistic expectations regarding outcomes from CIs. Objective The objective of the present study is to know the parents' expectation from children using CIs. Methods For this study, we recruited 23 parents of children using CIs. We administered 15 questions translated in to Hindi related to communication abilities, social skills, academic achievement, change in future life, rehabilitation demand, and stress due to hearing impairment. Results The response of the questions (5-point rating scale) related to communication abilities showed that parents were expecting children using CIs to use the telephone (95%), to be able to detect soft sounds (99%), to listen in crowds (86%), to be able to easily understand others (76%), and to show improvement in communication skills (78%). Similarly, for questions related to social skills showed 90% of the parents expecting that their children with CIs should be able to easily make friends with normal hearing peers, and 80% of the parents were expecting the children to achieve high standards in their reading and writing skills. Questions related to change in future life showed 86% of the parents expecting their children with CIs to act like normal hearing children. Further, 78% parents showed positive response regarding importance of intensive training. However, 70% of the parents reported stress in the family due to the existence of the hearing impaired child. Conclusion Overall, the existing questionnaire-based study showed that parents have high expectations from their children with cochlear implant.

A Comparative Study on Hearing Aid Benefits of Digital Hearing Aid Use (BTE) from Six Months to Two Years.

Introduction For many reasons, it is important for audiologists and consumers to document improvement and benefit from amplification device at various stages of uses of amplification device. Professional are also interested to see the impact of amplification device on the consumer's auditory performance at different stages i.e. immediately after fitting and over several months of use. Objective The objective of the study was to measure the hearing aid benefit following 6 months - 1-year usage, 1 year - 1.5 years usage, and 1.5 years - 2 years' usage. Methods A total of 45 subjects participated in the study and were divided equally in three groups: hearing aid users from 6 months to 1 year, 1 year to 1.5 year, and 1.5 year to two years. All subjects responded to the Hearing Aid Benefit Questionnaire (63 questions), which assesses six domains of listening skills. Result Results showed the mean scores obtained were higher for all domains in the aided condition, as compared with unaided condition for all groups. Results also showed a significant improvement in the overall score between first-time users with hearing aid experience of six months to one year and hearing aid users using hearing aids for a period between 1.5 and 2 years. Conclusion It is possible to conclude that measuring the hearing aid benefit with the self-assessment questionnaires will assist the clinicians in making judgments about the areas in which a patient is experiencing more difficulty in everyday listening environment and in revising the possible technologies.

Enhanced auditory evoked potentials in musicians: A review of recent findings.

Auditory evoked potentials serve as an objective mode for assessment to check the functioning of the auditory system and neuroplasticity. Literature has reported enhanced electrophysiological responses in musicians, which shows neuroplasticity in musicians. Various databases including PubMed, Google, Google Scholar and Medline were searched for references related to auditory evoked potentials in musicians from 1994 till date. Different auditory evoked potentials in musicians have been summarized in the present article. The findings of various studies may support as evidences for music-induced neuroplasticity which can be used for the treatment of various clinical disorders. The search results showed enhanced auditory evoked potentials in musicians compared to non-musicians from brainstem to cortical levels. Also, the present review showed enhanced attentive and pre-attentive skills in musicians compared to non-musicians.

Pre-attentive auditory discrimination skill in Indian classical vocal musicians and non-musicians.

OBJECTIVE: To test for pre-attentive auditory discrimination skills in Indian classical vocal musicians and non-musicians. DESIGN: Mismatch negativity (MMN) was recorded to test for pre-attentive auditory discrimination skills with a pair of stimuli of /1000 Hz/ and /1100 Hz/, with /1000 Hz/ as the frequent stimulus and /1100 Hz/ as the infrequent stimulus. Onset, offset and peak latencies were the considered latency parameters, whereas peak amplitude and area under the curve were considered for amplitude analysis. STUDY SAMPLE: Exactly 50 participants, out of which the experimental group had 25 adult Indian classical vocal musicians and 25 age-matched non-musicians served as the control group, were included in the study. Experimental group participants had a minimum professional music experience in Indian classic vocal music of 10 years. However, control group participants did not have any formal training in music. RESULTS: Descriptive statistics showed better waveform morphology in the experimental group as compared to the control. MANOVA showed significantly better onset latency, peak amplitude and area under the curve in the experimental group but no significant difference in the offset and peak latencies between the two groups. CONCLUSION: The present study probably points towards the enhancement of pre-attentive auditory discrimination skills in Indian classical vocal musicians compared to non-musicians. It indicates that Indian classical musical training enhances pre-attentive auditory discrimination skills in musicians, leading to higher peak amplitude and a greater area under the curve compared to non-musicians.

Comparison of Pre-Attentive Auditory Discrimination at Gross and Fine Difference between Auditory Stimuli.

Introduction Mismatch Negativity is a negative component of the event-related potential (ERP) elicited by any discriminable changes in auditory stimulation. Objective The present study aimed to assess pre-attentive auditory discrimination skill with fine and gross difference between auditory stimuli. Method Seventeen normal hearing individual participated in the study. To assess pre-attentive auditory discrimination skill with fine difference between auditory stimuli, we recorded mismatch negativity (MMN) with pair of stimuli (pure tones), using /1000 Hz/ and /1010 Hz/ with /1000 Hz/ as frequent stimulus and /1010 Hz/ as infrequent stimulus. Similarly, we used /1000 Hz/ and /1100 Hz/ with /1000 Hz/ as frequent stimulus and /1100 Hz/ as infrequent stimulus to assess pre-attentive auditory discrimination skill with gross difference between auditory stimuli. The study included 17 subjects with informed consent. We analyzed MMN for onset latency, offset latency, peak latency, peak amplitude, and area under the curve parameters. Result Results revealed that MMN was present only in 64% of the individuals in both conditions. Further Multivariate Analysis of Variance (MANOVA) showed no significant difference in all measures of MMN (onset latency, offset latency, peak latency, peak amplitude, and area under the curve) in both conditions. Conclusion The present study showed similar pre-attentive skills for both conditions: fine (1000 Hz and 1010 Hz) and gross (1000 Hz and 1100 Hz) difference in auditory stimuli at a higher level (endogenous) of the auditory system.

Temporal Resolution and Active Auditory Discrimination Skill in Vocal Musicians.

Introduction Enhanced auditory perception in musicians is likely to result from auditory perceptual learning during several years of training and practice. Many studies have focused on biological processing of auditory stimuli among musicians. However, there is a lack of literature on temporal resolution and active auditory discrimination skills in vocal musicians. Objective The aim of the present study is to assess temporal resolution and active auditory discrimination skill in vocal musicians. Method The study participants included 15 vocal musicians with a minimum professional experience of 5 years of music exposure, within the age range of 20 to 30 years old, as the experimental group, while 15 age-matched non-musicians served as the control group. We used duration discrimination using pure-tones, pulse-train duration discrimination, and gap detection threshold tasks to assess temporal processing skills in both groups. Similarly, we assessed active auditory discrimination skill in both groups using Differential Limen of Frequency (DLF). All tasks were done using MATLab software installed in a personal computer at 40dBSL with maximum likelihood procedure. The collected data were analyzed using SPSS (version 17.0). Result Descriptive statistics showed better threshold for vocal musicians compared with non-musicians for all tasks. Further, independent t-test showed that vocal musicians performed significantly better compared with non-musicians on duration discrimination using pure tone, pulse train duration discrimination, gap detection threshold, and differential limen of frequency. Conclusion The present study showed enhanced temporal resolution ability and better (lower) active discrimination threshold in vocal musicians in comparison to non-musicians.

Auditory Temporal Resolution in Individuals with Diabetes Mellitus Type 2.

Introduction "Diabetes mellitus is a group of metabolic disorders characterized by elevated blood sugar and abnormalities in insulin secretion and action" (American Diabetes Association). Previous literature has reported connection between diabetes mellitus and hearing impairment. There is a dearth of literature on auditory temporal resolution ability in individuals with diabetes mellitus type 2. Objective The main objective of the present study was to assess auditory temporal resolution ability through GDT (Gap Detection Threshold) in individuals with diabetes mellitus type 2 with high frequency hearing loss. Methods Fifteen subjects with diabetes mellitus type 2 with high frequency hearing loss in the age range of 30 to 40 years participated in the study as the experimental group. Fifteen age-matched non-diabetic individuals with normal hearing served as the control group. We administered the Gap Detection Threshold (GDT) test to all participants to assess their temporal resolution ability. Result We used the independent t-test to compare between groups. Results showed that the diabetic group (experimental) performed significantly poorer compared with the non-diabetic group (control). Conclusion It is possible to conclude that widening of auditory filters and changes in the central auditory nervous system contributed to poorer performance for temporal resolution task (Gap Detection Threshold) in individuals with diabetes mellitus type 2. Findings of the present study revealed the deteriorating effect of diabetes mellitus type 2 at the central auditory processing level.

Assessment of rock musician's efferent system functioning using contralateral suppression of otoacoustic emissions.

OBJECTIVE: Contralateral suppression of oto acoustic emission (OAE) is referred as activation of efferent system. Previous literature mentioned about the importance of contralateral suppression of OAEs as a tool to assess efferent system in different groups of population. There is dearth of literature to explore the efferent system function in experienced musicians exposed to rock music using TEOAEs and DPOAEs. METHODS: Two groups of participant (14 rock musicians and 14 non-musicians) in the age range of 18-25 years were involved in the study. Contralateral suppression of TEOAEs and DPOAEs were measured using ILO (Version 6) in both groups. RESULTS: Descriptive statistics showed higher suppression of TEOAEs and DPOAEs in rock-musicians at most of the frequencies in comparison to non-musicians. For DPOAE measures, Mann Whitney U test results revealed significantly greater DPOAE suppression only at 1 kHz and 3 kHz in rock-musicians compared to non-musicians. For within group comparison, Kruskal Wallis test results revealed there were significant difference observed across most of the frequencies i.e. at 1 kHz, 3 kHz and 6 kHz. For TEOAE measures, Mann Whitney U test results revealed that only at 2 kHz, TEOAE suppression in rock-musician was significantly greater compared to non-musicians. Similarly, Kuskal Wallis test results revealed that within group there were no significant differences observed for most of the frequencies except 2 kHz. CONCLUSIONS: Based on the above finding, present study concludes that rock musicians are having better efferent system compared to non-musicians. No suppression effect at few frequencies probably indicates more vulnerability at those frequencies. Contralateral suppression of DPOAE shows more significant finding in comparison to contralateral suppression of TEOAEs in present study.

Comparison of Cervical and Ocular Vestibular Evoked Myogenic Potentials in Dancers and Non-Dancers.

The objective of the study was to assess the sacculocollic and otolith ocular pathway function using cervical vestibular evoked myogenic potentials (cVEMP) and ocular vestibular myogenic potentials (oVEMP) in dancers and non dancers. Total 16 subjects participated in the study. Out of 16 participants, 8 were trained in Indian classical form of dance (dancers) and other 8 participants who were not trained in any dance form (non dancers). cVEMP and oVEMP responses were recorded for all the subjects. Non Parametric Mann-Whitney U test revealed no significant difference between dancers and non dancers for the latency and amplitude parameter for cVEMP and oVEMP, i.e. P13, N23 latency and P13-N23 complex amplitude and N10, P14 latency, N10-P14 complex amplitude respectively. The vestibular system comprises of several structures. It is possible that the dance style practiced by the dancer's group assessed in this study does not contribute towards improving the plasticity of the sacculocollic and otolith-ocular pathways. It can be concluded that not all forms of dance training brings about a change in the plasticity of the sacculocollic and otolithocular pathways.

Parental Expectation from Children with Cochlear Implants in Indian Context: a Questionnaire Based Study

Abstract Introduction Parental support is important in the habilitation/rehabilitation of children using cochlear implant devices. Hence, it is important for families to know the realistic expectations regarding outcomes from CIs. Objective The objective of the present study is to know the parents' expectation from children using CIs. Methods For this study, we recruited 23 parents of children using CIs. We administered 15 questions translated in to Hindi related to communication abilities, social skills, academic achievement, change in future life, rehabilitation demand, and stress due to hearing impairment. Results The response of the questions (5-point rating scale) related to communication abilities showed that parents were expecting children using CIs to use the telephone (95%), to be able to detect soft sounds (99%), to listen in crowds (86%), to be able to easily understand others (76%), and to show improvement in communication skills (78%). Similarly, for questions related to social skills showed 90% of the parents expecting that their children with CIs should be able to easily make friends with normal hearing peers, and 80% of the parents were expecting the children to achieve high standards in their reading and writing skills. Questions related to change in future life showed 86% of the parents expecting their children with CIs to act like normal hearing children. Further, 78% parents showed positive response regarding importance of intensive training. However, 70% of the parents reported stress in the family due to the existence of the hearing impaired child. Conclusion Overall, the existing questionnaire-based study showed that parents have high expectations from their children with cochlear implant.