Prawin Kumar

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.

Rise/fall and plateau time optimization for cervical vestibular-evoked myogenic potential elicited by short tone bursts of 500 Hz

Abstract Objective: Literature on clinical utility of cervical vestibular-evoked myogenic potential (cVEMP) has been increasing rapidly, though not without inconsistencies in spite of involving similar populations. Close examination of methods across studies exposed the use of variable stimulus parameters, especially rise/fall time (R/FT) and plateau time (PT) as the possible reason. However the effect of variation in R/FT and PT on cVEMP response parameters has been largely uncharted. Design: The study aimed at evaluating the impact of R/FT and PT on cVEMPs elicited by 500-Hz short tone-bursts (STBs) at 95 dB nHL using R/FT from 1 to 4 ms and PT from 0 to 3 ms. Study sample: 30 healthy individuals with normal audio-vestibular system. Results: Significant prolongation of latencies with increasing R/FT and PT (p < 0.05) was noticed. The amplitude however varied significantly only for some R/FTs and PTs. R/FT of 2 ms, in combination with 1-ms PT, produced large amplitudes with lowest variability in amplitude and latency parameters. Conclusions: R/FT of 2 ms along with PT of 1 ms formed a good amalgamation and could be considered optimum for clinical recording of cVEMPs elicited by 500-Hz STBs, although slight deviances in these parameters might not impact the outcome significantly.

Electrocochleography in individuals with Meniere's disease

Background: Electrocochleography (ECochG) is a useful tool helping in the diagnosis of Menieres disease (MD). Extra-tympanic ECochG is a non-invasive technique to record the amplitude of summating potential (SP) alone or the amplitude ratio of SP and action potential (AP). Objectives: The present study was aimed to measure the SP and AP amplitudes alone and the ratio (SP/AP) in individuals with normal hearing and in those with MD. Materials and Methods: A total of 63 ears from 34 individuals with normal hearing and those with MD were selected for the study. Individuals with MD had hearing impairment in the range of mild to moderate sensorineural hearing loss. Extra-tympanic non-invasive ECochG recording was done for all the participants. Results: The results of the study revealed that in individuals with normal hearing, 75.75% of the individual ear had SP responses noticeable, whereas in individuals with MD, only 46.66% had SP waveforms present. Further, the mean latency and amplitude of SP were found to be 0.93 msec and 0.29 μV, respectively, in Menieres ear, whereas in normal ears, they were 0.64 msec and 0.11 μV, respectively. In addition to that, a significant difference in SP/AP amplitude ratio between individuals with normal hearing and those with MD was also reported. Conclusion: Therefore, from the present study one can conclude that the SP values increase both in terms of latency and amplitude in pathological condition. Also, it can be concluded that SP/AP amplitude ratio can help in differentiating individuals with MD from individuals with normal hearing.

Prevalence of mismatch negativity with tonal stimuli in normal-hearing individuals

Electrophysiological measures are one of the objective modes of assessment to check the integrity of the auditory function. The endogenous potentials like mismatch negativity (MMN) are responses which are due to internal events such as cognition or perception. In clinical practice and researches it was observed that MMN not present in all normal hearing individual. So, there is a need to study prevalence of MMN in normal population, which helps the researchers and clinicians in interpreting clinical findings. 50 participants recruited in the age range of 18-25 years. MMN was recorded with pair of stimuli. The pair was having /1000Hz/ and /1100Hz/ with /1000Hz/ as frequent stimulus and /1100Hz/ as the infrequent stimulus. Out of 50 normal hearing subjects, MMN was present only in 33 normal hearing subjects (66%). So clinician should be cautious during interpretation of clinical findings using MMN in abnormal population.

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.

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.

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.

The Developement of Hindi Sentence Test for Speech Recognition in Noise

Background : The aim of the study was to develop a test material in Hindi language for assessing sentence recognition threshold in noise. Material and Methods : The study was conducted in two phases. First phase involved three experiments. First experiment consisted of the collection and recording of the sentence material. In the second experiment, sentence perception was assessed at five signal to noise ratios to check for the equalization of sentence material in terms of intelligibilty. This was done on 25 native speakers of Hindi language with normal hearing sensitivity. In the final experiment, 20 different lists with 10 sentences in each were formulated. The second phase of the experiment involved estimation of signal to noise ratio required to obtain 50% correct sentence identification score (SNR 50) and the test reliability of the lists was assessed. The estimation of SNR 50 was done on 30 native speakers of Hindi language with normal hearing sensitivity. Results : Twenty optimized lists were formulated. Lists were found to be of almost equal difficulty and to have good test reliability in normal-hearing listeners. The average SNR50 was -4.56 dB with a standard deviation of 0.45 dB. Conclusions : The developed test provides a reliable means of measuring sentence recognition threshold in noise for native speakers of Hindi.

Effect of short-duration noise exposure on behavioral threshold and transient evoked otoacoustic emission

Background: It is well known that the short- or long-duration exposure to loud noise can either cause temporary or permanent threshold shift. Pure tone audiometry is most widely used to predict the individual who is susceptible to such noise-induced hearing loss (NIHL). Transient evoked otoacoustic emission (TEOAE) is a noninvasive, objective technique and required less time to administer to find out such effect. However, one must know the sensitivity of TEOAEs to predict susceptibility of NIHL. Objectives: Thus, the present study was taken up to find out the susceptibility of TEOAE to identify the individual who is more susceptible by comparing behavioral temporary threshold shift (TTS). Materials and Methods: There were 28 ears in the age range of 18 to 30 years participated in the study. All participants were evaluated for pure tone thresholds and TEOAEs amplitude before and after exposure to the short-duration noise. Results: Results indicated that there were statistically significant differences observed for both behavioral thresholds shift and TEOAEs amplitude reduction after exposure to short-duration noise at 0.05 levels at different frequencies. Conclusion: Further, it was observed that though there was agreement between the two, TEOAE amplitude shift was not as much as pure tone TTS. Reason and the importance of the TEOAE to use as a tool to find out susceptibility are being discussed in the article.

Altered auditory and vestibular functioning in individuals with low bone mineral density: a systematic review

Alteration in the process of bone remodelling is associated with falls and fractures due to increased bone fragility and altered calcium functioning. The auditory system consists of skeletal structures and is, therefore, prone to getting affected by altered bone remodelling. In addition, the vestibule consists of huge volumes of calcium (CaCO3) in the form of otoconia crystals and alteration in functioning calcium levels could, therefore, result in vestibular symptoms. Thus, the present study aimed at compiling information from various studies on assessment of auditory or vestibular systems in individuals with reduced bone mineral density (BMD). A total of 1977 articles were searched using various databases and 19 full-length articles which reported auditory and vestibular outcomes in persons with low BMD were reviewed. An intricate relationship between altered BMD and audio-vestibular function was evident from the studies; nonetheless, how one aspect of hearing or balance affects the other is not clear. Significant effect of reduced bone mineral density could probably be due to the metabolic changes at the level of cochlea, secondary to alterations in BMD. One could also conclude that sympathetic remodelling is associated with vestibular problems in individual; however, whether vestibular problems lead to altered BMD cannot be ascertained with confidence. The studies reviewed in the article provide an evidence of possible involvement of hearing and vestibular system abnormalities in individuals with reduced bone mineral density. Hence, the assessment protocol for these individuals must include hearing and balance evaluation as mandatory for planning appropriate management.