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Purpose This study was carried out to understand the neural intricacies of auditory spatial processing in listeners with sensorineural hearing impairment (SNHI) and compare it with normal hearing (NH) listeners using both local and global measures of waveform analyses. Method A standard group comparison research design was adopted in this study. Participants were assigned to 2 groups. Group I consisted of 13 participants with mild–moderate flat or sloping SNHI, while Group II consisted of 13 participants with NH sensitivity. Electroencephalographic data using virtual acoustic stimuli (spatially loaded stimuli played in center, right, and left hemifields) were recorded from 64 electrode sites in passive oddball paradigm. Both local (electrode-wise waveform analysis) and global (dissimilarity index, electric field strength, and topographic pattern analyses) measures were performed on the electroencephalographic data. Results Results of local waveform analyses marked the appearance of mismatch negativity in an earlier time window, relative to those reported conventionally in both the groups. The global measures of electric field strength and topographic modulations (dissimilarity index) revealed differences between the 2 groups in different time periods, indicating multiphases (integration and consolidation) of spatial processing. Further, the topographic pattern analysis showed the emergence of different scalp maps for SNHI and NH in the time window corresponding to mismatch negativity (78–150 ms), suggestive of differential spatial processing between the groups at the cortical level. Conclusions The findings of this study highlights the differential allotment of neural generators, denoting variations in spatial processing between SNHI and NH individuals.

Background and Objectives: This study compared the effectiveness of two spatial training programs using real and virtual sound sources in refining spatial acuity skills in listeners with normal hearing. Subjects and Methods: The study was conducted on two groups of 10 participants each; groups I and II underwent spatial training using real and virtual sound sources, respectively. The study was conducted in three phases: pre-training, training, and post-training phases. At the pre-and post-training phases, the spatial acuity of the participants was measured using real sound sources through the localization test, and virtual sound sources through the virtual acoustic space identification (VASI) test. The thresholds of interaural time difference (ITD) and interaural level difference (ILD) were also measured. In the training phase, Group I participants underwent localization training using loudspeakers in free field, while participants in Group II were subjected to virtual acoustic space (VAS) training using virtual sound sources from headphones. Both the training methods consisted of 5-8 sessions (20 min each) of systematically presented stimuli graded according to duration and back attenuation (for real source training) or number of VAS locations (for virtual source training). Results: Results of independent t-scores comparing the spatial learning scores (pre vs. post-training) for each measure showed differences in performance between the two groups. Group II performed better than Group I on the VASI test, while the Group I out-performed Group II on the ITD. Both groups improved equally on the localization test and ILD. Conclusions: Based on the present findings, we recommend the use of VAS training as it has practical implications due to its cost effectiveness, need for minimal equipment, and end user usefulness.

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.

Background and Objectives: The influence of musical aptitude on cognitive test performance in musicians is a long-debated research question. Evidence points to the low performance of nonmusicians in visual and auditory cognitive tasks (working memory and attention) compared with musicians. This cannot be generalized to all nonmusicians, as a sub-group in this population can have innate musical abilities even without any formal musical training. The present study aimed to study the effect of musical aptitude on the working memory and selective attention.Subjects and Methods: Three groups of 20 individuals each (a total of 60 participants), including trained-musicians, nonmusicians with good musical aptitude, and nonmusicians with low musical aptitude, participated in the present study. Cognitive-based visual (Flanker’s selective attention test) and auditory (working memory tests: backward digit span and operation span) tests were administered.Results: MANOVA (followed by ANOVA) revealed a benefit of musicianship and musical aptitude on backward digit span and Flanker’s reaction time (p<0.05). Discriminant function analyses showed that the groups could be effectively (accuracy, 80%) segregated based on the backward digit span and Flanker’s selective attention test. Trained musicians and nonmusicians with good musical aptitude were distinguished as one cluster and nonmusicians with low musical aptitude formed another cluster, hinting the role of musical aptitude in working memory and selective attention.Conclusions: Nonmusicians with good musical aptitude can have enhanced working memory and selective attention skills like musicians. Hence, caution is required when these individuals are included as controls in cognitive-based visual and auditory experiments.

The present study is intervention-based research aimed at remediation of spatial deficits in listeners with sensorineural hearing impairment (SNHI), through the use of virtual acoustic technology. A mixed group design comprising both within (pre-test, post-test control group design) and across the groups (standard group) comparisons were performed. The study included 37 participants, who were divided into three groups. Groups I and II consisted of SNHI listeners, while group III comprised normal hearing (NH) listeners. The study was conducted in three phases. At the pre-training phase, electroencephalographic (EEG) recordings were acquired from all the three groups using spatial deviants presented in P300 paradigm. Following this, group I listeners underwent virtual acoustic space training (VAST), and post-training EEG recordings were obtained. EEG recordings were also acquired from group II listeners in second evaluation without subjecting them to any formal spatial training. Results of unpaired t-tests, grand average waveforms and scalp topographies of offline processed waveforms revealed significant differences between SNHI and NH listeners. Furthermore, spatio-temporal analyses showed the emergence of new scalp maps in post-training phase in trained listeners and no topographic changes in untrained SNHI group, suggestive of benefit derived from VAST right at the fundamental level (cortical) of 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.

Johanson Blizzard syndrome (JBS) is an autosomal recessive disorder that shows a multi-faceted impact on almost all body functions, including speech and hearing. This case presentation describes the comprehensive audiological and rehabilitative profile of an 8-year-old female child with JBS while correlating the test results to the physiological aspects of hearing. Case history revealed poor developmental motor skills, delayed speech and language development with hypothyroidism, and dysmorphic facial features including low bat ears, micrognathia, high arched palate, and hypoplasia of nasal alae. Conditioned pure-tone audiometric responses revealed profound hearing loss of cochlear origin in both ears, which was substantiated with bilateral A-type tympanogram in immittance evaluation. Otoacoustic emissions and auditory brain stem response were absent in both ears, consistent with the audiometric findings. Rehabilitation attempts with a cochlear implant and hearing aid in the opposite ears showed differential improvements, which were in harmony with the aided thresholds. The physiological basis for each finding and future implications are discussed.