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


 
 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).
 
 
 
 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.
 
 
 
 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 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.
 
 
 
 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.
