Comparison of gap in noise test results between congenital blind and sighted subjects with normal hearing

Main feature of auditory processing abilities is temporal processing including temporal resolution, temporal ordering, temporal integration and temporal masking. Many studies have shown the superiority of blinds in temporal discrimination over sighted subjects. In this study, temporal processing was compared in congenital blind subjects with sighted controls via gap in noise test (GIN). This analytic-prescriptive non-invasive cohort study was conducted on 22 congenital blinds (11 males and 11 females) with a mean age of 26.22 years and 22 sighted control subjects (11 males and 11 females) with a mean age of 24.04 years with normal hearing in faculty of Rehabilitation Tehran University of Medical Sciences. Gap in noise test results, approximate threshold and percent of corrected answers, were obtained and then, were analyzed by Mann-Whitney non-parametric statistical test. There was a significant difference in the approximate threshold and the percent of corrected answers between congenital blinds and sighted control subjects (p<0.05). However, there was no significant difference between males and females in this regard (p>0.05). Auditory temporal resolution ability, the lower approximate threshold and the more corrected answers in gap in noise, in blind subjects is better than the sighted control group and it might be related to the compensative neuroplasticity after visual deprivation.