Abstract
Purpose :
Total blindness enhances a range of auditory abilities and degrades others. However what is not known is the severity of visual loss needed for these changes in performance to occur. We assessed the accuracy of absolute distance perception in normally sighted controls and participants with a range of severities of visual loss for speech, music and noise stimuli, in anechoic and reverberant rooms.
Methods :
Anechoic and reverberant virtual rooms were generated using virtualization software. Participants heard static sound stimuli at virtual distances ranging from 1.2 to 13.8 m. Participant groups were 18 sighted controls (LogMAR = 0), 16 with mild visual impairment (LogMAR 0.1-1), 12 with mid-range visual impairment (LogMAR 1.1-2.9), and 10 with severe visual impairment (LogMAR 3-4). All were audiometrically tested and had normal hearing. Speech, music, or noise stimuli were presented, and participants were required to estimate the distance of the sound source. Over a series of trials, the type of stimulus was kept constant.
Results :
The results showed that for all conditions, the greater the severity of participant visual loss, the more their performance deviated from that obtained in normally sighted individuals (p<0.05). Participants with visual losses were least accurate when estimating the distance of near sounds, increasing the likelihood of collision and falls due to misjudging the location of the sound source.
Conclusions :
Based on the results, we propose that the calibration of the auditory system using visual information is dependent on the severity of visual loss.
This is a 2020 ARVO Annual Meeting abstract.