Abstract
Purpose :
Vision loss can impact a number of auditory abilities. Discriminating the distance between two sound sources has been shown to be enhanced in blind participants, while those with partial vision loss show similar performance with age-matched normally-sighted controls. On the other hand, estimating the distance of a sound (without any other sounds as reference) is significantly affected in both blind and vision impaired participants, suggesting that visual information is needed to calibrate audition. To examine whether performance for absolute judgement of sound source distance is influenced by the age of onset of vision loss.
Methods :
Data from 24 participants with varying levels of vision impairment (mild to severe), and 18 normally sighted were analysed. Vision impaired participants were categorised according to the onset of their vision loss (early onset:<10 years, late onset: >10 years), and were VA matched.
Participants were presented with sounds at different distances (ranging from 1.2 to 13.8 m) in a simulated reverberant (with echoes) or anechoic room. Distance judgments were obtained for speech, music, and noise stimuli. Each participant took part in 480 trials.
Results :
ANOVA showed a significant main effect of environmental condition (reverb vs anechoic, p<0.05) and also of the stimulus (p<0.05). Post hoc showed significant differences between early-onset and normally-sighted groups for near and mid-range distances (p<0.05). Late-onset and normally-sighted groups showed no significant difference in performance for a number of distances (p>0.05).
Conclusions :
Early-onset vision impairment results in significant differences in the estimation of sound sources for closer and mid-range distances, with sounds estimated as further away. This has important clinical implications as accurate judgments for closer sounds are needed to guide rapid motor responses to auditory events, e.g. planning a safe path through a busy street to avoid collisions with other people, and also for various daily activities of daily living.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.