Purchase this article with an account.
Andrew Joseph Kolarik, Brian Moore, Silvia Cirstea, Shahina Pardhan; Auditory spatial representations of distance are compressed in blind individuals. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):2623.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Blind individuals primarily rely on sound for spatial information about their environment in far space. However, it is currently unknown how well they are able to judge the distance of sound sources. We investigated whether lack of visual information, which aids in calibrating audition in far space, leads to poorer estimation of the apparent distance of sounds by blind participants.
Virtualization techniques were used to simulate virtual anechoic and reverberant rooms. Single, unmoving sounds were presented at virtual distances between 1.2 and 13.8 m to 10 blind and 12 normally sighted participants. All had normal hearing. Stimuli were speech, music or noise. Participants were instructed to report the apparent distance of each sound source. Within a series of trials the stimulus type was held constant.
For normally sighted participants, perceived distance to farther sounds was underestimated. For blind participants, the distances for closer sounds were overestimated, and those for farther sounds were underestimated. Accuracy of distance judgements was quantified as the mean unsigned error. For both groups, errors increased with increasing virtual distance, and errors were higher for the blind than the sighted group. A mixed-model ANOVA with distance, room reverberation, stimulus and blindness as factors showed main effects of distance and blindness (p<0.05). No other main effects or interactions were significant.
Absolute auditory distance judgements are less accurate for blind participants than for normally sighted controls. The internal representation of auditory distance for blind participants is compressed. These findings suggest that accurate calibration and fidelity for sound cues used to perceive auditory distance is compromised as a result of blindness.
This PDF is available to Subscribers Only