Spatial auditory representations by blind and sighted humans in the peripersonal space

NICOLÁS D. RODRIGUEZ ALTIERI; ESTEBAN N. LOMBERA; PABLO E. ETCHEMENDY; IGNACIO SPIOUSAS

Villa Carlos Paz

Congreso; XXXIV Reunión Anual SAN 2019; 2019

Sociedad Argentina de Neurociencias

Compared to sighted listeners, blind listeners tend to underestimate their egocentric distance judgments for sound sources located beyond the peripersonal space (the portion of space near the body where individuals can interact with objects), in the absence of additional sensory information. It has been hypothesized that this effect is the consequence of the lack of visual information about the source position. Visual information is thought to be used by sighted listeners throughout their lives to calibrate the auditory spatial information provided by the source and, therefore, build an accurate representation of the auditory space. However, in the absence of visual information, humans could use proprioceptive and tactile information as alternative sources of information when the auditory target is within hand reach. In order to test this hypothesis, we collected both auditory distance and auditory reachability judgments for blind and sighted listeners. Sound sources covered the range from 20 cm to 260 cm. We studied the group differences in distance estimations obtained by reaching (direct action) in the peripersonal space and verbal reports in both the peripersonal and extrapersonal space. We found two sub-populations among blind subjects, one that supports this hypothesis and another one that seems to be unable to discriminate auditory distance for the whole range of distances within the peripersonal space.