The link between blindness onset and audiospatial processing: testing audiomotor cues in acoustic virtual reality

Vision seems essential for cross-modal calibration of auditory cues in spatial perception. Previous findings showed that, in some specific tasks such as sound localization, blind individuals have enhanced skills, suggesting that the audiomotor loop might partially compensate for early visual loss in the calibration of auditory space; however, direct evidence is still lacking. Here, we proposed a method based on the alteration of the audiomotor loop. Acoustic virtual reality was used to measure the audiomotor loop's influence on the space perception of blind individuals. We developed a VR steering task by head or trunk pointing to auditory sources, where the audiomotor conflict is induced by letting trunk rotations change the auditory scene together with head rotations. Early blind, late blind, and sighted participants were tested to assess their sensitivity to the induced audiomotor conflict. The platform demonstrated its effectiveness in exposing participants' sensitivity to the audiomotor loop alteration. The early blind group was significantly more affected than the sighted group, while the late blind group did not significantly differ from any of the other groups. Our results confirm the increased role of the audiomotor loop for audiospatial information processing in blindness and advocate for the development of new spatial orientation training for blind people based on exploiting the audiomotor loop itself.