Sensory compensation in sound localization in people with one eye

Some blind people are better at locating sounds than people with normal vision indicating cross-modal plasticity. People who have lost one eye have a unique form of visual deprivation that reduces visual afferent signals by half and can potentially also lead to cross-modal (as well as intra-modal) plasticity. To look for evidence of auditory-visual cross-modal compensation, we measured binaural and monaural sound localization in one-eyed people and compared them with normally sighted controls. One-eyed people showed significantly better binaural sound localization than controls in the central region of space (±78° from straight ahead), but they mislocalized sounds in the far periphery (on both the blind and intact side) by up to 15° towards the centre. One-eyed people showed significantly better monaural sound localization compared with controls. Controls' performance became asymmetric when they had one eye patched. Patching improved accuracy in the viewing field but decreased accuracy in the occluded field. These results are discussed in terms of cross-modal sensory compensation and the possible contribution of visual depth to interpreting sound localization cues.