Extensive Audio-motor Experience Can Calibrate The Egocentric Space In Early Blindness

Combining and integrating cues from different sensory channels is fundamental in developing a spatial representation of the environment. In the sighted population, the visual channel is essential in the spatial representation calibration; indeed, blind individuals show some impairments. One may compensate the vision loss to some degree by exploiting the associations between a movement and the consequent change in perceived auditory scene, known as audio-motor contingencies. The compensation extent is unclear, but evidence suggests that it depends on the amount of both visual and motor experience.To quantify the extent of audio-motor compensation in relation to motor and audio-motor experience, we tested the spatial representation skills of a long-experienced early blind 5-a-side football player. We focused on auditory localization performance and sensitivity to an audio-motor contingency alteration. The study compared the player to groups of early blind (audio-motor experience without specific training) and sighted blindfolded people. We also tested an additional early blind individual without extensive audio-motor experience but who lost vision at an older age than the player, to control the effect of early visual experience alone.Participants were tested on a set of steering tasks in auditory virtual reality (VR). In such tasks, participants would rotate a flying arrow towards an acoustic target. Rotations of the head or trunk controlled the arrow trajectory. Additionally, in some conditions, the relationship between movement and change of acoustic perceptual scene was altered to expose the participants’ sensitivity to the audio-motor contingency alteration.The early blind player performance was analyzed with classical univariate single-case statistics and a multivariate support vector machine classifier. Univariate analyses suggested that the early blind player’s trunk motion is early blind-like. However, the multivariate classifier interpreted his overall performance as that of a sighted individual. The multivariate classifier labelled the visually experienced early blind's overall performance as early blind-like. We concluded that extensive audio-motor experience could compensate for early vision loss for what concerns the sensitivity to audio-motor contingency alterations. These results support the idea that adapted sports for visually impaired people are useful to improve their spatial representation and, consequently, their quality of life.