A spatial hearing deficit in early-blind humans

Citation
Mp. Zwiers et al., A spatial hearing deficit in early-blind humans, J NEUROSC, 21(9), 2001, pp. NIL_5-NIL_9
Citations number
34
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Neurosciences & Behavoir
Journal title
JOURNAL OF NEUROSCIENCE
ISSN journal
0270-6474 → ACNP
Volume
21
Issue
9
Year of publication
2001
Pages
NIL_5 - NIL_9
Database
ISI
SICI code
0270-6474(20010501)21:9<NIL_5:ASHDIE>2.0.ZU;2-N
Abstract
An important issue in neuroscience is the effect of visual loss on the rema ining senses. Two opposing views have been advanced. On the one hand, visua l loss may lead to compensatory plasticity and sharpening of the remaining senses. On the other hand, early blindness may also prevent remaining senso ry modalities from a full development. In the case of sound localization, it has been reported recently that, unde r certain conditions, early-blind humans can localize sounds better than si ghted controls. However, these studies were confined to a single sound sour ce in the horizontal plane. This study compares sound localization of early -blind and sighted subjects in both the horizontal and vertical domain, whe reas background noise was added to test more complex hearing conditions. The data show that for high signal-to-noise (S/N) ratios, localization by b lind and sighted subjects is similar for both azimuth and elevation. At dec reasing S/N ratios, the accuracy of the elevation response components deter iorated earlier than the accuracy of the azimuth component in both subject groups. However, although azimuth performance was identical for the two gro ups, elevation accuracy deteriorated much earlier in the blind subject grou p. These results indicate that auditory hyper-compensation in early-blind h umans does not extend to the frontal target domain, where the potential ben efit of vision is maximal. Moreover, the results demonstrate for the first time that in this domain the human auditory system may require vision to op timally calibrate the elevation-related spectral pinna cues. Sensitivity to azimuth-encoding binaural difference cues, however, may be adequately cali brated in the absence of vision.