Do the blind hear better? Investigations on auditory processing in congenital or early acquired blindness. II. Central functions.

The same 18 normally hearing students and 18 matched normal-sighted students, as in part I of this study, were compared in regard to pure-tone integration, speech discrimination ability and late cortical-evoked potentials. The blind subjects showed increased disinhibition ('cleaning') with broad-band noise and a decreased inhibition with the same stimulus at the contralateral ear, better speech discrimination, especially with regard to sentence tests without and with competing environment-simulating noise, and, by electric response audiometry (ERA), a shortened N1 latency. Thus, the hypothesis of a better utilization of auditory information after the loss of the visual information channel could be confirmed, and may be ascribed to the plasticity of the central nervous system.