A review of transneuronal changes of the auditory central nervous system as a consequence of auditory defects.

During the last three decades there have been numerous investigations revealing a consistent pattern of transneuronal changes of various portions of the central auditory nervous system which have been associated with either anatomical defects in the peripheral auditory apparatus (cochlear and/ or acoustic division of the VIII nerve), or with reduction of auditory stimulus to the cochlea (auditory deprivation). The changes are essentially consistent from species to species, and qualitatively similar regardless of the type of peripheral deficiency which was effected. These will be reviewed in this report. The physiological and behavioral consequences of these changes in other studies have also been reported, but will not be reviewed in this paper. The anatomical changes may or may not have implications in the care and habilitation of hearing deficits in man. As will be seen from the data, certain broad characteristics of the resultant central auditory nervous system changes are known in various species. Whether or not the same changes occur in man and how they might manifest themselves is unknown. It is hoped that one effect of this review will be to provide a basis to ask critical questions in the area of human audition and neuropathology.