ACOUSTICALLY AND ELECTRICALLY EVOKED AUDITORY BRAINSTEM RESPONSES Similarities and Differences

In early models of the generation of the human auditory brainstem respon se (ABR), the successive components were cons idered to arise in consecutive structures of the auditory pathway (e.g. Lev and Sohm er, 1972) . Waves I, II, III, IV,and V were in particular believed to originate from the 8th nerve, cochlear nuclei, superior olivary complex, lateral lemniscus and inferior colli culus, respectively. The sources of the latest ABR constituents, i.e. of Waves VI and VII, were connected to still further relays: the medial geniculate body and the acoustic radiation, respectively. Later, these early models underwent alterations (Kevanishvili, 1980; Caird and Klinke, 1984) . Both neurophysiological and neurosurgical evidence was presented substantiating subcollicular or even sublemniscal orig in of the main ABR complex waves including Wave V. The loci ofgeneration of the successive components were shifted downward in proportion. Wave VI, for instance, has been stated to be related to the inferior colliculus (Hall , 1992). Recording of electrically evoked ABR in cochlear implant patients offers a unique opportunity to revise the models of ABR generation.