In contrast to the extensive and systematic cortical ablation studies in animals, comparatively little is known about the effects on auditory responses of either cortical or subcortical lesions in the human auditory system.
In addition to the obvious problem of a meager supply of clinical material, the primary obstacle to experimental study in this area has, in large measure, been the extreme subtlety of the effects produced by lesions in the higher auditory pathways. They are not readily apparent in conventional audiometric tests lke the pure-tone audiogram or the conventional speech discrimination score at a substantial suprathreshold level.
Indeed, it is the thesis of the present paper that these effects can only be demonstrated by means of tasks placing relatively heavy demands on the auditory system. In Schuknecht's words,
The auditory manifestations in patients with temporal lobe lesions, acoustic neurinoma and presbycusis, suggest that lesions involving the auditory pathways result