TECTAL PLATE GLIOMAS .3. APPARENT LACK OF AUDITORY CONSEQUENCES OF UNILATERAL INFERIOR COLLICULAR LESION DUE TO LOCALIZED GLIOMA SURGERY

The authors present one of their cases operated on for intrinsic tecta l plate glioma. The complete resection of the right inferior colliculu s (I.C.) had no apparent auditory consequences. The pre- and post-oper ative tonal and vocal auditory tests were normal. The brain-stem audit ory evoked potentials (BAEPs) and middle latency potentials (MLPs) wer e recorded pre-, post- and intra-operatively. At the end of surgery al l waves were present with a marked delay of wave V and a slight delay of the Pa component. The dichotic test showed a significant right ear extinction but admittedly much less important than expected. The role of inferior colliculus (I.C.) in hearing is discussed.