BRAIN-STEM AUDITORY-EVOKED POTENTIALS AND NEUROPATHOLOGIC CORRELATES IN 26 DOGS WITH BRAIN-TUMORS

Brainstem auditory-evoked potentials (BAEPs) were recorded from 26 dog s with intracranial neoplasia. The tumors were grouped according to th eir neuroanatomic location. Normal BAEPs were recorded from 12 dogs wi th cerebral (6/7), diencephalic (4/4), cerebellar (1/1), and multifoca l tumors (1/5). Abnormal BAEPs were recorded from 14 dogs with cerebra l (1/7), cerebellar/brainstem (4/4), brainstem (5/5), and multifocal t umors (4/5). Analysis of the multifocal neoplasms showed that alterati ons of BAEPs correlated with the degree of brainstem involvement. Over all, 13 of the 14 dogs with abnormal BAEPs had tumors involving the br ainstem. The changes of the BAEP correlated with the extrinsic or intr insic location of the tumor relative to the brainstem. The BAEP reflec ted the right, left, or median location of the tumor in 7 of the 14 ab normal recordings. In 1 dog, the BAEP was abnormal contralateral to th e tumor side. A peripheral hearing disorder was excluded in most dogs based on the presence of peak 1.