BSR in the Topographical Differential Diagnosis of the Brain Stem Lesions

Abstract

Auditory brain stem responses (BSR) were studied in five cases including 2 acoustic neurinomas, degenerative type of myoclonus epilepsy, pontine glioma and the 4-th ventricle tumor.
They showed typical BSR suspecting of brain stem lesions, and the BSR patterns were compared with those of animal experiments for discussion of the topographical differential diagnosis. In two patients with acoustic neurinoma, nothing but wave I was recognized at the pathologic side, and normal BSR was recorded at the healthy side. The BSR was similar to that of a cat destructed ipsilateral cochlear nucleus.
In the patient with degenerative type of myoclonus epilepsy, wave I was reconized only in both sides.
In the patient with pontine glioma, wave 1, 2 and 3 at the right side and wave 1 and 2 at the left side were recognized, but the following components were obscured in both sides. The right side response was considered similar to BSR of a cat destructed bilat. inf. colliculus, and the left side one was similar to that of a cat with destruction of bilat. Sup. olivery nucleus complex.
In the patient with the 4-th ventricle tumor, wave 1, 2, 3 and 4 were recognized in both sides, and probably wave 5 was depressed in both sides. BSR was considered similar to that of a cat with destruction of contralateral inf. colliculus or contralateral sup. olivery nucleus complex. It was considered that the BSR pattern was suggestive of a medial lesion of the upper portion of the brain stem.
The data of animal experiments could not be applied to the clinical use, but it could be very useful for topographical differential diagnosis of the brain stem lesions.