Brain stem auditory evoked response correlates in patients with spinocerebellar lesions

Brain stem auditory evoked responses were obtained in three patients with spinocerebellar dysfunction for assessment of brain stem involvement and lateralization. Computed tomography scan in the three cases showed negative findings for the brain stem. The evoked potentials demonstrated involvement of the pontine tegmentum. Correlation was found for lateralization to the site of greater neurologic deficit. Brain stem auditory evoked response abnormalities reflect disturbance of neural function rather than the underlying anatomic change of that disturbance. It therefore appears to be a more sensitive type of testing than the computed tomography scan in detecting lesions that alter electrophysiology but do not produce alterations of morphology and radiodensity.