Brainstem auditory evoked potentials in 20 patients with palatal myoclonus.

Brainstem auditory evoked potentials (BAEPs) were obtained in 20 patients with palatal myoclonus. The group included 14 men and six women whose ages ranged from 19 to 82 years. Six of the patients had abnormal BAEPs: two with severe head trauma and one each with a brainstem infarct, tumor, demyelination, and an indeterminate inflammatory process. The 14 patients with normal BAEPs had palatal myoclonus secondary to head trauma (five patients), brainstem infarcts (four patients), cerebellar tumors (two patients), degenerative processes (two patients), and an Arnold-Chiari malformation (one patient). Since the auditory pathways are separate from the structures associated with palatal myoclonus, it is possible to have discrete lesions producing palatal myoclonus with sparing of the auditory structures, whereas diffuse or multifocal lesions of the brainstem are more likely to be associated with abnormal BAEPs.