Peripheral neuropathy in spinocerebellar degenerations.

Nerve conduction studies have been performed in 19 subject with hereditary spinocerebellar degenerations other than Friedreich ataxia. Clinically, they may be classified as olivopontocerebellar atrophy or cerebello-olivary degeneration. In 9 patients, sensory conduction was abnormal, and in the whole group there was a significant impairment of sensory conduction and mild slowing of motor conduction in the lateral popliteal nerve. Sural nerve biopsies were performed on 5 patients. In 3 cases there was a mild to moderate reduction of myelinated fibers of all diameters; unmyelinated fibers were normal. In 1 patient from a kindred with a spinocerebellar degeneration in which the inheritance was autosomal dominant, neuropathological findings at autopsy confirmed the clinical diagnosis of the Menzel type of olivopontocerebellar atrophy; there was a degeneration of dorsal root ganglion and anterior horn cells as well as of myelinated fibers of all diameters in the sural nerve.