[Auditory brainstem response and somatosensory evoked potential in Machado-Joseph disease in Japanese families].

To clarify physiological aspects of Machado-Joseph disease (MJD), we studied auditory brainstem response (ABR) and somatosensory evoked potential (SEP) in 17 clinically diagnosed patients with MJD aged 32-64 in Japanese families. ABR was recorded in 13 patients. In 8 patients, ABR were abnormal. In 5 patients, the latency of I wave was normal, but other waves could not be evoked. In the other 3 patients, I-III interpeak latency was prolonged. SEP was recorded in 15 patients. In SEP of median nerve, 11 patients had abnormal findings, and SEP of posterior tibial nerve revealed abnormal findings in all 15 patients. In all patients, responses from Erb's point and popliteal fossa were normal in latency, but other peaks were low in amplitude or absent, and the latency and central conduction time (CCT) were prolonged. The result of ABR indicated the involvement of the brainstem auditory pathways in MJD, and the result of SEP suggested that somatosensory pathways, particularly central pathways, would be involved in the disease process. ABR and SEP can be potential diagnostic methods for detection of subclinical abnormality in MJD patients.