Purpose: Although very rare, DRPLA is an important differential diagnosis in patients with progressive myoclonic epilepsy (PME). Recently, the diagnosis of DRPLA has become easier because of the widespread availability of DNA analysis. However, it is still important to develop tools for clinical diagnosis and to uncover the pathophysiology of DRPLA. The purpose of the present study was to investigate the usefulness of evoked potential recording for the clinical diagnosis of DRPLA and elucidation of its pathophysiology.