Benign adult familial myoclonus epilepsy is a progressive disorder: no longer idiopathic generalized epilepsy.

Brain dysfunction in Japanese benign adult familial myoclonus epilepsy (BAFME) has not been elucidated. To clarify diffuse brain dysfunction as indicated by posterior dominant rhythm (PDR) slowing in patients with BAFME. The frequency of PDR on EEG was studied in 19 BAFME patients (50.6±15.7 years) and 38 age-matched control subjects (50.1±14.5 years). We investigated the relationship between age and PDR in both groups. PDR frequency in the patient group (9.1±0.7 Hz) was significantly slower than that of age-matched control subjects (10.4±1.1 Hz; p<0.0001), regardless of the use of anticonvulsants. There was no significant difference in PDR slowing with age between groups. These findings suggest that Japanese patients with BAFME have mild diffuse brain dysfunction with minimal progression.