In 3 patients with Lafora disease specific ERGs were observed resembling closely those seen in the Schubert-Bronschein type of night blindness. In contrast to essential hemeralopia, where the b-wave is completely lacking a gradual recovery of the b-wave was recorded in Lafora disease. The recovery occurred within about 15 min of dark adaptation. ERG examinations may have diagnostic significance in patients with myoclonic epilepsy.
Adolescent Adult