We diagnosed abdominal myoclonus in an 8-year-old boy with terminal stage of neuronal ceroid lipofuscinosis (NCL). He was normal up to two years of age when he had onset of myoclonic seizures. Over time his seizures worsened. He lost speech and mobility by six years. Recently he was admitted with recurrent seizures and frequent jerking of the abdominal muscles. His three siblings had died of similar illness. Examination revealed choreathetoid movements of limbs, multifocal myoclonus, and diaphragmatic myoclonus (Web Video I). Surface electromyography (EMG) electrodes applied on the abdomen wall revealed around 120 contractions per minute. Electroencephalography (EEG) showed bihemispherical periodic discharges at rate of 1.5 to 2 per second, left side more than right. Intravenous bolus of phenytoin followed by midazolam infusion controlled his abdominal (diaphragmatic) contractions.

Fig. 1 Diaphragmatic myoclonus in a child (see Video at website).