Occipito-Frontal Sharp Waves—An Under-Recognized Electroencephalogram Pattern in Self-Limited Idiopathic Childhood Focal Epilepsy
We report four children who highlight the potentially under-recognized electroencephalogram pattern of bilaterally synchronous occipito-frontal sharp waves, which may occur in children with Panayiotopoulos type self-limited childhood epilepsy but may be easily confused with the patterns of symptomatic generalized epilepsy. Our patients were young, healthy children who had infrequent, predominantly nocturnal, fairly prolonged seizures characterized by altered consciousness, vomiting, and autonomic features, or in one case nocturnal secondary generalized tonic-clonic convulsion. Their electroencephalograms showed stereotyped abundant sleep-activated sharp waves with maximum negativity in bilateral occipital and frontal greater than centro-temporo-parietal regions. On a “double-banana” bipolar montage, the sharp waves had upward deflections in frontal electrodes, downward deflections at occipital electrodes, and a positive phase reversal in the middle of each chain. The lower-amplitude occipital discharges slightly preceded the frontal discharges, consistent with posterior-to-anterior propagation likely originating from mesial occipital regions. In the proper clinical context, recognizing the electroencephalogram pattern of bilateral occipito-frontal sharp waves affords confidence in a favorable prognosis, presents the option to possibly defer daily treatment with antiepileptic medication, and shifts the emphasis to rescue medication for isolated seizures.