Bihemispheric Seizure Without Generalization

A 70-year-old male without prior psychiatric history presented with recurrent episodes (<60 seconds each, every 5-10 minutes) of left hemibody and right lower extremity jerking movements concerning for seizure with preserved awareness (Video). Examination showed left hemiparesis (leg > arm) in addition to right lower extremity weakness. Computed tomography showed a right parafalcine acute subdural hematoma (SDH). Clinical events did not recur after intravenous lorazepam (4 mg) and levetiracetam load (3500 mg), and his weakness improved. He was continued on levetiracetam and has since remained seizure free for 16 months. A 60-minute awake/sleep electroencephalogram (EEG) obtained 12 hours after administration of antiseizure medications showed low amplitude theta slowing (posterior predominant) in the range of 5-7 Hz. There was no apparent epileptiform activity or other abnormalities during the awake and sleep recording or photic stimulation. Focal seizures originate from pathologic disruption of neuronal activity within an isolated brain region, almost exclusively from a single hemisphere. Focal seizures may generalize bilaterally with associated impaired awareness. This is the first visual report demonstrating focal, bihemispheric clinical seizures, without generalization or impaired awareness. Rarely patients with generalized motor involvement from seizures have had retained consciousness and memory. The parafalcine SDH likely promoted epileptogenicity of the bilateral hemispheres. Acute and chronic SDH commonly present with seizures. Although there were no supportive electrographic findings, parasagittal epileptogenic lesions may be difficult for both clinical and electrographic localization. Post-event paresis with clinical improvement in the hours after event cessation supports clinical seizure.