Generalized paroxysmal fast activity and tonic seizures in older adults

Generalized paroxysmal fast activity is an uncommon ictal EEG pattern usually associated with tonic seizures. Patients with generalized paroxysmal fast activity typically have multiple seizure types beginning in childhood and are refractory to antiepileptic drug therapy. We describe 3 hospitalized adult patients (age, older than 55 years) with new-onset tonic movements, noted during an acute illness, associated with generalized paroxysmal fast activity on EEG. These seizures were characterized by subtle stiffening of the arms, trunk, and face for up to 3 seconds. All patients had multiple medical problems and polypharmacy. None had a history of static encephalopathy, other epileptiform abnormalities on EEG, other seizure types, or significant neuroimaging abnormalities. In contrast to previously described reports in children, all three adults responded to antiepileptic drug monotherapy. EEG played a critical role in differentiating tonic seizures from nonepileptic movements in these three cases.