Postictal hyperfamiliarity for unknown faces

Hyperfamiliarity for unknown faces (HFUF) is a rare disorder in which unfamiliar people or faces appear familiar. Three young adults were admitted for acute symptomatic secondarily generalized tonic-clonic seizures (two) and psychomotor status (one). During the days following the seizures the patients continuously experienced a strong familiarity for unknown people, including other patients, visitors, and hospital staff. This disorder disappeared gradually, lasting a mean of 13 days. Brain MRI showed left amygdalohippocampal lesions, suggesting the etiology of encephalitis in two patients and multiple “active” demyelinating lesions in one patient. Interictal and ictal EEG findings showed left temporal epileptiform abnormalities. Two patients had a transitory defect of verbal memory. HFUF is a newly defined postictal symptom, more likely to arise from left temporal epileptic discharges. In our cases it was associated with acute lesions of the temporal areas, suggesting that its occurrence may also imply a structural etiology of epilepsy.