Temporal lobe epilepsy in childhood: clinical, EEG, and neuroimaging findings and syndrome classification in a cohort with new-onset seizures.

Sixty-three children with new-onset temporal lobe epilepsy (TLE) underwent extensive clinical, EEG, and neuroimaging investigation as part of a prospective, community-based cohort study of the natural history of TLE in childhood. Complex partial seizures occurred in 94% of the children, and tonic-clonic seizures occurred in 14%. Developmental, behavioral, or learning problems were present in 38%. Eighteen children (29%) had a significant illness/event prior to the onset of TLE, including febrile status epilepticus in seven, meningitis in four, respiratory arrest in two, and head injury in one. Magnetic resonance imaging or computed tomography revealed structural abnormalities of the temporal lobe in 24 children (38%), including hippocampal sclerosis (HS) in 13 and tumor in eight. There was a strong association between HS and a history of significant illness/event prior to the onset of TLE (p < 0.001). Analysis of past history and neuroimaging findings led us to propose three etiologically defined subgroups of TLE; developmental TLE (10 children with long-standing, nonprogressive temporal lobe tumors and malformations), TLE with HS/significant antecedents (18 children with HS or a history of a significant illness/event), and cryptogenic TLE (34 children with normal neuroimaging findings and no significant past history). Etiologic differences between children with new-onset TLE may confer prognostic information that will be useful for counselling families and planning treatment.