Summary:Purpose: To analyze the semiology of seizure onset and evolution in young children with posterior cortex epilepsy (PCE), compare this with adult reports, and assess agerelated differences.Methods: We videotaped and analyzed 110 seizures from 18 patients with PCE, aged 3-81 months. All had a good prognosis after posterior epileptogenic zone removal. Ictal events were categorized by behavioral, consciousness, autonomic, and sensory features, as well as motor patterns, which included myoclonic, tonic, clonic, unclassified motor seizures, and epileptic spasm. A time-scaled data sheet was developed to record each epileptic event as onset, very early, early, or late manifestation.Results: Patients had a high seizure frequency with Յ100 attacks/day; one third of them showed a cluster tendency. The mean duration of seizures was 67 s. The most common seizure components were motor manifestations (with myoclonic and tonic seizures), but psychomotor (automotor), hypomotor attacks, and isolated auras also were frequently observed. Clinical seizure spread was frequent; auras and visual sensory signs were difficult to record in this age. Typical phenomena during seizures included behavioral changes, ictal vocalization, smile, flush, head nod, oculomotor features, and late-appearing oral automatisms, whereas hypermotor and secondarily generalized tonic-clonic seizures were not seen.Conclusions: Our results suggest that PCE in infants and young children is very heterogeneous but shows important agerelated features. Compared with adults, children with PCE have shorter but more frequent seizures; they rarely report aura or visual sensory signs, only sporadically develop hypermotor and secondarily generalized tonic-clonic seizures, whereas ictal smile, flush, head nod, and behavioral change are typical features at this age. Because of frequent subtle ictal phenomena, long-term video-EEG monitoring is a useful diagnostic tool with infants and young children with PCE.