Abstracts

The previously proposed diagnostic criteria of benign partial epilepsy of infancy (BPEI) include partial seizures with onset at age one to month to the second year, normal development, normal imaging findings and normal interictal EEG. The incidence of BPEI is unknown. We investigated whether the presence of interictal spikes would alter the clinical course in children who otherwise fulfill the criteria for BPEI, and estimated the incidence of BPEI.
In 1993-2000, we diagnosed and treated epilepsy in 235 infants, including all infants with epilepsy who were born in Helsinki in 1997-2000. 34 infants fulfilled the entry criteria of seizure onset at age 2-18 months, normal development, normal EEG background activity and normal MRI, if done (26 had MRI). All infants were followed until at least two years of age (18 to five years). 25 infants were diagnosed with BPEI, based on DQ over 70 or average to superior milestones, seizure-freedom at two years and no later seizure relapses.
The first recorded EEG of nine infants with BPEI (36%) revealed low-amplitude sleep-activated interictal parieto-occipital or central spikes or polyspikes. No spikes were seen on follow-up EEG recordings in these infants or in those who did not have spikes on the first EEG. Seizure outcome and development were similar in infants with and without spikes. BPEI was diagnosed in five of 25 253 infants born in Helsinki in 1997-2000.
Interictal sleep-activated parieto-occipital or central spikes may occur shortly after seizure onset in BPEI. They do not have prognostic significance and should not be used as exclusion criteria. The incidence of BPEI appears to be approximately 0.2 per thousand.
[Supported by: Funded by a research grant from the Hospital for Children and Adolescents, Helsinki University Hospital]