Aim  The aim of this study was to describe the frequency, risk factors, manifestations, and outcome of epilepsy in children with hemiplegic cerebral palsy (CP) due to perinatal arterial ischaemic stroke (AIS).

Method  The study group comprised 63 participants (41 males, 22 females) from a population-based CP register whose brain imaging showed perinatal AIS. Information collected included occurrence of neonatal seizures, family history of epilepsy, motor function and epilepsy onset, treatment, and outcome. Electroclinical findings were classified according to seizure semiology, seizure type, and epilepsy syndrome.

Results  Mean age of participants at the time of study was 10 years 6 months (SD 4y 7mo, range 4–20y). Gross Motor Function Classification System levels I and II were reported in 96% of participants, and Manual Ability Classification System levels I and II were reported in 79% of children. Thirty-four children (54%) developed epilepsy. Term delivery and more severe motor impairment were associated with epilepsy, but neonatal seizures and family history of epilepsy were not. Initial seizures were epileptic spasms, focal seizures, or myoclonic seizures. Focal seizure semiology suggested Rolandic or occipital seizure origin in the majority of children. Focal epileptic discharges in children with focal seizures had features of idiopathic partial epilepsy. Only 15% of children had active epilepsy 10 years after onset.

Interpretation  Despite a high incidence of epilepsy in children with hemiplegic CP due to AIS, the prognosis for seizure remission is good. Many children have clinical features, electroencephalography findings, and remission typical of idiopathic partial epilepsy.