*4.3.1 Epilepsy*

Epilepsy is a chronic brain disease characterized by two or more unprovoked or reflex seizures more than 24 hours apart or presence of an epilepsy syndrome [70]. Epilepsy remains a common accompanying disorder in CP occurring in 30–60% of children diagnosed with CP [71, 72]. Both CP and epilepsy in most cases arise from the same underlying neuropathological substrate [71]. Cerebral dysgenesis (disorders of cortical malformation like lissencephaly, cortical dysplasia, heterotopias, corpus callosal agenesis), cortical infarctions (perinatal stroke and meningoencephalitis) and diffuse cortical neuronal necrosis (severe neonatal encephalopathy/HIE) are neuropathological substrates for both CP and epilepsy [71]. Thus the aetiology of epilepsy in CP could be structural (cerebral dysgenesis, infarctions, postnatal head trauma), postinfectious (CMV, Toxoplasmosis, post meningoencephalitis) or genetic [70]. The latter occurs in cases of CP who on newer genetic testing techniques (WES, WGS) also show genetic or copy number variants pathogenic for epilepsy with or without a family history of epilepsy [70]. Epilepsies in CP are more common in spastic quadriplegia and hemiplegia owing to the cerebral cortical involvement in spastic quadriplegia and hemiplegia and are relatively uncommon in spastic diplegia due to the relative sparing of the cortex in PVL of prematurity [71–73].

It has been reported that epilepsy is more prevalent in severe CP/GMFCS levels IV-V and in the presence of co-morbid intellectual disability (ID) [72]. These findings most likely relate to the degree/topography of cortical injury since diffuse cortical neuronal necrosis (SNN) from severe neonatal encephalopathy/HIE or cortical malformations result in spastic quadriplegia that is usually associated with severe gross motor dysfunction (non-ambulatory status) [2, 49].
