Malformations of cortical development and epilepsy: A cohort of 150 patients in western China

PURPOSE Malformations of cortical development (MCDs) are abnormalities of the cerebral cortex that arise from abnormal formation of the cortical plate, and have become increasingly identified as an important etiology for refractory epilepsy. Little is known about the spectrum, distribution and clinical features of MCDs, especially in resource-limited regions. This study investigates the distribution of MCDs and compares the clinical features and long-term prognosis between the two forms of MCDs: Simple and Multiple. METHOD One hundred and fifty epilepsy patients (138 adults, 12 pediatric patients) with radiologically diagnosed MCDs were identified at a tertiary epilepsy center in western China. Patients were divided into three subtypes according to the Barkovich classification. They were further divided into either Simple or Multiple MCD forms based on whether they had a single type of MCDs or other co-existing developmental brain abnormalities. RESULTS The most common type of MCD is focal cortical dysplasia. We found perinatal insults more common in group III patients. Multiple MCD was identified in 36 of 150 patients, and was associated with higher rates of delayed milestones (p=0.005), cognitive impairment (p=0.023) and neurological deficits (p=0.002) compared to Simple MCD. Extra-temporal epilepsy was more commonly seen among individuals with Multiple MCD (p=0.017). Participants with Multiple MCD were younger at time of seizure onset (p=0.003) and at assessment (p=0.002), had a lower seizure-free rate (p=0.033) and had worse outcomes overall. Patients with heterotopias were more commonly associated with other abnormalities. CONCLUSION MCDs are a critical cause of epilepsy and pose a big challenge for resource-limited countries. Imaging techniques are crucial in diagnosing and classifying cortical deformities. Multiple malformations lead to more severe clinical features and worse prognosis. Identifying and classifying MCDs can help physicians to better estimate patient prognosis and seek the best, individualized therapeutic options.