[Frequency and current clinical diversity of cerebral cortical dysgenesis]

The extended use of MRI has increased the number of patients diagnosed of cortical dysgenesis and has changed the clinical spectrum usually associated with this disorder. The aim of this study was to know the frequency and clinical variety of cortical dysgenesis in our current patient population.

All patients with dysgenesis of the neocortex or of the hippocampus, according to radiological or pathological features, were selected from the total number of patients attended during 1996 at an outpatient hospital-based neuropediatric clinic. Malformations of cerebellar cortex and neurocutaneous syndrome were excluded.

Twenty-one patients (1.3% of all patients attended at the clinic) studied by MRI showed polymicrogyria (43%) which was of perisilvian localization in three patients, heterotopias (33%), dysplasia of the hippocampus (24%), agyria-pachygria (14%) and hemimegaencephalia (5%). Three patients underwent surgical interventions. Epilepsy was present in 90%, mental retardation in 68%, cerebral palsy 47%, infantile spasms 40%, microcephally 25%, autism 10%, hyperkinesis 5% and learning disabilities in 33% of those school age children free of mental retardation.

The actual prevalence of cortical dysgenesis at our clinic is similar to that of neurodevelopmental impairments following birth-asphyxia (1.2%), amounting to two thirds of those following prematurity and to half of those following a brain injury of late prenatal onset. Except for the almost constant presence of epilepsy, especially infantile spasms, clinical symptomatology is diverse and occurs in a similar percentages in brain lesions acquired during labour or during late pregnancy. Hyperkinesis and autism have a similar prevalence to that seen in the total number of patients attended at the clinic during 1996.