Predictive variables for mental retardation in a Pediatric Epilepsy Monitoring Unit. Neuropsychological assessment

We sought to describe the epidemiological and clinical data from our patients in the Pediatric Epilepsy Monitoring Unit (PEMU) of the Sant Joan de Deu Hospital of Barcelona, and determine the variables of risk for mental retardation. A retrospective review of PEMU reports and hospital discharge summaries from March 2005 to December 2008 was conducted. The data from patients with intelligence quotient (IQ) estimated, older than 3 years of age and with epileptic electroencephalography (EEG) activity was analyzed in 158 patients (8.8 +/- 5.2 years; 55.1% boys). Of those pediatric patients, 63 had IQ less than 70 and 47 an IQ greater than or equal to 70. Intractable epilepsy was present in all of them. The percentage of the patients with mental retardation is significantly higher in patients with onset of epilepsy before 24 months (68.3%) than patients with later onset (27.7%). Onset of seizures, EEG findings and epilepsy etiology are significant risk factors for mental retardation. Early age at seizure, multifocal epilepsy and cryptogenic etiology are factors of worse prognosis to normal development of cognitive functions in pediatric intractable epilepsy.