Epileptic EEG discharges and short non-convulsive crisis: Influence on cognitive and psychobehavioural functions in youths

Abstract

Learning and behavioural difficulties often occur in benign childhood epilepsy. In recent years, several electroencephalogram (EEG) characteristics have been related to the occurrence of learning and behavioral problems. We determined if the cognitive characteristics of epileptic children depend exclusively on illness factors, or if epileptic electroencephalogram discharges during the crisis contribute to these changes. We studied a randomly selected group of 150 youths with short non-convulsive crises, who completed cognitive testing and electroencephalographic studies. The inclusion criteria were: undefined crisis, variations in cognitive function and/or frequent epileptiform discharges on the electroencephalogram. Previous research indicates that the type of epilepsy and the patient's educational level can influence cognitive functioning. The electroencephalographic epileptic discharges during the crisis has been found to influence cognitive transitory functions such as vigilance or swiftness of mental functions. The type of epilepsy is correlated statistically with impairment of learning ability tests: reading (F, 5.487, P = 0.005) and mathematics (F, 3.007, P < or = 0.05). In addition, 40% of the epileptic patients had behavioural disordered versus 16% for the control group (P < 0.02). Our results show dissociation between the characteristic directly dependent on epilepsy, particularly the type of epilepsy, on stable cognitive functions, such as the progress in school, and the effect of parosystic anomalies or the immediate effect of crisis and EEG dischargeson cognitive processes.