Neuropsychological correlates of subclinical paroxysmal EEG activity in children with epilepsy. 2: Quantitative aspects.

Altered cognitive functioning has often been reported in patients with epilepsy. In our study we looked for quantitative correlation between the recurrence of Subclinical Spike-and-Wave Discharges (SSWD) during EEG recording, the scores on the intelligence test (WISC) and the electro-clinical characteristics of 29 epileptic children with subclinical discharges of generalized spike-and-wave complexes. In our sample we found a below-normal mean IQ, with greater impairment on performance than on verbal tasks. No clear quantitative correlation was found between the weighted scores on the various subtests and the "time density" of the spike-and-wave complexes. These findings suggest that the SSWD interfere with cognitive development (mainly with visuo-spatial and sensorimotor coordination abilities) and selectively impair some of the functions involved in the cognitive processes.