Psychological effects of subclinical epileptiform EEG discharges. I. Scholastic skills.

The possible effects of subclinical epileptiform EEG discharges on educational skills have been studied. Twenty children with proven or suspected epilepsy and known subclinical EEG discharges underwent telemetric EEG and video monitoring during standard tasks of reading, mental arithmetic and manual dexterity, and at rest. The discharge rate was significantly lower at rest than during execution of a task. For both reading and arithmetic, the discharge rate was higher when the child was presented with material appropriate to his own level of ability than when easier or more difficult material was given. High discharge rates were associated with low test performance particularly for arithmetic. Reading speed was significantly increased during the discharges, but overall reading efficiency was significantly reduced with respect to the non-discharge condition. The decrement of reading efficiency was greater for longer than for shorter discharges. The findings confirm that otherwise subclinical EEG discharges may be accompanied by momentary impairment of scholastic skills. The interaction between discharges and cognitive function is, however, complex and the nature and level of difficulty of the task in turn affects the rate of EEG discharge.