[Do subclinical epileptiform discharges really affect short-term memory in children?].

Objective: Deficits in concentration, specific developmental disorders, and behaviour problems often impair the educational abilities of children and adolescents with epilepsy, even if the subjects are seizure-free. The impact of subclinical epileptiform discharges that persist despite adequate antiepileptic treatment is not yet understood. Some studies suggest that these lead to simultaneous transitory cognitive impairment, thereby affecting short-term memory functions. This study examines the impact of subclinical discharges on memory functions.

Method: 40 seizure-free children (10.3 +/- 3.5 years) with subclinical epileptiform discharges were examined by means of computerized EEG-coupled tests focussing on visuo-spatial and verbal short-term memory, in order to assess the temporal relation between discharges and test performance.

Results: No significant differences in cognitive performance were detected in phases with and without epileptiform discharges; neither discharges > 1.5 sec, nor multiple discharges within a test impaired performance. Moreover, performance was independent of the localisation of discharges and of the time of their occurrence during the test.

Conclusions: The present study showed no association between subclinical epileptiform discharges and error rates as indicators of transient cognitive impairment in visuo-spatial and verbal short-term memory. Hence, other mechanisms have to be taken into account to explain the known cognitive deficits in patients with epilepsy.