[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.