Cognitive functioning in idiopathic generalised epilepsies: a systematic review and meta-analysis.

Cognitive function in idiopathic generalised epilepsies (IGE) is of increasing research attention. Current research seeks to understand phenotypic traits associated with this most common group of inherited epilepsies and evaluate educational and occupational trajectories. A specific deficit in executive function in a subgroup of IGE, juvenile myoclonic epilepsy (JME) has been a particular focus of recent research. This systematic review provides a quantitative synthesis of cognitive function outcomes in 26 peer-reviewed, case-control studies published since 1989. Univariate random-effects meta-analyses were conducted on seven cognitive factor-domains and separately on executive function. Patients with IGE demonstrated significantly lower scores on tests across all cognitive factor-domains except visual-spatial abilities. Effect sizes ranged from 0.42 to 0.88 pooled standard deviation units. The average reduction of scores on tests of executive function in IGE compared to controls was 0.72 standard deviation units. Contrary to current thinking, there was no specific deficit in executive function in JME samples, nor in other IGE syndromes. Of more concern, people with IGE are at risk of pervasive cognitive impairment.