The effect of duration of epilepsy on IQ in children with CLRE; a comparison to SLRE and IGE

Up to one third of the children with epilepsy are classified as having cryptogenic localization epilepsy (CLRE). Unfortunately, not much is known on the prognosis of CLRE; it is assumed to be somewhere between the benign course of many idiopathic epilepsies and the more malignant course of most symptomatic epilepsies. The risk of cognitive decline over time seems to be increased for children with epilepsy, but no data are available specifically for CLRE. This study was a systematic cross-sectional open clinical and non-randomized investigation, which included 68 children with CLRE, 24 children with symptomatic localization related epilepsy (SLRE) and 21 children with idiopathic generalized epilepsy (IGE). One-way between-groups ANOVAs with Tukey post hoc testing were used to test differences in demographical variables and IQ between CLRE, SLRE and IGE and to test the influence of duration of epilepsy and other epilepsy factors on IQ. To test whether there were IQ differences between the three types of epilepsy regarding duration of epilepsy and other epilepsy factors, the Kruskal-Wallis test was used. In CLRE, intelligence is stable over time; IQ scores do neither improve nor deteriorate. Age at onset, seizure type, seizure frequency and the use of AED appeared to have no influence on intelligence in CLRE. Furthermore, over time, there appeared to be no differentiation regarding IQ between CLRE, SLRE and IGE.