Rationale:
Cognitive impairments and behavioral disturbances are common among children with epilepsy. New discoveries of genetic associations have changed the perspective on classifying and treating epilepsies of genetic origin. The aim of the present study was to investigate the cognitive and behavioral profile of three distinct groups of epilepsy with a genetic background for intergroup differences: 1) idiopathic generalized epilepsies/generalized genetic epilepsies (IGE/GEE group), 2) idiopathic focal epilepsies (IFE group) and 3) epilepsies with proven or strongly monogenetic or structural chromosomal etiology (GE group).
Method:
Cognitive assessment was performed in a tertiary epilepsy center of Munich (Germany) using the WPSSI, WISC-IV, WISC-V and WIE according to the age of the patient and time of the procedure. IQ Subtests were assigned to 4 subcategories (non-verbal, verbal, processing speed and working memory). Behavior was assessed by assigning T-values to CBCL questionnaire scores. Data was collected in an Excel spreadsheet and then analyzed with SPSS v.26. We used ANOVA with post-hoc Bonferroni-correction to explore differences between epilepsy groups. The exact Fisher-Test tested for differences of the proportion of mildly intelligence impaired children and patients with pathological behavioral issues between epilepsy groups. Results228 patients have undergone neuropsychological testing, whereof 130 patients were classified as either IFE, IGE/GGE or GE and 3 of those were excluded due to missing IQ and CBCL scores, giving a final cohort of 127 patients tested for IQ and/or CBCL (Table). Out of the 127 tested children, 56 were classified as IGE/GGE, 45 as GE and 26 as IFE. Total IQ was 89.0 ± 15.9, [84.5-93.4] for the IGE/GEE cohort; 94.8 ± 18.1, [87.3-102.3] for the IFE cohort and 76.4 ± 22.4, [67.6-85.3] for the GE cohort (p=0,001, Figure). Significant intergroup differences were also found. Total IQ was significantly lower within the GE group compared to either the IGE/GGE and IFE group (p=0.015 and p=0.001, respectively). The same was true for all but one (non-verbal IQ) subtests (between IGE/GGE and GE). The rate of patients with an IQ of < 70 in total IQ was higher within the GE group (40 %) compared to patients with IGE/GEE (14%) or IFE (7%) with all p< 0,05. There were no differences among groups found when comparing behavior, though GE patients means were the highest overall.
Conclusion:
The present study highlights different cognitive profiles throughout epilepsies with a genetic background. Children with GE reveal lower IQs compared to patients with IGE/GGE and IFE. These findings help in further delineating epilepsies despite their closely related etiological classification with regards to their cognitive performance. “Genetic” as an etiological term varies strongly in its effects and outcomes. Therefore, upholding a difference between “true” genetic and idiopathic epilepsies within the group of genetic etiology helps optimizing treatment, counselling for patients and eliminating confusion when speaking about the effects of genetics on epilepsy outcome.
Funding:
:No funding was available for this study.
FIGURES
Figure 1