Abstracts

Rationale: Attention deficit hyperactivity disorder (ADHD) is commonly observed in children with epilepsy. However, factors associated with development of ADHD and which might help to guide its therapeutic management remain to be determined. Methods: We conducted a multicenter prospective observational study which included children, aged 6-16 years, suffering from both epilepsy and ADHD according to DSM IV criteria. Children with significant intellectual disability (IQ < 70) were excluded. After inclusion, patients entered a 12-16 weeks follow-up period during which they were either treated with methylphenidate or they did not receive specific ADHD-treatment, at the discrétion of the treating physician. Severity of ADHD was evaluated with the ADHD-rating scale IV. The level of significant clinical response was defined at 25% reduction in the total score. Results: 149 patients were included (mean age 9.6±2.3 years). 47 children had non-idiopathic focal epilepsy, 42 idiopathic focal epilepsy, 26 childhood absence epilepsy, 20 other forms of idiopathic generalized epilepsy and 14 unclassified epilepsy. 79 patients were seizure free at inclusion, including 31 for whom AED treatment was not considered necessary. In the remaining patients, the mean seizure frequency during the four weeks preceding study inclusion was 11.6±39.5. Fifty-three patients had school difficulties. At inclusion, the ADHD Rating Scale-IV total score was 30.2±9.5, the inattentive subscore was 17.1±4.8 and the hyperactive subscore was 12.9±6.9. We did not detect differences of ADHD Rating Scale-IV total score or subscores across patients' age or gender, age at epilepsy onset, epilepsy syndrome, seizure frequency or number of ongoing antiepileptic drugs. No correlation between school difficulties and ADHD severity was observed. Methylphenidate was introduced in 50 patients (34%), including 40 in whom follow-up evaluation is currently available. These latter had higher ADHD Rating Scale-IV total score than patients in whom no specific ADHD-treatment was introduced (32.5±10.2 vs 28.7±8.8, p=0.019). After a follow-up of three months, patients treated with methylphenidate demonstrated a mean decrease of ADHD Rating Scale-IV total score of 11.1±11.5 points. 25 patients (63%) demonstrated ≥25% decrease of ADHD Rating Scale-IV total score and 13 (32%) ≥50% decrease. Mean decrease of ADHD Rating Scale-IV scores did not significantly vary across patients' age or gender, age at epilepsy onset, epilepsy syndrome, seizure frequency or number of ongoing antiepileptic drugs. Conclusions: We did not detect any epilepsy-related factor associated with severity of ADHD. A third of patients did not respond to methylphenidate. A better understanding of the pathological process which underlies ADHD development in childhood epilepsy is required to develop alternative and/or complementary therapeutic strategies. Funding: This study was funded by the French Ministry of Health (PHRC national 2011) and the Network for investigation of medicinal products in children (RIPPS).