Abstracts

Rationale: Sleep disorders are common comorbidities of epilepsy especially refractory epilepsy. A third of the adults with refractory epilepsy have obstructive sleep apnea (OSA) but limited data exist about sleep disorders in children with refractory epilepsy. The purpose of this study was to identify the spectrum of sleep disorders in children with epilepsy undergoing evaluation for epilepsy surgery. We also wanted to identify the epilepsy related predictors for specific sleep disorders. Methods: We retrospectively analyzed data collected prospectively from our database. The patients undergoing evaluation for epilepsy surgery were sent for sleep evaluation and polysomnography based on clinical judgment or sleep screen failure (20 questions, non-validated questionnaire). International classification of sleep disorders-2 (ICSD-2) criteria were used for the diagnosis of sleep disorders. We used Fisher's exact test to identify if there were any differences between the two most common sleep disorder groups for variables such as MRI lesions, tone, and the type of seizures. We also analyzed the group difference based on BMI using the Wilcoxon rank sum test. Results: We identified 17 subjects, 9 female subjects, with an average age of 7.8 (standard deviation [SD] 5.7) and BMI of 18.6 (SD 4.9). Eleven subjects had surgery including six with corpus callosotomy, two with functional hemispherotomy and three with vagus nerve stimulator placement. Six subjects did not have surgery at the time of the data analysis either due to lack of seizures during epilepsy monitoring or not qualifying for epilepsy surgery. Sleep disorders diagnosis included primary snoring (n= 3), hypoxemia (n=2), hypoventilation (n=1), cataplexy (n=1), central sleep apnea (n=1), OSA (n=6), insomnia (n=6) and periodic limb movement disorder (n=2). One subject had insomnia which resolved when his electrical status epilepticus of sleep (ESES) improved. Five subjects had two sleep disorders. No significant differences were identified for variables which included seizure type (focal Vs generalized onset, p=1.0) MRI lesion (present Vs absent, p=1.0), tone (normal Vs abnormal, p=1.0) and BMI (p=0.46) for OSA and insomnia groups. All except one subject who underwent surgery had poor seizure outcome with ILAE score 4/5. Conclusions: We identified that the most common sleep disorders in children with refractory epilepsy, undergoing pre-surgical evaluation were insomnia and OSA. There were no predictors for OSA Vs insomnia in this series. All subjects who had sleep evaluation were identified to have a more diffuse seizure onset. All except one subject who underwent surgery had poor seizure outcome with ILAE scores 4 or 5. This is unsurprising since 9 of 11 procedures were palliative. The impact of sleep disorders on outcome after focal resection should be examined. Further larger studies are needed to identify the spectrum of sleep disorders in children with refractory epilepsy, the predictors for sleep disorders and the bidirectional impact of sleep disorder and epilepsy.