Refractory epilepsy and obstructive sleep apnea: Is there an association?

Background: A high prevalence of obstructive sleep apnea (OSA) has been reported in medically refractory epilepsy patients, and there is increasing evidence that treatment of OSA in refractory epilepsy patients would reduce seizure frequency. Objective: Studying the frequency of occurrence of OSA in a group of refractory epilepsy patients, compared to a matched group with medically controlled epilepsy. Methods: Sixty patients with epilepsy, 30 patients with controlled epilepsy (group I), and 30 patients with refractory epilepsy (group II) were included. All patients underwent overnight polysomnogram and sleep EEG and completed Sleep Apnea Sleep Disorders Questionnaire (SASDQ). All patients had normal general and neurological examination. Results: The frequency of OSA was found to be 10% in patients with controlled epilepsy, while its frequency in patients with refractory epilepsy was found to be 16.7%, yet this was statistically insignificant. In addition, O2 desaturation nadir was higher in group II, compared to group I with no statistical significance. In the controlled epilepsy group, we found that older patients tend to have higher Apnea–Hypopnea Index (AHI). Moreover, it was found that older subjects, with early onset of epilepsy, and longer duration of the illness tend to have higher AHI in group II. Conclusion: There is an association between refractory epilepsy and OSA, especially regarding O2 desaturation during sleep. In addition, older age, early onset of epilepsy, and longer duration of illness are independent risk factors for the OSA in patients with refractory epilepsy.