Identification and treatment of obstructive sleep apnea in adults and children with epilepsy: a prospective pilot study

Abstract

Objective

To determine the effect of treating obstructive sleep apnea (OSA) on seizure frequency in adults and children with epilepsy in a prospective study. Several case series documented an improvement in seizure control with treatment of coexisting OSA, but published series did not sample a clinic population, were not prospective in design, and did not account for concurrent changes in antiepileptic drug (AED) doses or levels.

Patients and methods

Adult patients and the parents of pediatric patients seen in the University of Michigan Epilepsy and Pediatric Neurology Clinics were given validated questionnaires. Thirteen adults (aged 20–56) and 5 children (aged 14–17) were selected for polysomnography (PSG) based on frequency of seizures and risk for OSA. Seizure frequency was compared during 8-week baseline and treatment phases and AED levels were done to document stability in medication levels.

Results

Six of 13 adults and 3 of 5 children met PSG criteria for OSA. Three adults and 1 child were treated with continuous positive airway pressure (CPAP), were tolerant of the device, and had no change in AED doses; all four had at least a 45% reduction in seizure frequency during CPAP treatment. One adult was treated with an oral appliance with a reduction in nocturnal seizures only, and 2 adults and 2 children were intolerant of CPAP.

Conclusions

Treatment of OSA in patients with epilepsy may improve seizure control and a large randomized placebo-controlled trial appear warranted.

Introduction

Obstructive sleep apnea (OSA) and epilepsy are both common conditions that are interrelated. In prior work, we reported that up to one-third of adults with medically refractory seizures have OSA, defined by an apnea–hypopnea index (AHI) of five events or more per hour [1]. Twelve percent of subjects in this report had moderate OSA, defined by an AHI of 20 or greater. Patients with epilepsy may have coexisting OSA not only because this sleep disorder is so common but also because of the effects of epilepsy treatments on breathing during sleep. Antiepileptic drugs (AEDs) may promote weight gain [2] or affect upper airway tone [3], thereby contributing to OSA. Devices such as the vagus nerve stimulator (VNS) may affect upper airway musculature or brainstem networks that regulate respiration during sleep [4].

Several case series in adults and two in children have reported the coexistence of OSA with epilepsy and the improvement in seizure control or daytime sleepiness when OSA was treated [5], [6], [7], [8], [9], [10]. Limitations of these studies, inherent to small case series, include: (1) only small numbers of selected patients treated for OSA are reported; (2) none of the studies systematically screened large groups of epilepsy patients to identify and treat those with OSA; (3) sleepiness was not assessed using physiologic measures; and (4) apart from the study by Vaughn et al. [7], subjects did not keep seizure calendars and AEDs were not monitored with serum levels.

In this pilot study, we screened patients with epilepsy seen in adult and pediatric clinics for the presence of sleep-disordered breathing with validated questionnaires followed by comprehensive sleep evaluations. Those meeting study criteria were invited to participate in a longitudinal study of the effects of treating OSA on epilepsy and underwent polysomnography (PSG). Throughout the study, seizure calendars were used to document seizure occurrence. AED doses were kept constant throughout the study and AED levels were checked during the baseline and treatment phases. Our hypothesis was that treating OSA would improve seizure frequency.