Obstructive sleep apnea in drug-resistant epilepsy: A significant comorbidity warranting diagnosis and treatment

Effects of vagus nerve stimulation on the quality of sleep and sleep apnea in patients with drug-resistant epilepsy: A systematic review

OBJECTIVE

The objective was to systematically evaluate the current evidence surrounding the effect of vagus nerve stimulation (VNS) on quality of sleep and obstructive sleep apnea (OSA) among patients with epilepsy.

METHODS

A literature search was conducted using the Embase and MEDLINE databases. Studies were included if they involved patients with drug-resistant epilepsy treated with VNS and used validated tools to report on quality of sleep or sleep apnea. The literature search yielded 112 citations related to VNS and sleep quality, and 82 citations related to sleep apnea. Twelve articles were included in the review, of which five measured quality of sleep among patients who underwent VNS, six studies measured sleep apnea, and one study measured both outcomes.

RESULTS

Studies measuring quality of sleep used different methods, including sleep quality questionnaires and the percentage of sleep in each cycle. Studies also varied in patient populations, the use of control groups, and whether multiple measurements were taken for each patient. Some studies found improved sleep quality after VNS, whereas others found reductions in deep sleep stages. Additionally, mixed results in sleep quality were found when comparing patients with epilepsy who received VNS treatment versus patients with epilepsy who did not receive VNS treatment. Variables such as VNS intensity and age could potentially confound quality of sleep. Studies measuring sleep apnea consistently found increased proportions of patients diagnosed with OSA or increased sleep index scores after VNS implantation.

SIGNIFICANCE

Overall, the effect of VNS on quality of sleep remains unclear, as studies were very heterogeneous, although the effect on sleep apnea has consistently shown an increase in sleep apnea severity indices after VNS implantation. Future studies with consistent measures and discussions of confounding are required to determine the effect of VNS on quality of sleep, and the effect of VNS parameters should be further explored among patients who develop sleep apnea.

Factors determining the long-term compliance with PAP therapy in patients with sleep-related epilepsy

INTRODUCTION

In adult patients with epilepsy, treatment of comorbid obstructive sleep apnea syndrome (OSAS) by positive airway pressure (PAP) therapy results in improvements in the control of seizures. This is the first study investigating the long-term compliance with PAP therapy in patients with sleep-related epilepsy and OSAS.

METHODS

In this longitudinal study, patients with sleep-related epilepsy and OSAS were followed-up for five years. The compliance with PAP therapy was defined as the use of PAP therapy for at least four hours per night for more than 70 % of nights.

RESULTS

A total of 58 patients with sleep-related epilepsy and OSAS completed study protocol. Eleven patients (19.0 %) refused PAP treatment for OSAS, and 13 patients (22.3 %) showed irregular use. Remaining 34 patients (58.7 %) were compliant with PAP therapy. Females were found to be more compliant than males (p = 0.027), while the age was not found to correlate with the compliance (p = 0.721). Epilepsy-related factors including the types of seizures, whether pure sleep-related or mixed (p = 0.403), localization (p = 0.920) or lateralization (p = 0.697) of discharges, showed no effect on the compliance with PAP therapy. On the other hand, patients with a lower number of seizures (p = 0.042) or with a lower seizure frequency (p = 0.048) showed better compliance with PAP therapy. Polysomnographic parameters including severity of OSAS failed to show a significant correlation.

CONCLUSION

Our findings showed that about two thirds of the study population was compliant with PAP therapy after a mean follow-up duration of almost three years. Newly-diagnosed patients, mostly females, with a lower number of total seizures and lower seizure frequency seem to be more compliant with PAP therapy, which implies the significance of investigation and treatment of OSAS as early as possible in the patients with sleep-related seizures.