Sleep apnea treatment may reduce risk of epileptic seizures

WASHINGTON – In patients with epilepsy, treatment of obstructive sleep apnea with continuous positive airway pressure may lead to substantial and sustained reductions in seizure activity, according to data presented at the annual meeting of the American Epilepsy Society.

The reduction in seizure activity with continuous positive airway pressure (cPAP) in patients with epilepsy contributes to other evidence that poor sleep quality is an important but preventable risk factor for seizures, according to Thapanee Somboon, MD, a research fellow at the Sleep Disorders Center at the Cleveland Clinic in Ohio.

^{Ted Bosworth/Frontline Medical News}

Dr. Thapanee Somboon

In this study, which was characterized as the largest yet to evaluate the effect of cPAP on seizure activity, all 197 patients had epilepsy but only 122 had obstructive sleep apnea (OSA). Of those with OSA, 73 were treated with cPAP and 49 were not. An additional 75 patients with epilepsy but no OSA were also treated with cPAP. Seizure activity in all groups was evaluated over a period of 1 year.

Treatment success, defined as no seizure activity or at least a 50% reduction from baseline in seizure activity, was achieved in 85% of those with OSA treated with cPAP, 55% of those with OSA that did not receive cPAP, and 65% of those who were treated with cPAP but did not have OSA.

The difference was even greater among those with seizure activity in the 6 months prior to cPAP use. In these, a 50% or greater reduction in seizure activity was achieved in 63% of those with OSA treated with cPAP but in only 14% of those with OSA that did not receive cPAP. In the group without OSA, 44% achieved a 50% or greater reduction in seizure activity from baseline on cPAP.

“Epilepsy patients without OSA also appeared to benefit from cPAP, although prospective data are needed to further explore this observation,” Dr. Somboon said.

All patients remained on antiepileptic drugs over the course of study, and the drug levels were not different between groups, according to Dr. Somboon. About half of all three groups were seizure free in the 6 months prior to cPAP. Those with OSA who received cPAP had a higher body mass index than did those who were not treated (34.6 vs. 31.1; P less than .001), but they were of similar age (47.6 vs. 47.9 years). Those without OSA who were treated with cPAP had a lower BMI (27.5; P less than .001) and were 10 years younger than were those with OSA (37.7 years; P less than .001). About two-thirds of all three groups had a history of focal seizures.

When expressed as odds ratios (OR), those treated for OSA had almost 10 times the likelihood of treatment success at 1 year (OR, 9.58; P less than .001), although being seizure free in the 6 months prior to cPAP had a 20-fold increased likelihood of treatment success (OR, 20.88; P less than .001).

Sleep disturbances and OSA are more common in patients with epilepsy than age-matched controls, according to Dr. Somboon, who cited published studies substantiating these statements. She noted that there are also previously published studies associating improved sleep hygiene, including improved sleep hygiene achieved with cPAP, with a reduced risk of seizure activity in epilepsy patients. However, at present there are no guideline recommendations for screening patients with epilepsy for OSA or other causes of impaired sleep, according to Dr. Somboon.

Although Dr. Somboon acknowledged that the data collected in this study cannot provide a definitive link between cPAP treatment, improved sleep, and reduced risk of seizure activity, this study does support these associations in the context of other evidence.

“We think clinicians should routinely screen patients with epilepsy for OSA and consider cPAP as a strategy to reduce seizure risk,” she said.

Dr. Somboon reported no financial relationships relevant to the study.