Sleep Disorders and Epilepsy

Obstructive sleep apnea (OSA) has been linked to increased risk for cardiovascular and metabolic disorders. Research suggests that the same mechanisms involved in the development of these disorders may increase seizure susceptibility, and OSA may be involved. Sleep deprivation and fragmentation, intermittent hypoxia, autonomic dysregulation, and increased systemic inflammation associated with OSA may all play roles.¹ A recent literature review has suggested that 10% of adults with epilepsy, 20% of children with epilepsy, and up to 30% of patients with drug-resistant epilepsy may have OSA.²

A new study, however, may muddy the picture. The study took place in Oman between June 2011 and April 2012, and looked at a small sample of 100 patients (55 men, 45 women) with epilepsy. Results of the study suggested that the risk of OSA was only “marginally greater” in patients with epilepsy, compared to the general population. Epilepsy patients in the study had an overall OSA prevalence of 9%.³ Whether or not these results generalize to larger, more diverse populations (like the US), remains an open question.

Further evidence from small studies, however, has found that positive airway pressure (PAP) therapy, considered first-line treatment in OSA, may improve seizure control. Recent retrospective analyses at the Cleveland Clinic looked at 132 patients with epilepsy. Participants were 65% female, with a mean age of about 40.2 years, and 57.6% had OSA (56.6% on PAP with 83.7% fully adherent, and 43.4% untreated). Successful outcomes were defined as ≥50% seizure reduction or seizure-free both at baseline and followup.^1,4

Results showed:

• The PAP group had significantly higher successful outcomes (83.7%) compared to the OSA group (39.4%, P<0.001), and the group without OSA (53.6%, P=0.003).

• The PAP group had significantly greater reductions in seizures, compared to other groups

• After adjusting for potential confounders, the odds of successful outcomes in PAP-treated patients were 9.9 and 3.91 times those with untreated OSA and no OSA, respectively.

• The group with PAP-treated OSA had 32.3 and 6.13 times the odds of having successful outcomes compared to the group with untreated OSA and with no OSA, respectively.

Continuous positive airway pressure (CPAP) has also been linked to reduction in seizures among patients with OSA and epilepsy.⁵ Another study at the Cleveland Clinic looked at the effect of CPAP on measures of sleep quality in nine adults with drug-resistant epilepsy and OSA

Results showed:

• CPAP normalized the apnea-hypopnea index in all patients and improved sleep architecture, with significant improvement in oxygen saturation, arousals, stage 1 sleep, REM sleep latency, and an increase in REM sleep percentage.

Bottom Line: While the underlying mechanisms remain to be resolved, these studies seem to indicate that, once patients with epilepsy develop OSA, treating OSA can result in improved seizure control.

Take Home Points

• OSA has been linked to increased seizures in patients with epilepsy, but the underlying mechanism remains to be resolved.

• Treating OSA with PAP or CPAP may improve seizure control in patients with epilepsy and OSA.

References:

1. Pornsriniyom D, et al. Effect of positive airway pressure therapy on seizure control in patients with epilepsy and obstructive sleep apnea. Epilepsy Behav. 2014;37:270-275. Epub 12 Aug 2014.

2. Manni R, et al. Comorbidity between epilepsy and sleep disorders. Epilepsy Res. 2010;90(3):171-177. Epub 31 May 2010.

3. Al-Abri M, et al. Frequency of obstructive sleep apnea syndrome among patients with epilepsy attending a tertiary neurology clinic. Oman Med J. 2015;30(1):31-35.

4. Foldvary-Schaefer N. Treating sleep disorders can improve neurologic outcomes. Cleveland Clinic. 26 May 2015. Accessed 8 June 2015. 

5. Pornsriniyom D, et al. Continuous positive airway pressure therapy for obstructive sleep apnea reduces interictal epileptiform discharges in adults with epilepsy. Epilepsy Behav. 2014;37:171-174. Epub 18 Jul 2014.