Approximately 50 to 70 million US adults suffer from sleep or wakefulness disorders, and the Centers for Disease Control and Prevention deems insufficient sleep a public health epidemic.1 Inadequate sleep has been linked with elevated risk for a range of health issues, including heart disease, stroke, depression, diabetes, hypertension, and cancer.1,2
For people with epilepsy, sleep problems can be especially risky, possibly triggering seizures and impacting overall seizure control. “This is a very complex and dynamic relationship,” Bradley V. Vaughn, MD, a professor of neurology at the University of North Carolina School of Medicine, Chapel Hill, who co-authored a recent paper on the topic, told Neurology Advisor.3 “Part of the link is that, in general, the brain performs better when an individual has good quality and quantity of sleep, and each stage of sleep appears to have a different relationship with epilepsy,” he said.
Seizures are more likely to occur during the non-rapid eye movement (REM) stages of sleep, possibly because there are “more neurons in the resting state to participate in both interictal and ictal discharges,” Dr Vaughn explained. Animal models suggest that REM sleep may protect against seizures and the progression that occurs during kindling, he said, and it “appears to be a state that has great localizing of interictal discharges to the epileptic focus than other stages including wake.” It is also known that sleep deprivation and disruption can make seizures more likely to occur; for example, obstructive sleep apnea appears to increase seizures in people with epilepsy, and one study found that the use of positive airway pressure reduced seizure frequency in patients with both disorders.4
A study published in Epilepsy Research investigated the link between insomnia, seizure control, and quality of life among 207 patients with epilepsy.5 Participants completed the Insomnia Severity Index (ISI) and the Quality of Life in Epilepsy Inventory (QOLIE-P-10), and the presence or absence of seizures pertaining to the preceding 4 was noted. Various data regarding demographics, sleep patterns, and mood were also recorded. Results showed that 43% of patients had clinically significant insomnia, and 51% had mild insomnia. Patients with continuing seizures had significantly worse ISI scores than those who were seizure free, and the variables associated with more severe insomnia included “(y)ounger age, shorter duration of epilepsy, use of sedative/hypnotics, medical and sleep comorbidities, delayed sleep timing and chronotype, excessive sleepiness, and depression,” the authors reported. Consistent with previous findings, more severe insomnia was also associated with worse QOL.
The study was not designed to determine cause and effect, but because it is known that seizures can be triggered by sleep deprivation or interruption, “we can infer that insomnia as a cause of insufficient sleep may worsen seizure control as well,” study co-author Mark Quigg, MD, MSc, a professor of neurology at the University of Virginia, told Neurology Advisor. “Furthermore, it may not be a one-way street, as other studies have demonstrated some effects of epileptic seizures or medications on the underlying sleep architecture,” he said.