Sleep apnea and low oxygen levels during sleep are linked to epilepsy that first manifests after the age of 60, termed late-onset epilepsy, according to a study supported by the National Institutes of Health (NIH) and featured in the journal Sleep. This connection remains significant even when accounting for other well-established risk factors for late-onset epilepsy and sleep apnea, such as hypertension and stroke. These insights could enhance our understanding of the relationship between sleep disorders and late-onset epilepsy and could highlight new avenues for therapeutic intervention.
Rebecca Gottesman, M.D., Ph.D., who is the chief of the Stroke Branch at the NIH’s National Institute of Neurological Disorders and Stroke (NINDS) and also a contributor to the study, noted the growing body of evidence suggesting that late-onset epilepsy could signal underlying vascular or neurodegenerative disease, possibly serving as a preclinical indicator of such conditions. She highlighted that among various age groups, older adults display the highest rates of newly diagnosed epilepsy, with nearly half of these cases having no apparent cause. Although sleep apnea is prevalent among individuals with epilepsy, its precise role is not thoroughly understood.
The research team, headed by Christopher Carosella, M.D., an assistant professor of neurology at Johns Hopkins University in Baltimore, pinpointed cases of late-onset epilepsy using Medicare claims and examined sleep data from over 1,300 participants involved in a study focused on sleep-disordered breathing and cardiovascular health. They discovered that individuals experiencing nocturnal hypoxia, where oxygen saturation drops below 80% during sleep, were three times more likely to develop late-onset epilepsy compared to those without such severe drops in oxygen levels. Moreover, participants who reported having sleep apnea later in life were twice as likely to develop late-onset epilepsy as those without this sleep condition.
The researchers found that the severity of hypoxia during sleep was linked to an increased likelihood of developing late-onset epilepsy, independent of other concurrent medical conditions and demographic factors. Interestingly, the study did not find a correlation with the apnea-hypopnea index, a standard measure of sleep apnea severity.
The study highlights that sleep apnea is a known risk factor for various other aspects of poor brain health, including increased risks of stroke and dementia. However, its association with epilepsy had not been previously established. The findings suggest that chronic, repeated exposure to low oxygen levels overnight could induce brain changes that eventually escalate the risk of epilepsy. While the study does not confirm whether treating or preventing sleep apnea could reduce epilepsy risk, it implies that addressing sleep apnea might be a crucial strategy for mitigating the risk of late-onset epilepsy.
Dr. Carosella expressed optimism about the implications of their findings, stating that identifying a reversible cause for any idiopathic epilepsy is a long-standing ambition among epilepsy researchers and clinicians. He hopes this study represents an initial step towards this goal and encourages further evaluation and treatment of sleep disorders in epilepsy patients.
Given the broader implications of sleep apnea on cardiovascular and brain health, these findings could also help identify individuals at risk for these conditions, potentially opening doors to preventative treatments and interventions.
More information: Christopher M Carosella et al, Sleep apnea, hypoxia, and late-onset epilepsy: the Atherosclerosis Risk in Communities study, SLEEP. DOI: 10.1093/sleep/zsad233
Journal information: SLEEP Provided by NIH/National Institute of Neurological Disorders and Stroke
