Generalized epilepsy tied to increased risk of sleep apnea vis a vis focal epilepsy: Study

They also found that older age, a higher body-mass index and a history of high blood pressure were associated with a higher risk of obstructive sleep apnea in people with epilepsy.

The researchers found no significant difference in excessive daytime sleepiness -- a common symptom of people with obstructive sleep apnea and epilepsy -- between the types of epilepsy.

An estimated 22 million Americans suffer from sleep apnea, with 80 percent of the cases of moderate and severe obstructive sleep apnea going undiagnosed. More than three million Americans have epilepsy, with more than 80 percent experiencing focal-onset seizures. About two-thirds of patients with epilepsy can have their seizures controlled with medication. Sleep apnea can be treated in a variety of ways, such as use of continuous positive airway pressure (CPAP), wearing an oral appliance to keep the throat open while sleeping and weight loss.

"Possible reasons for higher risk of OSA in people with generalized epilepsy include greater brainstem dysfunction, altered control of the muscles of the upper airway, instability in the respiratory control system and differences in the anatomy of the upper airway," Scharf said.

Although the number of antiepileptic medications used was similar between the two groups, patients with generalized epilepsy may have started these medications at a younger age and have used them longer, which also could be a factor, he said.