New Epilepsy, Sleep Apnea Tool: Don’t Get Caught Napping

April 29, 2014

Screening for and then treating obstructive sleep apnea may help improve seizure control in epilepsy, a new study shows.

Screening for and then treating obstructive sleep apnea (OSA) may help improve seizure control in epilepsy, according to results of a new study.

“Treating OSA is an under-recognized, but important, adjunctive therapy to medications, with potential to significantly improve seizure control,” Joon Kang, MD, an epilepsy fellow at Thomas Jefferson University Hospital in Philadelphia, told ConsultantLive in an exclusive interview before her presentation of the study at a poster session at the American Academy of Neurology annual meeting in Philadelphia.

OSA often coexists in patients with epilepsy at a prevalence rate that is higher than seen in the general population. Clinical experience shows that “sleep disruption and deprivation facilitates interictal epileptiform discharges and exacerbates seizures,” said Dr Kang. “Patients with OSA have frequent, abrupt arousals, which fragments and lightens sleep, resulting in sleep deprivation and overall poor sleep quality.”

OSA also has been linked to cerebral hypoxemia and cardiovascular dysfunction (decreased output and arrhythmias), which also may play a role in reducing the seizure threshold, Dr Kang said.

Dr Kang and principal investigator Maromi Nei, MD, Associate Professor of Neurology at Thomas Jefferson, investigated the presence of OSA in patients with refractory versus well-controlled epilepsy and their associated risk factors, using 2 validated screening questionnaires for OSA.

The study included 83 consecutive patients (46 men, 37 women), mean age 40 years, who presented to the Jefferson Comprehensive Epilepsy Center and had established epilepsy. About half of the patients had refractory epilepsy, and OSA screening results were positive in about half of the patients.

Compared with well-controlled epilepsy, the refractory group scored higher on both questionnaires and had a higher incidence of positive screening results, but the difference was not statistically significant, Dr Kang said. The 2 screening questionnaires had excellent agreement and correlation.

“Very few epilepsy centers have implemented OSA screening into routine practice,” said Dr Kang. “Screening questionnaires, such as the sleep apnea–sleep disorder questionnaire and STOP-BANG, are cost-effective and efficient ways to identify the under-recognized disease.”

The STOP-BANG is an easily administered, 8-item screening tool that had not yet been validated in epilepsy. The STOP-BANG acronym comes from the 8 items: Snoring, Tired, Observed, (blood) Pressure, BMI, Age, Neck circumference, Gender. Each item is scored based on a yes/no answer. “A score of more than 3 positive answers has shown high sensitivity for detecting OSA, depending on severity. It takes less than 2 minutes to complete,” Dr Kang said. She added that neck circumference is a much better indicator of central obesity and body fat than body mass index.

Primary care physicians should keep OSA risk factors and symptoms in mind when collecting a history on patients with epilepsy, Dr Kang said. “The common risk factors for OSA include obesity, older age, male gender, alcohol consumption, and tobacco use, and the main symptoms of OSA are loud snoring, restless sleep, and daytime sleepiness,” she noted. “STOP-BANG can be then used to help identify the potential patients that may benefit from further objective testing, such as polysomnography. The STOP-BANG is a very quick, simple screening tool with high sensitivity.”

Dr Kang concluded, “Identifying and treating OSA in epilepsy patients may be an important adjunct to anticonvulsant therapy in improving seizure control.”