Obstructive sleep apnea in refractory epilepsy: A pilot study investigating frequency, clinical features, and association with risk of sudden unexpected death in epilepsy

Abstract

Summary: Objective: We aimed to determine the frequency of probable obstructive sleep apnea (pOSA) in refractory epilepsy monitoring unit inpatients and clinical features associated with pOSA, including risk for Sudden Unexpected Death in Epilepsy (SUDEP). Methods: We prospectively recruited 49 consecutive adult patients admitted to the Mayo Clinic Epilepsy Monitoring Unit with focal, generalized or unclassified epilepsy syndromes. pOSA was identified using oximetric oxyhemoglobin desaturation index (ODI) and the Sleep Apnea-Sleep Disorders Questionnaire (SA-SDQ) and STOP-BAG screening tools. Revised SUDEP-7 (rSUDEP-7) risk inventory scores were calculated, and epilepsy patients with and without pOSA were compared with Wilcoxon signed rank tests. Correlation and regression analyses were utilized to determine relationships between pOSA and rSUDEP-7 scores. Results: Thirty-five percent of patients had pOSA with a mean ODI of 11.3 ± 5.1/hour (range 5.1–22.8). Patients with pOSA were older, heavier, and more frequently had a focal epilepsy syndrome and longer epilepsy duration, with higher SA-SDQ and STOP-BAG scores (all p<0.05). Median rSUDEP-7 score was 3 ± 1.4 (0–6). Higher rSUDEP-7 scores were positively correlated with higher ODI (p=0.036). rSUDEP-7 score ≥ 5 was associated with pOSA by ODI, SA-SDQ, and STOP-BAG questionnaire criteria (p<0.05). Significance: Our pilot study identified a high frequency of probable OSA in refractory epilepsy monitoring patients, finding that probable OSA patients were older, heavier, with higher screening symptoms for sleep apnea and more frequent focal seizures with a longer epilepsy duration. We also found a possible association between OSA and SUDEP risk. Identification and treatment of OSA in patients with epilepsy could conceivably provide a novel approach toward preventing the risk of SUDEP. Future studies with polysomnography are needed to confirm predictive features for OSA in epilepsy populations, and to determine whether OSA is associated with SUDEP risk.

Risks and predictive biomarkers of sudden unexpected death in epilepsy patient

“…56 Sleep-disordered breathing (SBD) in patients with epilepsy, and its relation with the revised SUDEP-7 inventory, were investigated in two series. 57,58 In the first study, an obstructive apnea syndrome was diagnosed in 35% of the 49 patients and was associated with high score (≥ 5) at the revised SUDEP-7 inventory. 57 The second study investigated SBD together with periictal cardiorespiratory dysfunction and sex-steroid hormones.…”

“…57,58 In the first study, an obstructive apnea syndrome was diagnosed in 35% of the 49 patients and was associated with high score (≥ 5) at the revised SUDEP-7 inventory. 57 The second study investigated SBD together with periictal cardiorespiratory dysfunction and sex-steroid hormones. 58 SBD was observed in 88% of cases, but did not correlate with the other biomarkers, including the revised SUDEP-7 inventory score.…”

Let’s talk SUDEP

“…General health status of the subjects is of importance for the SUDEP and SUDEP plus definitions. Underlying health problems, like arrhythmia and sleep related breathing problems, especially obstructive sleep apnea are more common in epileptic population; furthermore they also pose rather easily modifiable risk factors for SUDEP, when properly recognized and treated (84,85).…”

Dead in the Night: Sleep-Wake and Time-Of-Day Influences on Sudden Unexpected Death in Epilepsy

“…Sleep disordered breathing may also play a meaningful role in the nocturnality of SUDEP. Refractory epilepsy patients are at an increased risk of sleep disordered breathing, particularly obstructive sleep apnea [OSA; (64, 65)]. OSA increases a patient's risk of sudden cardiac death (66).…”