Ting Wei Liao ¹ Chun-Wei Chang ¹ Mei-Yun Cheng ¹ Tony Wu ¹ Ning-Hung Chen ¹ Shih-Wei Lin ¹ Li-Pang Chuang ^2*

• ¹ Linkou Chang Gung Memorial Hospital, Linkou, Taiwan
• ² Linköping University, Linköping, Östergötland, Sweden

Background: Patients with epilepsy (PWE) have a higher likelihood of developing obstructive sleep apnea (OSA). However, there are still limited literature investigating the phenotypes of OSA in this population. This study aimed to evaluate the respiratory arousal threshold (rAT) in PWE with concurrent OSA. Method: Patients were recruited from the Sleep Center and Epilepsy Center at Chang Gung Memorial Hospital between January 2010 and June 2022. We included adult patients who had undergone overnight in-laboratory polysomnography after the onset of epilepsy. Additionally, age-, sex-, and apnea-hypopnea index (AHI)-matched patients with OSA only were included as controls. Low rAT was defined using predictive models based on polysomnography criteria. Results: We enrolled 48 PWE, of which 36 patients (75%) had concurrent OSA, and 108 patients with OSA only. Patients with both epilepsy and OSA were notably older upon PSG examination and had a later onset of epilepsy compared to patients with epilepsy only. PWE had a higher number of concomitant antiseizure medications and hypnotics compared to patients with OSA only. Among those with OSA, 19 (52.8%) with both epilepsy and OSA and 68 (63.0%) with OSA only were predicted to have a low rAT. The low rAT group exhibited significantly lower AHI, lower desaturation index, and higher mean SpO2 levels. However, no statistically significant differences were observed in continuous positive airway pressure treatment outcomes between individuals with low and high rAT. Conclusions: Our study provides insights into the presence of a low rAT in PWE and OSA, with no significant difference in its ratio compared to OSA controls. Further studies are needed to identify factors contributing to the higher prevalence of OSA in PWE.