Isolated sleep paralysis linked to impaired nocturnal sleep quality and health-related quality of life in Chinese-Taiwanese patients with obstructive sleep apnea

Isolated sleep paralysis (ISP) is a rapid eye movement (REM) sleep parasomnia and has a special meaning in Chinese population. Worsening of obstructive sleep apnea (OSA) occurs especially during REM sleep. The relationship between ISP and OSA is unclear. The aim of this study was to investigate the impact of ISP on sleep and life quality in Chinese-Taiwanese OSA patients. We recruited 107 OSA patients diagnosed by polysomnography (PSG) in Southern Taiwan. ISP was evaluated by self-reported sleep questionnaire. We used Chinese version of Epworth Sleepiness Scale (ESS), Pittsburgh Sleep Quality Index (PSQI), and Short-Form 36 (SF36) to evaluate daytime sleepiness, nocturnal sleep quality, and health-related quality of life, respectively for OSA patients. Student's t-test was used to compare PSG parameters, ESS, PSQI, physical and mental component of SF-36 (P-SF36 and M-SF36) between OSA patients with and without ISP. Stepwise multiple regression was used to find out the factors independently associated with ESS, PSQI, P-SF36, and M-SF36. Forty-one of 107 patients (38.3%) had ISP. It showed no significant difference in PSG parameters between OSA patients with and without ISP. OSA patients with ISP had significantly higher ESS (P = 0.010), higher PSQI (P = 0.007), lower P-SF36 (P = 0.020), and lower M-SF36 (P = 0.001) than those without ISP. ISP was an independent factor associated with ESS (P = 0.017), PSQI (P = 0.001), and M-SF36 (P = 0.030) after adjusting for other confounding variables. ISP was independently associated with excessive daytime sleepiness, worse sleep quality, and impaired mental health-related quality of life in Chinese-Taiwanese OSA patients.