Clinical Characteristics of Patients with Periodic Limb Movement in Sleep Who Showed Excessive Daytime Sleepiness

Background: Some patients with periodic limb movement in sleep (PLMS) have disrupted sleep and excessive daytime sleepiness (EDS). The clinical characteristics of patients with PLMS and EDS remain to be elucidated. Objective: To address the clinical characteristics of patients with PLMS affected by EDS, we assessed the clinical variables in patients with and without EDS and determined the influencing factors using polysomnography (PSG). Methods: This retrospective study included 306 patients with PLMS who did not take drugs. They visited our clinic between March 2015 and February 2021. Their sleep was recorded using PSG. PLMS was defined as having brief (0.5-5 seconds) repetitive limb movements, with a frequency of 15 or more times per hour. The Epworth Sleepiness Scale (ESS) was used as a subjective sleepiness indicator. Using the ESS, EDS was defined as a score ≧11. Multivariable logistic regression analysis was performed to determine the factors influencing EDS in patients with PLMS. Results: Of the 306 patients, 43 had PLMS. EDS was detected in 23 patients with PLMS. Logistic regression analyses revealed lower odds of EDS in men (odds ratio［OR］0.187, 95% confidence interval ［CI］ 0.041-0.856, P = 0.0307) and older individuals (OR 0.92, 95% CI 0.862-0.982, P = 0.0119) among patients with PLMS. Conclusions: Older male patients with PLMS were less likely to have EDS. To our knowledge, this is the first study to demonstrate that men and older individuals had a lower likelihood of experiencing EDS among patients with PLMS.