Tehran University of Medical Sciences Journal of Sleep Sciences 2476-2938 7 1-2 2023 06 25 16 21 EN Morteza Saeidi Department of Neurology, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran Fariborz Rezaeitalab Division of Sleep Medicine, Psychiatry and Behavioral Sciences Research Center, Neuroscience Research Center, Mashhad University of Medical Sciences, Mashhad, Iran Saeed Akhlaghi Department of Biostatistics, School of Health, Mashhad University of Medical Sciences, Mashhad, Iran Farnaz Kharaghani Department of Radiology, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran Hussein Sharara Department of Neurology, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran Mina Abbasi Student Research Committee, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran Mahshid Mahyad Department of Neurology, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran 2022 03 14 2022 11 19 Background and Objective: Periodic limb movements of sleep (PLMS) and obstructive sleep apnea (OSA) are two common sleep disorders that frequently co-occur in one subject. In this study, we evaluated the polysomnographic (PSG) features of patients with OSA with and without PLMS. Materials and Methods: Patients with OSA diagnosed by PSG who referred to our sleep clinic over 2 years were studied for PLMS during a standard diagnostic sleep study. PSG features including apnea-hypopnea index (AHI), oxygen desaturation index (ODI), and sleep quality were evaluated and compared between patients with OSA with and without PLMS. Results: We evaluated 122 patients with OSA, of whom 17 had comorbid PLMS. Mean sleep quality was significantly lower in patients with PLMS compared to those without PLMS (P < 0.05). There was no significant difference in terms of mean age, gender, arousal index (AI), ODI, and apnea/hypopnea between the two groups. Conclusion: Patients with OSA with PLMS comorbidity have remarkably lower sleep quality and this finding is independent of the severity of arousals or respiratory events. Proper evaluation, diagnosis, and treatment of PLMS comorbidity in patients with OSA might improve treatment response.  https://jss.tums.ac.ir/index.php/jss/article/view/229