Both of periodic limb movements during sleep (pLMS) and tinnitus were related with dopaminergic system dysfunction. However, it was still unclear whether PLMS, one kind of sleep disturbances, was associated with chronic tinnitus or not. Thus, we aimed to investigate this issue in humans. Clinical and overnight polysomnographic data of 2849 adults from a community hospital during Nov. 2011 to Jun 2017 in Taiwan was collected retrospectively. The association of PLMS and chronic tinnitus was analyzed by Student's t-test, Pearson's Chi-Square test, and multivariate logistic regression. The results showed that the mean age was 50.6 years old (standard deviation, SD = 13.3, range = 18~91) for all subjects. There were 1886 subjects without tinnitus and 963 subjects with tinnitus in this study. The PLMS was not significantly different between subjects without tinnitus (mean = 1.0/h, SD = 3.5/h) and subjects with tinnitus mean = 1.1/h, SD = 3
.4/h) by Student's t-test. The severity of PLMS was not significantly between non-tinnitus and tinnitus subjects by Pearson's Chi-Square test. Multivariate logistic regression also showed that PLMS was not significantly associated with tinnitus after adjusting age, sex, subjective hearing loss, Parkinson's disease, and insomnia. In conclusion, PLMS was not associated with chronic tinnitus in humans.Tinnitus is a phantom auditory perception. There were many types of tinnitus, for example auditory tinnitus, somatic tinnitus, vascular origin tinnitus, muscular origin tinnitus, etc. And, the prevalence of tinnitus depends on the type and/or definition for it. A nationwide survey of South Korea reported that the prevalence of any tinnitus was 20.7% among adults aged 20 to 98 years 1 . The prevalence of all types of tinnitus was higher in women than in men, and it increased with age 1 . The contributing factors and/or etiologies of tinnitus were numerous, including hearing impairment, cardiometabolic disorders, sleep disturbances and sleep apnea, migraine, and non-migraine headache, etc. 2-4 . And, tinnitus often comorbided with other diseases, such as anxiety, depression, brain tumors or stroke, and some symptoms including irritability, inability to concentration, and sleep disturbances [5][6][7] .Dysfunction in the cochlea, and neural reorganization in the auditory and non-auditory cortices have been reported to be associated with auditory tinnitus 8 . In addition to neuroinflammation and/or oxidative stress damages 9-13 , increased expression of N-methyl D-aspartate (NMDA) receptor (NR) gene 14 , decreasedγ-amino butyric acid (GABA) receptor (GR) and cannabinoid receptor genes were found in the cochlea and some brain areas 9,15 . Increased expresssion of K + -Cl − cotransporter (KCC2) gene was also found in salicylate-induced tinnitus 16 . Besides, dysfunction of dopaminergic system was reported to be related with tinnitus formation 17,18 . On the other hand, the pathophysiology of periodic limb movements during sleep (PLMS) was reported to be related with dysfunction of dopaminergic sy...