By Daniel A. Barone, MD, FAASM, FANA

Assistant Attending Neurologist, NewYork-Presbyterian Hospital, and Assistant Professor of Clinical Neurology, Weill Cornell Medical College

SYNOPSIS: In this retrospective, cross-sectional study of men, both sleepwalking and rapid eye movement sleep behavior disorder were associated with the development of Parkinson’s disease.

SOURCE: Zhang X, Molsberry SA, Pavlova M, et al. Association of sleepwalking and REM sleep behavior disorder with Parkinson disease in men. JAMA Netw Open 2021;4:e215713.

Rapid eye movement (REM) sleep behavior disorder (RBD) is one of the most well-known and extensively studied sleep features of Parkinson’s disease, both in terms of risk and as a sleep-related symptom. The non-REM parasomnia, sleepwalking, is not as well understood or studied. Sleepwalking might exhibit a significant prevalence in patients with Parkinson’s disease (approximately 10%), and the presence of non-REM parasomnias is associated with worse symptoms, cognitive impairment, and depression in those with Parkinson’s disease. However, despite these observations and the fact sleepwalking is somewhat rare in adults (1% to 2%), no study comparing individuals without Parkinson’s disease in direct comparison to those with Parkinson’s disease for risk estimation has been conducted.

Zhang et al aimed to answer the question of whether the presence of sleepwalking in men, either alone or comorbid with RBD, is associated with higher odds of developing Parkinson’s disease. To accomplish this, they surveyed a cohort of 25,694 men from the Health Professionals Follow-Up Study, which consisted of male health professionals in the United States followed from January 2012 until June 2018. The presence of probable sleepwalking and/or probable RBD was ascertained in 2012 via the Mayo Sleep Questionnaire. The diagnosis of Parkinson’s disease was determined by a movement disorder specialist through a review of medical records. The mean age of this cohort was 75.6 years, and the authors found that 223 were probable sleepwalkers, 2,720 were probable RBD, and 257 had Parkinson’s disease. The presence of confounders, such as age, smoking, caffeine intake, chronic disease status, and other sleep disorders, was adjusted for in a two-tailed logistic regression analysis. This led to the observation that those with probable sleepwalking, probable RBD, or both probable sleepwalking and probable RBD had higher odds of Parkinson’s disease (P < 0.05): probable sleepwalking, OR = 4.80; probable RBD, OR = 6.36; both probable sleepwalking and probable RBD, OR = 8.44. Thus, it appears both probable sleepwalking and probable RBD, alone and in conjunction, were significantly associated with higher odds of developing Parkinson’s disease. The authors noted arousal regulation during sleep is likely to be affected by Parkinson’s disease-related neurodegeneration.

COMMENTARY

As the authors wrote, this is the first paper commenting on a non-REM parasomnia as a risk for Parkinson’s disease. However, despite the novelty of this design, there were significant limitations. This was a questionnaire-based methodology for assessing the presence of sleep disorders and a medical records review for making a diagnosis of Parkinson’s disease. However, this new line of thinking should open the doors to prospective evaluation of the risk for development of Parkinson’s disease in other parasomnias and sleep disorders. For example, in an earlier study based on the Health Professionals Follow-Up Study, the presence of restless legs syndrome (RLS) was associated with higher odds of constipation and probable RBD, both of which are risk factors for Parkinson’s disease.1 Long-term studies evaluating the risk of neurodegeneration in those with non-REM parasomnias and other sleep disorders (such as RLS and periodic limb movements of sleep) are needed now. Perhaps this marks the beginning of a paradigm shift to a better understanding of the risk of neurodegeneration in patients with sleep disorders other than RBD.

REFERENCE

  1. Iwaki H, Hughes KC, Gao X, et al. The association between restless legs syndrome and premotor symptoms of Parkinson’s disease. J Neurol Sci 2018;394:41-44.