Subtle gait changes in patients with REM sleep behavior disorder
Funding agencies: NIH, National Institute on Aging (NAI) (U01 AG006786, P50 AG016574, AG015866, R01 AG034676); the Robert H. and Clarice Smith and Abigail Van Buren Alzheimers Disease Research Program of the Mayo Foundation; Mangurian Foundation.
Relevant conflicts of interest/financial disclosures: E.M.M., B.P.B., T.J.H.C., J.H.H., K.B.: Nothing to report. V.S.P. receives research support from the NIH. B.F.B. has served as an investigator for clinical trials sponsored by Cephalon, Inc., Allon Pharmaceuticals and GE Healthcare; he receives royalties from the publication of a book entitled Behavioral Neurology of Dementia (Cambridge Medicine, 2009); he serves on the Scientific Advisory Board of the Tau Consortium; he has received honoraria from the American Academy of Neurology; he receives research support from the National Institute on Aging and the Mangurian Foundation. T.J.F receives support from the National Institute on Aging and the Mangurian Foundation. R.O.R. is supported by the NIH/NIA and the Driskill Foundation. M.M.M. receives support from the NIH/NIA and the Lewy Body Dementia Association. D.S.K. serves as Deputy Editor for Neurology; served on a Data Safety Monitoring Board for Lilly Pharmaceuticals; served as a consultant to TauRx, was an investigator in clinical trials sponsored by Baxter, Elan Pharmaceuticals, and Forest Pharmaceuticals in the past 2 years; and receives research support from the NIH. R.C.P. serves on scientific advisory boards for Pfizer, Inc., Janssen Alzheimer Immunotherapy, Elan Pharmaceuticals, and GE Healthcare; receives royalties from the publication of Mild Cognitive Impairment (Oxford University Press, 2003); and receives research support from the NIH/NIA.
Many people with rapid eye movement (REM) sleep behavior disorder (RBD) have an underlying synucleinopathy, the most common of which is Lewy body disease. Identifying additional abnormal clinical features may help in identifying those at greater risk of evolving to a more severe syndrome. Because gait disorders are common in the synucleinopathies, early abnormalities in gait in those with RBD could help in identifying those at increased risk of developing overt parkinsonism and/or cognitive impairment. We identified 42 probable RBD subjects and 492 controls using the Mayo Sleep Questionnaire and assessed gait velocity, cadence, and stride dynamics with an automated gait analysis system. Cases and controls were similar in age (79.9 ± 4.7 and 80.1 ± 4.7, P = 0.74), Unified Parkinson's Disease Rating Scale Part III (UPDRS) score (3.3 ± 5.5 and 1.9 ± 4.1, P = 0.21) and Mini–Mental State Examination scores (27.2 ± 1.9 and 27.7 ± 1.6, P = 0.10). A diagnosis of probable RBD was associated with decreased velocity (−7.9 cm/s; 95% confidence interval [CI], −13.8 to −2.0; P < 0.01), cadence (−4.4 steps/min; 95% CI, −7.6 to −1.3; P < 0.01), significantly increased double limb support variability (30%; 95% CI, 6–60; P = 0.01), and greater stride time variability (29%; 95% CI, 2–63; P = 0.03) and swing time variability (46%; 95% CI, 15–84; P < 0.01). Probable RBD is associated with subtle gait changes prior to overt clinical parkinsonism. Diagnosis of probable RBD supplemented by gait analysis may help as a screening tool for disorders of α-synuclein. © 2013 International Parkinson and Movement Disorder Society