Neurology 2021 01 12;96(4):e563-e574. Epub 2020 Oct 12.
From the Departments of Biomedical Engineering (A.G.S., S.B.B.) and Neurology (A.G.S.), Case Western University School of Medicine; Neurological Institute (A.G.S.), University Hospitals Cleveland; Neurology Service (A.G.S.), Louis Stokes Cleveland VA Medical Center, OH; Department of Neurology (L.S., G.K.-B., A.F., S. Factor, H.A.J.), Human Genetics (H.A.J.), and Pediatrics (H.A.J.), Emory University School of Medicine, Atlanta, GA; Institute of Neurogenetics (C.K., J.J., S.L., N.B., A.M., T.B.), University of Lübeck, Germany; Department of Neurology (M.V., E.R., C.B.), Pitié-Salpêtrière Hospital, Paris, France; Department of Neurology (J.J.), Baylor College of Medicine, Houston, TX; Neurology and Neurosurgery (J.J.-S.), Icahn School of Medicine at Mount Sinai, New York, NY; Department of Neurology (N.P.), Henry Ford Health System, West Bloomfield, MI; Department of Psychiatry and Neurology (L.M.), Baylor College of Medicine, Houston, TX; Department of Neurological Sciences (C.C.), Rush University Medical Center, Chicago, IL; Department of Neurology (R.L.B.), University of Rochester, NY; Department of Neurology (B.D.B.), University of Colorado School of Medicine, Aurora; Department of Neurology (I.M., A.W.S.), Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville; Department of Neurology (S.G.R.), University of Maryland School of Medicine, Baltimore; University of Tennessee Health Science Center (M.S.L.), Memphis; Department of Neurosciences (A.B.), Mental Health and Sensory Organs, Suicide Prevention Center, Sant'Andrea Hospital, Sapienza University of Rome; IRCCS Neuromed (G.F.), Pozzilli, Italy; The University of Alabama at Birmingham (N.S.); Methodist Neurological Institute (W.O.), Houston, TX; Department of Neurology (S.P.R.), University of New Mexico Health Sciences Center, Albuquerque; Department of Neurology (R.S.-P.), Mount Sinai Beth Israel, New York, NY; Lou Ruvo Center for Brain Health (Z.M.), Cleveland Clinic, Las Vegas, NV; Booth Gardner Parkinson's Care Center (P.A.), Kirkland, WA; Mayo Clinic (C.A.), Scottsdale, AZ; Andre Barbeau Movement Disorders Unit (S.C.), Montreal University Hospital Center (CHUM); Movement Disorder Clinic (S.H.F.), Toronto Western Hospital, Division of Neurology University of Toronto, Canada; UC Davis School of Medicine (A.B.), Sacramento; The Parkinson's and Movement Disorder Institute (D.T.), Orange Coast Memorial Medical Center, Fountain Valley, CA; Department of Medicine (O.S.), Medical Genetics, and Pediatrics, University of Alberta, Canada; Department of Neurology (S. Frank), Beth Israel Deaconess Medical Center, Boston, MA; and Neurology, Radiology, Neuroscience, Physical Therapy and Occupational Therapy (J.P.), Washington University School of Medicine, St Louis, MO.
Objective: To assess the clinical manifestations and predictors of different types of tremors in individuals with different types of isolated dystonia.
Methods: Clinical manifestations of tremor were assessed in a multicenter, international cross-sectional, cohort study of 2,362 individuals with all types of isolated dystonia (focal, segmental, multifocal, and generalized) recruited through the Dystonia Coalition.
Results: Methodical and standardized assessments of all participants in this cohort revealed the overall prevalence of any type of tremor was 53.3%. The prevalence of dystonic tremor varied from 36.9% to 48.4%, depending on criteria used to define it. To identify the factors associated with tremors in dystonia, the data were analyzed by generalized linear modeling and cluster analyses. Generalized linear modeling indicated 2 of the strongest factors associated with tremor included body region affected by dystonia and recruitment center. Tremor was also associated with severity of dystonia and duration of dystonia, but not with sex or race. The cluster analysis distinguished 8 subgroups within the whole cohort; defined largely by body region with dystonia, and secondarily by other clinical characteristics.
Conclusion: The large number of cases evaluated by an international team of movement disorder experts facilitated the dissection of several important factors that influence the apparent prevalence and phenomenology of tremor in dystonia. These results are valuable for understanding the many differences reported in prior studies, and for guiding future studies of the nosology of tremor and dystonia.