Anatomical categorization of isolated non-focal dystonia: novel and existing patterns using a data-driven approach
J. R. Younce,
R. H. Cascella,
B. D. Berman,
H. A. Jinnah,
H. A. Jinnah,
S Bellows,
J. Feuerstein,
A. Wagle Shukla,
A. Mahajan,
F. C. F. Chang,
K. R. Duque,
S. Reich,
S. Pirio Richardson,
A. Deik,
N. Stover,
J. M. Luna,
S. A. Norris,
S. A. Norris
Affiliations
J. R. Younce
Department of Neurology and Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
R. H. Cascella
School of Medicine, Washington University, St. Louis, MO, United States
B. D. Berman
Department of Neurology, Virginia Commonwealth University, Richmond, VA, United States
H. A. Jinnah
Department of Neurology, Emory University, Atlanta, GA, United States
H. A. Jinnah
Department of Human Genetics, Emory University, Atlanta, GA, United States
S Bellows
Department of Neurology, Baylor College of Medicine, Houston, TX, United States
J. Feuerstein
Department of Neurology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
A. Wagle Shukla
Department of Neurology, University of Florida, Gainesville, FL, United States
A. Mahajan
Rush Parkinson’s Disease and Movement Disorders Program, Rush University Medical Center, Chicago, IL, United States
F. C. F. Chang
0Movement Disorders Unit, Neurology Department, Westmead Hospital & Sydney Medical School, University of Sydney, Sydney, NSW, Australia
K. R. Duque
1James J. and Joan A. Gardner Family Center for Parkinson’s Disease and Movement Disorders, Department of Neurology, University of Cincinnati, Cincinnati, OH, United States
S. Reich
2Department of Neurology, University of Maryland, Baltimore, MD, United States
S. Pirio Richardson
3Department of Neurology, University of New Mexico and New Mexico VA Healthcare System, Albuquerque, NM, United States
A. Deik
4Parkinson Disease and Movement Disorders Center, Department of Neurology, University of Pennsylvania, Philadelphia, PA, United States
N. Stover
5Department of Neurology, Heersink School of Medicine, The University of Alabama at Birmingham, Birmingham, AL, United States
J. M. Luna
6Department of Radiology, School of Medicine, Washington University, St. Louis, MO, United States
S. A. Norris
6Department of Radiology, School of Medicine, Washington University, St. Louis, MO, United States
S. A. Norris
7Department of Neurology, School of Medicine, Washington University, St. Louis, MO, United States
According to expert consensus, dystonia can be classified as focal, segmental, multifocal, and generalized, based on the affected body distribution. To provide an empirical and data-driven approach to categorizing these distributions, we used a data-driven clustering approach to compare frequency and co-occurrence rates of non-focal dystonia in pre-defined body regions using the Dystonia Coalition (DC) dataset. We analyzed 1,618 participants with isolated non-focal dystonia from the DC database. The analytic approach included construction of frequency tables, variable-wise analysis using hierarchical clustering and independent component analysis (ICA), and case-wise consensus hierarchical clustering to describe associations and clusters for dystonia affecting any combination of eighteen pre-defined body regions. Variable-wise hierarchical clustering demonstrated closest relationships between bilateral upper legs (distance = 0.40), upper and lower face (distance = 0.45), bilateral hands (distance = 0.53), and bilateral feet (distance = 0.53). ICA demonstrated clear grouping for the a) bilateral hands, b) neck, and c) upper and lower face. Case-wise consensus hierarchical clustering at k = 9 identified 3 major clusters. Major clusters consisted primarily of a) cervical dystonia with nearby regions, b) bilateral hand dystonia, and c) cranial dystonia. Our data-driven approach in a large dataset of isolated non-focal dystonia reinforces common segmental patterns in cranial and cervical regions. We observed unexpectedly strong associations between bilateral upper or lower limbs, which suggests that symmetric multifocal patterns may represent a previously underrecognized dystonia subtype.
