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Pirio Richardson S, Altenmüller E, Alter K, Alterman RL, Chen R, Frucht S, Furuya S, Jankovic J, Jinnah HA, Kimberley TJ, Lungu C, Perlmutter JS, Prudente CN, Hallett M. Research Priorities in Limb and Task-Specific Dystonias. Front Neurol 2017; 8:170. [PMID: 28515706 PMCID: PMC5413505 DOI: 10.3389/fneur.2017.00170] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Accepted: 04/11/2017] [Indexed: 11/13/2022] Open
Abstract
Dystonia, which causes intermittent or sustained abnormal postures and movements, can present in a focal or a generalized manner. In the limbs, focal dystonia can occur in either the upper or lower limbs and may be task-specific causing abnormal motor performance for only a specific task, such as in writer’s cramp, runner’s dystonia, or musician’s dystonia. Focal limb dystonia can be non-task-specific and may, in some circumstances, be associated with parkinsonian disorders. The true prevalence of focal limb dystonia is not known and is likely currently underestimated, leaving a knowledge gap and an opportunity for future research. The pathophysiology of focal limb dystonia shares some commonalities with other dystonias with a loss of inhibition in the central nervous system and a loss of the normal regulation of plasticity, called homeostatic plasticity. Functional imaging studies revealed abnormalities in several anatomical networks that involve the cortex, basal ganglia, and cerebellum. Further studies should focus on distinguishing cause from effect in both physiology and imaging studies to permit focus on most relevant biological correlates of dystonia. There is no specific therapy for the treatment of limb dystonia given the variability in presentation, but off-label botulinum toxin therapy is often applied to focal limb and task-specific dystonia. Various rehabilitation techniques have been applied and rehabilitation interventions may improve outcomes, but small sample size and lack of direct comparisons between methods to evaluate comparative efficacy limit conclusions. Finally, non-invasive and invasive therapeutic modalities have been explored in small studies with design limitations that do not yet clearly provide direction for larger clinical trials that could support new clinical therapies. Given these gaps in our clinical, pathophysiologic, and therapeutic knowledge, we have identified priorities for future research including: the development of diagnostic criteria for limb dystonia, more precise phenotypic characterization and innovative clinical trial design that considers clinical heterogeneity, and limited available number of participants.
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Affiliation(s)
- Sarah Pirio Richardson
- Department of Neurology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Eckart Altenmüller
- Institute for Music Physiology and Musicians' Medicine (IMMM), Hannover University of Music, Drama and Media, Hannover, Germany
| | - Katharine Alter
- Functional and Applied Biomechanics Section, Rehabilitation Medicine, National Institute of Child Health and Development, National Institutes of Health, Bethesda, MD, USA
| | - Ron L Alterman
- Division of Neurosurgery, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - Robert Chen
- Division of Neurology, Department of Medicine (Neurology), Krembil Research Institute, University of Toronto, Toronto, ON, Canada
| | - Steven Frucht
- Robert and John M. Bendheim Parkinson and Movement Disorders Center, Mount Sinai Hospital, New York, NY, USA
| | - Shinichi Furuya
- Musical Skill and Injury Center (MuSIC), Sophia University, Tokyo, Japan
| | - Joseph Jankovic
- Department of Neurology, Baylor College of Medicine, Houston, TX, USA
| | - H A Jinnah
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, USA.,Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, USA.,Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
| | - Teresa J Kimberley
- Department of Rehabilitation Medicine, Division of Physical Therapy and Rehabilitation Science, University of Minnesota, Minneapolis, MN, USA
| | - Codrin Lungu
- Division of Clinical Research, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Joel S Perlmutter
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA.,Department of Radiology, Washington University School of Medicine, St. Louis, MO, USA.,Department of Neurosciences, Washington University School of Medicine, St. Louis, MO, USA.,Department of Physical Therapy, Washington University School of Medicine, St. Louis, MO, USA.,Department of Occupational Therapy, Washington University School of Medicine, St. Louis, MO, USA
| | - Cecília N Prudente
- Department of Rehabilitation Medicine, Division of Physical Therapy and Rehabilitation Science, University of Minnesota, Minneapolis, MN, USA
| | - Mark Hallett
- Human Motor Control Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
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