title: Determinants of disability in cervical dystonia.
abstract: Cervical dystonia (CD) is characterized by involuntary muscle contractions causing abnormal postures and/or twisting movements of the head and neck. These motor symptoms can have a major impact on disability. Treatment with botulinum toxin injections aims to reduce motor symptoms, and therefore disability. Despite motor improvements, many patients still experience difficulties with performing daily life activities. To optimize treatment, other factors that determine disability should be identified.
  
  
  
  To explore and identify clinical characteristics that relate to disability in CD.
  
  
  
  Data on disability, severity of dystonia, anxiety, depression, pain and quality of life of 96 CD patients was analyzed with a principal component analysis (PCA). Multiple regression analysis was performed to determine which components derived from the PCA explain most of the variance in disability.
  
  
  
  PCA revealed five components (disability, psychiatric features, pain, physical function and severity of dystonia), explaining 74.4% of the variance in disability. Multivariate association between disability and the other components was statistically significant (R2change 0.433, F change (4-86) = 22.39, p = .000). Psychiatric features had the largest contribution to disability (standardized beta = 0.555, p = 0.000) followed by pain (standardized beta = 0.232 p = 0.004). Physical functioning (standardized beta = 0.059 p = 0.507) and severity of dystonia (standardized beta = -0.001 p = 0.991) had no significant contribution.
  
  
  
  In CD patients, psychiatric features and pain are important determinants of disability. Interventions to reduce psychiatric problems and pain should have a more prominent role in the treatment of CD patients in order to improve disability levels.
authors.affiliation: ACHIEVE Centre of Expertise, Faculty of Health, Amsterdam University of Applied Sciences, Amsterdam, The Netherlands; Department of Neurology, University Medical Centre Groningen, Groningen, The Netherlands; Department of Neurology, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: J
authors.initials: J
authors.lastname: van den Dool
authors.affiliation: Department of Neurology, University Medical Centre Groningen, Groningen, The Netherlands.
authors.forename: M A J
authors.initials: MA
authors.lastname: Tijssen
authors.affiliation: Department of Neurology, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: J H T M
authors.initials: JH
authors.lastname: Koelman
authors.affiliation: ACHIEVE Centre of Expertise, Faculty of Health, Amsterdam University of Applied Sciences, Amsterdam, The Netherlands; Department of Rehabilitation, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: R H H
authors.initials: RH
authors.lastname: Engelbert
authors.affiliation: ACHIEVE Centre of Expertise, Faculty of Health, Amsterdam University of Applied Sciences, Amsterdam, The Netherlands. Electronic address: b.visser2@hva.nl.
authors.forename: B
authors.initials: B
authors.lastname: Visser
mesh_terms: D000328:Adult; D000368:Aged; D001905:Botulinum Toxins / Q000627:therapeutic use; D003430:Cross-Sectional Studies; D004185:Disability Evaluation; D006233:Persons with Disabilities; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019964:Mood Disorders / Q000209:etiology; D009498:Neurotoxins / Q000627:therapeutic use; D017063:Outcome Assessment, Health Care; D010146:Pain / Q000188:drug therapy / Q000209:etiology; D025341:Principal Component Analysis; D011569:Psychiatric Status Rating Scales; D011788:Quality of Life; D012189:Retrospective Studies; D014103:Torticollis / Q000188:drug therapy / Q000503:physiopathology* / Q000523:psychology*; D055815:Young Adult
chemical_list: D009498:Neurotoxins; D001905:Botulinum Toxins
keywords: Cervical dystonia; Disability; Non-motor symptoms; Spasmodic torticollis