title: Muscle selection for treatment of cervical dystonia with botulinum toxin--a systematic review.
abstract: BACKGROUND
  Cervical dystonia, also called spasmodic torticollis, is the most common form of (primary) dystonia. Intramuscular injections with botulinum toxin are the first line of treatment for cervical dystonia. To optimise the treatment response to botulinum toxin correct muscles should be selected. Clinical evaluation is important for muscle selection but the value of additional tests to identify dystonic muscles remains unclear.
  
  
  OBJECTIVE
  To evaluate all relevant literature regarding the best approach to select dystonic muscles for treatment with botulinum toxin.
  
  
  METHODS
  We conducted a systematic review of studies that had investigated methods of selecting muscles for treatment with botulinum toxin. In addition, we compared all prospective botulinum toxin trials using either clinical evaluation or polymyographic electromyography for muscle selection.
  
  
  RESULTS
  Forty relevant studies were included and polymyographic electromyography recordings were most often employed. In several studies, polymyographic electromyography revealed a different pattern of muscle involvement compared to that found during clinical evaluation. In one randomized controlled trial polymyographic electromyography significantly improved the outcome of botulinum toxin treatment. A limited number of studies used positron emission tomography -computed tomography imaging or frequency analysis of the electromyography signal to identify dystonic muscles but their effect on the outcome of treatment has never been studied.
  
  
  CONCLUSIONS
  Polymyographic electromyography may improve the outcome of botulinum toxin treatment in cervical dystonia, but evidence is limited and larger studies are needed.
authors.affiliation: Department of Neurology and Clinical Neurophysiology, Academic Medical Centre, Amsterdam, The Netherlands.
authors.forename: S W R
authors.initials: SW
authors.lastname: Nijmeijer
authors.forename: J H T M
authors.initials: JH
authors.lastname: Koelman
authors.forename: D J
authors.initials: DJ
authors.lastname: Kamphuis
authors.forename: M A J
authors.initials: MA
authors.lastname: Tijssen
mesh_terms: D018726:Anti-Dyskinesia Agents / Q000627:therapeutic use*; D001905:Botulinum Toxins / Q000627:therapeutic use*; D004576:Electromyography; D006801:Humans; D007273:Injections, Intramuscular / Q000592:standards; D009334:Neck Muscles / Q000187:drug effects / Q000503:physiopathology*; D014103:Torticollis / Q000188:drug therapy*
chemical_list: D018726:Anti-Dyskinesia Agents; D001905:Botulinum Toxins