Cortical excitability is abnormal in patients with the “fixed dystonia” syndrome

Authors

  • Laura Avanzino MD,

    1. Sobell Department of Motor Neuroscience, Institute of Neurology, University College London, London, United Kingdom
    2. Department of Neurosciences, Ophthalmology and Genetics, University of Genoa, Italy
    Search for more papers by this author
  • Davide Martino MD,

    1. Sobell Department of Motor Neuroscience, Institute of Neurology, University College London, London, United Kingdom
    2. Department of Neurologic and Psychiatric Sciences, University of Bari, Italy
    Search for more papers by this author
  • Bart P. C. van de Warrenburg MD, PhD,

    1. Sobell Department of Motor Neuroscience, Institute of Neurology, University College London, London, United Kingdom
    2. Department of Neurology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
    Search for more papers by this author
  • Susanne A. Schneider MD,

    1. Sobell Department of Motor Neuroscience, Institute of Neurology, University College London, London, United Kingdom
    Search for more papers by this author
  • Giovanni Abbruzzese MD,

    1. Department of Neurosciences, Ophthalmology and Genetics, University of Genoa, Italy
    Search for more papers by this author
  • Giovanni Defazio PhD,

    1. Department of Neurologic and Psychiatric Sciences, University of Bari, Italy
    Search for more papers by this author
  • Anette Schrag MD,

    1. Royal Free and University College Medical School, University College London, London, United Kingdom
    Search for more papers by this author
  • Kailash P. Bhatia MD,

    1. Sobell Department of Motor Neuroscience, Institute of Neurology, University College London, London, United Kingdom
    Search for more papers by this author
  • John C. Rothwell PhD

    Corresponding author
    1. Sobell Department of Motor Neuroscience, Institute of Neurology, University College London, London, United Kingdom
    • Sobell Department of Motor Neuroscience, Institute of Neurology, University College London; London WC1N 3BG, United Kingdom

    Search for more papers by this author

Abstract

A form of fixed dystonia (FD) without evidence of basal ganglia lesions or neurodegeneration has been recently characterized (Schrag et al., Brain 2004;127:2360-2372), which may overlap the clinical spectrum of either complex regional pain syndrome or psychogenic dystonia. Transcranial magnetic stimulation studies in typically mobile dystonia revealed abnormal motor cortical excitability and sensori-motor integration. We compared 12 patients with limb FD to 10 patients with primary adult-onset typically mobile dystonia and 11 age-matched healthy volunteers. Measurements at the first digital interosseus representation area on both hemispheres included: short intracortical inhibition (SICI), contralateral silent period (cSP), and short and long afferent inhibition (SAI and LAI). Repeated measure ANOVA and post-hoc t-tests were used for statistical analysis. SICI was significantly reduced in both hemispheres of patients with “typical” and FD, compared to healthy subjects. For both hemispheres, cSP duration was shorter in both fixed and “typical” dystonia patients. SAI and LAI did not significantly differ between the three groups. The abnormal cortical excitability observed in FD might represent an underlying trait predisposing to different clinical forms of dystonia. © 2007 Movement Disorder Society

Ancillary