• Open Access

Sensory tricks in primary cervical dystonia depend on visuotactile temporal discrimination

Authors

  • Georg Kägi MD,

    1. Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, London, United Kingdom
    2. Department of Neurology, Kantonsspital St. Gallen, St. Gallen, Switzerland
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  • Petra Katschnig MD,

    1. Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, London, United Kingdom
    2. Department of Neurology, Medical University of Graz, Graz, Austria
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  • Mirta Fiorio PhD,

    1. Department of Neurological, Neuropsychological, Morphological and Movement Sciences, University of Verona, Verona, Italy
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  • Michele Tinazzi PhD,

    1. Department of Neurological, Neuropsychological, Morphological and Movement Sciences, University of Verona, Verona, Italy
    2. Neurology Unit, Borgo Trento Hospital, Verona, Italy
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  • Diane Ruge MD,

    1. Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, London, United Kingdom
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  • John Rothwell PhD,

    1. Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, London, United Kingdom
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  • Kailash P. Bhatia MD

    Corresponding author
    • Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, London, United Kingdom
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  • Relevant conflicts of interest/financial disclosures: Georg Kägi was supported by a grant from the Swiss Parkinson's Disease Association and the Halley Stewart Trust.

  • Full financial disclosures and author roles may be found in the online version of this article.

  • Author Roles: Georg Kägi contributed to the conception, organization, and execution of the clinical project and wrote the first draft. Petra Katschnig contributed to the organization and execution of the clinical project and reviewed and critiqued the manuscript. Mirta Fiorio contributed to the conception and organization of the clinical project and reviewed and critiqued the manuscript. Michele Tinazzi contributed to the conception and organization of the clinical project and reviewed and critiqued the manuscript. Diane Ruge contributed to the organization and execution of the clinical project and reviewed and critiqued the manuscript. John Rothwell contributed to the conception and organization of the clinical project and reviewed and critiqued the manuscript. Kailash P. Bhatia contributed to the conception and organization of the clinical project and reviewed and critiqued the manuscript.

    Financial Disclosures: Georg Kägi has received honoraria for attending meetings of Bayer and Lundbeck; has received grants from the Swiss Parkinson's disease Association, Medical Research Centre, and Kantonsspital St. Gallen, and is employed by Kantonsspital St. Gallen. Petra Katschnig has received honoraria for attending meetings from Boehringer Ingelheim, GlaxoSmithKline, Novartis, UCB, and Bayer and is employed by Medical University Graz, Austria. Mirta Fiorio is employed by the University of Verona. Michele Tinazzi is employed by the University of Verona. Diane Ruge has received grants from the Dorothy Feiss Scientific Research Grant and the Tourette Syndrome Association and is employed by University College London. John Rothwell has received grants from the European Union FP7 program (“Plasticise” and “Replaces”), Tourette Association, Dystonia Medical Research Foundation, and the Stroke Association and is employed by University College London. Kailash P. Bhatia is a Movement Disorders Society Scientific Advisory Board Member; has been an adviser and received honoraria, financial support to speak and attend meetings from GSK, Boehringer-Ingelheim, Ipsen, Merz, and Orion pharma companies; has received grants from Wellcome Trust and MRC award (ref. no. WT089698); is employed by University College London; and has received royalties from Oxford University Press for the book Oxford Specialist Handbook of Parkinson's Disease and Other Movement Disorders.

Correspondence to: Kailash P. Bhatia, Professor Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College of London, Queen Square, London WC1N 3BG, UK; k.bhatia@ion.ucl.ac.uk

Abstract

A characteristic feature of primary cervical dystonia is the presence of “sensory tricks” as well as the impairment of temporal and spatial sensory discrimination on formal testing. The aim of the present study was to test whether the amount of improvement of abnormal head deviation due to a sensory trick is associated with different performance of temporal sensory discrimination in patients with cervical dystonia. We recruited 32 patients with cervical dystonia. Dystonia severity was assessed using the Toronto Western Spasmodic Torticollis Rating Scale. Patients were rated according to clinical improvement to a sensory trick and assigned to 1 of the following groups: (1) no improvement (n = 6), (2) partial improvement (n = 17), (3) complete improvement (n = 9). Temporal discrimination thresholds were assessed for visual, tactile, and visuotactile modalities. Disease duration was shorter (P = .026) and dystonia severity lower (P = .033) in the group with complete improvement to sensory tricks compared with the group with partial improvement to sensory tricks. A significant effect for group and modality and a significant interaction between group × modality were found, with lower visuotactile discrimination thresholds in the group with complete improvement to sensory tricks compared with the other groups. In primary cervical dystonia, a complete resolution of dystonia during a sensory trick is associated with better visuotactile discrimination and shorter disease duration compared with patients with less effective sensory tricks, which may reflect progressive loss of adaptive mechanisms to basal ganglia dysfunction. © 2013 Movement Disorder Society

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