Bilaterally coherent tremor resembling enhanced physiological tremor: Report of three cases

Authors

  • John D. O'Sullivan MD,

    1. National Hospital for Neurology and Neurosurgery, Queen Square, London, United Kingdom
    2. Reta Lila Weston Institute of Neurological Studies, Royal Free and University College Medical School, University College London, London, United Kingdom
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  • John Rothwell PhD,

    1. Sobell Department of Neurophysiology, Institute of Neurology, University College London, London, United Kingdom
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  • Andrew J. Lees MD,

    1. National Hospital for Neurology and Neurosurgery, Queen Square, London, United Kingdom
    2. Reta Lila Weston Institute of Neurological Studies, Royal Free and University College Medical School, University College London, London, United Kingdom
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  • Peter Brown MD

    Corresponding author
    1. National Hospital for Neurology and Neurosurgery, Queen Square, London, United Kingdom
    2. Sobell Department of Neurophysiology, Institute of Neurology, University College London, London, United Kingdom
    • Sobell Department of Neurophysiology, Institute of Neurology, University College London, Queen Square, London, WC1N 3BG, United Kingdom
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  • A videotape accompanies this article.

Abstract

The contribution of the central nervous system to tremor pathogenesis is unclear. Poor side-to-side coherence in physiological, essential, and parkinsonian tremors suggests distinct bilateral generators. By contrast, significant bilateral coherence demonstrated in orthostatic tremor and in enhanced physiological tremor (EPT) in patients with persistent mirror movements favours single or closely linked bilateral oscillators. We describe three patients (aged 21–37 years) who developed unusual bilateral postural and kinetic tremors at 6–13 Hz resembling EPT. The tremor involved all limbs, and in two cases the face or jaw, in the absence of other significant neurological features. Significant side-to-side coherence was demonstrated in each case using cross-correlation of electromyographic recordings from homologous muscle pairs. We postulate that these unusual tremors originate from a single brainstem source or from bilateral oscillators closely linked at or below this level. © 2002 Movement Disorder Society

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