Get access

Coherence analysis in the myoclonus of corticobasal degeneration

Authors

  • Pascal Grosse MD,

    Corresponding author
    1. Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, London, United Kingdom
    2. Neurologische Klinik und Poliklinik, Charité, Campus Virchow-Klinikum, Berlin, Germany
    • Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, 8-11 Queens Square, London WC1N 3BG
    Search for more papers by this author
  • Andrea Kühn MD,

    1. Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, London, United Kingdom
    2. Neurologische Klinik und Poliklinik, Charité, Campus Virchow-Klinikum, Berlin, Germany
    Search for more papers by this author
  • Carla Cordivari MD,

    1. Department of Clinical Neurophysiology, National Hospital for Neurology and Neurosurgery, London, United Kingdom
    Search for more papers by this author
  • Peter Brown MD

    1. Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, London, United Kingdom
    Search for more papers by this author

Abstract

We investigated whether myoclonus in corticobasal degeneration (CBD) is cortical or subcortical in origin. Many authors have suggested that the myoclonus in CBD is a subtype of cortical myoclonus, despite the fact that back-averaging fails to detect a cortical correlate to spontaneous or action induced jerks and giant sensory evoked potentials are seldom found. Electroencephalographic–electromyographic (EEG–EMG) and EMG–EMG frequency analysis may be more sensitive to cortical drives when EMG bursts occur at a high frequency and at low amplitudes as in CBD. We evaluated EEG–EMG and EMG–EMG coherence and phase in 5 patients with clinically probable CBD and unilateral, action-induced and stimulus-sensitive myoclonus. We found negligible corticomuscular coherence despite a dramatically exaggerated EMG–EMG coherence. We conclude that an inflated EMG–EMG coherence is found in some patients with CBD and that this is unlikely to be due to an exaggerated cortical drive. © 2003 Movement Disorder Society

Get access to the full text of this article

Ancillary