Get access

Triad stimulation frequency for cortical facilitation in cortical myoclonus

Authors

  • R. Hanajima MD, PhD,

    Corresponding author
    1. Department of Neurology, Division of Neuroscience, Graduate School of Medicine, the University of Tokyo, Tokyo, Japan
    • Department of Neurology, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan

    Search for more papers by this author
  • Y. Terao MD, PhD,

    1. Department of Neurology, Division of Neuroscience, Graduate School of Medicine, the University of Tokyo, Tokyo, Japan
    Search for more papers by this author
  • S. Nakatani-Enomoto MD,

    1. Department of Neurology, Division of Neuroscience, Graduate School of Medicine, the University of Tokyo, Tokyo, Japan
    2. Department of Neurology, Fukushima Medical University, Fukushima, Japan
    Search for more papers by this author
  • S. Okabe MD, PhD,

    1. Department of Neurology, Division of Neuroscience, Graduate School of Medicine, the University of Tokyo, Tokyo, Japan
    Search for more papers by this author
  • Y. Shirota MD,

    1. Department of Neurology, Division of Neuroscience, Graduate School of Medicine, the University of Tokyo, Tokyo, Japan
    Search for more papers by this author
  • S. Oominami MD,

    1. Department of Neurology, Division of Neuroscience, Graduate School of Medicine, the University of Tokyo, Tokyo, Japan
    Search for more papers by this author
  • H. Matsumoto MD, PhD,

    1. Department of Neurology, Division of Neuroscience, Graduate School of Medicine, the University of Tokyo, Tokyo, Japan
    Search for more papers by this author
  • S. Tsuji MD, PhD,

    1. Department of Neurology, Division of Neuroscience, Graduate School of Medicine, the University of Tokyo, Tokyo, Japan
    Search for more papers by this author
  • Y. Ugawa MD, PhD

    1. Department of Neurology, Division of Neuroscience, Graduate School of Medicine, the University of Tokyo, Tokyo, Japan
    2. Department of Neurology, Fukushima Medical University, Fukushima, Japan
    Search for more papers by this author

  • Relevant conflict of interest: Nothing to report. This work was supported in part by Research Project Grant-in-aid for Scientific Research No. 20591019(RH); No. 22390181 (YU) and No 22590954 (YT) of the Ministry of Education, Culture, Sports, Science, and Technology of Japan; the Research Committee on rTMS Treatment of Parkinson's Disease, the Ministry of Health and Welfare of Japan; the Research Committee on Dystonia, the Ministry of Health and Welfare of Japan; the Committee of the Study of Human Exposure to EMF, Ministry of Public Management, Home Affairs, Post and Telecommunications.

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

    Author Roles: 1) Research project: A. Conception, B. Organization, C. Execution; 2) Statistical Analysis: A. Design, B. Execution, C. Review and Critique; 3) Manuscript: A. Writing of the first draft, B. Review and Critique. R Hanajima: 1A, 1B, 1C, 2A, 2B, 3A, 3B. Y Terao:2C, 3C. S Nakatani-Enomoto: 1C 2B. S Okabe:1C ,Y Shirota: 1C, S Ohminami: 1C, H Matsumoto: 1C, S Tsuji: 2C, 3C. Y Ugawa: 2C, 3C.

Abstract

Background:

Abnormally enhanced cortical rhythmic activities have been reported in patients with cortical myoclonus. We recently reported a new triad-conditioning transcranial magnetic stimulation (TMS) method to detect the intrinsic rhythms of the primary motor cortex (M1). Triad-conditioning TMS revealed a 40-Hz intrinsic rhythm of M1 in normal subjects. In this investigation, we study the motor cortical facilitation induced by rhythmic triple TMS pulses (triad-conditioning TMS) in patients with cortical myoclonus.

Methods:

Subjects were 7 patients with cortical myoclonus (28–74 years old) and 13 healthy volunteers (30–71 years old). Three conditioning stimuli over M1 at the intensity of 110% active motor threshold preceded the test TMS at various interstimulus intervals corresponding to 10–200 Hz. The resulting amplitudes of conditioned motor evoked potentials recorded from the contralateral hand muscle were compared with those evoked by the test stimulus alone.

Results:

The facilitation at 25 ms (40 Hz) observed in normal subjects was absent in patients with cortical myoclonus. Instead, triad-conditioning TMS induced facilitation at a 40 ms interval (25 Hz) in cortical myoclonus.

Discussions:

This change in the timing of facilitation may be explained by a shift of the most preferential intrinsic rhythm of M1, or by some dysfunction in the interneuronal network in cortical myoclonus. © 2011 Movement Disorder Society

Ancillary