This Article Full Text Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Braune, H. J. Articles by Fritz, C. Search for Related Content PubMed PubMed Citation Articles by Braune, H. J. Articles by Fritz, C.

(Stroke. 1995;26:550-553.)
© 1995 American Heart Association, Inc.

Articles

Transcranial Magnetic Stimulation–Evoked Inhibition of Voluntary Muscle Activity (Silent Period) Is Impaired in Patients With Ischemic Hemispheric Lesion

Hans J. Braune, MD Christof Fritz, MD

From the Department of Neurology, University of Marburg (Germany).

Correspondence to Dr Hans-Joachim Braune, Neurologische Universitätsklinik und Poliklinik, Rudolf-Bultmann-Straße 8, D-35033 Marburg, Germany.

Background and Purpose Transcranial magnetic stimulation of the motor cortex is well established as a valuable method for noninvasive examination of the central motor system. In addition to exciting corticospinal cells and evoking a direct motor response, the magnetic stimulus delivered during voluntary activity produces a prolonged postexcitatory inhibition (silent period) of activity. We investigated silent period changes in patients with ischemic stroke of different clinical degrees.

Methods Standardized transcranial magnetic stimulation during sustained muscle contraction was performed at the vertex. Electromyographic activity was recorded via surface electrodes placed over the abductor digiti minimi muscle on both sides. We examined 50 patients with stroke (divided into three subgroups according to the degree of impairment) and 50 healthy control subjects.

Results In the control group we found no statistically significant interside difference in the duration of the silent period, whereas a marked interindividual variation was found. In patients with prior minor stroke who showed no residual motor disturbance, we found a significant prolongation of the postexcitatory inhibition recorded from the affected side compared with the healthy side. This interside discrepancy was even more pronounced in patients with minor hemiparesis and patients with moderate hemiparesis.

Conclusions Our findings suggest that the measurement of the silent period elicited by transcranial magnetic stimulation is a useful and sensitive neurophysiological parameter in the management of stroke. Particularly in the subgroup of patients with no residual clinical signs of central motor impairment, it is capable of detecting subclinical motor function disturbances.

Key Words: cerebral ischemia • cerebral ischemia, transient • motor activity • stimulation, transcranial magnetic • stroke assessment

This article has been cited by other articles:

				O. B.C. Swayne, J. C. Rothwell, N. S. Ward, and R. J. Greenwood Stages of Motor Output Reorganization after Hemispheric Stroke Suggested by Longitudinal Studies of Cortical Physiology Cereb Cortex, August 1, 2008; 18(8): 1909 - 1922. [Abstract] [Full Text] [PDF]

				K. R. Kessler, A. Schnitzler, J. Classen, and R. Benecke Reduced inhibition within primary motor cortex in patients with poststroke focal motor seizures Neurology, October 8, 2002; 59(7): 1028 - 1033. [Abstract] [Full Text] [PDF]