Measurement of neuromagnetic fields accompanying movements by patient with acute stroke

The recovery mechanism of stroke patients with motion disorder is becoming clear through observation of changes in the activated area in the brain cortex, using brain function imaging. At the present stage, however, consistent results have not been obtained. Consequently, this study attempts an analysis of the neuromagnetic fields by combining the conventional equivalent current dipole method and the MCE method, which can reveal changes in multiple activity sources accompanying the recovery of brain function by stroke patients and those observable in healthy subjects. In the experiment, button-pressing by the thumb is performed by a patient group and a normal group, and the neuromagnetic field response and the force of the motion are simultaneously measured. Thus, the task consists of simple button-pressing motion and the generation of a force of specified magnitude. In the normal group, activation is observed in the motor area on the other side of the moving limb. In stroke patients, on the other hand, activation is observed on the same side as the moving limb, which agrees with the results of preceding studies. Neural activity is sometimes observed near the damaged lesion, suggesting that the brain on the ipsilateral hemisphere of the moving limb, or neural activity near the damaged lesion, is enhanced in the recovery of motor function after an acute stroke. It is concluded that a temporal course of changes in the activated area in the brain of patients with acute stroke, which exhibits patterns different from the neuromagnetic field of normal subjects, can be observed. © 2006 Wiley Periodicals, Inc. Syst Comp Jpn, 37(7): 12–25, 2006; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/scj.20448