Cerebral motor control in patients with brain tumors around the central sulcus studied with synthetic aperture magnetometry

Abstract

Abstract Synthetic aperture magnetometry (SAM) was applied to investigate changes in the mechanism of cerebral motor control in patients with tumors around the central sulcus in relation to the clinical relevance. MEG records were made during a resting state and a repetitive hand grasping task in patients with brain tumors around the central sulcus and in four control subjects. Topographic appearance of abnormal focal slowing in the delta, theta, and alpha bands (N = 10) and event related desynchronizations (ERD) in the alpha, beta, and low gamma bands during the motor tasks (N = 6) were analyzed statistically with SAM in relation to clinical signs and symptoms. Distribution of enhanced focal delta activity coincident with the motor cortices responsible for weakness. Volumetric analysis revealed emergence of tumor-related focal delta activity was greater for intra-axial tumors involving subcortical fibers than for other extra-axial tumors. In addition, patients with increased volume of enhanced delta activity exhibited poor functional recovery in the early post-operative period. Beta ERD in patients during affected side hand movement was also localized exclusively to the ipsilateral hemisphere contrary to the normal pattern. The characteristic focal delta distribution and the altered patterns of ERD in the patient group suggest not only close relation of cortical function and existing pathology but recruitment of diverse motor areas which may be required for the effective movement of the affected side.