Alteration of motor related field in patients with occlusive vascular diseases

Cerebral occlusive vascular disease has been well investigated in aspect of a risk factor for stroke, however, whether it causes any alteration in brain function is poorly understood. To investigate this, we examined the motor related magnetic field in 20 patients with cerebral occlusive disease (12 with atherosclerotic (AS group) and 8 with non-atherosclerotic lesions (NAS group)) and 7 control subjects, and evaluated the spatial distribution and the intensity (t-value) of event related desynchronization in beta band during hand grasping and finger tapping tasks using synthetic aperture magnetometry. According to the laterality index (L.I.) calculated from peak t-values on both hemispheres, activation pattern was classified into 3 types, as contralateral—(L.I. > 0), bilateral—(0.1 < L.I. < 0), and ipsilateral activation—(L.I. < − 0.1). During the contra-lesional hand grasping tasks, 9 of 12 patients in AS group and 1 of 8 in NAS group showed ipsilateral activation. This abnormal activation pattern was not observed in the control group. The L.I during hand grasping in AS group was significantly lower than those of other 2 groups, whereas there was no significant difference in the L.I. during finger tapping tasks among 3 groups. Abnormal distribution of motor related magnetic field, ipsilateral activation, might indicate subclinical functional alteration induced by cerebral ischemia due to atherosclerosis.