2Central Clinical Hospital, Russian Academy of Science, Moscow, Russia email@example.com
The dependence of the interaction of the upper and lower extremities from motor task was investigated. Nine healthy subjects and 10 patients after stroke with varying degree of hemiparesis in lying position executed out of phase or in phase arm movements in the horizontal plane without and with stepping movements of the legs in various combinations. Similar movements were made in passive mode. The electromiographic (EMG) activity of arms and legs muscles and kinematics of movement of the upper and lower extremities were registered. In healthy subjects during passive movements a reflex muscle activity of arms modulated with the cycle of movement was observed, which reached an average of 30%-40% of its value with voluntary movements (condition A). In patients
with passive movements the reflex activity in paretic arm muscles was smaller, than in healthy subjects, and the activity in the muscles of the non paretic arm was similar to healthy. With increasing the degree of paresis the reflex activity of muscles caused by passive arm movements worsened. When combined, the unidirectional, out of phase movements of arms and legs the highest activation interlimb connections between the generator mechanisms of upper and lower extremities with the greatest degree of mutual interaction was observed, that resulted in reduction of muscle activity in the arms while increasing activity in the legs. In patients a similar influence of this motor synergy on the activity in the arm muscles was observed, although the degree of mutual interaction was less than in healthy, and in leg muscles the increasing of EMG activity was observed only in the biceps muscle of hip, but for all that in the remaining muscles no significant changes were observed. During fulfilling of another motor task the less binding of neural networks responsible for generating the rhythmic movements of the arms and legs was presented. Thus, in the context of our research on healthy subjects with arm movements in different planes, you can activate the functional connections between the cervical and lumbosacral spinal cord in human, influencing on these relationships by engaging the upper and lower limbs in a joint cyclic movements. Motor task, in which unidirectional, out of phase movements of the arms and legs are realized, is, probably the most appropriate to use in order to restore motor functions in patients after stroke.
The work was supported by grant RFBR ofi-m № 11-04-12139.