Feed-forward control of post-stroke movement disorders by on-demand type stimulation of the thalamus and motor cortex.

Deep brain stimulation (DBS) of the thalamus (Vo/Vim) has become popular as a means of controlling involuntary movements, including post-stroke movement disorders. We have also found that post-stroke movement disorders and motor weakness can sometimes be controlled by motor cortex stimulation (MCS). In some forms of movement disorders, motor dysfunction becomes evident only when patients intend to move their body. We have developed an on-demand type stimulation system which triggers stimulation by detecting intrinsic signals of intention to move. Such a system represents feed-forward control (FFC) of involuntary movements. We report here our experience of DBS and MCS for controlling post-stroke movement disorders, and discuss the value of FFC. Excellent control of post-stroke movement disorders was achieved by conventional DBS and/or MCS in 20 of 28 patients with hemichoreoathetosis, hemiballism tremor, and motor weakness. FFC was tested in 6 patients who demonstrated excellent control of post-stroke postural tremor or motor weakness by conventional DBS or MCS. The on-demand stimulation provided satisfactory FFC in 4 of 4 patients with postural tremor and 2 of 2 patients with motor weakness, when the activity of muscles involved in posturing or intention to move was fed into the system. These findings justify further clinical studies on DBS and MCS in patients with post-stroke movement disorders. The on-demand type stimulation system may also be useful for overcoming various post-stroke movement disorders.