Muscle movement is caused by electrical impulses originating in the brain, which are transmitted via nerve cells to the muscles.

Before stroke

When a person wishes to initiate muscle movement, the brain sends electrical signals to the muscles. Upon arrival of these signals, the muscles respond by contracting. The electrical muscle signals can be measured and they are called electromyographic signals: EMG. 

EMG signals before stroke

If due to brain damage caused by a stroke, regular electrical impulses are not generated or they can no longer reach muscles, normal muscle contraction becomes impossible.

After stroke

Although there are mostly minuscule "left over" EMG signals, these are very often extremely small and unable to control muscles. This often leads to irreversible damage and loss of muscle function, resulting in muscle paralysis, such as "claw" hand or "drop foot" (gait problems). 

EMG signals after stroke

After a stroke, the patient is rehabilitated by physical therapy. Often it includes Functional Electrical Stimulation (FES) or NeuroMuscular Electrical Stimulation (NMES) in order to avoid muscle spasticity. This is done in the hope that there will be some form of spontaneous recovery and that the muscles will not become too stiff. In most cases, however, spontaneous recovery will not occur and the patient will be left with severe disuse muscle atrophy and paralyzed muscles, greatly affecting the quality of life. 

Devastating paralysis of muscles can often be prevented if the patient is offered the possibility to re-learn the use of the affected muscles by improving electrical muscle activity. This goal is achieved by combining EMG measurement and NMES muscle stimulation technologies in the Biomove system. 

In almost all cases, there is still a very small amount of electricity (EMG) which reaches the muscles. These small "left over" EMG signals are picked up by "stick on" electrodes placed over the paralyzed muscles.

The Biomove device then amplifies these small signals and when an internal preset "trigger" level is reached, the built-in electro stimulator returns an electrical stimulation impulse (NMES) to the same muscles.

The muscles now respond as originally "instructed" by the patient's own brain signal. This way the patient is able to obtain direct muscle movement, assisted by the Biomove device. 

After stroke with EMG triggered NMES

EMG signals after stroke with EMG triggered NMES

The patient uses this method of cognitive re-learning to rehabilitate the muscles of the otherwise paralyzed hand or foot. By using this advanced form of biofeedback, the central nerve system learns which part of the brain to activate. By training at home with the Biomove EMG triggered NMES device, important improvement of overall electrical activity of the paralyzed muscles is obtained, originating from the brain itself. This leads towards regaining significant muscle control by the patient. 

The combination of EMG and electrical muscle stimulation (EMG controlled NMES) enables the patient to take full advantage of even the tiniest electrical activity remaining after a cerebrovascular accident (CVA) or stroke, contributing significantly towards successful rehabilitation.

How stroke rehabilitation works