A research project investigating a method for restoring lost
movements in people with a
upper motor neuron lesion (e.g Ictus - stroke, spinal cord injury, etc )
The basic idea is to 'boost' impaired movements by measuring the intention and activate necessary muscles in a manner that is close to normal motions.
Muscle contractions are generating a weak signal (myoelectric activity), which can be measured by sensitive electronic circuits. From the myoelectric signal (MeS), the amount of movement that the subject is attempting can be estimated. Even paretic muscles, with only twitches of contraction, may be used for estimating the users intent to move.
On the contrary, if the circumstances are right, muscles can also be made contract by stimulating them with electricity. When the muscle-contraction is functional, we call it Functional Electrical Stimulation - FES.
So the concept is actually simple: The MeS represents intent to move - the FES induces the movement. In combination, we can then let the mind control the lost movements - again. Ideally, the MeS controlled FES should acting like a servo control or power steering in a car - a small steering effort is augmented by actuators to provide the power needed for turning heavy wheels, so the driver only needs to provide modest effort. In our case, the driver is a part of the muscle still under volitional control and the actuator is the FES of the paralyzed part of the muscle (or a synergistic muscle).
While the concept is simple and intuitive (Vodovnik 1965), there are some technical and physiological obstacles. Furthermore, there are the questions about feasibility for activities of daily living and the clinical relevance for rehabilitation.