Myoelectric Prosthosis

Myoelectric Prosthesis: Use single from the neuromuscular system to activate specific component functions. Combinations of conventional and myoelectric components may be considered within the same prosthesis.

Components: In a myoelectric controlled prosthesis an electric potential produced by a contracting muscle activates a battery-driven motor that operates a prosthetic component. Proportional control of the motor is by regulation of the extent or speed of movement. The system has the following advantages and disadvantages.

Advantages:

1) Use of natural muscle stimuli.
2) More accurate control with less energy expenditure.
3) Eliminates the shoulder harness.
4) Decreased body movement to control prosthesis.

Disadvantages:

1) Very expensive.
2) In the event of a breakdown, it needs very skilled technical backup to repair.
3) Component operation is noisy and slow.
4) The energy source is from a battery, which would have to be re-charged daily.
5) Lack of propriceptive feedback as from the harness in body powered systems.
6) It is heavy.
7) It cannot control fine rhythmic and fast movements.
8) There is poor control of co-contracting muscles and thereby fine motor control.

Permanent fitting of the myoelectric controls involves locating suitable sites for the electrodes, providing the socket with electrode placement, controls, battery pack and on-off switch.