Abstract:
The very Underlying Principle of Control for the Otto Bock Myoelectric System is
“Muscle contraction should lead to function.” If you think about picking up an object
with your sound hand, you simply pick up the object. An amputee must concentrate on
more activities than that of an individual with a sound hand. If an amputee wears a
prosthesis they must first open their hand, then position their hand over the object, then
close their hand around the object and finally determine how much grip force should be
applied to the object. With all of those things to consider, the relationship between their
input signal (EMG) and the output of the hand (motor speed or grip force) must remain
constant to minimize the learning curve. If the relationship is variable, the patient must
relearn how to control the hand depending on the variables and thus control can be very
unpredictable. The analogy is getting into someone’s car that just had a brake job done.
You are used to putting high pressure on the pedal in your car in order to slow the car
down so when you touch the pedal in the other car, it brakes very abruptly. You need to
relearn the relationship between pedal pressure and braking speed. This is something we
need to avoid in myoelectric fittings. Therefore, the microprocessor control in the Otto
Bock system contains features to minimize the effects of outside influences.
