Pressure-Sensitive Controls: Update on Development and Clinical Trials

WILLIAM NICHOL, CPO(C)*


Clinical experience with fitting very high level upper-limb amputees with electronically controlled prostheses has confirmed the need for a reliable pressure-sensitive control. During the past two years we have embarked on a project to develop a reliable device specifically designed for installation into a prosthesis. The final design of the bidirectional controller has provided a compact, reliable,' modular system that can be easily incorporated into a prosthesis, quickly and accurately adjusted to each patient, and readily repaired when malfunction occurs. Initial clinical trials were with shoulder disarticulation patients using multifunction membrane assemblies to control the hand, wrist, and elbow. The trials proved very successful and all original objectives were met. Further trials occurred with very young wrist disarticulation patients utilizing two single function switches activated by wrist flexion and extension to control the terminal device. As these patients grow, they may be changed to myoelectric control, depending upon the amount of space available for the necessary electronics. The pressure-sensitive controlling device has proved to be an alternative where myoelectric control is difficult to obtain. The success achieved with the initial clinical trials allows us to incorporate the system in our prescription procedures.

*Rehabilitation Centre for Children, 633 Wellington Crescent, Winnipeg, Manitoba R3M 0A8