Brain Activation in a Myoelectric Prosthetic Hand: The Role of the Brain in the Rehabilitation of Amputees

Author(s): da Paz AC, Braga LW

Source:  J Pediatr Orthop, 2007; 27:947-951.


The concept of brain activation of a myelectric prosthesis is intriguing.  The increasing number of amputees from the war makes this even more pertinent.  These authors attempt to investigate whether stimuli from the sensorimotor cortex, observed through functional magnetic resonance imaging, permits control of a myelectric prosthetic hand.

This is a self-controlled study designed with a single 13 year old girl with congenital amputation of the right hand.  She was tested as to whether or not the brain could control fine motor movement of her myelectric hand.  Software was developed that supplied a graphic tool to stimulate movement of the prosthesis.  To further enhance the learning process, a functional MRI scanner simulator was built for the purpose of correlating electromygraphic signals with movements obtained in the myelectric hand.  Split screen software was also developed to see an artificial image of a hand moving in random rhythm during opening and closing.

Brain activation patterns were observed when the patient contracted the remaining stump muscles, and when she thought about opening and closing her myelectric hand after learning this process.  Functional MRI showed brain activation and various motor activities associated with perception of movement.   Contralateral activity in the cerebellum showed that she was attempting to mentally modulate the movements of opening and closing her prosthetic hand during fMRI.  To validate the experiment, the results show that the patient exhibited similar sensor motor activities in the contralateral hemisphere during similar movements of the unaffected hand.

These results are encouraging and indicate that fMRI may be a useful measure for working a prosthetic hand.  Rehabilitation could be adopted that would utilize functional MRI of the brain to learn a terminal device.  The brain could than control speed, force, and modulation of a myelectric prosthesis dependant upon impulses admitted by these specific areas of the brain.  Further research in brain control and improvement of myelectric prosthesis may lead to a better prosthesis in the future.

Amputee, Myoelectric, Prosthesis, Brain, Rehabilitation

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