The objective of the proposed research is to develop a six channel implantable stimulator that can effect selective arrest of different diameter fibers of peripheral and central nerves. The most immediate application of the device is to effect control of micturition and defecation in individuals with spinal cord injuries. Although development of the electrode system for this application is complete, there are no implantable stimulators available that can produce the specific waveform required. In addition, effective selectivity in the sacral roots requires six isolated output channels. In Phase I, a circuit design was developed to meet these requirements. Preliminary bench-top testing with breadboards has been completed, as well as animal studies. The tests have shown the new design to be effective in producing selective activation of the parasympathetic fibers controlling the lower bowel and bladder, without concurrent activation of the sphincters. External stimulator prototypes, macro versions of the proposed implantable stimulators, are now in progress. In Phase ll, the design will be miniaturized using Multi-Chip Module technology, a RF power and communication link between the stimulator and an external controller will be developed, the implantable package will be designed, and thorough testing of the overall system will be conducted in both animal and human subjects.
Restoration of control of the bladder and bowel to individuals with spinal cord injuries will significantly impact their quality of life and the cost of health care. These patients often require costly treatment of complications in these systems. It is estimated that there are l 76,000 people in the United States with spinal cord injuries and that at least 8000 new injuries occur each year.
