A four-channel IBM PC/AT compatible biphasic pulse generator for nerve stimulation.

An IBM PC/AT compatible four-channel biphasic pulse generator has been developed to assist in functional electrical stimulation (FES) related research. Each channel uses a bipolar 12-bit digital-to-analog converter (DAC) to generate biphasic voltage pulses between +/- 5 VDC and three 16-bit timers to control first, second, and interphase durations. Two vectored interrupt generators are available for precise pulse timing control. Potential uses of this device include FES research, the characterization of the recruitment properties of percutaneous electrodes in multichannel stimulation systems, or as a subassembly in commercial medical devices requiring electrical simulation in an IBM PC/AT platform.

Therapeutic FES: from rehabilitation to neural prosthetics.

The purpose of this paper is to review the therapeutic applications of electrical stimulation and to focus on functional neuromuscular electrical stimulation (FES), which is the production of useful muscle contractions for joint stability and limb movement. The use of FES to improve patient function during the recovery period after illness or injury and the transition to FES neural prosthetic systems for patients who do not fully recover will be discussed. Emphasis will be given to the maintenance of posture and the production of purposeful movement from the perspective of technologies and clinical strategies that are available today and from the perspective of those technologies that have the potential for transfer to community health care in the near future.

Magnetic-induction hyperthermia. Results of a 5-year multi-institutional national cooperative trial in advanced cancer patients.

Nine US institutions performed 14,807 Phase I-II treatments of magnetic-induction (Magnetrode [Henry Medical Electronics, Inc., Los Angeles, CA]) hyperthermia in 1170 adults. All had advanced tumors: 20% had untreated inoperable cancer or disease progression despite surgery (10%), radiation therapy (XRT) (3%), chemotherapy (27%), or combinations (40%); 67% had pain; and 79% had reduced activity. Eighteen percent were advanced primaries, 26% were recurrent, and 56% metastatic tumors in the head and neck (7%), body wall (7%), extremity (4%), abdominal cavity (17%), pelvis (17%), lung (15%), or liver (30%); 36% were less than 5 cm and 64% greater than or equal to 5 cm. Treatments were to safe tolerance for 30 to 60 minutes for five or more treatments. Results in 960 evaluable patients were complete response 9% (1-34 months; median, 7 months), partial response 18% (1-39 months; median, 4 months), minimal response 10% (1-15 months; median, 3 months), and no change 33% (1-32 months; median, 3 months), with decreased pain in 30% and improved activity in 21%, independent of histologic type or site. Regression was dependent on treatment type and minimum temperature: heat only, 23%; heat + XRT, 60%; heat + less-than-standard XRT because of prior XRT failure, 39%, heat + intravenous (IV) chemotherapy, 28%; heat + same previously failed IV chemotherapy, 20%; heat + intraarterial (IA) chemotherapy, 28%; heat + same previously failed IA chemotherapy, 15%; heat + standard XRT + chemotherapy, 58%; heat + less-than-standard XRT + chemotherapy, 47%; less than 40 degrees C, 31%; 40 to 40.9 degrees C, 45%; 41 to 41.9 degrees C, 54%; 42 to 42.9 degrees C, 47%; 43 to 43.9 degrees C, 40%; 44 to 44.9 degrees C, 33%; 45 to 45.9 degrees C, 55%; 46 to 46.9 degrees C, 63%; greater than 47 degrees C, 100%. There were 49 (0.33%) skin burns and 2 systemic injuries (stomach ulcer at 1 month; lung fibrosis at 9 months). This trial indicates that localized hyperthermia has a significant role in palliation of human advanced solid cancer.