Graduate students in the University of Texas at Arlington’s Colleges of Engineering and Science have combined their talents to create a wireless, integrated sensor-and-stimulator system to alleviate acute pain. Their system is unique in that it will do this automatically and as only as needed.

The system was devised over a two-year period by Psychology doctoral students Jiwei He and Christopher Hagains and Electrical Engineering doctoral student Thermpon Ativanichayaphong. Their faculty advisors were Electrical Engineering’s Dr. J. C. Chiao and Psychology’s Dr. Yuan Bo Peng.

Clinical studies have shown that brain stimulation can provide significant pain relief. However, current stimulators are open-loop systems; doctors can only make adjustments based on the patient’s verbal responses and results in a constant and fixed-strength stimulation. The students have developed a closed-loop system that can automatically provide optimal pain relief signals, based on the physiological responses recorded from neurons associated with pain.

This feedback system works by constantly recording pain impulses via a sensor implanted on the spinal cord. These signals are wirelessly transmitted to a computer, which evaluates the impulses and wirelessly sends corrective signals to implants in the brain. This applies electrical stimulation to brain neurons, effectively inhibiting the pain. Eventually, the computer in this loop will be miniaturized and worn by the patient. Because of the feedback mechanism, neurostimulation is delivered only when and in the amount required to alleviate pain. In preliminary studies on confined rats, it was possible to get complete inhibition of pain. Their prototype device will now be used for further study of neuronal activities in freely moving rats. Human test are still several years away.