Medical electronics: Biomedical engineers are exploiting electric signals to and from the body to aid rehabilitation of the handicapped

Twenty months ago 3 bullet intended for another man shattered the spine of Bassam Khawam, paralyzing him from the waist down, Doctors told Mr. Khawam, a 24-year old industrial engineer who lives in Cleveland, Ohio, that he would never walk again. But last April he showed an audience at the national convention of the Spinal Cord Society in St. Paul, Minn., that he could walk. By pressing a switch on his electronic walker, Mr. Khawam triggered a sequence of electric pulses from electrodes inserted into his leg muscles. These pulses, with their timing and voltage programmed by a computer strapped to Mr. Khawam's waist, caused first one leg and then the other to step forward.