Electric Arms & Hands

To the 2,000 doctors attending last week's assembly of the International College of Surgeons in Madrid, one of the most interesting exhibits was a one-legged man who was darting around a stone pavement, cutting intricate figures on roller skates. He had been fitted with an artificial leg, and taught to use it, by Dr. Henry H. Kessler of Newark, N. J.

To Kessler and other orthopedists, the rehabilitation of a man with a missing leg is fairly simple. A missing arm or hand is far more of a challenge. Kessler told the assembled surgeons about progress in electrical substitutes. Here the crucial job is to find an effective hook-up between muscle (or tendons) and the switches which control the supply of current from batteries to tiny electric motors.

One electric arm which Dr. Kessler described was made by International Business Machines Corp. The switches are operated by pressure of the toes. Electric motors supply power to bend and extend the elbow and wrist, to rotate the lifelike, plastic hand and to open and close the fingers and thumb.

In the latest model now being worn by I.B.M. Consultant John Seeley (who is helping Manhattan's Alderson Research Laboratories to test it), the switches have been shifted from the toes to the stump at the shoulder. This puts into practice one of the principles espoused by Orthopedist Kessler: the controls must be as nearly natural as possible, so that the wearer will have to learn a minimum of new reflexes and responses. Seeley, who lost both arms at 14 when he was run over by a train, now works his electric arm by six switches which are actuated by twitches of his shoulder muscles. With his new arm, he can dress himself (except for fastening his collar button), feed himself, write letters.

As an aid in rehabilitation, Kessler pointed out, orthopedists can now take advantage of the amputee's familiar "phantom limb" sensation, i.e., after an amputation, patients often "feel" pain in the lost member. Instead of trying to get rid of this sensation, doctors in Vaduz, capital of the postage-stamp principality of Liechtenstein, have been urging patients to cultivate it, e.g., by flexing the muscles in the arm stump, as if opening and closing the hand. Thus the muscle is kept active, and rehabilitation (with an electric hand) can be speeded up.

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