CONFINEMENT to a wheelchair is not merely annoying and degrading.It is positively bad for the health. Those permanently so confined often suffer urinary, respiratory, cardiovascular and digestive-system problems, as well as osteoporosis and pressure sores-and among their number was, until recently,Amit Goffer.In 1997 Dr Goffer, an Israeli engineer, suffered an accident that left him partially paralysed.Being an engineer, however,he decided to do something about it. The result is a pair of“robotic trousers” that he calls ReWalk.

The idea of a powered,artificial exoskeleton will be familiar to cinema-goers from films such as“Aliens’and“Avatar”. In both of these movies, however, the device imagined acts to amplify the power and strength of the user.ReWalk, an exoskeletal version of the legs' bones and muscles, and the pelvic girdle, has a more modest aim: to restore to the user the power and strength he has lost.

ReWalk consists of a set of pastic-covered aluminium struts, linked by actuator motors, that are strapped to the user's legs and waist, and a backpack.With these,and a pair of crutches for

back-up, a user can walk around.An array of sensors distributed along the struts and around the wearer's body feeds information to a computer in the backpack. The computer then tells the actuators what to do.

The wearer starts by telling the computer what he is trying to achieve. A remote control strapped to one of his wrists offers several modes ofaction:“stand”,“sit”,“walk”, “ascend' and “descend’(the last two being pertinent to climbing and coming down staircases).Once strapped in, he starts by pressing the “walk” mode, pushes his crutches outward and is off. Algorithms devised

by Drooters colleagues at Argo Medical Technoiogies in Yokneam Ilit, the firm he founded to develop ReWalk, analyse the data from the sensors and use the result to operate the actuators appropriately. Experience shows the device can be worn all day, every day, without discomfort The wearer need remove it only at night, when he goes to bed.

ReWalk is now undergoing trials. Besides those in lsrael itself, these are being conducted in

America and Europe.Two versions of the device are being developed.One for supervised use in hospitals and rehabilitation centres, is already available for sale in Europe at a price of €87,500($120000) and has just been approved in America.The other, for the unsupervised use of those who have undergone such training, is still under scrutiny, but Dr Goffer hopes it will be cleared for sale by the end of the year.

Dr Goffer says that his aim is to enable paralysed people to lead a normal life.Apart from giving users the ability to walk, stand and climb stairs, the device has another important impact-on their dignity.When someone is in a wheelchair his head is at the height of an average person's waist. This literal diminution of his stature inevitably reduces his metaphorical stature,too. Once able to stand up his stature, in both senses of the word, is restored-and that, as much as the health and mobility benefits, is no mean gain.

Ironically, none of this is yet of use to Dr Goffer. He is too paralysed in his upper body to be able to operate ReWalk. Smarter means of communication between man particularly paralysed man--and machine are being devised all the time, so that may yet change. But for now he takes his comfort from the sight of his invention helping others to stand tall.