Technology: Smart angle on stroke rehabilitation

 作者:汪囔     |      日期:2019-02-28 07:20:01
By ROSIE MESTEL in LOS ANGELES Cheap, simple machines built by engineers in California could help stroke patients recover the use of their limbs and relearn common, day-to-day tasks. Dubbed ‘rehabilitators’, they could make the most of the physiotherapy a patient receives after a stroke. At present such therapy is limited by the shortage of physiotherapists, the high cost of individual sessions and the imprecision of human help when patients are relearning physical tasks. Every year tens of thousands of people in the US suffer strokes that affect only one side of the body, and require an average of three months of physiotherapy. The computer-controlled rehabilitators were designed in the laboratory of Steve Lehman, a muscle physiologist and bioengineer at the University of California at Berkeley. One of them, built by his colleagues David Reinkensmeyer and Peter Lum, trains a patient to lift a lightweight tray with both hands. When the patient attempts to lift it, a sensor registers the tray’s angle. If the tray is level, the machine does nothing. If the tray is slanted, the machine helps the weaker arm and hums loudly to tell the patient that their coordination is off. And, as new neural pathways are set up in the brain and coordination improves, patients can monitor their progress by the reduction of the humming. Machines like the tray-lifter can increase a patient’s physiotherapy time because one physiotherapist could supervise the treatment of several patients. This is important, because studies have shown that the more physiotherapy patients get, the better their recovery is likely to be. The machines are also more accurate than a human therapist who cannot calculate the precise amount of aid that the patient needs. The tray-lifting machine continually monitors the angle of the tray, and continually adjusts the amount of help it provides, offering the patient no more help than necessary. And where a therapist’s assessment of a patient’s progress is subjective, the mechanical rehabilitators can assess it very precisely by referring back to records of previous sessions. Also, such machines allow the pa-tients to progress at their own speed: ‘The idea is to be independent,’ says Lehman. Reinkensmeyer and Lum are gearing up to compare the benefits of their tray-balancing rehabilitator with conventional therapy: a small-scale clinical trial starts soon in Chicago. Meanwhile, they have other rehabilitators on the drawing board. One would assist patients while they practised unscrewing a jar or squeezing an object as if to pick it up. Another would have a springy rod that supported the patient’s torso as they leaned on a table with their weakened arm – just as they might do if leaning over to wipe the table with the other hand. As the patient became stronger, the rod would provide less support. Eventually, Lehman’s group envisions a whole gymful of machines, each designed for a different task. A physical therapist would supervise a dozen or so stroke patients at a time, each working away at their own exercise. But the researchers stress that the rehabilitators are not intended to replace physiotherapists, but to free them to interact with the patient instead of giving mechanical help. And while far fancier devices can be built with today’s technology, the no-frills design of the rehabilitators is deliberate: ‘We don’t want to increase the cost of health care,