Stroke patients who are given therapy to improve mobility also see a dramatic improvement in brain activity, scientists have found.

Research findings presented at the annual meeting of the American Association for the Advancement of Science showed areas of activity in the brain responsible for movement could double in size after intensive therapy.

Conventional therapy after a stroke often involves just an hour or two of physiotherapy a week. But stroke patients treated at the University of Alabama Medical Center received three weeks of intensive therapy for at least six hours a day.

The patients repeated simple physical exercises, such as picking up small objects over and over again, each time trying to complete the tasks more quickly.

Re-learning tasks

The study subjects were forced to use their less mobile arms or hands, while their able limbs were held in splints.

Dr Edward Taub, who developed the therapy, said at the end of the three weeks, 75% of patients had dramatically improved the mobility of their affected limbs - and the results appeared to be permanent.

Dr Taub said brain scans of the patients showed areas of activity in the brain responsible for mobility had increased in size. This, he said, suggested the patients' brains were re-learning movement through repetition in the same way that children learned how to walk, or musicians learned how to play an instrument.

The technique is being used in a small number of clinics in several countries. But a large-scale trial involving thousands of stroke patients is now being sponsored by the US National Institutes of Health.

The technique is also being trialled on people with brain injuries and cerebral palsy.