Mind power could be used to control artifical limbs, scientists believe.
Implants would be required
Tests on humans show a link between a pattern of brain signals and certain limb movements, a team at Duke University, North Carolina found.
Previous research has shown monkeys can move a cursor on a computer screen using thought-waves alone.
However, implants of microchips into the brain of paralysed patients would be necessary to allow them to control a robot arm or computer.
Professor Miguel Nicolelis at Duke University led the latest research, which he said could lead to treatment for people with paralysis.
Patients would be able to control the movement of a robot arm or leg by thinking about it.
The electrical signals produced by the brain would be picked up by the chip and sent to the robotic arm.
Tests were carried out on Parkinson's Disease patients who played a computer game as they underwent a brain operation under local anaesthetic.
Tiny electrodes recorded signals coming from the brain as the patients used a joystick to play the game.
The results showed the pattern of brain signals that correspond to certain movements of a limb can be mapped.
This makes it possible to produce a chip which knows what the signals sent by the brain mean.
Professor Nicolelis said: "It is very encouraging because it replicated some of the results we saw in monkeys.
"It could allow severely paralysed patients to regain mobility."
He hoped the technique could be in place in two to five years.
Professor Stephen Jackson at the Institute of Neuroscience in Nottingham, said similar research had been done in the UK.
He said he "did not think it would be very long" before it would be possible to drive an artificial limb by signals from the brain.
Professor Roger Lemon, director of the Insititute of Neurology at University College London, stressed it was not the thought that controlled muscle movement but the neural signals sent by the brain.
Though the idea has been around for 40 years it was only recently that it had been possible to put implants into the brain safely, said Professor Lemon.