Stroke Patients Move Robotic Arms Using Their Minds

Being paralyzed can be quite a frustrating experience for stroke victims as well as quadriplegics. Not being able to use their arms can be quite depressing, making people feel helpless. But a recent study may indicate that it is possible for paralyzed patients to someday control the use of robotic arms just by mere thought.

Researchers at Brown University have been able to effectively show that it is possible for paralyzed patients to gain control of robotic arms using only their thoughts. Stroke patients in the trial were able to move robotic arms with sensors attached to their brains using only their thoughts and imagining how to move the arms as if it was their own. The technology is based on an investigational neural interface system known as BrainGate. With it the quadriplegics were able to direct the robotic arms to move and touch foam balls.

One patient was even able to grab a bottle of coffee and drink it from a straw. The actions of the said patient, who was paralyzed by a brainstem stroke 15 years ago, may indicate a game-changing breakthrough for people who have undergone central nervous system injury.

“Although robotic reach-and-grasp actions were not as fast or accurate as those of an able-bodied person, our results demonstrate the feasibility for people with [quadriplegia], years after injury to the central nervous system,” the researchers wrote on their report which can be found on the May 17 issue of Nature.

“Though further developments might enable people with [quadriplegia] to achieve rapid, dexterous actions under neural control, at present, for people who have no or limited volitional movement of their own arm, even the basic reach and grasp actions demonstrated here could be substantially liberating, restoring the ability to eat and drink independently,” the researchers further stated.

Leigh Hochberg, MD, PhD, of Brown University in Providence, R.I., and colleagues have previously reported that quadriplegic patients can be made to use a neural interface system in order to move a cursor on a computer screen and even click on it. Further studies showed that able-bodied monkeys can use their neural signals in order to move a robotic arm. The BrainGate2 pilot clinical trial was conducted in order to see if similar results can be achieved with human patients.

The researchers were able to see favorable results from two human participants who initially lacked the function of their four limbs and could not speak. A 96-channel microelectrode was implanted into the motor cortex of the patients, the area of the brain that controls movement. Neural signals being sent by the brain are detected by the electrodes in the implanted sensor and then being sent and translated by an external computer which then controls the movements of two robotic arms of the DLR Light-Weight Robot III which was designed by the German Aerospace Center as an assistive device. The DEKA Arm system was also used in the said trial which was designed as an advanced limb replacement for arm amputees. The participants tried to move the robotic arms to grasp foam ball targets attached to a flexible support using only their brain signals.

One participant was able to perform 158 trials over four sessions and was able to successfully touch the targets 48.8 percent for the DLR trials and 69.2 percent for the DEKA trials. Another participant performed 45 trials in a single session and was successful 95.6 percent of the time using only the DEKA system. The use of the robotic arm shows promise in aiding people suffering from paralysis, especially in doing certain activities essential for daily living.”The use of neural interface systems to restore functional movement will become practical only if chronically implanted sensors function for many years,” the researchers further added.

Source: Everyday Health


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