1,000-day performance milestone reached by BrainGate system

March 25th, 2011 - 6:22 pm ICT by ANI  

Washington, Mar 25 (ANI): An implanted brain chip has allowed a woman with tetraplegia to accurately control a computer cursor through neural activity alone more than 1,000 days after the device was implanted, according to experts.

The BrainGate neural interface system can detect and record brain signals, allowing paralysed persons to have point-and-click control of a computer.

The woman, identified as S3, performed two ‘point-and-click’ tasks each day by thinking about moving the cursor with her hand. In both tasks she averaged greater than 90 percent accuracy. Some on-screen targets were as small as the effective area of a Microsoft Word menu icon.In each of her two tasks, performed in 2008, she controlled the cursor movement and click selections continuously for 10 minutes.

The first task was to move the cursor to targets arranged in a circle and in the centre of the screen, clicking to select each one in turn.

The second required her to follow and click on a target as it sequentially popped up with varying size at random points on the screen.

“This proof of concept - that after 1,000 days a woman who has no functional use of her limbs and is unable to speak can reliably control a cursor on a computer screen using only the intended movement of her hand - is an important step for the field,” said Leigh Hochberg, a Brown engineering associate professor and director of the BrainGate pilot clinical trial at Massachusetts General Hospital.

“Our objective with the neural interface is to reach the level of performance of a person without a disability using a mouse,” said lead author John Simeral, assistant professor of engineering at Brown.

“These results highlight the potential for an intracortical neural interface system to provide a person that has locked-in syndrome with reliable, continuous point-and-click control of a standard computer application,” he added.

Under development since 2002, the investigational BrainGate system is a combination of hardware and software that directly senses electrical signals produced by neurons in the brain that control movement.

By decoding those signals and translating them into digital instructions, the system is being evaluated for its ability to give people with paralysis control of external devices such as computers, robotic assistive devices, or wheelchairs.

The system is currently in pilot clinical trials.

“Neuroengineers have often wondered whether useful signals could be recorded from inside the brain for an extended period of time,” said Hochberg.

“This is the first demonstration that this microelectrode array technology can provide useful neuroprosthetic signals allowing a person with tetraplegia to control an external device for an extended period of time,” he added.

The results appear online March 24 in the Journal of Neural Engineering. (ANI)

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