When the connection from the brain to the spinal cord has been severed, as it is in severely paralyzed, or quadriplegic people, the primary motor cortex in the brain remains healthy, but the command signals from the brain are ineffective because they are cut off from the muscles.
Afflicted individuals are hence unable to use their hands to use computers or operate basic controls and equipment.
Although there are devices that provide benefits to many of these individuals, including tongue or sip and puff switches, they are limited in functionality, ease of use and speed.
Now researchers at Cyberkinetics are working on an alternative approach – one that makes use of a device that is implanted in the brain.
The BrainGate Neural Interface, as the complete system is called, operates by using an implantable chip to continuously detect and digitise the activity of neuron populations in the primary motor area of the cerebral cortex, signals which are then processed, analysed and decoded by a computer to allow a patient to control a mouse on a computer screen.
Last month, Cyberkinetics announced that it has begun a feasibility study that will test the system out on five quadriplegic patients between the ages of 18 and 60. Each patient will undergo surgery in which the sensor portion of the BrainGate neural interface will be implanted on the surface of the primary motor cortex, the portion of the brain responsible for movement.
There are two primary goals of the pilot clinical study: the first is to characterise the safety profile of the device and the second is to evaluate the quality, type, and usefulness of neural output control that patients can achieve.
The study is expected to last for about 13 months for each patient, during which time they will perform tasks with the device such as attempting to control the movement of a cursor on a screen by imagining movement of their arm to move the cursor toward a specific target.
At the end of the study, each patient will undergo another surgery to have the device removed or have the option to participate in future studies. Cyberkinetics anticipates reporting initial study results in late 2004.