Mind Over Matter: BCIs on the Fast Track for the New Age

In past discussions on brain-computer interfaces (BCIs), parallels were drawn between emerging applications and the idea of the "bionic man." However, a presentation by John P. Donoghue, PhD, during a "Hot Topics" plenary session on May 2 at the 59th Annual Meeting of American Academy of Neurology in Boston suggests that current neural interface technology is much more about the marvels of the human neuron and will than about machinery.

Research is showing that activity remains in the motor cortex long after injury caused by either trauma, as in spinal cord injury, or neurodegeneration, as in amyotrophic lateral sclerosis (ALS), according to Donoghue, who is the Henry Merritt Wriston Professor at Brown University in Providence, Rhode Island. In an ongoing new drug application-approved study involving 4 tetraplegic patients that is being conducted by Donoghue and colleagues, it was observed that electroencephalographic spikes were present in all of the participants. Two of the 4 were paralyzed because of spinal cord injury, 1 because of brain stem stroke, and 1 because of end-stage ALS. "All very different disease states," Donoghue said to stress the broad spectrum of potential applicability of BCIs. "In every case, we saw that spikes were present in lower cortex years after injury," he said. "Of importance is that this activity can be modulated-that is, a motor cortex sitting dormant for years can make something happen."

To prove his point, Donoghue showed a video of a woman with brain stem stroke who, 9 years after injury, could activate a neuron to move a computer cursor to repeatedly and precisely hit a target on cue.

It's a matter of training patients to modulate the amplitude of field and evoked action potentials by imagining a movement, explained Donoghue. In so doing, patients are able to move computer cursors and other mechanical devices, such as robotic prosthetic arms.

For action potentials to work with interfaces, implantation of a neurosensor in close proximity to a neuron in the appropriate motor cortex area is required. At present, Donoghue and his team are working with BrainGate technology that uses an electrode array the size of a "baby aspirin" and consists of 100 microelectrodes, each the diameter of a hair. "It is placed in the arm area of the motor cortex where signals related to intended movement can be picked up," explained Donoghue. "The signals pass through a percutaneous connector to the outside and are processed through electronic equipment. Intentions to move objects are translated into cursor control."

The technology has the potential to significantly improve the quality of life of persons who are tetraplegic or "locked in." It is also helping clinical researchers better understand conditions that result in paralysis. Donoghue showed video footage of 2 patients with spinal-cord injuries: one used a specially designed program that allowed him to open e-mail and perform other functions, the other was immediately able to control a robotic hand and a toy robot. Donoghue also showed footage of a computer-based speller (the use of which he described as "like a finger typing") and a computer display that allows a patient to select and change television channels.

Streamlining the hardware is the next challenge, said Donoghue. "We have a lot of external electronics and we are dependent on the technician. We need a fully automated, implantable system," he said, adding that animal studies are currently under way.

He and colleagues intend to use the technology to reanimate limbs. "Our goal is to connect BrainGate to a functional electronic stimulation (FES) device to allow real movement of a limb," said Donoghue. "This is not a dream, but something that is already in development." He showed footage of the patient with brain stem stroke activating a virtual arm. The data collected from the exercise is being used to program a BrainGate-FES device that will allow the patient to make voluntary movements with her actual arm. "Within 5 years, people will be able to move paralyzed limbs through this technology" Donoghue asserted.

While researchers work toward developing fully implantable systems, existing research is providing a window into brain disease that was heretofore inaccessible, concluded Donoghue. He added that the technology is being used to study other neurological diseases in hopes of finding novel interventions.