Sarah Goodwin

Kathi Ovnic
Holly Korschun
September 2, 1999

Neuroscientists at Emory University School of Medicine and Neural Signals, Inc. who last year implanted a neurotrophic electrode into the brain of a paralyzed, speech-impaired patient, continue to help the patient learn to communicate by moving a cursor on a computer screen. Following the brain implant almost a year ago in March 1998, the patient first learned to express himself by indicating phrases on the computer screen such as "I am thirsty" and "It was nice talking to you." More recently he has learned to move the cursor to letters of the alphabet and spell his own name and the name of his doctors.

The neurotrophic electrode was invented by Philip R. Kennedy, M.D., Ph.D., neurologist and neuroscientist who won this year's Discover Magazine Award for Technological Innovation in the Assistive Technology category. Dr. Kennedy and Roy A. E. Bakay, M.D., a neurosurgeon at Emory University School of Medicine, first implanted the electrode in December 1996 in a woman who was "locked in" and unable to speak due to amyotrophic lateral sclerosis (ALS, or Lou Gehrig's disease). At the time of her death from ALS, the patient was learning to control the neural signals from her implant. Results from this research were published in the June 1998 issue of NeuroReport.

Last year the team implanted the neurotrophic electrode into the brain of a patient who is paralyzed from the neck down and has been unable to speak since a brainstem stroke late in 1997. The patient is at the Emory-affiliated Atlanta Veterans Affairs Medical Center and has been learning to use a computer over the past few months to communicate with simple phrases and letters. Dr. Kennedy likens the technology to "a mental mouse" that allows the patient to move the cursor as if he held a computer mouse in his hand.

In July 1999, Drs. Kennedy and Bakay implanted a third patient with two electrodes. The team expects brain tissue to grow into the electrode tips within several months so that recordings may begin. This intelligent patient has a muscle disease that has rendered him paralyzed and mute.

Drs. Kennedy and Bakay are hopeful that the new technology will eventually progress to the point where patients will be able to communicate smoothly and accomplish tasks such as turning on light switches and sending email. "A person can interact with the world if they can use a computer," Dr. Bakay said. "This development will open up a tremendous amount of opportunity for patients who have lost the ability to move and talk because of stroke, spinal cord injury or diseases like Lou Gehrig's disease."

The neurotrophic electrode is implanted into the motor cortex of the brain using a tiny glass encasing. Neurotrophic growth factors are implanted into the glass, and the cortical cells grow into the electrode and form neural contacts. It takes several weeks for the cortical tissue to grow into the electrode.

The neurons in the brain transmit an electronic signal when they "fire." Recording wires placed inside the glass cone pick up the neural signals from the ingrown brain tissue and transmit them through the skin to a receiver and amplifier outside of the scalp. The system is powered by an induction coil placed over the scalp. There are no wires going through the skin. The recorded neural signals are connected to the computer and are used as a substitute for the mouse cursor. The patient is able to hear noises that indicate when his brain is thinking in a way that will allow him to focus on the cursor and move it.

"The trick is teaching the patient to control the strength and pattern of the electric impulses being produced in the brain," Dr. Bakay said. "After some training, the patient is able to 'will' a cursor to move and then stop on a specific point on the computer screen."

"This new technique has profound implications for paralyzed people everywhere, whether paralyzed by spinal cord or brainstem injury, or by such devastating diseases as ALS," Dr. Kennedy says. "For spinal cord injured patients who have uncontrolled muscles, these neural signals could provide some control of electrical stimulators that activate the paralyzed muscles, thus bypassing the area of spinal cord injury ("spinal bypass"). Right now we are concentrating our efforts on the relatively easier task of providing a communication link to a computer for locked-in patients."

Dr. Kennedy discussed the neurotophic electrode research at last year's Neural Prostheses Workshop at the National Institutes of Health and at the Society for Neurosciences annual meeting last October. Dr. Bakay presented the research at the Society for Neurosurgeons meeting last fall. Both scientists were honored with the Health Care Heroes Award presented by the Atlanta Business Chronicle in May of this year.

Dr. Kennedy's research in developing the electrode technology was supported by the Emory/Georgia Tech Biomedical Research Consortium, with additional support from the American Paralysis Association, the Department of Veterans Affairs and the National Institutes of Health (NIH).

As the principal investigator and project director, Dr. Kennedy has 100% interest in a patent on the electrode and may collect royalties or other income on it. The terms of this arrangement have been reviewed and approved by Emory University in accordance with its conflict of interest policies.