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Purpose:
The aim of this site is to discuss an emerging technology developed by Emory University neuroscientist Philip R. Kennedy, M.D., and Emory neurosurgeon Roy E. Bakay, M.D.. They have developed an electrode brain implant that is allowing speech-impaired patients to communicate through a computer. Dr. Kennedy, who refers to this technology as "cognitive engineering," developed and patented the neurotrophic brain implant while on the faculty of the Georgia Institute of Technology in the late 1980s. He later worked with Dr. Bakay to implant the electrode in primates at the Yerkes Primate Research Center at Emory. The implant has been tested on three individuals; the most recent was implanted with two electrodes in July 1999. (See Sources)
"Cognitive engineering has potential for helping many different kinds of patients. 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," said Bakay. Though the brain implant could someday be used to help paralyzed patients move limbs or prosthetic devices, current focus has been on patients who are "locked-in"-unable to communicate with the world around them.
Dr. Warren Selman, a neurosurgeon at University Hospitals of Cleveland not involved in the research, expressed caution about using the technology on anybody except patients with long-term paralysis. "You'd hate to put something in somebody in an area they're going to recover."
(Below: JR, a paralyzed stroke victim, the second recipient of the brain implant.)
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 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 are placed inside the glass cone to 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. (See diagram)
FIG. 1. Schematic drawing of the electrode showing the glass conical shaped tip in which the peripheral nerve is placed just prior to implantation. The glass cone contains gold recording wires and is placed below the surface of the cortex. The connecting pins are cemented in place and the electronic devices are plugged in and cemented to the skull. The scalp is closed in layers. There is no battery. The transmitted signals are picked up by the receiving coil placed within 10 inches of the scalp.
Before the device is implanted, physicians examine the brain with an MRI to learn precisely the areas that control muscle movements. When the patient thinks about moving an arm, for example, the MRI shows the increased activity in certain areas: blood flow increases and the brain cells "fire," or conduct impulses.
FIG. 2. (A) Axial functional MR image obtained while the patient imagined movements of the left hand, indicating active neurons in the right motor area 4. (B) Corresponding MR image obtained prior to surgery.
Neural signals are used to drive the computer cursor in the same way a computer mouse is moved back and forth. The recorded neural signals are connected to the computer and are used as a substitute for the mouse cursor. The patient learns to control the strength and pattern of the electric impulses being produced in the brain, and after some training is able to 'will' a cursor to move and then stop on a specific point on the computer screen. The researchers are hopeful that the new technology will eventually allow patients to communicate smoothly and accomplish tasks such as turning on light switches and sending email. They also plan to try connecting the neural signals to a muscle stimulator in a patient's paralyzed limb so the patient can move the limb using the same principle used to move the computer cursor.
The primary goal of the brain implant is to re-connect the "locked-in" patient with the world around her by offering her a means of communicating. The new affordances are not truly "new", but rather "regained". Recovered actions include interactions with a computer, communication with the outside world, and control of the patient's nearby surroundings. The brain implant affords the expression of mental desire taken for granted by most able-bodied people.
The brian implant seeks to link the brain to computer actions by associating neuron firing with mouse movement. "It's like we're making the mouse the patient's brain," said Dr. Bakay. 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. At this level, the obvious metaphor is one which allows direct manipulation of objects on a screen-like a mouse or basic hand movements.
The Emory University scientists and patients have learned through trial and error how to tailor thoughts of movement for each patient. For example, thinking about moving the hand and foot may make the cursor move up and down for one patient. "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. ...As the technology improves, controlling movement or speaking will become more and more automatic for patients."
In this respect, the interaction has the potential to become quite literally invisible. A computer user rarely attends to the hand and mouse that move the cursor on the screen. Likewise, the user of the brain implant will not attend to the relearned mental activity that has translated "move my hand" into "move the mouse vertically." The invisibility is achieved more so, since mental activity alone accomplishes the task.
The ultimate goal, however, far surpasses the metaphor of the mental mouse. "After [mastering mouse movements] we'd like for them to use the computer to control their environments, turn lights on and off, adjust a bed, call an attendant, turn the TV on or off. Finally, we hope they will be able to run prosthetic devices, wheelchairs, even prosthetic limbs," Bakay stated. Future steps may also include training "a whole series of cells to do things."
In the future, the "mental mouse" could be extended to the "mental world," wherein anyone (paralyzed or not) could simply ?will? computer-controlled devices to operate. Removing all outward signs of interface would achieve the ultimate in ubiquitous computing.
This technology is not commercially available, as it is still in the early stages of testing and development. Though Dr. Kennedy will be seeking a patent on his work, it would be premature to refer to the brain implant as a commercial product.
The patients who have the greatest need for the brain implant are often terminally ill. This poses problems for long-term development. The first recipient of the brain implant, for instance, died within three months of her operation due to complications from ALS. The second recipient also had physical set-backs that limited his control of the implant. The mind doesn't work well when one is sick, and the target user will never be in perfect health.
The technology is inherently dangerous and complicated, involving advanced elements of neurology, electrical engineering, computer science, and surgery. It is a far more complex system than the computers that read the eye movements of paralyzed patients.
The user must go through a training program before she can learn to start and stop her brain's electrical activity. Patients have experienced problems in mastering these skills, though ultimately changes in the system (which also needs to "learn") aid in solving many problems.
Financial support has always been a constraint for technology aiding the disabled, but the brain implant has had unique funding difficulties. Bakay said the research was so futuristic that he couldn't secure the usual government funding at first. Only after he and his colleagues proved the system viable did he receive a research grant for research with three more patients.
The applications of the brain implant aim to free the most "trapped" members of society and is an excellent example of technology's ability to improve the quality of human life. Not only will handicapped individuals be freed from the physical constraints that have isolated them from others, but they will be able to become active members of society, potentially changing the social stigma associated with being handicapped.
As the technology expands to a broader range of (able-bodied) users, however, the potential for public fear increases dramatically. People are generally afraid of brain implants, as they conjure up science fiction plots, mind control, and robotic take-overs. Even the current articles about this now-limited technology introduce it with quips referring to "Star Wars" and "Star Trek". Though the direction of control is from the brain to the equipment (as opposed to sending signals to the brain), the general public may not welcome the addition of telepathy to the common experience of mankind. The direct correspondence of thought to action inhibits a "filter" system that prevents rash behavior in most people. The implications of systems that enable such impulse behavior are truly frightening. While such an extreme may seem unlikely, the current brain implant was also unlikely just decades ago.
News Articles:
"BodyTechnic: New funding for brain implants" UK Tech News, Dec 1998
"Brain implant allows paralyzed man to control computer", The Detroit News, October, 1998
[link no longer active]
"Brain implant helps speech-impaired patients communicate via computer" Health Sciences News, Emory University, Dec, 1998
"Brain implants give the paralyzed a voice", National Spinal Cord Injury Association, April, 1999
[link no longer active]
"Brain Implants That Allow 'Willful Thinking'" Principles of Psychobiology, 1998
"Emory neuroscientists use brain implant to help paralyzed and speech-impaired patients communicate via computer" Health Sciences News, Emory University, September, 1999
"Paralyzed man controls computer via brain implant" Reuters, October, 1998Scientific Publication:
"Restoration of neural output from a paralyzed patient by a direct brain connection", Kennedy & Bakay. (Link takes you to a list of articles from Issue 8 of 1998 NeuroReport. Scroll down to find the correct article.)
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I do not have legal rights to any of the images or quotes I have used for this web page nor do I claim scientific authorship. I just think this technology is really cool. Please do not sue me or approach me as an expert. (=
CS147 technology evaluation by Anne Bracy, December 1999
from coursework @ Stanford University
