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Exciting new research into how signals from the brain can be captured by a

computer or other device to carry out an individuals command may allow people withmotor disabilities to more fully communicate and function in their daily lives.

Over the past several years, scientists have begun to address the needs of people withsevere disabilities brought on by paralysis or injury by developing brain-computer

interfaces (BCIs). These systems allow people to use signals directly from the brain for

communication and control of movement. The research has progressed to a point whereclinical applications can be anticipated, says Jonathan Wolpaw, MD, chair of the

symposium, "Brain-Computer Interfaces for Communication and Control."

Research in technologies for obtaining brain signals for BCI applications has led to the

development of implantable BCI devices that could be used by people with severe motor

disabilities. In other work, investigators report advances in BCI-based movement control.

The BCIs already available and those under development differ greatly in the brain

signals they use, in how they detect those signals, in the methods they use to translate thesignals to carry out the persons commands, and in the kinds of devices the signals

control.

Groundbreaking work conducted by Douglas J. Weber, PhD, at the University of Alberta,

Edmonton, Canada, and his colleagues has led to the development of an implantable

microelectrode array that can record neural sensory responses resulting from movements

of the leg. The investigators have developed an analysis technique that allows accurate

prediction of leg positions from the patterns of recorded neural activity.

The technique relies on the fact that multiple sensors acting together provide the centralnervous system with important feedback for controlling movement. For example, sensors

called muscle spindles that are embedded in muscle fibers measure the length and speed

of muscle stretch, while other sensors in the skin respond to stretch and pressure. Whenan individual is paralyzed by injury or disease, neural signals from these sensors cannot

reach the brain, and thus cannot be used to control motor responses. Paralysis also keeps

neural signals originating in the motor regions of the brain from reaching the muscles.

The work of Weber and his colleagues shows that it is possible to extract feedback

information from the bodys natural sensors that could then be used to control a

prosthetic device, allowing an individual to regain some command and control of his orher own movements.

A sterile surgical procedure is used to implant arrays of 36 microelectrodes into thedorsal root ganglion, part of the spinal nerve that contains the nerve cell bodies that house

these natural sensors. Historically, it was difficult to record from these sensors because

their cell bodies are located in this difficult-to-reach nerve bundle entering the spinal

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online, interface with the Internet, and possibly adjust lights or other devices in his or her

environment.

Cyberkinetics was founded by a team of researchers from Brown University led by John

Donoghue, PhD. Cyberkinetics is seeking to commercialize a neural output device to help

patients with severe motor impairment. All the authors are Cyberkinetics employees andshareholders.

"The disadvantage of the computerized assistive devices used today is that they requirean individual to use substitute signals like voice or eye movement to manipulate a mouse

or keyboard," said Donoghue. "The advantage of BrainGate is that it records directly

from the brain and thus can translate brain activity into the intended hand movement over

mouse or keyboard."

The BrainGate BCI consists of a microelectrode array sensor implanted into the motor

cortex, an external cart containing computer hardware, and software that processes and

decodes neural signals. Although no humans have been implanted with BrainGate yet, thedevice has been designed to meet human safety requirements.

Cyberkinetics hopes to start a pilot clinical trial with four to five quadriplegic individuals

in 2004. Once the BrainGate device has been shown to record neural activity in paralyzed

patients, then the team at Cyberkinetics will explore how the signals can be translated

into output signals that could be used to control a computer.

In other work being presented at the symposium, Andrew Schwartz, PhD, will show how

his group at the University of Pittsburgh is extending their work in cortical prostheses torobot control. Previously the group showed that closed-loop control of a cortical

prosthesis can produce excellent brain-controlled movements in virtual reality. After

showing that a monkey can use direct brain control to control a robotic arm in 3D spacewhile watching the movement in virtual reality, the researchers are now moving on to

have the animal see and control the arm directly, without the virtual reality display.

Although learning to use the robot as a tool seems to be more difficult for the animal, ithas nevertheless learned to use the robot to reach targets held by the investigator.

Jonathan Wolpaws laboratory at the Wadsworth Center of the New York State

Department of Health is finding that a non-invasive BCI, using EEG activity recordedfrom the scalp, can provide rapid multidimensional control of a movement signal with

precision and speed comparable to that achieved in monkeys by invasive BCIs. This

remarkable control by a non-invasive BCI depends on an adaptive training algorithm thatidentifies and focuses on the particular EEG features that the person is best able to

control, and encourages the person to improve that control further. These initial results

suggest that people with severe motor disabilities might use brain signals to operate arobotic arm or a neuroprosthesis without the risks involved in having electrodes

implanted in their brains.

Andrea Kuebler, PhD, of the University of Tuebingen in Germany is exploring the

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complex technical and human issues involved in providing severely disabled people with

BCI-driven communication and control devices. Her group has compelling new data

indicating that simple BCIs could greatly improve the quality of life of people with themost severe disabilities. These data imply that even people who are totally paralyzed can

lead lives they enjoy if they can communicate even to a limited extent with caregivers,

family members, and friends. By showing the potential clinical benefits of BCIs, thesesurprising results provide new incentive for their continued development and application.

Dawn McCoy | Source: EurekAlert!