An asynchronous brain computer interface
Researchers from Oxford University are developing a new asynchronous system to interface with the brain which will allow a more effective way to control wheelchairs or robotic arms with the power of the human mind. The Engineer Online writes that such an asynchronous brain computer interface (BCI) would permit a more precise and nuanced control of external mechanisms than existing synchronous BCI technology. This new system will use only one electrode and allow sophisticated controls over the speed of these external devices. Even if this new BCI technology is being designed to help severely disabled people, it could have other applications for the gaming and entertainment industries or even to control vehicles.
Most of the existing BCI systems are now using several electrodes attached to a user's head which measure micro-voltages from the activity of the brains. Then these signals are translated into movements and commands sent to the devices to operate. But the new system will use only one electrode.
Prof Stephen Roberts of Oxford’s engineering science department, who is leading the project, said the team hopes to develop BCI algorithms sophisticated enough to allow graduated, proportional control of movement rather than a simple on or off switch.
"It is reasonably simple to use an interface to turn something on or off with a binary control switch. That is well-proven technology," he said. "But to control a robot arm, that binary control isn’t good enough. You need to be able to control the amount of movement and speed."
Here is an example of a brain computer interface (Credit: Oxford's Pattern Analysis and Machine Learning Research Group). As you can see, the goal of using a single electrode has not been reached yet.
What would be the advantage of an asynchronous system?
Existing BCIs display a cue on a computer screen at regularly spaced intervals, inviting the user to think left, right, up or down. The brain’s signals are then monitored and the system decides which way the user intends the cursor to move. The asynchronous system will wait passively until the user thinks of a movement and then detect when that change occurs.
According to Roberts this would be a huge step forward. "An enormous amount of work is yet to be done to get to that stage," he said. "To be able to get to an asynchronous system, it will have to be able to both detect the signal and then categorise the movement it is conveying."
According to the research team, there are still lots of progress to do before such a system becomes commercially available. But what will it be used for?
Although the immediate benefits of the technology will be for the severely disabled, Roberts believes that it could eventually be used for a number of broader applications as well as in rehabilitative work for people with spinal injuries or strokes.
In the longer term, a future adaptive asynchronous BCI system could have applications in the gaming or entertainment industry or could even be used to control vehicles, claimed Roberts.
For more information about this research effort, please visit the Brain Computer Interfacing Project web pages.
Sources: The Engineer Online, October 14, 2005; and various web sites
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