הרי העתק אחד לאחד של המאמר המקורי: Virtual world sharpens mind-control
A simulated world that can be explored simply by thinking about putting one foot in front of the other might offer new rehabilitation possibilities for disabled patients.
This is the vision behind a project that connects a brain-computer interface (BCI) to an immersive virtual world.
One team, from the Graz University of Technology in Austria, specialises in measuring signals from the brain, via electrodes or implants. The other, from University College London (UCL), UK, focuses on building highly immersive virtual reality worlds.
The two groups came together through a European consortium called PRESENCCIA. The goal is to create a virtual world through which a person can navigate using just their imagination.
Electrodes are attached to a person's scalp and electroencephalogram (EEG) equipment is used to monitor electrical activity within their brain.
In this way, the system can be trained to identify the distinctive patterns of neuronal activity produced when they imagine walking forwards, or think about moving either their left or right arm. These thoughts can then be used to navigate or make an on-screen character, or avatar, move forwards or turn left or right.
In addition, there is no need for the operator to wear a head-mounted display – they sit inside a room (located at UCL) inside which stereo video footage is projected onto three walls and the floor. A pair of shuttered glasses creates the illusion of 3D to intensify the overall feeling of being inside the simulated reality. Popular tool
After having a healthy volunteer test the system, the researchers asked a man paralysed almost entirely from the neck down to try it out.
He was asked to walk up to different virtual characters and wait for each character to say hello. The subject was able to do so about 90% of the time. See video of the virtual world navigation experiment here (MPEG format, 11.5 MB).
“The patient loved it,” says Doron Friedman, a member of the UCL group, and now at the Interdisciplinary Centre Herzliya in Israel. “He said it was a great feeling to think about moving his feet and to actually 'move'.”
Friedman notes that virtual reality is becoming a popular tool for physical or psychological rehabilitation, and says the new system could offer novel possibilities.
Virtual reality provides a controlled environment in which patients can perceive themselves performing any manner of task. It also offers a way to stimulate the brain without requiring physical movement. For example, researchers at the UK's University of Manchester are (see Using virtual reality to treat phantom limb pain).
“A system such as this could be very motivational for a patient to use for training,” says Jessica Bayliss at Rochester Institute of Technology, in New York, US, who also specialises in brain-computer interfaces and virtual reality. “It reminds me of how people with various handicaps are playing World of Warcraft, because they are able to do things in the virtual world that they can't do in the real world. Remote control
The technology might be used to help people who have experienced a stroke recover greater control over their movements, suggests Christoph Guger, of Guger Technology in Graz, who helped develop the EEG part of the experimental set-up.
But he admits that proving the approach is beneficial can sometimes be difficult: “It is very difficult to say whether improvements were just something that would have happened anyway.”
A team at Southampton University, UK, led by Christopher James, is already using BCIs to treat patients recovering from a stroke. “One might argue that being immersed like this makes the imagined movements stronger,” James told New Scientist.
Ultimately, it is also hoped that brain-sensing technology could enable disabled people to control operate devices remotely (see Wheelchair moves at the speed of thought).
Emily Keshner, who works with brain-computer interfaces at Northwestern University in Illinois, US, believes the new system brings this vision a step closer. “This approach to virtual reality will also increase the prospects for severely disabled individuals to participate in the workplace and in social interactions,” she says.
But James warns that using BCI technology also has its drawbacks. “It requires sustained attention and I can imagine it can be quite draining,” he says.
He adds that it may only ever be possible to perform a limited range of virtual movements through mind control: “At this stage a few types of movement is the limit, and even then not 100% of the time.”