Thought control under your hat
An electrode-covered hat can translate brain waves into computer commands, according to a new study.
This noninvasive thought decoder could someday let people with a disability communicate by using their brains alone, operate word processing programs or control movement of a robotic prosthesis.
The U.S. study is published in the current issue of the journal Proceedings of the National Academy of Sciences.
"It looks sort of like a light-weight elastic version of an old-fashioned rubber swimming cap, with small metal discs that are connected by a ribbon cable to EEG amplifiers and the computer," Wolpaw said.
Wolpaw and colleague Dr Dennis McFarland said that brain activity can be detected from the scalp, from the cortical surface, or from within the brain itself.
Some devices are implanted into the brain, but Wolpaw and McFarland said their new cap was noninvasive and posed minimal, if any, risk to the wearer.
The problem with such caps in the past is that, like a bad radio, they would pick up all sorts of brain waves, to the point where the desired ones were lost or reduced to a quiet buzz amongst the din.
The new cap system, which scientists call a brain-computer interface (BCI), has better tuning. It also has an enhanced decoder that not only conveys the user's intent to the computer, but also focuses on thought patterns determined to be successful in operating the computer.
As a result, the device becomes easier for the wearer to use over time.
Under test conditions
Wolpaw and McFarland tested the system on two adults with a disability and two adults without.
For the tests, a square would appear from various angles on a computer screen. A cursor would then appear on the screen. The users had to move the cursor to the square target by thought alone.
The researchers checked on the users' muscle movements to ensure that only mind control, and not muscles, was moving the cursor.
All of the test subjects hit the targets using the BCI, but the wheelchair users excelled over users without a disability.
"Based on many scientists' work, including work in our lab, showing that the nervous system has tremendous ability to adapt to new needs, it is possible that areas of sensorimotor cortex deprived of their normal function might conceivably acquire a new function, such as EEG-based cursor control, more readily," Wolpaw said.
Dr William Heetderks, director of the neural prosthesis program at the National Institutes of Health, said the results were "very encouraging".
Heetderks believed that once such devices were available, they would "profoundly improve lives of some individuals whose thoughts and desires are otherwise locked within their bodies".
Assistant Professor Dawn Taylor from Case Western Reserve University and a research associate at the Cleveland Veterans Affairs Medical Center, believed that both invasive and noninvasive BCIs would benefit patients.
She said that her colleagues were restoring arm and hand movement to paralysed individuals through implanted stimulators that activated muscles. She also supports Wolpaw's work.
"Noninvasive BCIs have the potential to greatly improve the lives of the 'locked in' or completely paralysed individuals by providing them with an efficient means to use a computer," Taylor said.
"With the right customised software, these most severely disabled individuals will be able to communicate by typing, control assistive robots, and control devices, such as their light or television."
People without a disability, who might be interested in giving up their keyboards, should not look for BCIs in the marketplace anytime soon.
"In the past, there have been a few failed attempts to commercialise noninvasive brain recording devices for playing video games, or creating 'mental music or art'," Taylor said.
"However, the noninvasive BCIs are still not as effective for playing video games as the standard hand controllers, so it is unlikely that these devices will catch on with the general public."