IDENTIFYING telltale brain patterns promises to usher in a new era in which all manner of objects can be controlled by thought. But telling brain patterns apart is devilishly difficult. Now cybernetics researchers think a mild buzz from the gadgets that make phones vibrate will focus the mind.
Controlling electric wheelchairs using the power of the mind is emerging as a realistic option for some people with neurodegenerative conditions such as Lou Gehrig’s disease. Several groups have already developed such thought-controlled wheelchairs, including ‘s team at the University of Essex in Colchester, UK. His system involves wearing an electrode-filled skullcap connected to a PC running brain-computer interface (BCI) software. This can sense four types of thoughts, represented by electroencephalogram (EEG) potentials. The user thinks about their feet to move forwards, their tongue to stop, and their right or left hands to proceed in those directions.
But being able to move in only three directions is clearly very limiting. Sepulveda’s team tried to improve on its design by building powerful artificial intelligence software to identify brain patterns associated with thinking about more complex directions, but success eluded them. “It would only get it right about 60 per cent of the time, which is not enough for the real world,” says Sepulveda.
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Now Anne-Marie Brouwer and colleagues at the research organisation in Soesterberg, the Netherlands, believe they may have a more liberating approach. They have developed a system called tactile BCI, which uses a physical sensation to provoke an EEG potential called a P300. This is a specific brain response indicating a person’s strong interest in a particular stimulus. It gets its name because the signal arises 300 milliseconds after the stimulus.
The researchers placed 12 phone vibrators, positioned like the numbers on a clock, on a belt worn around the wheelchair user’s waist. These vibrate sequentially for 3 seconds each. If they wearer wants to go, say, in a 4 o’clock direction, they wait until the appropriate “tactor” vibrates and then think “that one”. “That generates a P300 and selects the movement direction you want,” says Brouwer.
“If the user wants to go in a 4 o’clock direction, they wait for the right vibration and think ‘that one’”
Tests with 50 volunteers produced good results. “Almost everyone who tried it liked it,” Brouwer says.
Tactile BCI could be an important advance, says Sepulveda. “I think Brouwer’s work will be useful. It explores a whole new channel – a tactile stimulus instead of a visual or auditory one.”
