Sunday, October 02, 2005

Communication aid for paralysed

Japanese scientists have developed a headband that can help people who can't move any muscles express their wishes by reading the flow of blood in their heads. To answer yes you focus your thoughts -- try to solve a math problem or remember the words to a song. That pulls the blood to the front of your brain. Relaxing and thinking of nothing leaves the blood as is. The headband has a little gadget that uses near-infrared rays to measure the flow of blood. In about 30 seconds you have your answer. It only works about 80% of the time but patients' families are glad for that.

I'm just wondering how you know whether a particular answer is one of the 80% or one of the 20%.

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