When I nod my head, hit it

That silly line from Three Stooges notwithstanding, there is some intriguing work being done involving the coincidence of brain activity and external suggestion.

For first time, doctors communicate with patient in persistent vegetative state

A 23-year-old woman who has been in a vegetative state since suffering devastating brain damage in a traffic accident has stunned doctors by performing mental tasks for them. Brain scans revealed that the woman, who has shown no outward signs of awareness since the accident in July last year, could understand people talking to her and was able to imagine playing tennis or walking around her home when asked to by doctors.

Neuroscientists at the Medical Research Council's cognition and brain sciences unit at Cambridge and the University of Liege in Belgium used a brain scanning technique called functional magnetic resonance imaging (fMRI) to detect signs of awareness in the woman, the first time scientists have been able to do so in a PVS patient.

Researchers led by Adrian Owen at Cambridge University began tests on the woman five months after her accident. Although she had emerged from a coma, she was diagnosed as being in a vegetative state, in which patients enter a cycle of sleeping and waking and even open their eyes, but are completely unresponsive.

Scientists ascertained that the woman could understand speech by playing a variety of sentences. Using the fMRI scanner, which takes snapshots of brain activity every second or two, they spotted different parts of her brain lighting up depending on which sentence she heard.

Previous attempts to spot signs of awareness in PVS patients have been inconclusive because brains can respond to some actions automatically. The uncertainty forced the scientists to come up with a test that would show categorically whether the patient was conscious or not.

Dr Owen said: "We said to her, when you hear the word 'tennis', we want you to imagine being on the centre court of Wimbledon playing a big rally and every time the ball comes to you, you struggle to get it back. Then, we had a second scenario in which we wanted her to imagine going from room to room in her home."

The two scenarios were chosen to trigger activity in different parts of her brain so they would be picked up by the scanner. While thinking about tennis, the scientists hoped to see a part of the brain called the premotor cortex, which governs limb movement, flicker into life. If she thought about walking around her flat, they expected to see a brain region called the parahippocampal gyrus, which handles mental maps of places, light up.

During the scans, the scientists said the words "tennis", "home" or "rest" every 30 seconds and looked for changes in her brain activity. Remarkably, after each word, her brain lit up as expected, suggesting she was responding to the instructions. Further tests showed her brain activity was indistinguishable from that of healthy volunteers doing the same task.

Scientists now have to discover how common it is for others in a vegetative state to be similarly aware of their surroundings. The woman in the study has since been able to follow her own reflection in a mirror, leaving open the possibility the brain scans may simply have picked up very early signs of her recovery.

Professor Colin Blakemore, neuroscientist and director of the Medical Research Council, said: "This is very impressive evidence for what continues to function in the brain, but function doesn't mean awareness or even potential for awareness. This is a strong indication that it is worth continuing to find ways of raising conscious awareness in such patients, because this work suggests the brain is still capable of cognitive function."

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