What nightmare could be worse than being buried alive? Conscious, terrified but unable to communicate through the impenetrable barrier of a coffin lid and a metre of earth. In the past few days, this horror has been transformed from the stuff of bad dreams to two very different front page stories.
First, the uplifting images of people pulled from the rubble of Haiti, up to 15 days after the earthquake. And now there is the extraordinary report from neuroscientists who have used a brain scanner to communicate with a different kind of trapped victim — a patient in a persistent vegetative state.
Let's be clear about what they did. The technique they used, functional Magnetic Resonance Imaging (fMRI), doesn't record brain activity directly. It detects signals related to changes in the flow of blood within the brain, in response to the local demands of active nerve cells, hungry for oxygen and glucose.
Blobs of meaning
Clever computer programs turn such measurements into those familiar pictures, looking like something you might see in a fancy restaurant in France — a slice of brain in aspic decorated with red and yellow blobs. The blobs reflect the slow and more widespread changes in blood flow that follow the frenetic activity of nerve cells. Interpreting the blobs is like trying to work out the exchange of banter. Brain scanning provides a window into the previously private world of the human mind. It can at least tell us which parts of the brain are active while a person sees, hears, thinks, remembers, plans and carries out actions. Adrian Owen at the MRC Cognition and Brain Sciences Unit in Cambridge and Steven Laureys of the University of Liege announced three years ago that the brains of some patients in a vegetative state could respond in much the same way as normal, conscious people when asked to imagine that they were walking around their homes or playing tennis.
These two kinds of thoughts produced distinctive patterns of blobs, corresponding to the parts of the brain involved in spatial navigation or skilled movements respectively.
Special patients
Most important, other patients did not show these indications of awareness, so there is something special about those who did. But it didn't prove that those special vegetative patients were actually aware of their thoughts of wandering around the house or playing tennis.
The new results are more compelling — and disturbing. The researchers managed to train one of their patients — a 29-year-old man whose brain was damaged in a car crash in 2003 — to use his brain activity to reply to questions. Wandering indicated "no", tennis was "yes". The "blobs" reliably gave the correct answers to simple questions.
Owen and Laureys have started similar tests on other patients and they think that perhaps one in six will be able to communicate via the scanner.
It was Bryan Jennett, a Glasgow neurosurgeon, who first distinguished vegetative state from coma — the state of profound unconsciousness that can occur after a head injury, stroke or infection. Comatose people sometimes wake up completely but at times progress into the vegetative state — a no man's land of mental ambiguity.
Reading the mind
In a vegetative state, patients go through the cycles of sleeping and "waking". What Owen and Laureys have provided is the possibility of entering the minds of such people. The questions they asked were trivial. But they could, of course, be questions such as "Are you in pain?"; "Are you happy?"; "Do you want to die?"
This is not the first case of technology poking into the privacy of individual lives.
Peep into a private world
We're accustomed to claims that the polygraph (which essentially measures the sweatiness of the skin) can show whether someone is lying. And DNA fingerprinting can determine paternity or presence at a crime scene. But the advance of technology to see inside the heads (and thus the minds) of living people opens up a bewildering range of opportunities to invade the privacy of thought.
An American company, No Lie MRI, already offers a brain-scanning lie-detection test, based on the different patterns of blobs associated with telling the truth and lying. But, just as for the polygraph, courts are reluctant to admit such evidence, partly because, unlike DNA testing, it has a tangible margin of error.
According to No Lie MRI, present accuracy is more than 90 per cent but this is predicted to rise to 99 per cent once product development is complete.
