medical and science information

Patients in a vegetative state are awake, not in a coma, but have no awareness because of severe brain damage.

Scanning technique

The scientists used functional magnetic resonance imaging (fMRI) which shows brain activity in real time.

They asked patients and healthy volunteers to imagine playing tennis while they were being scanned.

In each of the volunteers this stimulated activity in the pre-motor cortex, part of the brain which deals with movement.

This also happened in four out of 23 of the patients presumed to be in a vegetative state.

I volunteered to test out the scanning technique.

I gave the scientists two women's names, one of which was my mother's.

I imagined playing tennis when they said the right name, and within a minute they had worked out her name.

They were also able to guess correctly whether I had children.

Questions

This is a continuation of research published three years ago, when the team used the same technique to establish initial contact with a patient diagnosed as vegetative.

But this time they went further.

With one patient - a Belgian man injured in a traffic accident seven years ago - they asked a series of questions.

He was able to communicate "yes" and "no" using just his thoughts.

The team told him to use "motor" imagery like a tennis match to indicate "yes" and "spatial" imagery like thinking about roaming the streets for a "no".

The patient responded accurately to five out of six autobiographical questions posed by the scientists.

For example, he confirmed that his father's name was Alexander.

The study involved scientists from the Medical Research Council (MRC), the Wolfson Brain Imaging Centre in Cambridge and a Belgian team at the University of Liege.

Dr Adrian Owen from the MRC in Cambridge co-authored the report:

"We were astonished when we saw the results of the patient's scan and that he was able to correctly answer the questions that were asked by simply changing his thoughts."

Dr Owen says this opens the way to involving such patients in their future treatment decisions: "You could ask if patients were in pain and if so prescribe painkillers and you could go on to ask them about their emotional state."

It does raise many ethical issues - for example - it is lawful to allow patients in a permanent vegetative state to die by withdrawing all treatment, but if a patient showed they could respond it would not be, even if they made it clear that was what they wanted.

The Royal Hospital for Neurodisability in London is a leading assessment and treatment centre for adults with brain injuries.

Helen Gill, a consultant in low awareness state, welcomed the new research but cautioned that it was still early days for the research: "It's very useful if you have a scan which can show some activity but you need a detailed sensory assessment as well.

"A lot of patients are slipping through the net and this adds another layer to ensure patients are assessed correctly."

She said the hospital did a study of 60 patients admitted with a diagnosis of vegetative state and 43% could communicate.

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While much of the "obesity epidemic" currently affecting most Western countries has been attributed to a move towards high-calorie foods and more sedentary lifestyles, scientists have found evidence that genes may play a significant role in influencing weight gain in some people.

The latest study focused on the "morbidly obese", who have a Body Mass Index (BMI) of more than 40, and who are at the highest risk of health problems.

There are an estimated 700,000 of these people in the UK.

'Learning difficulties'

The first clue came by looking at a group of teenagers and adults with learning difficulties, who are known to be at higher risk of obesity, although the reasons for this are not entirely clear.

They researchers found 31 people who had nearly identical "deletions" in their genetic code, all of whom had a BMI of over 30, meaning they were obese.

Then a wider scan of the genetic makeup of a mixture of more than 16,000 obese and normal weight people revealed 19 more examples of the missing genes.

All of the people involved were classed as "morbidly obese", with a BMI of over 40, and at the highest risk of health problems related to their weight.

Most of them had been normal weight as toddlers, but then became overweight during later childhood.

None of the people studied with normal weight had the missing code.

The precise function of the missing genes is unclear, as is the precise nature of the relationship between learning difficulties and obesity - none of the people with the deletions in the wider study had learning problems.

Weight-loss surgery

Professor Philippe Froguel, from Imperial College, said: "It is becoming increasingly clear that for some morbidly obese people, their weight gain has an underlying genetic cause.

"If we can identify these individuals through genetic testing, we can then offer them appropriate support and medical interventions, such as the option of weight loss surgery, to improve their long-term health."

Dr Robin Walters, also from Imperial, said that while this particular set of deletions was rare - affecting some seven in 1,000 morbidly obese people - there were likely to be other variations yet to be found.

"The combined effect of several variations of this type could explain much of the genetic risk for severe obesity, which is known to run in families."

Dr Sadaf Farooqi, from Cambridge University, who collaborated with this research, and was involved in similar research published in December which pointed to another gene flaw which could be linked to obesity.

She said it was likely that a "patchwork" of different genetic variations would eventually emerge to explain more cases of obesity - perhaps by affecting appetite, or the rate at which the body burns fat.

She said: "There is still an important public health message about diet and exercise, but simply blaming people for their obesity is no longer appropriate."