Miércoles 17 de Septiembre de 2008, Ip nº 247

Can a damaged brain change its own structure and replace lost functions?
Por Penny Wark

As a role model for active old age, Stanley Karansky is exemplary. A doctor until he was 70, he retired, got bored, retrained as a GP and practiced for another ten years. At 89 he noticed that his words were becoming less fluent, his driving was deteriorating and he found himself withdrawing. This prompted him, at 90, to begin an auditory memory programme, played on his computer, and he worked on the exercises for 75 minutes, three times a week, for three months.

After six weeks he began to feel more alert, and the motor and social deterioration that he had observed began to reverse. “I was talking to people more and talking came more easily,” he says. “In the past few weeks I think my handwriting has improved.”

It is no coincidence that Karansky is a lifelong self-educator and that when he engages in something, whether it is serious mathematics, Su Doku, or a period of history, he gives it his full attention. This, says the psychiatrist Norman Doidge, is the necessary condition for creating change in the brain.

In his book, The Brain that Changes Itself, Doidge argues that the discovery that thoughts can change the structure and function of our brains - even into old age - is the most important breakthrough in neuroscience in 400 years. His collection of case histories, Karansky among them, is inspiring: people who have had strokes and been declared incurable have been helped to recover, learning disorders have been cured, IQs raised, obsessions and traumas overcome, and there are 80-year-olds whose memories have been restored to the function of people 20 years younger. “There are controlled studies for these things,” says Doidge. “It's a great example of adult plasticity.”

Plastic is the word Doidge uses to describe the malleable brain. Having spoken to the leading neuroscientists of the past 50 years, his fundamental premise is that the brain can and does rewire itself when it is damaged. The brain is a muscle that needs and likes exercise, he explains, and if you don't use it, you'll lose it. Hence the effectiveness of the exercises completed by Karansky and his elderly peers in the US: these involved determining whether sounds are sweeping up or down in frequency, giving the order in which a sequence of syllables have been heard, identifying similar sounds, and listening to stories and answering questions about them.

“In some situations brain exercises are more effective than medication,” says Doidge. “If a person is weak on cognition sometimes you can give them a stimulant that will boost the whole system over time, but you're far better off finding the weak area and exercising it. I've seen kids misdiagnosed with attention deficit disorder who have learning disorders and who can be helped. Once you have a programme for them that, like any exercise programme, doesn't ask someone who's 90lb to lift 300lb, but finds out what they can lift and incrementally increases it, suddenly they find they are growing. We also know that talk psychotherapies, when they work, lead to every bit as much brain change as medication does for depression and anxiety.

“We now know, and this is one of the most fabulous discoveries of the 20th century, that when learning occurs what happens in, say, a four-hour learning session, is that the number of connections between nerve cell A and nerve cell B might go from 1,300 connections to double that. It works by getting under the skin of our DNA, through turning certain genes on to make new proteins, which then move down the cell to make new structural connections. What this means is that thought turns genes on or off.”

If scientists have been slow to recognise the possibilities of the flexibility of the brain, this is because of the dominance of the traditional belief that the brain, like the heart, is mechanistic. If the brain is a machine in which one location controls one function, and that location is destroyed, so is the function. Doidge acknowledges that specific functions are correlated with specific locations, but insists that this does not rule out change. He regards the notion that it does as neurological nihilism.

“This means if you were born with mental limitations or developed them, you were stuck with that for life. If you had a stroke or brain damage, there was nothing that could be done. If you were ageing, mental exercise was unwarranted. Countless numbers of people were told that they would be unable to alter their brains. This was spectacularly wrong.”

When people who had brain damage did recover, their improvement was explained away, he says. When people had strokes, they were routinely told that long-term improvement would not happen. The technology to measure microscopic changes in the brain did not exist, and the brain's tendency to lay down established patterns - such as bad habits, accents - also mitigated against the possibility of a flexible brain.

By pulling together the piecemeal evidence that the brain can change, and by documenting the cases of dogged individuals who have rewired their brains, Doidge has identified a tidal shift in basic science and a potential one in medicine. The implications are monumental for the 150,000 people who have a stroke in Britain each year, which is currently the leading cause of disability. Add to that a population that is living longer and wants to remain mentally fit, and a culture quick to identify learning difficulties in children, but much slower to resolve their problems, and the potential of working on our plastic brains seems limitless.

But Doidge, based in New York and Toronto, is reporting from North America and even there this enlightened treatment is not yet commonly available. In Britain the notion that the brain can rewire itself has yet to enter mainstream medical thinking, says the Stroke Association.

Discussing this, Doidge is careful not to insult clinicians and their entrenched practices. “Periodically people have tried to get stroke patients more rehabilitation, and they would get submerged; their papers would be lost in the literature. In general, people just don't believe it so those who benefit from these treatments were relegated to anecdotal cases.

“One of the noble things about the medical profession has been its willingness to say to people who don't want to hear painful things: ‘Look, I think you've got a serious disorder, you have to get your affairs in order, wishful thinking won't help here'. In a society that is always pandering to people and shies away from hard truths, I admire that, but it's only a virtue if it's based on a full comprehension of the human brain's possibilities and its limits.

“Basically, for several hundred years neural science got it wrong. I'm not arguing that the brain is infinitely malleable, I'm trying to restore to the brain the plasticity that it does have. It is very hard work to reorganise your brain and in some cases it's not possible. In many others it is.”

  08/09/2008. Times Online.