SCIENTISTS treating a patient for obesity have made an accidental discovery which may revolutionise the treatment of Alzheimer's disease.
A surprise side-effect of experimental deep-brain stimulation surgery, intended to suppress a 50-year-old man's appetite, instead stimulated his memory, producing a vivid recollection of an experience in his life three decades earlier.
Th
e team is now testing the technique on patients with Alzheimer's in a trial which, if successful, could give hope to sufferers with the degenerative condition, with the prospect of producing a "pacemaker" for the brain.
Research leader Andres Lozano, professor of neurosurgery at the Toronto Western Hospital in Ontario, said three Alzheimer's patients had already been treated, with promising results.
The study, published online yesterday by the Annals of Neurology, said the discovery was made during an experimental study on the morbidly obese patient.
Brain surgery was a last resort after other attempts to restrict the appetite of the patient – who had a lifelong history of obesity and weighed 30 stones – had failed.
Researchers were trying to identify potential appetite-suppressant sites in the hypothalmus area of the brain using electrode implants when the patient reported a sudden feeling of déjà vu.
The man recalled in detail a memory from 30 years earlier, and as the intensity of the current increased, so did the detail of the memory.
Professor Lozano said: "He reported the experience of being in a park with friends from when he was around 20 years old, and as the intensity of stimulation increased, the details became more vivid.
"He recognised his girlfriend. The scene was in colour. People were wearing identifiable clothes and were talking."
After three weeks of continuous hypothalmic stimulation, the patient showed significant improvements in two learning tests.
He was also more likely to remember unrelated, paired objects in tests when the stimulation was switched on.
Prof Lozano, a world authority on deep-brain stimulation, added: "It gives us an insight into which brain structures are involved in memory.
"It gives us a means of intervening in the way we have already done in Parkinson's and for mood disorders such as depression, and it may have a therapeutic benefit in people with memory problems."
Rebecca Wood, chief executive of the Alzheimer's Research Trust, gave a cautious welcome to the findings, but said more research was required.
She said: "
With the number of people shown to have Alzheimer's forecast to double within a generation, we urgently need to find ways to tackle this awful disease."
The researchers are now testing the procedure on six Alzheimer's sufferers, three of whom have had £25,000 electrodes surgically implanted.
Prof Lozano said: "It is a very effective treatment for the motor problems associated with Parkinson's disease and it has been used on 40,000 people.
"We are in the early stages of using it with Alzheimer's patients and we don't know if it will work."
