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Scientists Discover Way to Reverse Memory Loss

Posted on: Wednesday, 30 January 2008, 12:55 CST

Canadian doctors have inadvertently discovered that electrical deep brain stimulation (DBS) could improve memory.  

The doctors were using the DBS technique as an experimental treatment for a 50-year-old diabetic with a sleep disorder who had failed to respond to diet, medications and psychological treatments.  The man had refused gastric surgery, and doctors thought DBS, although experimental, could be an effective treatment.  DBS has been found in animal studies to have an impact on appetite, but has not been widely tested as a treatment for obesity in humans.

However, after the treatment, doctors noticed the man began experiencing vivid memories.  

Lead researcher Professor Andres Lozano, of the Toronto Western Hospital, told BBC News, "This is a single case that was totally unexpected.  We knew immediately this was important. We are sufficiently intrigued to see if this could help people with memory disorders."

Lozano said the new discovery could lead to electrical stimulation treatments for brain disorders such as Alzheimer’s disease.

DBS been used for decades with some success in treating severe headaches, Parkinson’s disease, chronic pain and depression . Side effects, often temporary, can include apathy, hallucinations, depression, and compulsive behaviors.

The DBS procedure begins with electrodes that are implanted in the hypothalamus, an area of the brain thought to control appetite.  The procedure is done under local anesthesia so the patient can remain awake and their responses monitored.  A “pacemaker” in the chest stimulates the electrodes.

In the case of Lozano’s 50-year-old diabetic patient, once the electrodes were stimulated by the electrical impulses the patient began experiencing feelings of déjà vu, followed by a sudden perception of being with his friends at a park.   He felt as though he was 30 years younger, and that his girlfriend from that time was there.  It was as though he was an observer, seeing these scenes play out in color.  

The doctors said the details in the man’s visions became more vivid as the intensity of the stimulation increased.

After a two-month recovery, the patient’s electrodes were stimulated again, and as before he experienced a similar effect.  After three weeks of constant electrical stimulation the patient performed better in memory tests than he had prior to the DBS treatment.

After one year, the patient again performed well in memory tests as long as the electrodes were stimulated, but not as well when they were not.

"We hopefully have found a circuit in the brain which can be modulated by stimulation, and which might provide benefit to patients with memory disorders," said Professor Lozano.

Professor Lozano is now leading a pilot study to determine if DBS can help six patients with early Alzheimer's disease.  

"As it is difficult to experiment on the living human brain, big leaps in understanding have occasionally been made from unexpected results when treating something unrelated or observations from rare genetic diseases and unusual lesions,” said Susanne Sorensen, of the Alzheimer's Society, in a BBC News interview.

"The observations of memories recovery made during this attempt to treat extreme obesity, could be just such a 'stroke of luck'."

Rebecca Wood, Chief Executive of the Alzheimer's Research Trust, told BBC she welcomed the move but said further work was clearly needed.

"It will be interesting to see whether this method offers any benefit to people with Alzheimer's.  With the number of people with Alzheimer's forecast to double within a generation, we urgently need to find ways to tackle this awful disease, but research is hugely under-funded," she added.

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Toronto Western Hospital

Source: redOrbit Staff

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