Other uses of system

Implanting electrodes into the brain isn’t new.

Between 85,000 and 100,000 people around the world have had DBS to block the tremors of Parkinson’s disease and other movement disorders. The continuous jolts quiet overactive nerve cells, with few side effects.

It was in one of those experiments that Canadian researchers back in 2003 stumbled onto the Alzheimer’s possibility. They switched on the electrical jolts in the brain of an obese man and unlocked a flood of old memories. Continuing his DBS also improved his ability to learn.

Alzheimer’s doesn’t just steal memories, it eventually robs sufferers of the ability to do the simplest of tasks. How could stimulating a brain so damaged do any good?

At least early in the disease, Alzheimer’s kills only certain spots. But the disease’s hallmark gunky plaques act as a roadblock, stopping the “on” switch so that healthy circuits farther away are deactivated, explained Dr. Andres Lozano, a neurosurgeon at Toronto Western Hospital whose research sparked the interest.

“It’s like going through Grand Central Station and trying to affect all the trains going in and coming out,” he said.

Lozano’s team found the first clue that it’s possible by implanting six Alzheimer’s patients in Canada. After at least 12 months of continuous stimulation, brain scans showed a sign of more activity in areas targeted by Alzheimer’s. Suddenly, the neurons began using more glucose, the fuel for brain cells.

The evidence is preliminary and will take years of study to prove, but “this is an exciting novel approach,” said Dr. Laurie Ryan of the National Institutes of Health’s aging division.