In what they’re calling a world first, a group of Canadian scientists have used a technique involving electrical brain stimulation to treat Alzheimer’s disease -- and their findings were completely unexpected.

Alzheimer’s disease and dementia affect nearly 36 million people, including more than 747,000 Canadians. These incurable diseases literally shrink the brain as they eat away at memory and other mental faculties.

The cause of these conditions, apart from age, isn’t well understood. But Andres Lozano, a neurosurgeon at the Toronto Western Research Institute, said his team didn’t expect the results they found while studying the effects of something called deep brain stimulation on Alzheimer’s patients.

In the trial, the patients were treated with steady electrical pulses through a brain implant (powered by a pacemaker) over the course of a year. Similar techniques have been used to treat Parkinson’s disease and other neurological disorders.

Four of Lozano’s six patients continued to regress over the period of study, with their brains shrinking in size as predicted.

“But in two patients, we were completely surprised,” said Lozano. “Because not only did the brain not shrink in these two patients, the brain actually grew. The hippocampus grew.”

The hippocampus is the part of the brain that Alzheimer’s hits first and hardest, according to Lozano. But in his study, instead of continuing to wither, two of the patients’ brains ended up with a moderate amount of growth from the treatment -- a five to eight per cent increase in size -- to almost pre-disease states.

The study is published in the journal Brain Stimulation.

Lozano said the two patients’ conditions had both progressed only mildly, compared to others whose brain circuitry was decayed because of more advanced Alzheimer’s. Lozano suspected stimulation had spurred the growth of tissue.

“We think the reason for that is, as you’re more advanced, these circuits are completely destroyed as the illness progresses,” he said. “So we think we went in too late in some of the patients.”

Though the results are promising, researchers are still cautious. For one, said neurology professor Howard Chertkow, the study would need to be replicated with more than two patients.

Chertkow, who works at the Jewish General Hospital at McGill University, also pointed out that Alzheimer’s disease affects more than just memory, which this treatment targeted.

“There are changes in emotion, changes in personality, other changes in thinking,” he said. “These are different networks in the brain which would not be affected by this stimulation.”

And though he also said the treatment had the potential to be restrictively expensive -- $10,000 to $20,000 per patient -- Chertkow said he’s still excited about the research.

“This shows for the first time that stimulation with electricity or magnetism can affect the growth of new nerve cells in the hippocampus in the brain,” he said.

And Lozano said the second phase of his team’s study will involve 42 patients with early symptoms of the disease, giving the researchers a more robust data set.

Lozano said the results of that study will be available in May.

With a report from CTV’s medical specialist Avis Favaro and producer Elizabeth St. Philip