Cognitive function and memory once thought to be irrevocably damaged by Alzheimer’s disease may be repaired, Canadian researchers say.

Deep brain stimulation (“DST”), the process of applying electrical impulses to specific areas of the brain, was shown in a small study to reverse some the damage caused by the neurological disorder.

DST was applied to the area of the brain that relays messages to and from the hippocampus, where short-term memories get converted into long-term memories. It’s also one of the first areas of the brain to shrink in patients with Alzheimer’s.

After one year of DST, the hippocampus shrank by an expected 5 percent for four of the study subjects. But the hippocampus of the two others actually grew by 5 and 8 percent. Additional testing revealed that these two participants also had improved cognitive functioning.

“How big a deal is 8 percent? It is huge,” said Dr. Andres M. Lozano of Toronto Western Hospital in Ontario. “We’ve never seen the hippocampus grow in Alzheimer’s under any circumstance.”

DST is already used in some 90,000 people worldwide with Parkinson’s disease. The recent findings were presented at the Society for Neuroscience’s annual meeting in November, and researchers plan to begin a larger trial next year.