Tests on mice suggest the brain damage caused by Alzheimer’s disease may be at least partly reversible, researchers reported Thursday.

Their genetically altered mice regained the ability to navigate mazes after the genes that caused their dementia were de-activated.

This suggests that the brain damage caused by Alzheimer’s is not permanent, they wrote in their report, published in the journal Science.

“I was astonished. I didn’t believe the results when I saw them,” said Alzheimer’s researcher Karen Ashe of the University of Minnesota, who led the study.

“When I saw the memory getting better I actually thought I had done something wrong in the experiment.”

Alzheimer’s is a brain-destroying disease that affects an estimated 4.5 million people in the United States alone and millions more globally. As the population gets steadily older, experts estimate this number will balloon to as many as 16 million by 2015 in the United States.

Outward symptoms start with memory loss, which progresses to complete helplessness as brain cells are destroyed. In the brain, neurons die as messy plaques and tangles of protein form.

More here.