Despite intensive, worldwide research efforts for more than three decades to better understand Alzheimer's disease, there are still numerous mysteries surrounding the condition.

Alzheimer's disease is a slowly progressing brain disorder. In people with the condition, abnormal deposits of a protein called amyloid-beta forms sticky plaques in the brain, and strands of the protein tau twist around, causing tangles that ultimately kill brain cells and cause a loss of memory, thinking and reasoning skills.