Both groups underwent Positron emission technology (PET) brain scans before and after 18 months of treatment.
The research team found that people, who were given Aricept showed an increased rate of metabolism and looked more normal than the brains of those who took the placebo.
Moreover, both the groups scored the same on memory tests, however, implying that PET scans may be more sensitive than neuropsychological tests in detecting drugs' effects.
The researchers suggest that the treatment of early symptoms of memory loss may protect the brain and help people with mild age-related memory impairment.
The finding also shows how PET offers researchers a tool for tracking the effectiveness of drugs prescribed to treat age-related cognitive decline.
The findings were presented at the "Hot Topics" poster session of the International Conference on Alzheimer's Disease 2008, hosted by the Alzheimer's Association.