March 16 (HealthDay News) -- A loss of cells in the hippocampus area of the brain precedes Alzheimer's disease, a new study finds.

The research included 64 Alzheimer's patients, 44 people with mild cognitive impairment (the stage of memory problems that occurs before Alzheimer's), and 34 people with no memory or thinking problems. The Dutch team used MRI to measure the volume of the entire brain, as well as the hippocampus, in all the participants at the start of the study and again an average of 18 months later in order to calculate the rate of brain shrinkage.

During the study, 23 of the people with mild cognitive impairment were diagnosed with Alzheimer's disease, along with three of the healthy volunteers. Among participants who didn't have Alzheimer's at the start of the study, those with smaller hippocampal volumes and higher rates of shrinkage were two to four times more likely to develop Alzheimer's than those with larger hippocampal volumes and a slower rate of shrinkage, the team found.

"This finding seems to reflect that at the stage of mild cognitive impairment, considerable atrophy has already occurred in the hippocampus. In people who already have Alzheimer's disease, the loss of nerve cells is more widespread throughout the brain," study author Dr. Wouter Henneman, of VU University Medical Center in Amsterdam, The Netherlands, said in an American Academy of Neurology news release.

The study was published in the March 17 issue of the journal Neurology.

SOURCE: American Academy of Neurology, news release, March 16, 2009