A medication commonly taken for Alzheimer's disease is linked with beneficial changes in the brain.

In Alzheimer's disease, there is shrinkage of a part of the brain called the hippocampus, which is associated with memory and learning. Researchers at Duke University in the US now reveal that taking the drug donepezil can slow down hippocampal shrinkage.

Donepezil is known as a cognitive enhancer, a drug that can address the memory deficit that is the hallmark of Alzheimer's disease. This is the first time that the impact of such a drug on brain structure has been studied in Alzheimer's disease. The researchers used magnetic resonance imaging to track changes in the brains of a group of 67 patients with mild to moderate Alzheimer's disease while on either donepezil or placebo.

In the placebo group, the hippocampus shrank by 8.2 per cent, while the decrease in volume was only 0.4 per cent for those on donepezil. The researchers used another technique called magnetic resonance spectroscopy to track levels of a brain chemical called N-acetylaspartate. This increased among those on donepezil, but went down in those on placebo. There was a strong link between levels of N-acetylaspartate and cognitive performance. It's not yet known why or how donepezil can protect the hippocampus, but it seems likely that its impact on N-acetylaspartate is responsible for its beneficial effect on cognition.

Source

American Journal of Psychiatry 1st November 2003