Source: Circulation  |  Posted 9 years ago

Dutch researchers have found brain activation in the fusiform and frontal cortices is enhanced by rivastigmine among some patients with mild Alzheimer's disease.

Previous clinical trial have shown that rivastigmine enhances cholinergic activity, and decrease the rate of deterioration in Alzheimer's disease. However, uncertainty remains about the part of the brain in which the effects are exerted.

Neurologists at Vrije Universiteit Medical Centre and Department of Radiology, Amsterdam, The Netherlands, used functional magnetic resonance imaging (fMRI) to determine the location of brain changes, and then relate these changes to cognition among the patients.

Twelve patients with mild Alzheimer's disease were enrolled in the study. Seven of the patients received a single dose of rivastigmine before undergoing fMRI during face decoding to test its effect on brain activation. Five other patients underwent the same procedure during a parametric working memory task.

Researchers found that rivastigmine increased bilateral activation in the fusiform gyrus during face decoding. In addition, enhanced brain activation was shown in the prefrontal cortex during a simple working memory task. A further increase in working memory load increased activation, but in certain areas there also was decreased activation.

They said their findings link previous research "which had shown an increase in cognitive performance in patients with mild Alzheimer's disease following treatment with a cholinesterase inhibitor" to altered brain activity.

"Although the results cannot be generalised to the Alzheimer's disease population at large, they provide evidence that in mild Alzheimer's disease, rivastigmine enhances brain activation in the fusiform and frontal cortices," they conclude. "This is compatible with the concept of cholinergic circuitry."