Donepezil Enhances Frontal Functional Connectivity in Alzheimer's Disease: A Pilot Study

Abstract

Background: We have previously shown that increased resting-state functional magnetic resonance imaging (fMRI)-based functional connectivity (FC) within the frontal resting-state networks in Alzheimer's disease (AD) patients reflects residual, possibly compensatory, function. This suggests that symptomatic treatments should aim to enhance FC specifically in these networks. Methods: 18 patients with probable AD underwent brain MRI and neuropsychological assessment at baseline and after 12 weeks of treatment with donepezil. We tested if changes in cognitive performance after treatment correlated with changes in FC in resting-state networks known to be altered in AD. Results: We found increases in FC in the orbitofrontal network that correlated with cognitive improvement after treatment. The increased FC was greatest in patients who responded most to treatment. Conclusion: This ‘proof of concept' study suggests that changes in network-specific FC might be a biomarker of pharmacological intervention efficacy in AD.

Keywords

• Alzheimer’s disease
• Donepezil
• Cholinesterase inhibitors
• Functional magnetic resonance imaging
• Resting-state networks
• Functional connectivity