Are Cholinesterase Inhibitors Effective in Improving Balance in Parkinson’s Disease?

Background:Cholinesterase inhibitors have been reported to reduce falls in a double blind pilot study. The mechanism by which cholinesterase inhibitors reduce falls is unknown. Methods: A pilot, double-blind, placebo-controlled, crossover study examined the effects of donepezil on posturography and frontal executive function. Participants received 6 weeks of treatment with placebo and donepezil in random order, separated by a month washout. Inclusion criteria were an MMSE > 27 and balance impairment on clinical and sensory orientation posturography (SOT) assessments. Results: Ten participants completed the study. Donepezil improved postural sway in SOT condition 4 (C4, eyes open, sway referenced surface) (p<0.03). The change seen in executive performance (measured by the Trail B-A time) when on donepezil correlated with improvement in SOT C4, r=0.80, p=0.001. Conclusion: Cholinesterase inhibitors improved two functions related to fall risk, standing balance on an unstable surface and executive set-switching in subjects with PD. We hypothesized that the cholinesterase inhibitor, donepezil, affects fall risk by improving sensory orientation set-switching for balance related to improvements in executive setswitching.