OBJECTIVE: The primary aim of this study was to determine if donepezil (a centrally acting cholinesterase inhibitor) improves measures of balance in persons with Parkinson's disease (PD) compared to a placebo. BACKGROUND: Cholinesterase inhibitors have a positive impact on cognitive function in persons with PD and cognitive impairment or dementia.(Cochrane 2012) A small study also showed a reduction in falls in persons with PD without dementia.(Chung 2010) DESIGN/METHODS: This was a double-blind placebo controlled crossover study. Participants received 6 weeks of treatment with either placebo or donepezil, then a month washout, then another 6 weeks of treatment opposite to the first. Inclusion criteria were an MMSE>27 and balance impairment on clinical and posturography assessments (SOT <70). RESULTS: Ten participants' data was used in the analysis. The mean age, UPDRS motor score, and PD disease duration were 69.6+5.9 years, 24+7, and 10.5+8 years at the initial visit. Mean scores on Stroop conflict time and trails B-A at baseline were 105+48s and 59+32s respectively. The mean composite SOT scores improved from 60+16 to 61+15 during the placebo phase and 59+11 to 62+14 during the donepezil phase. This change was not significant, p=0.7. However, in looking at the single conditions of the SOT, there was a statically significant change seen in condition 4 (Eyes Open, Sway referenced, p<0.03). Out of 10 participants, 4 improved more than 40[percnt], 4 improved mildly (between 15[percnt] and 30[percnt]), and 2 didn't show improvements in C4 during the active phase of the study. In addition, there was a significant correlation between improvement in cognitive performance and balance, r=0.8, p=0.001. CONCLUSION:In this pilot study there was statistically significant improvement in one component of the SOT. A subset of patients appeared to have an improvement in balance. It appears that improvements in balance and executive functions are related.

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