 Power analysis and sample size calculation are not relevant in this study given its exploratory nature. The investigators expect to recruit a total of 60 patients to complete the cross-over study for analysis purposes. This number is based on similar design studies, particularly one by Wagg et al. looking at the effects of solifenacin and oxybutynin in older adults with mild cognitive impairment 6. Many other similar studies with groups of subjects varying between 40 and 77 have demonstrated efficacy differences of anticholinergics in a cross-over fashion 7-9. 