Gait Changes with Anti-Dementia Drugs: A Prospective, Open-Label Study Combining Single and Dual Task Assessments in Patients with Alzheimer's Disease

Background No comparison of anti-dementia drugs-related gait changes has been previously conducted combining single and dual task assessments. Objectives (1) To quantify and compare gait changes among patients with possible or probable Alzheimer's disease before and after the use of acetylcholinesterase inhibitors (i.e., donepezil, galantamine, rivastigmine) or memantine, and among controls with possible or probable Alzheimer's disease using no anti-dementia drugs; and (2) to determine whether gait changes differed between acetylcholinesterase inhibitors and memantine. Methods A total of 86 patients with mild-to-moderate possible or probable Alzheimer's disease were included in this quasi-experimental study (19 patients using acetylcholinesterase inhibitors, 36 patients using memantine and 31 age- and gender-matched patients without anti-dementia drugs). Mean values and coefficient of variation of walking speed and stride time were measured with the GAITRite (R) system while usual walking and while walking with backward counting. Results In single task, patients using memantine had a greater decrease in coefficient of variation of stride time (-2.3 %) compared to those using acetylcholinesterase inhibitors (1.3 %, P = 0.043) and no anti-dementia drugs (1.6 %, P = 0.026). In dual task, patients using acetylcholinesterase inhibitors had a greater decrease in coefficient of variation of stride time (-5.5 %) compared to those using memantine (2.0 %, P = 0.002) and no anti-dementia drugs (4.1 %, P = 0.05). Conclusions Our findings showed a double dissociation in the effect of anti-dementia drugs on gait variability in patients with possible or probable Alzheimer's disease: memantine improves gait variability while single tasking, whereas acetylcholinesterase inhibitors improves gait variability while dual tasking.