Timing Variability during Gait Initiation Is Increased in People with Alzheimer’s Disease Compared to Controls

Abstract

Background/Aims: Variability of constant speed walking is closely related to falls risk in people with Alzheimer’s disease (AD) who fall at 3 times the rate of normal elders. Falls are likely to be provoked during gait initiation, so this study aimed to determine if people with mild-moderate AD have greater variability of gait at initiation. Methods: Measures of step and stride length and time, step width and double support time were recorded during gait initiation for 10 males and 10 females with AD and 20 age- and gender-matched controls. Variability was calculated using the coefficient of variation (CV). Effect size was calculated using Cohen’s d. Results: During gait initiation AD participants had greater variability than controls in stride timing (AD CV = 4.65, Control CV = 3.64; p < 0.05, d = 0.71) and double support proportion (AD CV = 9.40, Control CV = 7.62; p < 0.05, d = 0.8). Conclusion: Increased timing variability in people with AD occurs during gait initiation as well as during constant speed walking and is evident in the early disease stages.

Spatiotemporal variability during gait initiation in Parkinson's disease

“…Length, width, and time of the first ST limb step were calculated similarly for the contralateral (ST) limb. Similar to previous literature, the coefficient of variation (CV = SD/mean * 100%) was used to describe within-subject variability of the length, width, and time of the first SW and ST steps [4,11,13]. …”

“…Step length variability of the stepping limb during maximal-velocity GI was significantly greater in a small sample of individuals with PD compared to age-matched peers [12]. More recently, Wittwer and colleagues reported significantly increased temporal variability during GI in persons with Alzheimer’s disease who fall at three times the rate of healthy elderly adults [13]. The results from these studies provide early support that step variability during GI is a relevant marker of gait stability in older persons with and without neurodegenerative disease.…”

Associations Between Cognitive and Gait Performance During Single- and Dual-Task Walking in People With Parkinson Disease

“…The coefficient of variation (CV) (CVϭSD/mean ϫ 100%) was calculated to determine within-subject variability of stride time, stride length, step width, and swing time. 24 To measure the change in gait due to a simultaneous cognitive task, dualtask cost was calculated as the log transformed (to normalize for skewed variables) ratio of dual-task to single-task value for each gait outcome measure. 23…”

Wii-Fit for Improving Gait and Balance in an Assisted Living Facility: A Pilot Study

“…Compared to cognitively intact older adults, patients with AD have a threefold increase in falls causing fractures, hospitalization, and increased rate of institutionalization [2]. Poor balance and gait abnormalities seen in AD such as shortened step length, increased stride length variability, and decreased gait speed are risk factors for falls [3, 4].…”