The interplay between gait, falls and cognition: can cognitive therapy reduce fall risk?

Abstract

In this article, we briefly summarize the incidence and significant consequences of falls among older adults, the insufficient effectiveness of commonly used multifactorial interventions and the evidence linking falls and cognitive function. Recent pharmacologic and nonpharmacologic studies that evaluated the effects of cognitive therapy on fall risk are reviewed. The results of this article illustrate the potential utility of multiple, diverse forms of cognitive therapy for reducing fall risk. The article also indicates that large-scale, randomized controlled trials are warranted and that additional research is needed to better understand the pathophysiologic mechanisms underlying the interplay between human mobility, fall risk and cognitive function. Nonetheless, we suggest that multimodality interventions that combine motor and cognitive therapy should, eventually, be incorporated into clinical practice to enable older adults and patients to move safer and with a reduced fall risk.

Figure 1. Kaplan–Meier curves for the cumulative risk of dementia, comparing older adults with and without gait alterations at baseline

Those with gait alterations at baseline were much more likely to develop vascular dementia, as much as 6 years later. These findings highlight the connection between gait and cognitive function. One possible explanation is that these attributes of gait rely on, and are therefore sensitive to, subtle changes in executive function; these changes are precursors of the development of cognitive decline and dementia. Dotted lines represent the 95% CIs. Adapted with permission from [65].

Figure 2. Survival curves illustrating the percentage of participants who did not fall (the y-axes) as a function of time after the baseline testing and (A) executive function or (B) dual tasking gait variability

Participants with worse EF (lowest quartile) or relatively increased DT gait variability were more likely to become fallers and recurrent fallers (not shown) sooner than those with better EF (highest quartile) or DT gait (highest quartile). DT: Dual tasking; EF: Executive function. Adapted from [68].

Figure 3. Effects of methylphenidate or placebo on cognition and gait in older adults

(A) Effects of a single dose of 20 mg of M or placebo on cognitive function (% correct or accuracy), (B) stride time variability and (C) TUG times in older adults. There was small time variability and TUG performance in response to MPH, but not in response but to placebo. MPH: Methylphenidate; NS: Not significant; TUG: Timed Up and Go. Data from [119].

Figure 4. Examples of the effects of four different forms of cognitive therapy on usual-walking gait speed and dual-tasking gait speed

Values shown are change with respect to baseline. Note that 5 cm/s and 10 cm/s have been identified as the MCD and substantial difference [177]. (A) Effects of 4 months of donepezil use on gait speed in patients with Alzheimer’s disease and compared with control patients with mild cognitive impairment. Data from [122]. (B) Effects of dual-task training during walking on gait speed in older adults with balance impairment, compared with subjects who only practiced walking. Data from [138]. (C) Effects of 8 weeks of computerized cognitive training (while seated) in sedentary older adults, compared with wait list controls. Data from [147]. (D) Effects of 6 weeks of TT augmented with VR among patients with PD, compared with an active control comparison of 6 weeks of TT alone. Usual-walking gait speed increased in both the TT alone and TT + VR groups; however, DT gait speed only improved who participated in TT + VR. Data from [148]. AD: Alzheimer’s disease; DT: Dual tasking; MCD: Minimal clinically significant difference; MCI: Mild cognitive Parkinson’s impairment; disease; TT: Treadmill training; VR: Virtual reality.

Figure 5. Mean fall frequency was almost 50% lower during the 6-week period when subjects with Parkinson’s disease were taking donepezil, compared with the 6-week period when they were taking placebo

Note that those subjects who had relatively high fall frequencies on placebo seemed to be most responsive to donepezil. Data from [123].

Figure 6. Effects of five sessions of computerized dual-task training, while seated, on postural control in older adults

Sway magnitude during dual tasking was reduced (better) after training, while there was no effect in the controls. Adapted with permission from [146].