Behavioral and neural correlates of imagined walking and walking-while-talking in the elderly

Abstract

Cognition is important for locomotion and gait decline increases the risk for morbidity, mortality, cognitive decline, and dementia. Yet, the neural correlates of gait are not well established, because most neuroimaging methods cannot image the brain during locomotion. Imagined gait protocols overcome this limitation. This study examined the behavioral and neural correlates of a new imagined gait protocol that involved imagined walking (iW), imagined talking (iT), and imagined walking-while-talking (iWWT). In Experiment 1, 82 cognitively-healthy older adults (M=80.45) walked (W), iW, walked while talking (WWT) and iWWT. Real and imagined walking task times were strongly correlated, particularly real and imagined dual-task times (WWT and iWWT). In Experiment 2, 33 cognitively-healthy older adults (M=73.03) iW, iT, and iWWT during functional magnetic resonance imaging. A multivariate Ordinal Trend (OrT) Covariance analysis identified a pattern of brain regions that: (1) varied as a function of imagery task difficulty (iW, iT and iWWT), (2) involved cerebellar, precuneus, supplementary motor and other prefrontal regions, and (3) were associated with kinesthetic imagery ratings and behavioral performance during actual WWT. This is the first study to compare the behavioral and neural correlates of imagined gait in single and dual-task situations, an issue that is particularly relevant to elderly populations. These initial findings encourage further research and development of this imagined gait protocol as a tool for improving gait and cognition among the elderly.

Keywords: dual-task; fMRI and aging; gait; imagery.

Copyright © 2014 Wiley Periodicals, Inc.

Figures

Figure 1

The temporal correspondence between real and imagined walking tasks in Experiment 1. A. The correlation between real and imagined walking times. B. The correlation between real and imagined Walking‐While‐Talking times.

Figure 2

Pattern expression scores as a function of imagery task difficulty in Experiment 2.

Figure 3

Brain regions that increase and decrease as a function of task difficulty in Experiment 2. Brain regions that increase as a function of task difficulty (iWWT > iT > iW) are displayed in red‐yellow and brain regions that decrease as a function of task difficulty (iWWT 

Figure 4

The correlation between pattern expression scores and kinesthetic imagery ratings on the VVIQ in Experiment 2.

Figure 5

The correlation between pattern expression scores and kinesthetic imagery ratings following imagery training in Experiment 2.

Figure 6

The correlation between pattern expression scores and percent accuracy during actual Walking‐While Talking in Experiment 2.