Balance recovery stepping responses during walking were not affected by a concurrent cognitive task among older adults

Abstract

Background: Most of older adults' falls are related to inefficient balance recovery after an unexpected loss of balance, i.e., postural perturbation. Effective balance recovery responses are crucial to prevent falls. Due to the considerable consequences of lateral falls and the high incidence of falls when walking, this study aimed to examine the effect of a concurrent cognitive task on older adults' balance recovery stepping abilities from unannounced lateral perturbations while walking. We also aimed to explore whether cognitive performance accuracy is affected by perturbed walking and between task trade-offs.

Methods: In a laboratory-based study, 20 older adults (> 70 years old) performed the following test conditions: (1) cognitive task while sitting; (2) perturbed walking; and (3) perturbed walking with a concurrent cognitive task. The cognitive task was serial numbers subtraction by seven. Single-step and multiple-step thresholds, highest perturbation achieved, 3D kinematic analysis of the first recovery step, and cognitive task performance accuracy were compared between single-task and dual-task conditions. Between task trade-offs were examined using dual-task cost (DTC).

Results: Single-step and multiple-step thresholds, number of recovery step trials, number of foot collision, multiple-step events and kinematic recovery step parameters were all similar in single-task and dual-task conditions. Cognitive performance was not significantly affected by dual-task conditions, however, different possible trade-offs between cognitive and postural performances were identified using DTC.

Conclusions: In situations where postural threat is substantial, such as unexpected balance loss during walking, balance recovery reactions were unaffected by concurrent cognitive load in older adults (i.e., posture first strategy). The study was approved by the Helsinki Ethics Committee of Soroka University Medical Center in Beer-Sheva, Israel (ClinicalTrials.gov Registration number NCT04455607 , ID Numbers: Sor 396-16 CTIL; 02/07/2020).

Keywords: Balance-perturbations; Compensatory-reactions; Dual-task; Falls.

Conflict of interest statement

The authors declare that they have no competing interests.

© 2022. The Author(s).

Figures

Fig. 1

A Single-step and multiple-steps thresholds and the highest perturbation achieved during single-task and dual-task perturbed walking (Mean ± SEM). *p = 0.036; [B] The number of foot collisions and multiple steps events during single-task and dual-task perturbed walking trials. Abbreviations: PwST Perturbed walking condition without a concurrent cognitive task, PwDT Perturbed walking condition with a concurrent cognitive task

Fig. 2

Spatiotemporal parameters (Mean ± SD) of recovery stepping responses during single- and dual-task perturbed walking. Figs. A–E: [A] Margins of Stability, [B] Reaction Time, [C] Step Length, [D] Swing Time, [E] Step Time. Linear regression coefficients are noted, as well as results of the Wilcoxon signed rank test; * p = 0.052, **p = 0.041., ***p = 0.026. Abbreviations: PwST Perturbed walking condition without a concurrent cognitive task; PwDT Perturbed walking condition with a concurrent cognitive task

Fig. 3

Cognitive performance accuracy (mean ± SEM) in the three task conditions (correct answers/total numbers counted, in %). Abbreviations: Sit Sitting task condition, UPwDT unperturbed walking condition with a concurrent cognitive task, PwDT Perturbed walking condition with a concurrent cognitive task

Fig. 4

DTC (%) of the recovery stepping response parameters are plotted against cognitive performance DTC, of each participant. [A-C] Recovery stepping response DTC calculated for each parameter as the difference between the performance during PwDT and PwST divided by performance in PwST (see formula in methods). Cognitive performance DTC was calculated as follows: [A] the difference between cognitive performance during PwDT and UPwDT, divided by performance during UPwDT, [B] the difference between cognitive performance during UPwDT and sitting, divided by cognitive performance during sitting; [C] the difference between cognitive performance during PwDT and during sitting, divided by cognitive performance during sitting