Mild Cognitive Impairment Affects Obstacle Negotiation in Older Adults: Results from “Gait and Brain Study”

Abstract

Background: Older adults with Mild Cognitive Impairment (MCI) are at higher risk of falls and injuries, but the underlying mechanism is poorly understood. Inappropriate anticipatory postural adjustments to overcome balance perturbations are affected by cognitive decline. However, it is unknown whether anticipatory gait control to avoid an obstacle is affected in MCI. Objective: Using the dual-task paradigm, we aim to assess whether gait control is affected during obstacle negotiation challenges in older adults with MCI. Methods: Seventy-nine participants (mean age = 72.0 ± 2.7 years; women = 30.3%) from the “Gait and Brain Study” were included in this study (controls = 27; MCI = 52). In order to assess the anticipatory control behaviour for obstacle negotiation, a 6-m electronic walkway embedded with sensors recorded foot prints to measure gait speed and step length variability, during early (3 steps before the late phase) and late (3 steps before the obstacle) pre-crossing phases of an ad hoc obstacle, set at 15% of participant’s height. Participants walked under single- and dual-task gait (counting backwards by 1’s from 100 while walking) conditions. Three-way mixed repeated-measures analysis of variance models examined differences in gait performance between groups when transitioning between pre-crossing phases towards an obstacle during single- and dual-task conditions. Analyses were adjusted for age, sex, years of education, lower limb function, fear of falling, medical status, depressive symptoms, baseline gait speed and executive function. Results: A significant three-way interaction among groups, pre-crossing phases and task showed that participants with MCI attenuated the gait deceleration (p = 0.02) and performed fewer step length adjustments (p = 0.03) when approaching the obstacle compared with controls while dual-tasking. These interactions were attenuated when executive function performance was added as a covariate in the adjusted statistical model. Conclusion: Older adults with MCI attenuate the anticipatory gait adjustments needed to avoid an obstacle when dual-tasking. Deficits in higher-order cognitive processing may limit obstacle negotiation capabilities in MCI populations, being a potential falls risk factor.

Functional parameters indicative of Mild Cognitive Impairment: a Systematic Review using Instrumented Kinematic Assessment

“…These results were in line with some studies that have identified reduced gait speed as a predictor of preclinical stages of dementia or mild cognitive impairmetnt [23-25, 29, 30, 33-36]. Within the kinematic analysis of the walking speed, the coefficient of variation in the median walking speed, gait speed, gait variability as well as gait symmetry, specially in Dual Task conditions, were parameters which may be impaired in MCI Patients [62,63,[66][67][68] according to included studies of the present systematic review.…”

“…The present systematic review establish that gait speed, especially on the dual task conditions [62,67,68], was signifi cantly reduced in subjects with mild cognitive impairment. These results were in line with some studies that have identified reduced gait speed as a predictor of preclinical stages of dementia or mild cognitive impairmetnt [23-25, 29, 30, 33-36].…”

Complex Gait Is Related to Cognitive Functioning in Older People: A Cross-Sectional Study Providing an Innovative Test

“…Whereas walking on curved paths is considered more difficult than that on straight paths, older adults with poor cognitive flexibility tend to exhibit risky walking behavior during more complex walking situations compared to older adults with good cognitive flexibility [40]. In this sense, deficits in higher-order cognitive processing may limit obstacle negotiation abilities in people with MCI, being a potential falls risk [41]. Based on these findings, and considering the third objective of the current study, the data showed that CGT performance was associated with EF (analyzed by PMT and TWT) and the number of falls in the preceding 3 years.…”

Mapping Associations Between Gait Decline and Fall Risk in Mild Cognitive Impairment

“…Higher‐level brain functions, which depend on cortical control, have been linked with less automatic controlled gait parameters or “nonrhythmic” gait parameters . These nonrhythmic parameters, including gait speed and stride‐to‐stride variability, subtly change during consciously anticipated upcoming balance threats while walking . On the other hand, lower‐level “locomotor centers” of gait control, located in midbrain and spinal regions, mainly regulate more automatic gait functions (“rhythmic” gait parameters) by rhythmically activating hip flexor muscles to generate legs' forward swing and step cadence .…”

“…13 These nonrhythmic parameters, including gait speed and stride-to-stride variability, subtly change during consciously anticipated upcoming balance threats while walking. 14,15 On the other hand, lower-level "locomotor centers" of gait control, located in midbrain and spinal regions, mainly regulate more automatic gait functions ("rhythmic" gait parameters) 16,17 by rhythmically activating hip flexor muscles to generate legs' forward swing and step cadence. 18 Together, these studies provide evidence that different gait parameters are controlled by independent neural pathways.…”