Associations Between Gait-Related Falls and Gait Adaptations When Stepping Onto a Curb: A Prospective Falls Study

Differences of gait adaptability behavior between young and healthy older adults during a locomotor pointing task in virtual reality

BACKGROUND

Gait adaptability training programs to prevent falls in healthy older adults can be proposed in virtual reality. The development of training programs requires the characterization of the target population.

RESEARCH QUESTION

Before proposing an innovative training program to develop gait adaptability behavior of healthy older adults in fully immersive virtual reality, we had to compare gait adaptability behavior between healthy older adults and young adults in virtual reality.

METHODS

Twenty healthy older adults (with no fall history) and twenty young adults performed a goal-directed locomotion task in a totally secure virtual reality set-up. Gait adaptability behavior was investigated via a set of measures taking into account gait speed, pointing accuracy, and the evolution of the relationship between the participant and the environment through both inter-trial and trial-by-trial analyses. Mann-Whitney tests and linear regressions were performed to determine potential age differences.

RESULTS

The results reveal some common and specific strategies in gait adaptability behavior between healthy older and young adults. In both populations, successive gait adjustments depend on the state of the agent-environment system. However, older adults walked more slowly than young adults (p < .001) with a greater coupling at the end of the target approach (p = .003).

SIGNIFICANCE

In the context of fall prevention in healthy older adults, fully immersive VR appears as a relevant tool to propose relevant gait training programs to improve gait adjustments.

How Reliable and Valid are Dual-Task Cost Metrics? A Meta-analysis of Locomotor-Cognitive Dual-Task Paradigms

OBJECTIVE

To assess the retest reliability, predictive validity, and concurrent validity of locomotor and cognitive dual-task cost (DTC) metrics derived from locomotor-cognitive dual-task paradigms.

DATA SOURCES

A literature search of electronic databases (PubMed, PsycINFO, MEDLINE, CINAHL, and Scopus) was conducted on May 29th, 2021, without time restriction.

STUDY SELECTION

For 1559 search results, titles and abstracts were screened by a single reviewer and full text of potentially eligible papers was considered by 2 independent reviewers. 25 studies that evaluated retest reliability, predictive validity, and concurrent validity of locomotor-cognitive DTC in healthy and clinical groups met inclusion criteria.

DATA EXTRACTION

Study quality was assessed using the Consensus-Based Standards for the Selection of Health Measurement Instrument checklist. Data relating to the retest reliability, predictive validity, and concurrent validity of DTC were extracted.

DATA SYNTHESIS

Meta-analysis showed that locomotor DTC metrics (intraclass correlation coefficient [ICC]=0.61, 95% confidence interval [CI; 0.53.0.70]) had better retest reliability than cognitive DTC metrics (ICC=0.27, 95% CI [0.17.0.36]). Larger retest reliability estimates were found for temporal gait outcomes (ICC=0.67-0.72) compared with spatial (ICC=0.34-0.53). Motor DTC metrics showed weak predictive validity for the incidence of future falls (r=0.14, 95% CI [-0.03.0.31]). Motor DTC metrics had weak concurrent validity with other clinical and performance assessments (r=0.11, 95% CI [0.07.0.16]), as did cognitive DTC metrics (r=0.19, 95% CI [0.08.0.30]).

CONCLUSIONS

Gait-related temporal DTC metrics achieve adequate retest reliability, while predictive and concurrent validity of DTC needs to be improved before being used widely in clinical practice and other applied settings. Future research should ensure the reliability and validity of DTC outcomes before being used to assess dual-task interference.

Acute effect of traditional and adaptive metronomes on gait variability in older individuals with a history of falls

BACKGROUND

Metronome cueing has been shown to reduce gait variability and thereby potentially reduce falls risk in individuals with Parkinson's disease. It is unclear however, if metronome cueing has a similar effect in healthy older adults with a history of falls.

AIM

To investigate whether a traditional and/or an adaptive metronome, based on an individual's gait pattern, were effective in reducing gait variability in older adults with a history of falls.

METHODS

Twenty older adults (15 women, 71 ± 4.9 years) with a history of falls were included in this cross-over study. Participants received two types of cueing (adaptive and traditional metronome) 1 week apart. The variability of the participants' stride time, stride length, walking speed and duration of double leg support were recorded during three walking conditions (baseline, during feedback and post-feedback gait). Repeated-measures ANOVA was used to assess the possible effects of the two cueing strategies on gait variables.

RESULTS

Compared with the baseline condition, participants had significantly increased stride time variability during feedback (F (2) = 9.83, p < 0.001) and decreased double leg support time variability post-feedback (F (2) 3.69, p = 0.034). Increased stride time variability was observed with the adaptive metronome in comparison to the traditional metronome.

CONCLUSION

Metronome cueing strategies may reduce double leg support variability in older adults with a history of falls but seem to increase stride time variability. Further studies are needed to investigate if metronome cueing is more beneficial for individuals with greater baseline gait variability than those included in the current study.

Conceptualizing the Human Health Outcomes of Acting in Natural Environments: An Ecological Perspective

Human-nature interactions have been presented as important for promoting and sustaining wellbeing and health benefits. Research has shown that pictures of nature, interacting with nature, physical activity in nature, immersion in nature and even feeling connected to nature can improve health. While considerable research supports this notion that nature can have positive health impact, theoretical and conceptual frameworks that help explain how the natural environment provides benefits to human health and wellbeing have proved limited. In extreme cases, theoretical approaches reinforce a problematic notion where nature is viewed as a separate entity, as a treatment to be taken as prescribed to remediate health problems that arise. Such approaches are limited as they fail to address how beneficial person-nature relations may be captured in interventions. There is a need for a deeper understanding of the processes underlying the observed benefits of the person-nature link in order to design effective research and interventions. It is especially important to consider the implications of research on person-nature relations for people living in urban contexts. In this paper, we present an ecological perspective building on James Gibson's conceptualization of human behavior. Specifically, we outline a framework that emphasizes the person-environment system as the most appropriate scale of analysis. We present three relevant concepts from the ecological approach: form of life, affordances and niche construction, as helpful for appreciating how acting in natural environments might benefit human health and wellbeing. This approach urges policy makers and urban designers to rethink environmental designs to provide and support a landscape of affordances that makes use of the richness of natural environments.

Randomised Controlled Trial Of The Effect Of Tai Chi On Postural Balance Of People With Dementia

Purpose

To investigate the effect of Tai Chi exercise on postural balance among people with dementia (PWD) and the feasibility of a definitive trial on falls prevention.

Patients and methods

Dyads, comprising community-dwelling PWD and their informal carer (N=85), were randomised to usual care (n=43) or usual care plus weekly Tai Chi classes and home practice for 20 weeks (n=42). The primary outcome was the timed up and go test. All outcomes for PWD and their carers were assessed six months post-baseline, except for falls, which were collected prospectively over the six-month follow-up period.

Results

For PWD, there was no significant difference at follow-up on the timed up and go test (mean difference [MD] = 0.82, 95% confidence interval [CI] = -2.17, 3.81). At follow-up, PWD in the Tai Chi group had significantly higher quality of life (MD = 0.051, 95% CI = 0.002, 0.100, standardised effect size [ES] = 0.51) and a significantly lower rate of falls (rate ratio = 0.35, 95% CI =0.15, 0.81), which was no longer significant when an outlier was removed. Carers in the Tai Chi group at follow-up were significantly worse on the timed up and go test (MD = 1.83, 95% CI = 0.12, 3.53, ES = 0.61). The remaining secondary outcomes were not significant. No serious adverse events were related to participation in Tai Chi.

Conclusion

With refinement, this Tai Chi intervention has potential to reduce the incidence of falls and improve quality of life among community-dwelling PWD [Trial registration: NCT02864056].

Principles of the Guidance of Exploration for Orientation and Specification of Action

To control movement of any type, the neural system requires perceptual information to distinguish what actions are possible in any given environment. The behavior aimed at collecting this information, termed "exploration", is vital for successful movement control. Currently, the main function of exploration is understood in the context of specifying the requirements of the task at hand. To accommodate for agency and action-selection, we propose that this understanding needs to be supplemented with a function of exploration that logically precedes the specification of action requirements with the purpose of discovery of possibilities for action-action orientation. This study aimed to provide evidence for the delineation of exploration for action orientation and exploration for action specification using the principles from "General Tau Theory." Sixteen male participants volunteered and performed a laboratory-based exploration task. The visual scenes of different task-specific situations were projected on five monitors surrounding the participant. At a predetermined time, the participant received a simulated ball and was asked to respond by indicating where they would next play the ball. Head movements were recorded using inertial sensors as a measure of exploratory activity. It was shown that movement guidance characteristics varied between different head turns as participants moved from exploration for orientation to exploration for action specification. The first head turn in the trial, used for action-orientation, showed later peaks in the velocity profile and harder closure of the movement gap (gap between the start and end of the head-movement) in comparison to the later head turns. However, no differences were found between the first and the final head turn, which we hypothesized are used mainly for action orientation and specification respectively. These results are in support of differences in the function and control of head movement for discovery of opportunities for action (orientation) vs. head movement for specification of task requirements. Both are important for natural movement, yet in experimental settings,orientation is often neglected. Including both orientation and action specification in an experimental design should maximize generalizability of an experiment to natural behavior. Future studies are required to study the neural bases of movement guidance in order to better understand exploration in anticipation of movement.