Dual-task interference as a function of varying motor and cognitive demands

Dual-task effects of walking-speed on inhibitory control and decision-making under risk

The effect of simultaneously performing two tasks (dual-task effects, DTEs) has been extensively studied, mainly focusing on the combination of cognitive and motor tasks. Given their potentially detrimental impact on real-life activities, the impact of DTEs has been investigated in both healthy individuals and patients. In this Registered Report, we aimed to replicate previous DTEs when a task requiring executive-inhibitory skills is involved while also expanding the evidence on basic facets of decision-making. We recruited 50 healthy young participants who performed a stop-signal task and two gambling tasks (loss-aversion and risk-aversion) while sitting and while walking at three treadmill speeds (normal, slow and fast). We report a significant difference in performance during single-task and dual-task, although with high individual variability. The data show no effect of the walking speed on all the cognitive tasks. Analyses on postural alignments, assessed in the cadence, gait cycle length and stance phase, confirm previous results on cognitive prioritization strategies of healthy individuals. Based on our results, we highlight the need to further investigate prioritization strategies when tasks involving higher cognitive functions are performed along a motor task in healthy individuals and patients with the aim of offering targeted training and rehabilitation protocols. The stage 1 protocol for this Registered Report was accepted in principle on 28/06/22. The protocol, as accepted by the journal, can be found at: https://doi.org/10.17605/OSF.IO/5MWH7 .

Momentary clumsiness and attention: Everyday interactions (and risks) in the world

Typically, explorations into risk-taking involve the conscious undertaking of actions that are potentially harmful. Rarely considered in such risk-taking contexts, however, are everyday, innocuous behaviors that nevertheless have the potential to cause some level of harm to actors; such behaviors could be considered as lying on a continuum of risky activity. The current study explored individual and developmental differences in one such category of behavior, entitled "momentary clumsiness". Momentary clumsiness refers to a tendency to perform movements involving non-optimal motor control, such as knocking over a glass of liquid or tripping while walking up stairs. This project explored the link between such behaviors and attentional factors. Specifically, twenty participants in three age groups (7- and 8-year-olds, 11- and 12-year-olds, and young adults) completed the experiment in 2 testing sessions. Momentary clumsiness was assessed by a 2-week daily phone interview, and was correlated with Stroop performance. The incidence of momentary clumsiness remained steady with age and was not related to motor ability or anthropometric measures. A high incidence of momentary clumsy behaviors was associated with a narrow focus of attention, and specifically, the tendency to ignore irrelevant and distracting stimuli. These findings are interpreted with respect to the relation between action and attentional focus, and provide a basis for extending our conceptualizations of injury proneness and risk-taking into a continuum of behaviors, varying in their degree of riskiness.

Comparing the effectiveness of dual-task and single-task training on walking function in stroke recovery: A systematic review and meta-analysis

BACKGROUND

Stroke is a prevalent neurological disease with high morbidity and disability. Single-task walking training has limitations, and dual-task walking training has emerged. Yet, research on the relative effectiveness of dual- and single-task training for stroke patients' walking function is inconclusive. This study aims to systematically compare the efficacy of dual-task with single-task training interventions on improving walking function among stroke survivors.

METHODS

A comprehensive search of electronic databases was conducted to identify randomized controlled trials investigating the application of dual-task training on walking function in stroke patients. Two reviewers independently screened the references, selected relevant studies, extracted data, and assessed the risk of bias. The primary outcome measures related to walking function included step speed, step length, stride length, step frequency, Berg balance scale (BBS), and timed up and go (TUG) test. The Cochrane risk of bias tool was used for methodological quality assessment of the included literature. Statistical analysis was performed using RevMan 5.4 software. Furthermore, the quality of evidence of the outcome measures was evaluated using the GRADEPro software.

RESULTS

A total of 17 studies were enrolled in this systematic review and meta-analysis. The results revealed that dual-task training exhibited significantly superior efficacy compared to single-task training in enhancing step speed, step length, stride length, step frequency, and BBS score (P < .05). However, no significant difference was observed in the TUG test (P = .100).

CONCLUSION

Compared with traditional single-task training, dual-task training could be more effective in improving walking function among stroke patients, especially with regard to temporal and spatial parameters such as step length and speed, stride frequency and BBS score, but the effect on enhancing TUG test still remains unclear. These findings would help clinicians to formulate a more rational stroke rehabilitation strategy.

Towards a comprehensive framework for complex walking tasks: Characterization, behavioral adaptations, and clinical implications in ageing and neurological populations

Complex walking tasks, including change of direction, patterns and rhythms, require more attentional resources than simple walking and significantly impact walking performance, especially among ageing and neurological populations. More studies have been focusing on complex walking situations, with or without the addition of cognitive tasks, creating a multitude of walking situations. Given the lack of a clear and extensive definition of complex walking, this narrative review aims to identify and more precisely characterize situations and related tests, improve understanding of behavioral adaptations in ageing and neurological populations, and report the clinical applications of complex walking. Based on the studies collected, we are proposing a framework that categorizes the different forms of complex walking, considering whether a cognitive task is added or not, as well as the number of distinct objectives within a given situation. We observed that combining complex walking tasks with a cognitive assignment places even greater strain on attentional resources, resulting in a more pronounced decline in walking and/or cognitive performance. This work highlights the relevance of complex walking as a simple tool for early detection of cognitive impairments and risk of falls, and its potential value in cognitive-motor rehabilitation. Future studies should explore various complex walking tasks in ageing and neurological populations, under varied conditions in real-life or in extended virtual environments.

Central imaging based on near-infrared functional imaging technology can be useful to plan management in patients with chronic lateral ankle instability

BACKGROUND

Near infrared brain functional imaging (FNIRS) has been used for the evaluation of brain functional areas, the imaging differences of central activation of cognitive-motor dual tasks between patients with chronic lateral ankle instability (CLAI) and healthy population remain unclear. This study aimed to evaluated the role of central imaging based on FNIRS technology on the plan management in patients with CLAI, to provide insights to the clinical treatment of CLAI.

METHODS

CLAI patients treated in our hospital from January 1, 2021 to June 31, 2022 were selected. Both CLAI patients and health controls were intervened with simple task and cognitive-motor dual task under sitting and walking conditions, and the changes of oxygenated hemoglobin concentration in bilateral prefrontal cortex (PFC), premotor cortex (PMC) and auxiliary motor area (SMA) were collected and compared.

RESULTS

A total of 23 participants were enrolled. There were significant differences in the fNIRS ΔHbO2 of barefoot subtractive walking PFC-R and barefoot subtractive walking SMA-R between experimental and control group (all P < 0.05). There was no significant difference in ΔHbO2 between the experimental group and the control group in other states (P > 0.05). There was no significant difference in ΔHbO2 between the experimental group and the control group in each state of the brain PMC region.

CONCLUSION

Adaptive alterations may occur within the relevant brain functional regions of individuals with CLAI. The differential activation observed between the PFC and the SMA could represent a compensatory mechanism emerging from proprioceptive afferent disruptions following an initial ankle sprain.

Functional near-infrared spectroscopy evidence of cognitive-motor interference in different dual tasks

Dual tasks (DTs) combining walking with a cognitive task can cause various levels of cognitive-motor interference, depending on which brain resources are recruited in each case. However, the brain activation and functional connectivity underlying cognitive-motor interferences remain to be elucidated. Therefore, this study investigated the neural correlation during different DT conditions in 40 healthy young adults (mean age: 27.53 years, 28 women). The DTs included walking during subtraction or N-Back tasks. Cognitive-motor interference was calculated, and brain activation and functional connectivity were analysed. Portable functional near-infrared spectroscopy was utilized to monitor haemodynamics in the prefrontal cortex (PFC), motor cortex and parietal cortex during each task. Walking interference (decrease in walking speed during DT) was greater than cognitive interference (decrease in cognitive performance during DT), regardless of the type of task. Brain activation in the bilateral PFC and parietal cortex was greater for walking during subtraction than for standing subtraction. Furthermore, brain activation was higher in the bilateral motor and parietal and PFCs for walking during subtraction than for walking alone, but only increased in the PFC for walking during N-Back. Coherence between the bilateral lateral PFC and between the left lateral PFC and left motor cortex was significantly greater for walking during 2-Back than for walking. The PFC, a critical brain region for organizing cognitive and motor functions, played a crucial role in integrating information coming from multiple brain networks required for completing DTs. Therefore, the PFC could be a potential target for the modulation and improvement of cognitive-motor functions during neurorehabilitation.

Dual-task performance and balance in patients with severe COPD: a cross-sectional study

BACKGROUND

Chronic obstructive pulmonary disease (COPD) significantly impacts respiratory and motor function, balance, and cognition, leading to muscle weakness and impaired exercise capacity. The impairments often result in challenges with daily activities, particularly those requiring dual-tasking.

OBJECTIVES

The study investigated whether patients with severe COPD would exhibit more significant cognitive and motor performance decline during dual tasks compared to healthy controls.

DESIGN

This study employed a cross-sectional design to compare cognitive and motor performance in dual tasks between patients with severe COPD and healthy controls.

METHODS

We included 44 patients with severe COPD and 43 healthy individuals. Participants underwent various tests, including pulmonary function tests, six-minute walking tests, dual Timed Up and Go tests (TUG), dual single-leg stance tests (SLS), Berg Balance Scale assessments, and Falls Efficacy Scale International evaluations (FES-I).

RESULTS

The COPD group had significantly lower scores in the Berg Balance Scale (BBS; 44.79 ± 4.70 vs 52.67 ± 2.16, p < 0.0001) and longer times for the TUG test (12.44 s; [11.44, 13.50] vs 9.14 s; [7.91, 10.11], p < 0.0001) and shorter times for the SLS test (14.15 s; [12.31, 15.65] vs 26.20 s; [23.45, 30.88], p < 0.0001), indicating poorer functional mobility and balance. Furthermore, dual-task interference (DTI) outcomes revealed poorer performance in the COPD group (p < 0.0001). The fear of falling (FES-I) was increased in the COPD group. There was a significant positive correlation between DTI TUG and FES-I (r = 0.35, p = 0.01) and a negative correlation between DTI SLS and BBS (r = -0.41, p = 0.005) in the COPD group.

CONCLUSION

The study reveals significant impairments in DTI and balance among patients with severe COPD. Patients with severe COPD performed worse in tests involving dual tasks. They had poorer balance overall compared to healthy controls, with longer times for the dual Timed Up and Go test and shorter times for the SLS test, indicating a higher susceptibility to DTI and a greater fear of falling.