Gait performance of the elderly under dual-task conditions: Review of instruments employed and kinematic parameters

Effects of age, sex, frailty and falls on cognitive and motor performance during dual-task walking in older adults

BACKGROUND

Dual-task (DT) walking is of great interest in clinical evaluation to evaluate the risk of falling or cognitive declines in older adults. However, it appears necessary to investigate deeply the confounding factors to better understand their impact on dual-task performance.

OBJECTIVE

To evaluate the effect of age, sex, falls and frailty on cognitive and motor parameters in dual-task walking.

SUBJECTS

66 older participants (mean age = 75.5 ± 6.3; mean height = 165.8 ± 8.4 cm; mean weight = 68.4 ± 14 kgs) were split into groups based on their age, sex, fall and frailty status.

METHODS

Participants performed single-task walking, single-task cognitive (serial subtraction of 3), and dual-task walking (subtraction + walking) for 1 min at their fast pace. Gait speed, step length, step length variability, stance and swing phase time, single and double support, cadence, step time variability and gait speed variability were recorded in single- and dual-task walking and used to calculate the dual-task effect (DTE) as ((DT - ST) / ST) ∗ 100). The cognitive score (DTEcog) was calculated as the number of correct responses minus errors. Generalized linear mixed models (GLMM) were used to compare the effects of falls, frailty, age and sex on gait and cognitive variables.

RESULTS

The interaction frailty*sex and frailty*age were the major effect on the DTEs. Specifically, the DTE was higher in women than men and in the frail group compared to non-frail.

CONCLUSIONS

The present findings provide a better understanding on the confounding factors explaining the behavior in DT that could be used to develop more effective dual-task clinical programs for community-living older adults.

The effect of different dual tasks conditions on gait kinematics and spatio-temporal walking parameters in older adults

BACKGROUND

Dual-task (DT) walking has increasingly been investigated over the last decade because of its valuable role as a clinical marker of both cognitive impairment and fall risk in older adults based on cognitive and motor performance (DTEcog, DTEmotor). However, there is still a lack of information on what type of dual task to choose and which is the most adapted to the population of interest.

RESEARCH QUESTION

To evaluate the effect of different dual-tasks (DT3, DT7, FLU, STROOP) on the spatiotemporal and kinematic parameters of hip, knee, and ankle joints.

METHODS

Thirty-eight older adults were recruited (9 men, 29 women, mean age = 77.5 +/- 6.5 years, mean height = 163.6 +/- 8.6 cm, mean weight = 67.5 +/- 15.3 kg). They performed a single and dual-task walk with the 4 types of tasks during 1 min, equipped with an inertial system. Dual-task effect (DTE) on spatiotemporal and kinematic variables as well as cognitive score and speed were calculated.

RESULTS

An alteration in most of the spatiotemporal parameters was observed in each DT condition (p < 0.05), especially in arithmetic tasks (DT3, DT7), while no DT effect was noticed on kinematic parameters (RMSE<3°) except on hip and knee angular velocities (RMSE>15°). Arithmetic tasks seemed to alter more spatiotemporal and kinematic parameters than the verbal fluency or STROOP test. However, DT7 appeared to be too difficult for the population of interest.

SIGNIFICANCE

Arithmetic tasks seemed to be very pertinent as a clinical dual-task protocol for older adults. The use of an inertial system to retrieve kinematic variables is an improvement in these dual-task protocols.

Virtual functional mobility test: A potential novel tool for assessing mobility of individuals with Parkinson's disease in a multitask condition

There are few instruments available for evaluating functional mobility during multitasking in people with Parkinson's Disease (PD). Virtual Reality is a potentially tool capable of aiding in the evaluation of functional mobility. The purpose of this study is to verify the potential of the Virtual Functional Mobility Test (VFMT) as a clinical tool to assess functional mobility of people with PD during multitasking condition. 25 people with PD and 25 people without PD, matched for age and sex, were recruited. Participants were evaluated through the Trail Making Test, Timed "UP and GO" test, Timed "UP and GO" test in dual task condition and through the VFMT, composed of 1) a simple task, and 2) a complex task. The VFMT and clinical tests were sensitive to differentiate the groups, except the trail making test part B (p = 0.332) and complex task (p = 0.052). Strong correlations were observed between parts A and B of the trail making test (r = 0.75) and complex task (r = 0.72); Moderate correlations between Timed Up and Go test and Timed Up and Go test in dual task condition with simple task (r = 0.47) and complex task (r = 0.55), respectively, were found. The complex task and simple task showed excellent and moderate reliability intra-rater, respectively. It was concluded that the novel VFMT is feasible, sensible, reliable and has potential as an instrument for the evaluation of functional mobility during multitasking in people with PD.

Influence of Different Dual-Task Conditions During Straight or Curved Walking on Gait Performance of Physically Active Older Women With Cognitive Decline

Real-world walking requires shifting attention from different cognitive demands to adapt gait. This study aims to evaluate the effect of dual tasking on spatiotemporal gait parameters of older adults. Participants were asked to perform a primary complex single-walking task, consisting of a fast-paced linear and a curved gait. Primary task was performed separately and simultaneously with different motor and cognitive secondary tasks. Spatiotemporal gait parameters, walk ratio, and walk stability ratio were measured. Apart from stride length, which stood relatively unchanged, gait speed and cadence were strongly affected by cognitive dual tasking. Cadence seems to be the most impacted by dual tasking during curved gait as it combines challenges of both primary and secondary tasks. Also, during curved phase, walking ratio was significantly lower and stability ratio was greater demonstrating that participants adopted a cautious gait where maintenance of stability took preference over efficiency.

An interrater reliability study of gait analysis systems with the dual task paradigm in healthy young and older adults

Background and aims

One reason for the controversial discussion of whether the dual task (DT) walking paradigm has an added value for diagnosis in clinical conditions might be the use of different gait measurement systems. Therefore, the purpose was 1) to detect DT effects of central gait parameters obtained from five different gait analysis devices in young and old adults, 2) to assess the consistency of the measurement systems, and 3) to determine if the absolut and proportional DT costs (DTC) are greater than the system-measurement error under ST.

Methods

Twelve old (72.2 ± 7.9y) and 14 young adults (28.3 ± 6.2y) walked a 14.7-m distance under ST and DT at a self-selected gait velocity. Interrater reliability, precision of the measurement and sensitivity to change were calculated under ST and DT.

Results

An age effect was observed in almost all gait parameters for the ST condition. For DT only differences for stride length (p < .029, ɳ²_p = .239) as well as single and double limb support (p = .036, ɳ²_p = .227; p = .034, ɳ²_p = .218) remained. The measurement systems showed a lower absolute agreement compared to consistency across all systems.

Conclusions

When reporting DT effects, the real changes in performance and random measurement errors should always be accounted for. These findings have strong implications for interpreting DT effects.

The Effects of Transcranial Direct Current Stimulation on Dual-Task Interference Depend on the Dual-Task Content

Recently, some studies revealed that transcranial direct current stimulation (tDCS) reduces dual-task interference. Since there are countless combinations of dual-tasks, it remains unclear whether stable effects by tDCS can be observed on dual-task interference. An aim of the present study was to investigate whether the effects of tDCS on dual-task interference change depend on the dual-task content. We adopted two combinations of dual-tasks, i.e., a word task while performing a tandem task (word-tandem dual-task) and a classic Stroop task while performing a tandem task (Stroop-tandem dual-task). We expected that the Stroop task would recruit the dorsolateral prefrontal cortex (DLPFC) and require involvement of executive function to greater extent than the word task. Subsequently, we hypothesized that anodal tDCS over the DLPFC would improve executive function and result in more effective reduction of dual-task interference in the Stroop-tandem dual-task than in the word-tandem dual-task. Anodal or cathodal tDCS was applied over the DLPFC or the supplementary motor area using a constant current of 2.0 mA for 20 min. According to our results, dual-task interference and the task performances of each task under the single-task condition were not changed after applying any settings of tDCS. However, anodal tDCS over the left DLPFC significantly improved the word task performance immediately after tDCS under the dual-task condition. Our findings suggested that the effect of anodal tDCS over the left DLPFC varies on the task performance under the dual-task condition was changed depending on the dual-task content.

Autonomic Stress Response and Perceived Effort Jointly Inform on Dual Tasking in Aging

The study investigated, through neuroendocrinological, subjective and behavioral assessments, how aging individuals cope with locomotor-cognitive dual-tasking and whether physical activity habits influence the acute response to locomotor-cognitive performance. Seventy-nine healthy participants aged 55–85 years were assessed on locomotor (gait speed, stride length) and cognitive (working memory) performances under single- and dual-task (ST, DT) conditions, and habitual physical activity (daily steps). Rating of perceived exertion (RPE) was assessed immediately after performance. Salivary α-amylase (sAA) was measured prior, immediately and 5 min after performance. Gait and working memory variables, the area under the curve of sAA (AUC) and DT–ST differences (DT effects) were computed. AUC was higher when the ST or DT performance involved a locomotor component and showed a pre-to-post increment after DT only, whereas RPE was higher when performance involved a cognitive component. Daily steps neither predicted sAA, nor RPE. Associations between DT effects on sAA, RPE and performance emerged in high-active participants only. In aging individuals, DT walking elicits an autonomic stress response presumably led by the challenge to share resources relying upon common neural substrates. This autonomic response seems tuned to gait performance and subjective evaluation of effort in those more accustomed to walking.

How Older Adults Cope with Cognitive Complexity and Environmental Constraints during Dual-Task Walking: The Role of Executive Function Involvement

This cross-sectional study investigated the interactive dual-task (DT) effects of executive function demands and environmental constraints on older adults' walking and the moderating role of habitual physical activity (PA). Locomotor performance under different environmental constraints (flat versus obstructed walking) and cognitive performance with different executive function involvement (backward counting versus random number generation) were assessed under single-task (ST) and DT conditions in 135 participants (mean age 68.1 ± 8.4). The weekly number of daily steps was measured. Reciprocal DT effects of walking on cognitive performance and of the cognitive task on gait performance were computed and submitted to analyses of covariance with age, PA level, and cognitive functioning as covariates, followed by linear regressions with PA level as predictor. Cognitive task demands and environmental constraints individually and jointly affected gait variability (p = 0.033, ηp2 = 0.08) and executive function performance (p = 0.009, ηp2 = 0.09). Physical activity level predicted a low but significant percentage of variance of DT effects on gait only in flat walking (R2 = 0.04, p = 0.027). Results suggest that older individuals may adopt variable task prioritization in dual tasking depending on the type of executive function involvement and the environmental constraints on walking. Their DT ability was slightly affected by habitual PA.

Gait parameters in physically active and inactive elderly as well as young community-living people

BACKGROUND

This study aimed to reveal the effects of a complex exercise program on gait among older people through analyzing the gait parameters in three groups: 1) older individuals participating in complex exercise program called 60+; 2) older individuals who were physically inactive; and 3) young individuals.

METHODS

Fifty-seven community-living individuals were enrolled in this study. Variability of step length, step time, step width, and double support ratio as well as automaticity were measured.

RESULTS

We found that the variability of step length, step time, and double support ratio, as well as the cognitive automaticity index of physically inactive elderly individuals were significantly worse compared to both physically active elderly (step length P=0.007; step time P=0.002; double support ratio P=0.036; cognitive automaticity index P=0.006) and young individuals (step length P<0.001; step time P<0.001; double support ratio P=0.001; cognitive automaticity index P=0.003). However, the variability of gait step width did not differ among the three groups.

CONCLUSIONS

This study demonstrated that 60+ program has beneficial effects on gait parameters. Thus, the 60+ program can enrich the range of geriatric exercise programs aiming to improve gait safety.

Minimum toe clearance: probing the neural control of locomotion

Minimum toe clearance (MTC) occurs during a highly dynamic phase of the gait cycle and is associated with the highest risk of unintentional contact with obstacles or the ground. Age, cognitive function, attention and visual feedback affect foot clearance but how these factors interact to influence MTC control is not fully understood. We measured MTC in 121 healthy individuals aged 20–80 under four treadmill walking conditions; normal walking, lower visual field restriction and two Stroop colour/word naming tasks of two difficulty levels. Competition for cognitive and attentional resources from the Stroop task resulted in significantly lower mean MTC in older adults, with the difficult Stroop task associated with a higher frequency of extremely low MTC values and subsequently an increased modelled probability of tripping in this group. While older adults responded to visual restriction by markedly skewing MTC distributions towards higher values, this condition was also associated with frequent, extremely low MTC values. We reveal task-specific, age-dependent patterns of MTC control in healthy adults. Age-related differences are most pronounced during heavy, distracting cognitive load. Analysis of critically-low MTC values during dual-task walking may have utility in the evaluation of locomotor control and fall risk in older adults and patients with motor control deficits.