Influence of a Dual-Task on Toe Clearance of the Young and Elderly While Stepping Over an Obstacle

The effect of visual sensory interference during multitask obstacle crossing in younger and older adults

When older adults step over obstacles during multitasking, their performance is impaired; the impairment results from central and/or sensory interference. The purpose was to determine if sensory interference alters performance under low levels of cognitive, temporal, and gait demand, and if the change in performance is different for younger versus older adults. Participants included 17 younger adults (20.9±1.9 years) and 14 older adults (69.7±5.4 years). The concurrent task was a single, simple reaction time (RT) task: depress button in response to light cue. The gait task was stepping over an obstacle (8 m walkway) in three conditions: (1) no sensory interference (no RT task), (2) low sensory interference (light cue on obstacle, allowed concurrent foveation of cue and obstacle), or (3) high sensory interference (light cue away from obstacle, prevented concurrent foveation of cue and obstacle). When standing, the light cue location was not relevant (no sensory interference). An interaction (sensory interference by task, p<0.01) indicated that RT was longer for high sensory interference during walking, but RT was not altered for standing, confirming that sensory interference increased RT during obstacle approach. An interaction (sensory interference by age, p<0.01) was observed for foot placement before the obstacle: With high sensory interference, younger adults placed the trail foot closer to the obstacle while older adults placed it farther back from the obstacle. The change increases the likelihood of tripping with the trail foot for younger adults, but with the lead limb for older adults. Recovery from a lead limb trip is more difficult due to shorter time for corrective actions. Overall, visual sensory interference impaired both RT and gait behavior with low levels of multitask demand. Changes in foot placement increased trip risk for both ages, but for different limbs, reducing the likelihood of balance recovery in older adults.

The interactive effect of cognitive and physical dual task interventions on obstacle negotiation while walking in healthy young, and older, adults

Context

Dual task performance affects obstacle crossing ability in older adults. Previous studies suggest that cognitive dual tasking can lead to changes in obstacle crossing performance in older adults, but there is a lack of evidence to support changes in obstacle crossing performance due to the influence of motor dual tasking.

Aims

To investigate the interaction of cognitive and motor tasks, on obstacle crossing performance, in healthy young and older adults.

Settings and Design

This is a cross sectional comparative study, conducted at Mae Fah Luang University, Thailand.

Methods and Material

Sixty-four participants performed an obstacle crossing task under three conditions during a 4-meter walk test. These included walking at their normal speed with an obstacle in the middle of the walkway, followed by 2 further order-randomized walking conditions comprising a cognitive and a motor dual tasking walking condition. The spatio-temporal gait variables and obstacle crossing kinematic variables were measured using a Kinect three-camera system.

Statistical Analysis Used

The means for each variable, and for each condition, were analyzed using a mixed model analysis of variance (ANOVA) with walking conditions as covariant factors.

Results

A significant main interaction effect was found in gait speed (P < 0.001), step length (P = 0.046) and cadence (P = 0.011), but there was only a significant between-group difference in step length during obstacle crossing, while performing a cognitive dual task (P = 0.008) and a motor dual task (P < 0.001).

Conclusions

Older adults adopted a conservative strategy, and walked with a shorter step length, when stepping over an obstacle while performing a dual task.

Strategies for obstacle crossing in older adults with high and low risk of falling

[Purpose] Tripping is a frequent cause of falls among aging adults. Appropriate limb movements while negotiating obstacles are critical to trip avoidance. The aim of our study was to investigate the mechanics of obstacle crossing in older adults at low or high risk of falling. [Subjects and Methods] Twenty community-dwelling adults aged ≥55 years, were evaluated with the Tinetti Balance and Gait scale and classified as being at high or low risk of falling. Between-group comparisons of kinematics were evaluated for obstacle heights of 10%, 20%, and 30% of leg length. [Results] The high-risk group demonstrated greater toe-obstacle clearance of the leading leg. Increasing obstacle height led to increased maximal toe-obstacle clearance, toe-obstacle distance, and shortened swing phase of the leading limb. Adaptation of clearance height was greater for the trailing leg. Individuals at high risk of falling demonstrated less symmetry between the leading and trailing legs and a narrower step width, features that increase the likelihood of tripping. [Conclusion] Kinematic parameters of obstacle clearance, including the symmetry index described in our study, could provide clinicians with a quick screening tool to identify patients at risk of falling and to evaluate outcomes of training programs.

Does physical exercise improve obstacle negotiation in the elderly? A systematic review

BACKGROUND

Physical exercise improves walking in the elderly but much less is known about its effect on more challenged gait, such as obstacle negotiation. We conducted a systematic review to discuss the effects of regular physical exercise on kinematics and kinetics of obstacle negotiation in the elderly.

METHODS

A comprehensive literature search revealed 859 citations for review, whereof 206 studies entered the full-text analysis. After application of inclusion and exclusion criteria, 13 studies were included in this systematic review.

FINDINGS

Most of them presented a reasonable quality (average 0.68) but none of them reached the level of a randomized control trial. Interventions were heterogeneous, with training periods lasting from 5 days to 10 months. Studies assessed obstacle negotiation basically considering 3 types of testing paradigm, namely a walkway with either a single obstacle crossing, or with multiple obstacles, or else a treadmill with an obstacle avoidance task under time pressure.

INTERPRETATION

In general, longer training programs had better results and very short ones were not effective. A weekly frequency of 2-3 times was the most common among the studies showing positive effects. Regardless of exercises types performed, most of them were effective and so far, there is no consensus about the best exercise for improving obstacle negotiation. A lack of studies on this topic still is evident. Including a record of fall score can further help in deciding which programs are to be preferred.

Effects of regular exercise and dual tasking on spatial and temporal parameters of obstacle negotiation in elderly women

This study investigated the effects of regular exercise and dual tasking on bilateral spatial and temporal parameters of obstacle negotiation in elderly women. Sedentary (n=12) and physically active (n=12) elderly women volunteered to participate in this study. Gait kinematics were recorded during obstacle crossing when performing a dual task and when not performing a dual task. Physically active participants crossed obstacles more safely, in terms of clearance or distance to or over the obstacle, both with and without dual tasking, and usually for both lead and trail legs. Performing the dual task increased toe distance, and decreased heel distance and gait speed in the active participants, and increased toe clearance and heel distance, and decreased gait speed in the sedentary participants. Differences between preferred and non-preferred leg were accentuated for toe clearance in the lead limb. These results suggest that specialized exercises may not be needed for improvement in obstacle avoidance skills in the elderly, and participation in multi-activities, including aerobic exercises, may be sufficient.