Temporal characteristics of imagined and actual walking in frail older adults

Older adults do not consistently overestimate their action opportunities across different settings

Am I still able to climb the ladder? Aging accompanies changes in physical constitution and a higher risk of injuries. At the same time, the judgment of action opportunities needs to be highly adaptive to the given task setting. We examined older adults' (n = 40) judgment tendencies in four different tasks by use of a detection theory approach. The tasks' setting differed in their boundaries' proximity to the actor with either proximal (e.g., judging one's hand fit into an opening) or distal boundaries (e.g., judging the reachability of a distant object). The older participants showed significantly more liberal judgments in tasks with distal boundaries. Body awareness and alertness were associated with the extent of judgment disparity between setting types. Subsequently, we compared a gender- and education-matched subsample of the group (n = 24) to a younger sample (n = 24). Older participants' judgment tendencies were significantly more extreme, with stronger under- or overestimations depending on the type of setting. We discuss potential links between more extreme judgments in older adults and higher reliance on learned patterns. Future research is needed to further unravel these setting-dependent behavioral differences and the factors contributing to more extreme judgment tendencies with growing age.

Motor imagery does not effectively improve walking-related performance in older adults: A randomised controlled trial

BACKGROUND

Inaccurate perception of one's physical abilities is potentially related to age-related declines in motor planning and can lead to changes in walking. Motor imagery training is effective at improving balance and walking in older adults, but most research has been conducted on older adults following surgery or in those with a history of falls. Deficits in motor imagery ability are associated with reduced executive function in older adults with cognitive impairment.

OBJECTIVES

To determine whether walking-specific motor imagery training could improve walking performance (physical and imagined) in healthy older adults, and identify the relationship between actual and imagined movement, motor imagery accuracy and executive function across 5 different walking tasks in healthy older adults.

METHODS

A cohort of 53 community dwelling older adults took part in a 4-wk randomized controlled trial to assess the effect of motor imagery training on the physical and imagined performance of 5 walking-related tasks (3 narrow path walking tasks, Timed-up and go and step-over test), together with motor imagery clarity using the kinesthetic and visual imagery questionnaire (KVIQ-10). The association between physical performance, motor imagery accuracy and executive function were identified at baseline.

RESULTS

Four weeks of motor imagery training did not improve walking-specific performance (imagined or physical) compared to no-training. Motor imagery training did improve the visual clarity of imagined non-walking tasks. Executive function was significantly correlated with 2 out of 5 imagined walking tasks and 4 out of 5 physical walking tasks but was not associated with motor imagery accuracy.

CONCLUSION

Four weeks of motor imagery training is not effective at improving performance in walking-related tasks in healthy older adults. This lack of improvement may be due in part to the high functional ability of the cohort. Future research should assess the relationship between motor planning and executive function with more complex walking tasks.

TRIAL REGISTRATION

ANZCTR registration (ACTRN12619001784101).

Dissociation of perception and motor execution of lower limb in multi-directional movements

Estimating the action capability is vital for humans to move their bodies successfully. Researchers have proposed reachability as an overestimation of motor abilities by judging unreachable distances as reachable. The existing literature has mainly investigated the sagittal direction, but multi-directional reachability is unexplored. This study examined the relationship between perception and motor using the reaching of the lower limbs in multiple directions. We asked 16 adults to reach targets projected onto the floor at 21 locations (seven directions and three distances) to estimate the reaching time. We found that the reaching time slowed as the direction increased toward the contralateral side, but the subjective reaching time did not change with direction. Multiple regression analysis showed that the subjective reaching time could be calculated accurately, mainly using the duration from the toe leaving the ground to movement completion. These results suggest that changes in direction may not be perceived precisely by the motor system of the lower limbs and that the subjective reaching time was strongly affected by the time after the toe left the ground. Our findings provide novel insights into the relationship between motor and perception in multiple directions, which may provide a new strategy for the maximal performance of lower-limb movement.

The intrapersonal and interpersonal consequences of interpersonal synchrony

Interpersonal synchrony, the time-matching behaviors, is pervasive in human interactions. This resonation of movements or other forms was generally considered as one of critical survival skills for humans, as the important consequences of synchronizing with other persons in review of the empirical data in this article. These include positive affects towards and between interacting partners, but also include complex effects on the individual level. The intrapersonal effects of interpersonal synchrony are varied with positive or negative ones, including cognitive style, attitude bias, mood state, self-regulatory ability, and academic performance. At the interpersonal level, synchronized movement consistently affects the interaction with the partner and his/her affiliations, but they can be eliminated or magnified by several moderators, such as physiological arousal, shared intentionality, group bias, and musical rhythm. Finally, the research discussed the possible mechanisms underlying the effects of interpersonal synchrony in psychological and biological aspects.

Motor Imagery of Walking in People Living with and without Multiple Sclerosis: A Cross-Sectional Comparison of Mental Chronometry

Motor imagery represents the ability to simulate anticipated movements mentally prior to their actual execution and has been proposed as a tool to assess both individuals’ perception of task difficulty as well as their perception of their own abilities. People with multiple sclerosis (pwMS) often present with motor and cognitive dysfunction, which may negatively affect motor imagery. In this cross-sectional study, we explored differences in motor imagery of walking performance between pwMS (n = 20, age = 57.1 (SD = 8.6) years, 55% female) and age- and sex-matched healthy controls (n = 20, age = 58.1 (SD = 7.0) years, 60% female). Participants underwent mental chronometry assessments, a subset of motor imagery, which evaluated the difference between imagined and actual walking times across four walking tasks of increasing difficulty (i.e., large/narrow-width walkway with/without obstacles). Raw and absolute mental chronometry (A-MC) measures were recorded in single- (ST) and dual-task (DT) conditions. In ST conditions, pwMS had higher A-MC scores across all walking conditions (p ≤ 0.031, η² ≥ 0.119), indicating lower motor imagery ability compared to healthy controls. During DT, all participants tended to underestimate their walking ability (3.38 ± 6.72 to 5.63 ± 9.17 s). However, after physical practice, pwMS were less able to adjust their imagined walking performance compared to healthy controls. In pwMS, A-MC scores were correlated with measures of balance confidence (ρ = −0.629, p < 0.01) and the self-reported expanded disability status scale (ρ = 0.747, p < 0.01). While the current study revealed that pwMS have lower motor imagery of walking performance compared to healthy individuals, further work is necessary to examine how the disassociation between mental chronometry and actual performance relates to quality of life and well-being.

Increased Time Difference between Imagined and Physical Walking in Older Adults at a High Risk of Falling

Walking motor imagery ability is thought to be associated with a fear of falling; however, no studies have compared fall risk and motor imagery ability. This study aimed to ascertain the time difference between imagined and physical walking in older adults at low and high risks of falling. Motor imagery ability was assessed using mental chronometry, which measures the imagined time required for movement. Participants included 31 older adults classified as having a high (n = 15) or low (n = 16) risk of falling based on single leg stance time. The time required for imagined and physical walking was measured using 5 m long walkways with three different widths (15, 25, and 50 cm), and the temporal errors (absolute and constant error) were compared. Physical walking time was significantly longer in the high-risk group than in the low-risk group for the 15 and 25 cm wide walkways. The absolute error between the imagined and physical walking times was significantly larger in the high-risk group than in the low-risk group for the 15 and 25 cm wide walkways. There was also a significant difference in the constant error between the high- and low-risk groups between the imagined and physical walking times for all three walkways. Older adults who may be at a higher risk of falling showed longer walking times during action execution but overestimated their performance (i.e., they believe they would be faster) during motor imagery. Therefore, the time difference between imagined and physical walking could, in part, be useful as a tool for assessing fall risk based on motor imagery.