Age-related differences in functional tool-use are due to changes in movement quality and not simply motor slowing

Distal Versus Proximal Arm Improvement After Paired Vagus Nerve Stimulation Therapy After Chronic Stroke

OBJECTIVE

To evaluate differences in upper-extremity (UE) segment-specific (proximal or distal segment) recovery after vagus nerve stimulation (VNS) paired with UE rehabilitation (Paired-VNS) compared with rehabilitation with sham-VNS (Control). We also assessed whether gains in specific UE segments predicted clinically meaningful improvement.

DESIGN

This study reports on a secondary analysis of Vagus nerve stimulation paired with rehabilitation for UE motor function after chronic ischemic stroke (VNS-REHAB), a randomized, triple-blinded, sham-controlled pivotal trial. A Rasch latent regression was used to determine differences between Paired-VNS and Controls for distal and proximal UE changes after in-clinic therapy and 3 months later. Subsequently, we ran a random forest model to assess candidate predictors of meaningful improvement. Each item of the Fugl-Meyer Assessment-Upper Extremity (FMA-UE) and Wolf Motor Function Test (WMFT) was evaluated as a predictor of response to treatment.

SETTING

Nineteen stroke rehabilitation centers in the USA and UK.

PARTICIPANTS

Dataset included 108 participants (N=108) with chronic ischemic stroke and moderate-to-severe UE impairments.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

FMA-UE and WMFT.

RESULTS

Distal UE improvement was significantly greater in the Paired-VNS group than in Controls immediately after therapy (95% confidence interval, 0.27-0.73; P≤.001) and after 3 months (95% confidence interval, 0.16-0.75; P=.003). Both groups showed similar improvement in proximal UE at both time points. A subset of both distal and proximal items from the FMA-UE and WMFT were predictors of meaningful improvement.

CONCLUSIONS

Paired-VNS improved distal UE impairment in chronic stroke to a greater degree than intensive rehabilitation alone. Proximal improvements were equally responsive to either treatment. Given that meaningful UE recovery is predicted by improvements across both proximal and distal segments, Paired-VNS may facilitate improvement that is otherwise elusive.

The relationship between screen time and gross motor movement: A cross-sectional study of pre-school aged left-behind children in China

OBJECTIVE

To investigate the level of screen time and gross motor movement level and the correlation between them in left-behind children aged 3 to 6 years old in China.

METHODS

A randomized whole-group sampling method was used to study 817 left-behind children aged 3-6 years in 15 kindergartens in Xiangcheng city, Henan province. The third version of the Test of Gross Motor Development (TGMD-3) was used to test the children's gross motor movement level, and the screen time questionnaire was used to test the children's screen time level. The relationship between the two and the indicators was explored using Pearson's two-sided correlation and multilevel regression.

RESULTS

The average daily screen time of left-behind children aged 3-6 years old increased with age, and the reporting rate of >2 h/d ranged from 22.43% to 33.73%; gross motor movement of left-behind children aged 3-6 years old increased with age, with significant differences between age (p<0.05). There was a low to moderate negative correlation (r = -0.133 to -0.354, p<0.05) between screen time and gross motor movement in children aged 3-6 years, and multiple regression analysis showed that screen time was predictive of gross motor movement in children (p<0.05), with an explanation rate of 21.4%.

CONCLUSION

There is a correlation between screen time and gross motor movement development in children aged 3-6 years old left behind, and the gross motor movement ability of children aged 3-6 years old can be developed by reducing screen time and increasing physical activity.

Motor learning and performance in schizophrenia and aging: two different patterns of decline

Psychomotor slowing has consistently been observed in schizophrenia, however research on motor learning in schizophrenia is limited. Additionally, motor learning in schizophrenia has never been compared with the waning of motor learning abilities in the elderly. Therefore, in an extensive study, 30 individuals with schizophrenia, 30 healthy age-matched controls and 30 elderly participants were compared on sensorimotor learning tasks including sequence learning and adaptation (both explicit and implicit), as well as tracking and aiming. This paper presents new findings on an explicit motor sequence learning task, an explicit verbal learning task and a simple aiming task and summarizes all previously published findings of this large investigation. Individuals with schizophrenia and elderly had slower Movement Time (MT)s compared with controls in all tasks, however both groups improved over time. Elderly participants learned slower on tracking and explicit sequence learning while individuals with schizophrenia adapted slower and to a lesser extent to movement perturbations in adaptation tasks and performed less well on cognitive tests including the verbal learning task. Results suggest that motor slowing is present in schizophrenia and the elderly, however both groups show significant but different motor skill learning. Cognitive deficits seem to interfere with motor learning and performance in schizophrenia while task complexity and decreased movement precision interferes with motor learning in the elderly, reflecting different underlying patterns of decline in these conditions. In addition, evidence for motor slowing together with impaired implicit adaptation supports the influence of cerebellum and the cerebello-thalamo-cortical-cerebellar (CTCC) circuits in schizophrenia, important for further understanding the pathophysiology of the disorder.

Immersive Virtual Reality to Assess Arm Kinematics among Older Adults with and without Major Neurocognitive Disorder - An Exploratory Cross-Sectional Study

Despite the recommendation of improving assessment objectivity and frequency, the use of immersive virtual reality to measure and quantify movement quality remains underexplored. In this study, we aimed to evaluate the reliability, validity and usability of an immersive virtual reality application, KinematicsVR, to assess upper limb kinematics among older adults with and without major neurocognitive disorder. The KinematicsVR involves the drawing of three-dimensional straight lines, circles and squares using a controller in a virtual environment. Twenty-eight older adults with or without major neurocognitive disorder were recruited. Reliability was evaluated through correlations on test-retest and validity through correlations between KinematicsVR variables and other functional tests (TEMPA, BBT-VR and Finger-Nose Test). The usability of the KinematicsVR was assessed with the System Usability Scale questionnaire. Kinematic indexes were compared between eight adults with major neurocognitive disorder and eight matched controls. Results indicated that most variables provided by the KinematicsVR had excellent reliability for tasks involving the drawing of straight lines and circles, but moderate reliability for tasks involving the drawing of squares. Secondary analyses showed that the usability of the application was excellent but few significant and strong correlations were observed between variables of the KinematicsVR and the scores of the TEMPA scale, Finger-Nose Test and BBT-VR. Adults with major neurocognitive disorder, when compared to other older adults, made larger and less linear hand movements. These findings provide perspectives for the use of immersive virtual reality to improve assessment frequency and objectivity through the autonomous measure of upper limb kinematics in older adults.

Age-Related Differences in Motor Skill Transfer with Brief Memory Reactivation

Motor memories can be strengthened through online practice and offline consolidation. Offline consolidation involves the stabilization of memory traces in post-practice periods. Following initial consolidation of a motor memory, subsequent practice of the motor skill can lead to reactivation and reconsolidation of the memory trace. The length of motor memory reactivation may influence motor learning outcomes; for example, brief, as opposed to long, practice of a previously learned motor skill appears to optimize intermanual transfer in healthy young adults. However, the influence of aging on reactivation-based motor learning has been scarcely explored. Here, the effects of brief and long motor memory reactivation schedules on the retention and intermanual transfer of a visuomotor tracing task are explored in healthy older adults. Forty older adults practiced a virtual star-tracing task either three ("brief reactivation") or ten ("long reactivation") times per session over a two-week period. Comparison with a previously reported group of younger adults revealed significant age-related differences in the effect of the motor memory reactivation schedule on the intermanual transfer of the motor task. In older adults, unlike younger adults, no significant between-group differences were found by practice condition in the speed, accuracy, or skill of intermanual task transfer. That is, motor task transfer in healthy younger, but not older, adults appears to benefit from brief memory reactivation. These results support the use of age-specific motor training approaches and may inform motor practice scheduling, with possible implications for physical rehabilitation, sport, and music.

Mediation Analysis of the Effect of Visuospatial Memory on Motor Skill Learning in Older Adults

There is high inter-individual variability in motor skill learning among older adults. Identifying the nature of these individual differences remains challenging due to interactions between participant characteristics (e.g., age, cognition) and task-related factors (e.g., nature of task, level of skill pre-training), making it difficult to determine plausibly causal relationships. This study addresses these competing explanations by using mediation analysis to examine plausible causal inference between visuospatial memory and one-month retention of both gross and fine motor components of a functional upper-extremity task following training. Results suggest that better visuospatial memory results in more retention of fine but not gross motor skill, expanding on previous correlational studies in older adults and informing future interventions for maximizing motor learning in geriatric populations.