The effects of aging on visuomotor coordination and proprioceptive function in the upper limb

Assessing proprioceptive acuity in people with multiple sclerosis

Background

Proprioceptive acuity and impairments in proprioceptively guided reaches have not been comprehensively examined in people with multiple sclerosis (MS).

Objective

To examine proprioceptive acuity in people with MS who self-report and who do not self-report upper limb (UL) impairment, and to determine how people with MS reach proprioceptive targets.

Methods

Twenty-four participants with MS were recruited into two groups based on self-reported UL impairment: MS-R (i.e. report UL impairment; n  =  12) vs. MS-NR (i.e. do not report UL impairment; n  =  12). Proprioception was assessed using ipsilateral and contralateral robotic proprioceptive matching tasks.

Results

Participants in the MS-R group demonstrated worse proprioceptive acuity compared to the MS-NR group on the ipsilateral and contralateral robotic matching tasks. Analyses of reaches to proprioceptive targets further revealed that participants in the MS-R group exhibited deficits in movement planning, as demonstrated by greater errors at peak velocity in the contralateral matching task in comparison to the MS-NR group.

Conclusion

Our findings suggest that people with MS who self-report UL impairment demonstrate worse proprioceptive acuity, as well as poorer movement planning in comparison to people with MS who do not report UL impairment.

The Effects of a Virtual Reality Rehabilitation Task on Elderly Subjects: An Experimental Study Using Multimodal Data

Ageing populations are becoming a global issue. Against this background, the assessment and treatment of geriatric conditions have become increasingly important. This study draws on the multisensory integration of virtual reality (VR) devices in the field of rehabilitation to assess brain function in young and old people. The study is based on multimodal data generated by combining high temporal resolution electroencephalogram (EEG) and subjective scales and behavioural indicators reflecting motor abilities. The phase locking value (PLV) was chosen as an indicator of functional connectivity (FC), and six brain regions, namely LPFC, RPFC, LOL, ROL, LMC and RMC, were analysed. The results showed a significant difference in the alpha band on comparing the resting and task states in the younger group. A significant difference between the two states in the alpha and beta bands was observed when comparing task states in the younger and older groups. Meanwhile, this study affirms that advancing age significantly affects human locomotor performance and also has a correlation with cognitive level. The study proposes a novel accurate and valid assessment method that offers new possibilities for assessing and rehabilitating geriatric diseases. Thus, this method has the potential to contribute to the field of rehabilitation medicine.

Change in the Results of Motor Coordination and Handgrip Strength Depending on Age and Body Position-An Observational Study of Stroke Patients and Healthy Volunteers

Objective: The stroke is considered a common disease of the elderly. Young people also get sick, but the risk of stroke increases with the age of 60. Stroke, regardless of the age of the patients, causes functional deficits; therefore, the aim of the study was to analyze the significance of the body position and examined upper limb on the parameters of motor coordination and handgrip strength in various age groups of people after stroke and healthy people. Material and method: This is an observational study. A total of 117 people participated in the study (60 stroke patients and 57 healthy people without neurological disorders). Both patients and healthy volunteers were prospectively divided into three age groups: 18−45, 46−60, and 61+. The tests were carried out in two starting positions: sitting without back support and lying on the back with the upper limb stabilized against the body. HandTutorTM and a hand dynamometer were used to assess the motor coordination, including the maximum range of motion and frequency of movement, as well as the grip strength. Results: The passive stabilization of the trunk and shoulder improved the maximum wrist ROM (p < 0.001) and frequency of finger movements (Hz F5 p = 0.018; F3 p = 0.010; F2 p = 0.011), especially in the oldest stroke patients. In the group of healthy volunteers, the most statistically significant results were obtained in the age range of 46−60. They occurred in both stable (wrist maxROM p = 0.041 and Hz F5 p = 0.034; Hz F4 p = 0.010; Hz F3 p = 0.028; Hz F1 p = 0.034, maxROM F1 p = 0.041) and unstable positions (maxROM F5 p = 0.034; maxROM F4 p = 0.050; maxROM F3 p = 0.002; maxROM F2 p = 0.002). In the group of the oldest healthy people, only one significant result was obtained in the stable position (Hz F3 p = 0.043). Conclusion: Passive stabilization of the trunk and examined upper limb improves the results of motor coordination of the distal part of the upper limb in both study groups. Passive stabilization of the trunk and upper limb improves motor coordination, especially in the oldest group of patients, after stroke.

Straying Off Course: The Negative Impact of Mind Wandering on Fine Motor Movements

The goal of this study was to examine how various degrees of perceptual decoupling during mind wandering affect fine motor control. We hypothesized that while under normal circumstances attention ensures an optimal control strategy that leads to accurate motor performance, during mind wandering the process becomes disrupted. In this study, we conducted a computer-based experiment with a tracking task. During mind wandering, motor movements were more erratic and less variable, indicative of reduced attentiveness to the continuous demands of the external task. Importantly, the deeper the reported mind wandering, the less accurate and less variable were the mouse movements, suggesting that perceptual decoupling may take place in a graded rather than in an all or nothing manner. Greater movement intermittency was associated with higher tracking accuracy, suggesting that more corrective movements toward a moving target were functional to task performance. Moreover, greater variance in velocity was negatively correlated with tracking accuracy. These findings suggest that periods of inattention to the task have a negative impact on fine motor movement control by making behavior unpredictable, providing support for the idea that there is a decoupling of sensory-motor processes during mind wandering.

Cognitive, Motor and Social Factors of Music Instrument Training Programs for Older Adults' Improved Wellbeing

Given emerging evidence that learning to play a musical instrument may lead to a number of cognitive benefits for older adults, it is important to clarify how these training programs can be delivered optimally and meaningfully. The effective acquisition of musical and domain-general skills by later-life learners may be influenced by social, cultural and individual factors within the learning environment. The current study examines the effects of a 10-week piano training program on healthy older adult novices' cognitive and motor skills, in comparison to an inactive waitlisted control group. Fifteen participants completed piano training led by a music facilitator in small groups (max n = 4 per lesson class; two experimental, two waitlisted control groups). Data was collected using an explanatory sequential design: quantitative data from a battery of cognitive and motor tests was collected pre/post-test on all participants, with further post-test data from the waitlisted control group (n = 7). Qualitative data included weekly facilitator observations, participant practice diaries, and an individual, semi-structured, post-experiment interview. Bayesian modelling demonstrated moderate evidence of a strong positive impact of training on part A of the Trail Making test (TMT), indicating improved visuo-motor skills. Moderate evidence for negative impacts of training on part B of the Trail Making Test (and difference score delta) was also found, suggesting no benefit of cognitive switching. Qualitative results revealed that the group learning environment motivated participants to play in musical ensembles and to socialize. Motivation was optimal when all participants were happy with the chosen repertoire (participants reported they were motivated by learning to play familiar music) and when the facilitator observed that groups had formed cohesive bonds. Informed by these factors, exploratory analyses demonstrated strong evidence that a participant's lesson class had an impact on post-test scores (TMT part A). These results not only demonstrate the extent of cognitive benefits of a short-term piano training intervention for older adults, but also the importance of considering the group dynamics in the learning environment.

Effects of Simulated Horseback Riding on Balance, Postural Sway, and Quality of Life in Older Adults With Parkinson's Disease

The purpose of this study was to determine changes in balance, postural sway, and quality of life after 6 wk of simulated horseback riding in adults diagnosed with Parkinson's disease. Eight older adults completed two 60-min riding sessions weekly for 6 wk. Variables of balance, postural sway, and quality of life were measured 6 wks before and within 1 wk before and after the intervention. Berg Balance Scale scores decreased from baseline to preintervention (48.36 ± 5.97 vs. 45.86 ± 6.42, p = .050) and increased from preintervention to postintervention (45.86 ± 6.42 vs. 50.00 ± 4.38, p = .002). Cognitive impairment, a dimension of quality of life, improved from baseline to postintervention (37.5 ± 20.5 vs. 21.5 ± 14.4, p = .007). Six weeks of simulated horseback riding may improve balance and cognitive impairment in older adults with Parkinson's disease.

The influence of bowling velocity on movement variability in experienced older aged lawn bowlers

OBJECTIVES

This project examined the movement strategies adopted by highly experienced older aged lawn bowlers when performing Draw and Drive deliveries.

DESIGN

Cross-sectional.

METHODS

Twenty five experienced (10.2 ± 7.8 years) older aged lawn bowlers (67.3 ± 7.0 years) who play lawn bowls at least once per week volunteered to participate in this study. Participants performed 10 Draw and Drive deliveries at a target positioned 23 m away while standing on two force platforms (600 Hz), while an infrared motion capture system (200 Hz) recorded phases times and both foot and bowl positioning. Normalised root mean square (NoRMS) analyses was used to assess the bowl path consistency during the delivery phase. Correlation analyses assessed for relationships between age and experience and the spatiotemporal variables, with paired t-tests and effect size (ES) analyses used to examine differences between delivery types.

RESULTS

None of the spatiotemporal or NoRMS data achieved more than low correlations with either age or playing experience (R² < 0.2). Although bowl release velocities were significantly slower for the Draw 5.25 ± 0.72 m/s than for the Drive deliveries 6.40 ± 0.97 m/s (p < 0.001, ES = 1.96) there were limited changes in any of the spatiotemporal variables. NoRMS data remained largely unchanged between Draw (5.10 ± 1.65) and Drive (5.07 ± 1.49, p = 0.925, ES = 0.02) deliveries.

CONCLUSIONS

These highly experienced lawn bowlers are adapting their technique to the different task demands of the two delivery types without altering their specific movement strategies.

A Simple Target Interception Task as Test for Activities of Daily Life Performance in Older Adults

Previous research showed that a simple target interception task reveals differences between younger adults (YA) and older adults (OA) on a large screen under laboratory conditions. Participants intercept downward moving objects while a horizontally moving background creates an illusion of the object moving in the opposite direction of the background. OA are more influenced by this illusory motion than YA. OA seem to be less able to ignore irrelevant sensory information than YA. Since sensory integration relates to the ability to perform Activities of Daily Living (ADL), this interception task can potentially signal ADL issues. Here we investigated whether the results of the target interception task could be replicated using a more portable setup, i.e., a tablet instead of a large touch screen. For YA from the same, homogeneous population, the main effects were replicated although the task was more difficult in the tablet set-up. After establishing the tablet's validity, we analyzed the response patterns of OA that were less fit than the OA in previous research. We identified three different illusion patterns: a (large) illusion effect (indicating over integration), a reverse illusion effect, and no illusion effect. These different patterns are much more nuanced than previously reported for fit OA who only show over integration. We propose that the patterns are caused by differences in the samples of OA (OA in the current sample were older and had lower ADL scores), possibly modulated by increased task difficulty in the tablet setup. We discuss the effects of illusory background motion as a function of ADL scores using a transitional model. The first pattern commences when sensory integration capability starts to decrease, leading to a pattern of over-integration (illusion effect). The second pattern commences when compensatory mechanisms are not sufficient to counteract the effect of the background motion, leading to direction errors in the same direction as the background motion (reverse illusion). The third pattern commences when the task requirements are too high, leading OA to implement a probabilistic strategy by tapping toward the center of the screen.

Myocontrol is closed-loop control: incidental feedback is sufficient for scaling the prosthesis force in routine grasping

BACKGROUND

Sensory feedback is critical for grasping in able-bodied subjects. Consequently, closing the loop in upper-limb prosthetics by providing artificial sensory feedback to the amputee is expected to improve the prosthesis utility. Nevertheless, even though amputees rate the prospect of sensory feedback high, its benefits in daily life are still very much debated. We argue that in order to measure the potential functional benefit of artificial sensory feedback, the baseline open-loop performance needs to be established.

METHODS

The myoelectric control of naïve able-bodied subjects was evaluated during modulation of electromyographic signals (EMG task), and grasping with a prosthesis (Prosthesis task). The subjects needed to activate the wrist flexor muscles and close the prosthesis to reach a randomly selected target level (routine grasping). To assess the baseline performance, the tasks were performed with a different extent of implicit feedback (proprioception, prosthesis motion and sound). Finally, the prosthesis task was repeated with explicit visual force feedback. The subjects' ability to scale the prosthesis command/force was assessed by testing for a statistically significant increase in the median of the generated commands/forces between neighboring levels. The quality of control was evaluated by computing the median absolute error (MAE) with respect to the target.

RESULTS

The subjects could successfully scale their motor commands and generated prosthesis forces across target levels in all tasks, even with the least amount of implicit feedback (only muscle proprioception, EMG task). In addition, the deviation of the generated commands/forces from the target levels decreased with additional feedback. However, the increase in implicit feedback, from proprioception to prosthesis motion and sound, seemed to have a more substantial effect than the final introduction of explicit feedback. Explicit feedback improved the performance mainly at the higher target-force levels.

CONCLUSIONS

The study establishes the baseline performance of myoelectric control and prosthesis grasping force. The results demonstrate that even without additional feedback, naïve subjects can effectively modulate force with good accuracy with respect to that achieved when increasing the amount of feedback information.

Effect of Taichi Softball on Function-Related Outcomes in Older Adults: A Randomized Control Trial

The purpose of this present study was to examine the effect of Taichi softball (TCSB) on physical function in Chinese older adults. Eighty Chinese older adults were randomly assigned into either an experimental group experiencing four 90-minute TCSB sessions weekly for seven consecutive weeks or a control group. At baseline and 7 weeks later, all participants were asked to perform physical functional tests for both lower and upper limbs. Multiple separate Analyses of Variance (ANOVA) with repeated measures were applied to evaluate the effects of TCSB on function-related outcomes between baseline and postintervention in the two groups. The findings indicate that a short-term and intensive TCSB training program does not only improve low limb-related physical function such as dynamic balance and leg strength, but also strengthen upper limb-related physical function (e.g., arm and forearm strength, shoulder mobility, fine motor control, handgrip strength, and fine motor function). Health professionals could take into account TCSB exercise as an alternative method to help maintain or alleviate the inevitable age-related physical function degeneration in healthy older adults. In addition, researchers could investigate the effect of TCSB exercise on physical function in special populations such as patients with different chronic diseases or neurological disorder (e.g., Parkinson's disease).

Influence of age and cognitive performance on resting-state brain networks of older adults in a population-based cohort

Aging leads to global changes in brain structure and cognitive performance, with reorganization of functional brain networks. Importantly, these age-related changes show higher inter-individual variability in older subjects. To particularly address this variability is a challenge for studies on lifetime trajectories from early to late adulthood. The present study therefore had a dedicated focus on late adulthood to characterize the functional connectivity in resting-state networks (RSFC) in relation to age and cognitive performance in 711 older adults (55-85 years) from the 1000BRAINS project. The executive, left and right frontoparietal resting-state (RS) networks showed age-related increases in RSFC. However, older adults did not show changes in RSFC in the default mode network (DMN). Furthermore, lower performance in working memory (WM) was associated with higher RSFC in the left frontoparietal RS network. The results suggest age-related compensatory increases in RSFC which might help to maintain cognitive performance. Nevertheless, the negative correlation between RSFC and WM performance hints at limited cognitive reserve capacity in lower performing older adults. Consequently, the current results provide evidence for a functional reorganization of the brain until late adulthood that might additionally explain parts of the variability of cognitive abilities in older adults.

Regional cerebellar volumetric correlates of manual motor and cognitive function

Cerebellar volume declines with aging. Few studies have investigated age differences in regional cerebellar volume (RCV) and their association with motor and cognitive function. In 213 healthy older adults, we investigated the association of age with motor skills, cognition and RCV. Subsequently, we studied the association of RCV with motor skills and cognition. RCVs were derived from T1-weighted MRI scans using the automated SUIT segmentation method and clustered using principal component analysis (PCA). Motor skill (manual dexterity, tapping speed, bimanual visuomotor coordination, grip force) and cognition (mental rotation, verbal memory, inhibition, mental flexibility) were assessed. Behavioral measures were clustered into compounds using PCA: left hand motor skill, right hand motor skill, verbal memory and mental flexibility, and mental rotation & inhibition. Volume of the rostral middle frontal gyri (rMFG) and premotor areas (PMA) were related to performance for reference. Analyses were adjusted for age, sex, and education. Volume of the cerebellar anterior lobe and top of the superior posterior lobe were positively associated with motor skill. Volume of the bottom part of the posterior superior lobe and the inferior posterior lobe was positively associated with cognition. PMA volume was associated with cognition and motor skill and rMFG volume with motor skill. Although these results did not survive FDR correction, their effect sizes suggest that regional cerebellar volume selectively contributes to cognitive and motor skill. Effect sizes of cerebellar associations with performance were similar to those of rMFG/PMA and performance suggesting parallel contributions to performance.

The effect of intervention according to muscle contraction type on the cerebral cortex of the elderly

[Purpose] Here we investigated the activity of the cerebral cortex after resistance training in the elderly. We evaluated the clinical neuropsychological basis of 2 contractile types, and determined the usefulness of a movement-related cortical potential (MRCP) from an electroencephalography (EEG). [Subjects and Methods] The subjects were 11 females and 11 males aged between 65 and 70 years. The subjects were randomly assigned into a group that performed an eccentric contraction exercise (experimental group I, n=11) and a group that performed a concentric contraction exercise (experimental group II, n=11). We measured activities of the rectus femoris, vastus medialis, and vastus lateralis in the non-dominant lower extremity by using surface electromyography (EMG), and measured brain activity using EEG before conducting an intervention. An intervention was conducted 40 minutes per session, once a day, 3 times a week for 4 weeks. [Results] After the intervention, activity in C4, the Cz area and rectus femoris were significantly different. [Conclusion] Our results demonstrate that MRCP from an EEG has the advantage of being non-invasive and cost-effective. Nonetheless, prospective studies are needed to reveal the specific mechanism underlying eccentric contraction exercise, which can provide baseline data for research related to aging and neural plasticity.

Age-related differences in control of a visuomotor coordination task: a preliminary study

[Purpose] The purpose of the current study was to examine age-related differences in control of a perception-action coordination skill. We adapted a visuomotor tracking experiment requiring various coordination patterns between a limb’s motion and an external signal. [Subjects and Methods] A total of 12 subjects (6 elderly and 6 young) voluntarily participated in the study. The experimental session consisted of 3 trials for 3 different relative phase patterns: 0°, 90°, and 180°, defined by the relationship between the online visual feedback of the joystick motion and the white dot signal. [Results] The 0° and 180° tracking patterns were stable compared with the 90° tracking pattern for both age groups. The present results also showed that the elderly subjects were less stable than were young subjects for all tracking patterns. [Conclusion] The intrinsic coordination dynamics predicted by the Haken-Kelso-Bunz (HKB) mathematical model did not change with age, whereas utilization of visual feedback information declined overall. Further research is needed regarding methods for increasing utilization of visual feedback information from the perspective of rehabilitation.

Relationship between visuo-perceptual function and manual dexterity in community-dwelling older adults

[Purpose] The purpose of the present study was to examine the relationship between visual perceptual function and manual dexterity in community-dwelling older adults. [Subjects and Methods] Fifty-eight participants were recruited by convenience sampling from local rehabilitation centers. This was a cross-sectional study that used the following four clinical tools: the Mini-Mental State Examination, 9 Hole Pegboard, Box and Block Test, and Motor-free Visual Perception Test, Third Edition. [Results] The Motor-free Visual Perception Test, Third Edition and Mini-Mental State Examination correlated significantly and positively with Box and Block Test, and did correlate significantly and negatively with 9 Hole Pegboard. [Conclusion] The results of this study suggest that visual perceptual impairment and cognitive dysfunction may influence manual dexterity in older adults, and rehabilitation of upper extremity function, along with visual perception and cognitive training, may be beneficial for this population.

Using Nonlinear Tools to Evaluate Movement of Fragile Objects

We investigated the movement strategies of young, healthy participants (7 men/7 women) during the movement of a fragile object using nonlinear analysis. The kinematic variables of position, velocity, and acceleration were quantified using largest Lyapunov exponent (LyE) and approximate entropy (ApEn) analysis to identify the structure of their movement variability and movement predictability, respectively. Subjects performed a total of 15 discrete trials of an upper extremity movement task without crushing the object at each fragility condition, using each hand (left/right). We tested four fragility conditions hypothesizing that an increase in fragility would result in higher movement predictability and decreased temporal variability. Comparisons between the structure of movement variability and movement predictability were based on fragility condition, handedness, and kinematic measures. In this specific population, object fragility and participant handedness did not significantly impact the structure of movement variability (LyE) in the primary direction of movement (Z direction), although some effects were observed in the anterior/posterior directions. ApEn values were minimized across conditions, showing increased movement predictability, and is suggested for the analysis of discrete kinematic movements. In healthy populations, the results of this study suggest minimal effects on task performance and movement predictability as a result of object fragility.