Poor estimates of motor variability are associated with longer grooved pegboard times for middle-aged and older adults

Sensory and motor deficits as contributors to early cognitive impairment

INTRODUCTION

Age-related sensory and motor impairment are associated with risk of dementia. No study has examined the joint associations of multiple sensory and motor measures on prevalence of early cognitive impairment (ECI).

METHODS

Six hundred fifty participants in the Baltimore Longitudinal Study of Aging completed sensory and motor function tests. The association between sensory and motor function and ECI was examined using structural equation modeling with three latent factors corresponding to multisensory, fine motor, and gross motor function.

RESULTS

The multisensory, fine, and gross motor factors were all correlated (r = 0.74 to 0.81). The odds of ECI were lower for each additional unit improvement in the multisensory (32%), fine motor (30%), and gross motor factors (12%).

DISCUSSION

The relationship between sensory and motor impairment and emerging cognitive impairment may guide future intervention studies aimed at preventing and/or treating ECI.

HIGHLIGHTS

Sensorimotor function and early cognitive impairment (ECI) prevalence were assessed via structural equation modeling. The degree of fine and gross motor function is associated with indicators of ECI. The degree of multisensory impairment is also associated with indicators of ECI.

Practice-Induced Changes in Manual Dexterity of Older Adults Depend on Initial Pegboard Time

INTRODUCTION

The purpose of our study was to determine the influence of practice on the pegboard times and peg-manipulation phases of older adults who were classified as having either slow or fast initial pegboard times.

METHODS

Participants ( n = 26, 70 ± 6.6 yr) completed two evaluation sessions and six practice sessions in which they performed 25 trials (5 blocks of 5 trials) of the grooved pegboard test. All practice sessions were supervised, and the time to complete each trial was recorded. In each evaluation session, the pegboard was mounted on a force transducer so that the downward force applied to the board could be measured.

RESULTS

Participants were stratified into two groups based on the initial time to complete the grooved pegboard test: a fast group (68.1 ± 6.0 s) and a slow group (89.6 ± 9.2 s). Both groups exhibited the classic two-phase profile (acquisition + consolidation) for learning a de novo motor skill. Despite the similar learning profile for the two groups, there were differences between groups in the phases of the peg-manipulation cycle that became faster with practice. The fast group seemed to reduce trajectory variability when transporting the peg, whereas the slow group seemed to exhibit both a decrease in trajectory variability and greater precision when inserting pegs into the holes.

CONCLUSIONS

The changes underlying practice-induced decreases in grooved pegboard time differed for older adults who initially had either a fast or a slow pegboard time.

Influence of transcutaneous electrical nerve stimulation on walking kinematics and standing balance of older adults who differ in walking speed

The purpose was to determine the impact of transcutaneous electrical nerve stimulation (TENS) on measures of walking kinematics and standing balance of healthy older adults who were stratified into two groups based on differences in the distance walked during the 6-min test of walking endurance. Regression models were developed to explain the variance in the 6-min distance and to assess the predictive power of balance metrics to categorize the 26 older adults (72 ± 5.4 yrs) as either slow or fast walkers. Walking kinematics were measured during 6- and 2-min walk tests that were performed with and without the concurrent application of TENS to the hip flexor and ankle dorsiflexor muscles. Participants walked briskly during the 6-min test and at a preferred pace during the 2-min test. The supplementary sensory stimulation provided by TENS did not alter the power of the models to explain the variance in the Baseline 6-min distance: Baseline, R² = 0.85; TENS, R² = 0.83. In contrast, TENS improved the explanatory power of the data obtained during the 2-min walk to account for the variance in the Baseline 6-min distance: no TENS, R² = 0.40; TENS, R² = 0.64. Logistic regression models based on force-plate and kinematic data obtained during the balance tasks were able to discriminate between the two groups with excellent certainty. The impact of TENS was greatest when older adults walked at a preferred speed but not when they walked at a brisk pace or performed tests of standing balance.

Optimizing Fine Motor Coordination, Selective Attention and Reaction Time in Children: Effect of Combined Accuracy Exercises and Visual Art Activities

Optimizing fine motor coordination and cognitive abilities in middle childhood through new intervention programs remains one of the most essential orientations in motor development and skills proficiency. The present study aims to identify the effect of a structure-based program intervention, combining motor accuracy exercises with visual art activities (ceramics, pottery, and creations using raw materials), on fine motor coordination, selective attention, and reaction time in middle childhood. Sixty, right-handed typically developed male schoolchildren (age = 8.29 ± 0.74 years; body height = 130.25 ± 0.05 cm and body mass = 29.83 ± 4.68 kg; mean ± SD) volunteered to participate in the study. They were randomly assigned to a combined group intervention (MG) receiving a mixed program integrating visual art activities and motor accuracy exercises; an accuracy group intervention (AG) receiving oriented motor accuracy exercises; and a control group (CG). Selective attention, reaction time, and fine motor coordination skills (accuracy: darts throw; manual dexterity: grooved pegboard test) were measured. Repeated measure ANOVA, one-way ANOVA, and Kruskal-Wallis ANOVA were performed for analysis. The results showed higher changes in MG compared to AG in manual dexterity (p < 0.001), in motor accuracy (p < 0.001), and in reaction time (p < 0.01), but not in selective attention (p = 0.379). In addition, higher changes were recorded in AG compared to CG in motor accuracy (p < 0.05), reaction time (p < 0.05), and in selective attention (p < 0.01), but not in manual dexterity (p = 0.082). The structured combined program best assists accuracy, manual dexterity, reaction time, and selective attention. Therefore, instructors in sports academies and teachers at schools are advised to use the combined program in the training sessions and in the non-curricular activities, respectively, to improve fine motor coordination, selective attention, and reaction time in middle childhood.

Upper Limb Kinematics of Handwriting among Children with and without Developmental Coordination Disorder

Background: Children with developmental coordination disorder (DCD) often experience difficulties with handwriting legibility and speed. This study investigates the relationship between handwriting and upper limb kinematics to characterize movement patterns of children with DCD and typically developing (TD) children. Methods: 30 children with and without DCD matched for age, gender, and parent education were compared across handwriting abilities using a standardized handwriting assessment of both copied and dictated tasks (A-A Handwriting). The 3D motion capture system (Qualysis) was used to analyze upper limb kinematics and characterize movement patterns during handwriting and contrasted with written output. Results: Children with DCD wrote fewer legible letters in both copying and dictation. Children with DCD also showed poor automatization of key writing concepts. Atypical wrist postures were associated with reduced legibility for children with DCD (F (1,27) 4.71, p = 0.04, p-η2 = 0.15); whereas for TD children, better legibility was associated with greater variations in movement speed, particularly of the wrist (rho = −0.578, p < 0.05). Conclusion: Results reflect different movement parameters influencing handwriting in children with DCD. An improved understanding of the movement characteristics during handwriting of these children may assist intervention design.

A Prototype of an Electronic Pegboard Test to Measure Hand-Time Dexterity with Impaired Hand Functionality

This paper proposes an electronic prototype of the Grooved Pegboard Test (GPT), which is normally used to test the presence of hand dexterity. The prototype imitates the geometrical dimensions of an on-the-market GPT device, but it is electronic, not manual like the one available now for users. The suggested electronic GPT device makes automated time calculation between placing the first and the last peg in their designated locations, instead of manually observing a stopwatch normally used during the GPT. The electronic GPT prototype consists of a fabricated wooden box, electronics (switches and microcontroller), and liquid crystal display (LCD). A set of 40 normal volunteers, 20 females and 20 males, tested the designed prototype. A set of six volunteers with chronic medical conditions also participated in evaluating the proposed model. The results on normal volunteers showed that the proposed electronic GPT device yielded time calculations that match the population mean value of similar calculations by the GPT device. The one-sample t-test showed no significant difference in calculations between the new electronic GPT and the manual GPT device. The p-value was much higher than 0.05, indicating the possible use of the suggested electronic GPT device.

Treatment with electrical stimulation of sensory nerves improves motor function and disability status in persons with multiple sclerosis: A pilot study

Declines in motor function are closely associated with decreases in sensory function in multiple sclerosis (MS). The purpose of our study was to assess the changes in motor function and disability status elicited by transcutaneous electrical nerve stimulation (TENS) to limb muscles of individuals with MS. Fifteen persons with MS and 11 age-matched healthy controls were evaluated before and after receiving 9 treatment sessions during which TENS was applied over the tibialis anterior and rectus femoris muscles of each leg, and over the median nerve and the thenar eminence of each hand. Each evaluation session involved completing two questionnaires (fatigue and walking limitations) and assessing walking performance (2-min test and 25-ft test), dynamic balance (chair-rise test), manual dexterity (grooved pegboard test), and muscle function of hands and legs (strength and force steadiness tests). The MS group exhibited improvements in the 25-ft test (P = 0.001), 2-min test (P = 0.002), chair-rise test (P = 0.008), grooved pegboard test (P = 0.008), and reductions in the self-reported levels of fatigue and walking limitation scores (P = 0.02, d = 0.52; P = 0.008, r = 0.50 respectively). In contrast, there were no statistically significant changes in the Control group. There were no significant changes in either muscle strength or force steadiness for either group. TENS elicited significant improvements in motor function and self-reported disability status in persons with MS. Some improvements reached clinically meaningful levels.

Characteristics of rectus femoris activation and rectus femoris-hamstrings coactivation during force-matching isometric knee extension in subacute stroke

The spectral properties of surface electromyographic (EMG) signal in the rectus femoris (RF) and the coactivation in the medial hamstrings (MH) were investigated in 45 stroke subjects (22 ± 12 days post-onset) and 30 age-matched healthy controls who performed unilateral knee extensions at maximum effort (100% MVC) and during 5-s force-matching tasks (10, 30, 50% MVC). The spectral properties were obtained through a power spectrum analysis based on Fast Fourier Transform. The coactivation was measured as the MH amplitude (%max) and MH/RF amplitude ratio. Force variability was expressed as the coefficient of variation. Both knee extensors and flexors were weaker in the paretic leg than the non-paretic and control legs (p < 0.001). A significantly higher relative power in the 5-13 and 13-30 Hz bands was found in the paretic than the non-paretic leg across all force levels (p ≤ 0.001) without changes in the 30-60 and 60-100 Hz bands or the mean and median frequencies. Regarding the antagonist coactivation, MH amplitude in the paretic leg was higher than in the non-paretic leg (submaximal levels, p < 0.0001) and the control leg (all force levels, p = 0.0005) with no differences between legs in the MH/RF ratio. The steadiness of the knee extension force was not related to the spectral properties of the agonist EMG or antagonistic coactivation. Greater coactivation was associated with weaker paretic knee flexors (p ≤ 0.0002). The overall results suggest variably altered agonist activation and antagonistic coactivation over the range of isometric knee extension contractions in subacute stroke.

Assessing Additional Characteristics of Muscle Function With Digital Handgrip Dynamometry and Accelerometry: Framework for a Novel Handgrip Strength Protocol

Maximal handgrip strength (HGS) is a convenient and reliable, but incomplete, assessment of muscle function. Although low HGS is a powerful predictor of poor health, several limitations to maximal HGS exist. The predictive value of HGS is restricted because low HGS is associated with a wide range of unspecified health conditions, and other characteristics of muscle function aside from strength capacity are not evaluated. Current HGS protocol guidelines emphasize the ascertainment of maximal force, which is only a single muscle function characteristic. Muscle function is intrinsically multivariable, and assessing other attributes in addition to strength capacity will improve screenings for age-related disabilities and diseases. Digital handgrip dynamometers and accelerometers provide unique opportunities to examine several aspects of muscle function beyond strength capacity, while also maintaining procedural ease. Specifically, digital handgrip dynamometry and accelerometry can assess the rate of force development, submaximal force steadiness, fatigability, and task-specific tremoring. Moreover, HGS protocols can be easily refined to include an examination of strength asymmetry and bilateral strength. Therefore, evaluating muscle function with new HGS technologies and protocols may provide a more comprehensive assessment of muscle function beyond maximal strength, without sacrificing feasibility. This Special Article introduces a novel framework for assessing multiple attributes of muscle function with digital handgrip dynamometry, accelerometry, and refinements to current HGS protocols. Such framework may aid in the discovery of measures that better predict and explain age-related disability, biological aging, and the effects of comorbid diseases that are amenable to interventions. These additional HGS measures may also contribute to our understanding of concepts such as resilience. Using sophisticated HGS technologies that are currently available and modernizing protocols for developing a new muscle function assessment may help transform clinical practice by enhancing screenings that will better identify the onset and progression of the disabling process.

Time spent on the smartphone does not relate to manual dexterity in young adults

Background

The Grooved Pegboard Test (GPT) is widely adopted to evaluate manual dexterity, it presents normative data but the test is influenced by different factors. The influence of time spent on smartphones has not been considered before, for this reason, the objective of this study was to evaluate if smartphone use influences the time to complete the GPT. A total of 38 (21 women; 17 men) young adults 20.7 (1.5) years participated in the study. The time spent on the smartphones during the last seven days was recorded through the device itself and the GPT performance was measured. A correlation analysis between the time spent on the smartphone and GPT was performed while the t-test was adopted to evaluate gender differences.

Results

No statistically significant differences were detected between men and women in the time to complete the GPT (p = 0.20) and in the time spent on the smartphone (p = 0.87). The GPT and the time spent using the smartphone were not correlated (r = 0.044, p = 0.78).

Conclusion

The time spent on the smartphone by young adults does not influence the time to complete the GPT, indicating that smartphone use does not influence measures of manual dexterity.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12868-021-00639-y.

Force Steadiness: From Motor Units to Voluntary Actions

Voluntary actions are controlled by the synaptic inputs that are shared by pools of spinal motor neurons. The slow common oscillations in the discharge times of motor units due to these synaptic inputs are strongly correlated with the fluctuations in force during submaximal isometric contractions (force steadiness) and moderately associated with performance scores on some tests of motor function. However, there are key gaps in knowledge that limit the interpretation of differences in force steadiness.

The execution of the Grooved Pegboard test in a Dual-Task situation: A pilot study

Background

Manual dexterity is an important aspect in everyday life, which is widely studied through the Grooved Pegboard Test (GPT). Since Dual-Tasks (DT) activities are widely investigated and important to simulate everyday life situations, the objectives of the present pilot study were the evaluation of the effect of a cognitive task and a motor task during the performance of the GPT and the feasibility of the GPT in a DT contest. A secondary objective was to evaluate the training effect of the GPT.

Methods

A total of 31 young adults (20 man and 11 woman, age (SD): 27.7 (2.5)) performed the GPT eight times to understand the presence of a training effect before performing the GPT in DT. The additional tasks were a secondary cognitive task and a secondary motor task.

Results

All participants were able to complete the required conditions. The GPT performed in motor DT were significantly slower than those performed singularly (p < 0.01). The GPT performed with the cognitive task was slower than the secondary motor task (p < 0.05). A training effect was present up to the 4^th consecutive trial.

Conclusions

The GPT can be executed with a cognitive or motor task to increase the difficulty of the trial to better evaluate manual dexterity and cognitive capacities.

Differences in postural sway among healthy adults are associated with the ability to perform steady contractions with leg muscles

Upright standing involves small displacements of the center of mass about the base of support. These displacements are often quantified by measuring various kinematic features of the center-of-pressure trajectory. The plantar flexors have often been identified as the key muscles for the control of these displacements; however, studies have suggested that the hip abductor and adductors may also be important. The purpose of our study was to determine the association between the force capabilities of selected leg muscles and sway-area rate across four balance conditions in young (25 ± 4 years; 12/19 women) and older adults (71 ± 5 years; 5/19 women). Due to the marked overlap in sway-area rate between the two age groups, the data were collapsed, and individuals were assigned to groups of low- and high-sway area rates based on a k-medoid cluster analysis. The number of participants assigned to each group varied across balance conditions and a subset of older adults was always included in the low-sway group for each balance condition. The most consistent explanatory variable for the variance in sway-area rate was force control of the hip abductors and ankle dorsiflexors as indicated by the magnitude of the normalized force fluctuations (force steadiness) during a submaximal isometric contraction. The explanatory power of the regression models varied across conditions, thereby identifying specific balance conditions that should be examined further in future studies of postural control.