Hand Kinematics Characterization While Performing Activities of Daily Living Through Kinematics Reduction

The reliability of a Biometrics device as a tool for assessing hand grip and pinch strength, in a Polish cohort-A prospective observational study

The aim of the study was to assess the external and internal compatibility of the Biometrics E-LINK EP9 evaluation system device in the area of hand grip and pinch strength in the Polish population. The testing of hand grip and pinch strength was carried out among 122 healthy students. Two examiners performed hand grip and pinch strength measurements with a Biometrics E-LINK EP9 evaluation system device. Measurements were made for the right and left hands. The same people were tested again two weeks later, under the same conditions. The scores of one rater on the first and second tests were compared for reproducibility, and the scores of the two raters were compared to assess the reliability of the instrument. The measurements were found to be highly consistent both between the investigators and between the tests in the hand grip dynamometer test. The findings show high values of the Pearson's correlation coefficient equal or close to 1, as well as the interclass correlation coefficient (ICC) >0.9. Analysis of pinch strength measurements performed using the pinchmeter also found high values of the Pearson's correlation coefficient close to 1, as well as the interclass correlation coefficient >0.9; this reflects high agreement between the measurements performed by two investigators as well as assessments performed by one investigator at time intervals. These findings were confirmed by analyses performed using Bland-Altman plots. The measurements made with the Biometrics E-link EP9 evaluation system show high internal and external consistency in hand grip and pinch strength assessment. Biometrics E-link EP9 can be recommended for daily clinical practice.

Upper extremity kinematics: development of a quantitative measure of impairment severity and dissimilarity after stroke

Background

Strokes are a leading cause of disability worldwide, with many survivors experiencing difficulty in recovering upper extremity movement, particularly hand function and grasping ability. There is currently no objective measure of movement quality, and without it, rehabilitative interventions remain at best informed estimations of the underlying neural structures' response to produce movement. In this article, we utilize a novel modification to Procrustean distance to quantify curve dissimilarity and propose the Reach Severity and Dissimilarity Index (RSDI) as an objective measure of motor deficits.

Methods

All experiments took place at the Medstar National Rehabilitation Hospital; persons with stroke were recruited from the hospital patient population. Using Fugl-Meyer (FM) scores and reach capacities, stroke survivors were placed in either mild or severe impairment groups. Individuals completed sets of reach-to-target tasks to extrapolate kinematic metrics describing motor performance. The Procrustes method of statistical shape analysis was modified to identify reaching sub-movements that were congruous to able-bodied sub-movements.

Findings

Movement initiation proceeds comparably to the reference curve in both two- and three-dimensional representations of mild impairment movement. There were significant effects of the location of congruent segments between subject and reference curves, mean velocities, peak roll angle, and target error. These metrics were used to calculate a preliminary RSDI score with severity and dissimilarity sub-scores, and subjects were reclassified in terms of rehabilitation goals as Speed Emphasis, Strength Emphasis, and Combined Emphasis.

Interpretation

The modified Procrustes method shows promise in identifying disruptions in movement and monitoring recovery without adding to patient or clinician burden. The proposed RSDI score can be adapted and expanded to other functional movements and used as an objective clinical tool. By reducing the impact of stroke on disability, there is a significant potential to improve quality of life through individualized rehabilitation.

Decomposition and Reconstruction of Human Palm Movements

OBJECTIVE

The human hand is known to have excellent manipulation ability compared to other primate hands. Without the palm movements, the human hand would lose more than 40% of its functions. However, uncovering the constitution of palm movements is still a challenging problem involving kinesiology, physiology, and engineering science.

METHODS

By recording the palm joint angles during common grasping, gesturing, and manipulation tasks, we built a palm kinematic dataset. Then, a method for extracting the eigen-movements to characterize the common motion correlation relationships of palm joints was proposed to explore the palm movement constitution.

RESULTS

This study revealed a palm kinematic characteristic that we named the joint motion grouping coupling characteristic. During natural palm movements, there are several joint groups with a high degree of motor independence, while the movements of joints within each joint group are interdependent. Based on these characteristics, the palm movements can be decomposed into seven eigen-movements. The linear combinations of these eigen-movements can reconstruct more than 90% of palm movement ability. Moreover, combined with the palm musculoskeletal structures, we found that the revealed eigen-movements are associated with joint groups that are defined by muscular functions, which provided a meaningful context for palm movement decomposition.

CONCLUSION

This paper suggests that some invariable characteristics underlie the variable palm motor behaviors and can be used to simplify palm movement generation.

SIGNIFICANCE

This paper provides important insights into palm kinematics, and helps facilitate motor function assessment and the development of better artificial hands.

The BE-UJI hand function activity set: a reduced set of activities for the evaluation of the healthy and pathological hand

BACKGROUND

Hand kinematics during hand function tests based on the performance of activities of daily living (ADLs) can provide objective data to determine patients' functional loss. However, they are rarely used during clinical assessments because of their long duration. Starting with the 20 Sollerman Hand Function Test (SHFT) tasks, we propose identifying a reduced set of ADLs that provides similar kinematic information to the original full set in terms of synergies, ranges of motion and velocities.

METHODS

We followed an iterative method with the kinematics of 16 hand joints while performing the 20 ADLs of the SHFT. For each subject, ADLs were ordered according to their influence on the synergies obtained by means of a principal component analysis, the minimum number of ADLs that represented the original kinematic synergies (maximum angle of 30° between synergies), and the maintained ranges of joint movements (85% of the original ones) were selected for each subject. The set of the most frequently selected ADLs was verified to be representative of the SHFT ADLs in terms of motion strategies, ranges of motion and joint velocities when considering healthy subjects and Hand Osteoarthritis patients.

RESULTS

A set of 10 tasks, the BE-UJI activity set, was identified by ensuring a certain (minimum) similarity in synergy (maximum mean angle between synergies of 25.5°), functional joint ranges (maximum differences of 10°) and joint velocities (maximum differences of 15°/s). The obtained tasks were: pick up coins from purses, lift wooden cubes, pick up nuts and turn them, write with a pen, cut with a knife, lift a telephone, unscrew jar lids and pour water from a cup, a jar and a Pure-Pak. These activities guarantee using the seven commonest handgrips in ADLs.

CONCLUSION

The BE-UJI activity set for the hand function assessment can be used to obtain quantitative data in clinics as an alternative to the SHFT. It reduces the test time and allows clinicians to obtain objective kinematic data of the motor strategies, ranges of motion and joint velocities used by patients.

Hand-worn devices for assessment and rehabilitation of motor function and their potential use in BCI protocols: a review

Introduction

Various neurological conditions can impair hand function. Affected individuals cannot fully participate in activities of daily living due to the lack of fine motor control. Neurorehabilitation emphasizes repetitive movement and subjective clinical assessments that require clinical experience to administer.

Methods

Here, we perform a review of literature focused on the use of hand-worn devices for rehabilitation and assessment of hand function. We paid particular attention to protocols that involve brain-computer interfaces (BCIs) since BCIs are gaining ground as a means for detecting volitional signals as the basis for interactive motor training protocols to augment recovery. All devices reviewed either monitor, assist, stimulate, or support hand and finger movement.

Results

A majority of studies reviewed here test or validate devices through clinical trials, especially for stroke. Even though sensor gloves are the most commonly employed type of device in this domain, they have certain limitations. Many such gloves use bend or inertial sensors to monitor the movement of individual digits, but few monitor both movement and applied pressure. The use of such devices in BCI protocols is also uncommon.

Discussion

We conclude that hand-worn devices that monitor both flexion and grip will benefit both clinical diagnostic assessment of function during treatment and closed-loop BCI protocols aimed at rehabilitation.

Upper Limb Function Recovery by Combined Repetitive Transcranial Magnetic Stimulation and Occupational Therapy in Patients with Chronic Stroke According to Paralysis Severity

Repetitive transcranial magnetic stimulation (rTMS) with intensive occupational therapy improves upper limb motor paralysis and activities of daily living after stroke; however, the degree of improvement according to paralysis severity remains unverified. Target activities of daily living using upper limb functions can be established by predicting the amount of change after treatment for each paralysis severity level to further aid practice planning. We estimated post-treatment score changes for each severity level of motor paralysis (no, poor, limited, notable, and full), stratified according to Action Research Arm Test (ARAT) scores before combined rTMS and intensive occupational therapy. Motor paralysis severity was the fixed factor for the analysis of covariance; the delta (post-pre) of the scores was the dependent variable. Ordinal logistic regression analysis was used to compare changes in ARAT subscores according to paralysis severity before treatment. We implemented a longitudinal, prospective, interventional, uncontrolled, and multicenter cohort design and analyzed a dataset of 907 patients with stroke hemiplegia. The largest treatment-related changes were observed in the Limited recovery group for upper limb motor paralysis and the Full recovery group for quality-of-life activities using the paralyzed upper limb. These results will help predict treatment effects and determine exercises and goal movements for occupational therapy after rTMS.

Reducing Anthropomorphic Hand Degrees of Actuation with Grasp-Function-Dependent and Joint-Element-Sparse Hand Synergies

In this paper, a set of grasp-function-dependent and joint-element-sparse hand synergies was proposed. First, hand synergies were extracted from five basic categories of movements by principal component analysis (PCA). Then, varimax rotation was applied on these synergies, so each sparse synergy only represented a limited number of joints. Next, according to the contribution to these sparse synergies, finger joints were clustered into different joint modules. Finally, integrating the joint modules in different categories of hand movements, the minimum number of actuators and joint synergic modules for anthropomorphic hands were determined. The results showed that using 5 groups of joint modules and 7–9 actuators we can achieve the best performance of grasp function and motion flexibility. Furthermore, through the reasonable design of adaptive and hyperextension functional joint modules, anthropomorphic hands can better meet the requirements of different tasks like power grasping and precision pinching. Comparing with traditional finger-based actuation strategy, the joint coupling scheme achieved better anthropomorphic performance and larger workspace. These above findings will benefit the development of mechanical structure design and control method of anthropomorphic hands.

Using Sensorized Gloves and Dimensional Reduction for Hand Function Assessment of Patients with Osteoarthritis

Sensorized gloves allow the measurement of all hand kinematics that are essential for daily functionality. However, they are scarcely used by clinicians, mainly because of the difficulty of analyzing all joint angles simultaneously. This study aims to render this analysis easier in order to enable the applicability of the early detection of hand osteoarthritis (HOA) and the identification of indicators of dysfunction. Dimensional reduction was used to compare kinematics (16 angles) of HOA patients and healthy subjects while performing the tasks of the Sollerman hand function test (SHFT). Five synergies were identified by using principal component (PC) analyses, patients using less fingers arch, higher palm arching, and a more independent thumb abduction. The healthy PCs, explaining 70% of patients’ data variance, were used to transform the set of angles of both samples into five reduced variables (RVs): fingers arch, hand closure, thumb-index pinch, forced thumb opposition, and palmar arching. Significant differences between samples were identified in the ranges of movement of most of the RVs and in the median values of hand closure and thumb opposition. A discriminant function for the detection of HOA, based in RVs, is provided, with a success rate of detection higher than that of the SHFT. The temporal profiles of the RVs in two tasks were also compared, showing their potentiality as dysfunction indicators. Finally, reducing the number of sensors to only one sensor per synergy was explored through a linear regression, resulting in a mean error of 7.0°.

Intra-Subject and Inter-Subject Movement Variability Quantified with Muscle Synergies in Upper-Limb Reaching Movements

Quantifying movement variability is a crucial aspect for clinical and laboratory investigations in several contexts. However, very few studies have assessed, in detail, the intra-subject variability across movements and the inter-subject variability. Muscle synergies are a valuable method that can be used to assess such variability. In this study, we assess, in detail, intra-subject and inter-subject variability in a scenario based on a comprehensive dataset, including multiple repetitions of multi-directional reaching movements. The results show that muscle synergies are a valuable tool for quantifying variability at the muscle level and reveal that intra-subject variability is lower than inter-subject variability in synergy modules and related temporal coefficients, and both intra-subject and inter-subject similarity are higher than random synergy matching, confirming shared underlying control structures. The study deepens the available knowledge on muscle synergy-based motor function assessment and rehabilitation applications, discussing their applicability to real scenarios.

Correlation between the Ability to Manipulate a Touchscreen Device and Hand Strength and Manual Dexterity among Community-Living Older Individuals

Information regarding the relationship between the degree of hand function among the elderly as measured by traditional assessments and the ability to manipulate touchscreens is lacking. This study aimed to examine the correlation between the ability to manipulate a touchscreen device, as assessed using the touchscreen assessment tool (TATOO) (University of Haifa, Israel & Universetiy of Bologna, Italy), and hand strength and manual dexterity among independent community-living older individuals. Thirty-four community-living older adults (average age 79.4 ± 6.7 years) participated in single-session assessments lasting 45 min each. The assessment included hand strength measurement using the manual hand dynamometry and hydraulic pinch gauge, a functional dexterity test (FDT), and TATOO. No significant correlations were observed between most of the TATOO items (22 out of 26) and handgrip strength, pinch strength, and FDT results. Moderately significant correlations were demonstrated between the number of drag attempts in the “Drag to different directions” task and handgrip strength and manual dexterity (r value: −0.39, p value: 0.02; r value: 0.36, p value: 0.04, respectively). In addition, a moderately significant correlation was noted between the number of double taps and manual dexterity (r value: 0.32, p value: 0.07). These results indicate that more complex gestures that require greater accuracy (dragging task) or rapid movements (double tapping) are related to hand strength and manual dexterity. These results suggest that the manual gestures necessary for touchscreen operation entail unique and specific capabilities that are generally not captured by traditional tools. The clinical implication is that the hand function assessment toolbox should be expanded. Tools such as the TATOO should be used to capture skills required for touchscreen manipulation in the context of the modern digital milieu.

Self-Feeding Kinematics in an Ecological Setting: Typically Developing Children and Children With Cerebral Palsy

Assessment of self-feeding kinematics is seldom performed in an ecological setting. In preparation for development of an instrumented spoon for measurement of self-feeding in children with cerebral palsy (CP), the current work aimed to evaluate upper extremity kinematics of self-feeding in young children with typical development (TD) and a small, age-matched group of children with CP in a familiar setting, while eating with a spoon.

METHODS

Sixty-five TD participants and six children diagnosed with spastic CP, aged 3-9 years, fed themselves while feeding was measured using miniature three-dimensional motion capture sensors (trakStar). Kinematic variables associated with different phases of self-feeding cycle (movement time, curvature, time to peak velocity and smoothness) were compared across age-groups in the TD sample and between TD children and those with CP.

RESULTS

Significant between-age group differences were identified in movement times, time to peak velocity and curvature. Children with CP demonstrated slower, less smooth self-feeding movements, potentially related to activity limitations.

CONCLUSIONS

The identified kinematic variables form a basis for implementation of self-feeding performance assessment in children of different ages, including those with CP, which can be deployed via an instrumented spoon.

Synergy-Based Sensor Reduction for Recording the Whole Hand Kinematics

Simultaneous measurement of the kinematics of all hand segments is cumbersome due to sensor placement constraints, occlusions, and environmental disturbances. The aim of this study is to reduce the number of sensors required by using kinematic synergies, which are considered the basic building blocks underlying hand motions. Synergies were identified from the public KIN-MUS UJI database (22 subjects, 26 representative daily activities). Ten synergies per subject were extracted as the principal components explaining at least 95% of the total variance of the angles recorded across all tasks. The 220 resulting synergies were clustered, and candidate angles for estimating the remaining angles were obtained from these groups. Different combinations of candidates were tested and the one providing the lowest error was selected, its goodness being evaluated against kinematic data from another dataset (KINE-ADL BE-UJI). Consequently, the original 16 joint angles were reduced to eight: carpometacarpal flexion and abduction of thumb, metacarpophalangeal and interphalangeal flexion of thumb, proximal interphalangeal flexion of index and ring fingers, metacarpophalangeal flexion of ring finger, and palmar arch. Average estimation errors across joints were below 10% of the range of motion of each joint angle for all the activities. Across activities, errors ranged between 3.1% and 16.8%.