Simulated activities of daily living do not replicate functional upper limb movement or reduce movement variability

Event-Related EEG Desynchronization Reveals Enhanced Motor Imagery From the Third Person Perspective by Manipulating Sense of Body Ownership With Virtual Reality for Stroke Patients

Virtual reality (VR)-based rehabilitation training holds great potential for post-stroke motor recovery. Existing VR-based motor imagery (MI) paradigms mostly focus on the first-person perspective, and the benefit of the third-person perspective (3PP) remains to be further exploited. The 3PP is advantageous for movements involving the back or those with a large range because of its field coverage. Some movements are easier to imagine from the 3PP. However, the 3PP training efficiency may be unsatisfactory, which may be attributed to the difficulty encountered when generating a strong sense of ownership (SOO). In this work, we attempt to enhance a visual-guided 3PP MI in stroke patients by eliciting the SOO over a virtual avatar with VR. We propose to achieve this by inducing the so-called out-of-body experience (OBE), which is a full-body illusion (FBI) that people misperceive a 3PP virtual body as his/her own (i.e., generating the SOO to the virtual body). Electroencephalography signals of 13 stroke patients are recorded while MI of the affected upper limb is being performed. The proposed paradigm is evaluated by comparing event-related desynchronization (ERD) with a control paradigm without FBI induction. The results show that the proposed paradigm leads to a significantly larger ERD during MI, indicating a bilateral activation pattern consistent with that in previous studies. In conclusion, 3PP MI can be enhanced in stroke patients by eliciting the SOO through induction of the "OBE" FBI. This study offers more possibilities for virtual rehabilitation in stroke patients and can further facilitate VR application in rehabilitation.

Characterizing upper extremity kinematics in typically developing children during box and blocks test

Upper extremity kinematics are important for understanding functional ability and performance improvements. The Box and Blocks test (BBT) is a standardized functional test used to measure manual dexterity when evaluating children or patients following a stroke. The BBT measures the number of blocks moved in one minute and therefore, kinematic measures and compensatory strategies cannot be assessed. This study examined the correlation between upper extremity kinematics and cycle time per block movement during the BBT in three age groups (7-, 9-, and 11-year-olds). Participants completed one BBT session while test scores and kinematic measures (hand velocity and position and shoulder, elbow, and wrist range of motion and peak joint angles) were captured using standard three-dimensional motion capture techniques. Kinematic measures were determined for block movements during the middle of each BBT trial. A mixed-effects model was used to identify group differences (α = 0.05). BBT score was different (p = 0.005) between the 7- (44.88 ± 6.03) and the 11-year-old age group (56.95 ± 8.37) along with peak shoulder flexion (p = 0.024) and abduction (p = 0.022). Peak elbow flexion was different (p = 0.049) between the 9- and 11-year-old age groups. No differences were seen between the 7- and 9-year-old age groups. Pearson's Correlation Coefficients were determined between cycle time and each significant kinematic measure, where the cycle time is specific to each block movement (BBT score) and is correlated to the BBT score. This resulted in weak correlations for all the comparisons. Therefore, using BBT score alone is not representative of UE kinematics and both should be collected during this task to provide insight into movement mechanics in a pediatric population.

The third-person perspective full-body illusion induced by visual-tactile stimulation in virtual reality for stroke patients

This paper attempts to induce the third-person perspective full body illusion (3PP-FBI) with virtual reality (VR) in stroke patients. Nineteen individuals with stroke were recruited. The 3PP-FBI induction method, which was well-established in healthy individuals, using synchronous visual-tactile stimulation on one body part was used. Questionnaire scores and proprioceptive drift values were collected under different conditions for characterizing the induced 3PP-FBI. Results showed that synchronous visual-tactile stimulation of a single body part (back or upper limb) was sufficient to elicit 3PP-FBI in stroke patients, forming a sense of ownership (SOO) over the entire virtual body. Moreover, the intensity of 3PP-FBI was stronger when the back was stimulated, compared to stimulating the impaired upper limb. This study demonstrated the viability of visual-guided rehabilitation training while having a SOO to a virtual body from the third-person perspective, in anticipation of achieving better rehabilitation outcome for movements beyond the first-person perspective.

Exploring whole-body kinematics when eating real foods with the dominant hand in healthy adults

Despite the importance of eating movements to the rehabilitation of neurological patients, information regarding the normal kinematics of eating in a realistic setting is limited. We aimed to quantify whole-body three-dimensional kinematics among healthy individuals by assessing movement patterns in defined phases while eating real food with the dominant hand in a seated position. Our cross-sectional study included 45 healthy, right-hand dominant individuals with a mean age of 27.3 ± 5.1 years. Whole-body kinematics (joint angles of the upper limb, hip, neck, and trunk) were captured using an inertial sensor motion system. The eating motion was divided into four phases for analysis: reaching, spooning, transport, and mouth. The mean joint angles were compared among the phases with Friedman's analysis of variance. The maximum angles through all eating phases were 129.0° of elbow flexion, 32.4° of wrist extension, 50.4° of hip flexion, 6.8° of hip abduction, and 0.2° of hip rotation. The mean shoulder, elbow, and hip joint flexion angles were largest in the mouth phase, with the smallest being the neck flexion angle. By contrast, in the spooning phase, the shoulder, elbow, and hip flexion were the smallest, with the largest being the neck flexion angle. These angles were significantly different between the mouth and spooning phases (p < 0.008, Bonferroni post hoc correction). Our results revealed that characteristic whole-body movements correspond to each phase of realistic eating in healthy individuals. This study provides useful kinematic data regarding normal eating movements, which may inform whole-body positioning and movement, improve the assessment of eating abilities in clinical settings, and provide a basis for future studies.

Compensatory strategies of body-powered prosthesis users reveal primary reliance on trunk motion and relation to skill level

BACKGROUND

While body-powered prostheses are commonly used, the compensatory strategies required to operate body-powered devices are not well understood. Kinematic assessment in addition to standard clinical tests can give a comprehensive evaluation of prosthesis user function and skill. This study investigated the movement compensations of body-powered prosthesis users and determined whether a correlation is present between compensatory strategies and skill level, as measured by a standard clinical test.

METHODS

Five transradial body-powered prosthesis users completed two standardized upper limb tasks. A 12-camera motion capture system was used to obtain three-dimensional angular kinematics for eight degrees of freedom at the trunk, shoulder, and elbow. Range of motion was compared to a normative dataset. Pearson's correlation was used to assess the relationship between the Activities Measure for Upper Limb Amputees and range of motion for each degree of freedom.

FINDINGS

Participants displayed a statistically significant (P < .05) increase in range of motion at the trunk for both tasks. Shoulder flexion/extension range of motion was significantly reduced (P < .05) compared to normative values, but shoulder abduction/adduction range of motion did not show a consistent difference compared to norms. Skill level was correlated with range of motion for specific degrees of freedom at the trunk, shoulder, and elbow.

INTERPRETATION

Body-powered prosthesis users compensated with trunk movement and showed reduced motion for shoulder flexion/extension, with relatively normal shoulder abduction/adduction. Skill level was correlated with angular kinematic strategies, which may allow targeting of specific therapeutic interventions for reducing compensatory movements.

Quantitative Eye Gaze and Movement Differences in Visuomotor Adaptations to Varying Task Demands Among Upper-Extremity Prosthesis Users

IMPORTANCE

New treatments for upper-limb amputation aim to improve movement quality and reduce visual attention to the prosthesis. However, evaluation is limited by a lack of understanding of the essential features of human-prosthesis behavior and by an absence of consistent task protocols.

OBJECTIVE

To evaluate whether task selection is a factor in visuomotor adaptations by prosthesis users to accomplish 2 tasks easily performed by individuals with normal arm function.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study was conducted in a single research center at the University of Alberta, Edmonton, Alberta, Canada. Upper-extremity prosthesis users were recruited from January 1, 2016, through December 31, 2016, and individuals with normal arm function were recruited from October 1, 2015, through November 30, 2015. Eight prosthesis users and 16 participants with normal arm function were asked to perform 2 goal-directed tasks with synchronized motion capture and eye tracking. Data analysis was performed from December 3, 2018, to April 15, 2019.

MAIN OUTCOME AND MEASURES

Movement time, eye fixation, and range of motion of the upper body during 2 object transfer tasks (cup and box) were the main outcomes.

RESULTS

A convenience sample comprised 8 male prosthesis users with acquired amputation (mean [range] age, 45 [30-64] years), along with 16 participants with normal arm function (8 [50%] of whom were men; mean [range] age, 26 [18-43] years; mean [range] height, 172.3 [158.0-186.0] cm; all right handed). Prosthesis users spent a disproportionately prolonged mean (SD) time in grasp and release phases when handling the cups (grasp: 2.0 [2.3] seconds vs 0.9 [0.8] seconds; P < .001; release: 1.1 [0.6] seconds vs 0.7 [0.4] seconds; P < .001). Prosthesis users also had increased mean (SD) visual fixations on the hand for the cup compared with the box task during reach (10.2% [12.1%] vs 2.2% [2.8%]) and transport (37.1% [9.7%] vs 22.3% [7.6%]). Fixations on the hand for both tasks were significantly greater for prosthesis users compared with normative values. Prosthesis users had significantly more trunk flexion and extension for the box task compared with the cup task (mean [SD] trunk range of motion, 32.1 [10.7] degrees vs 21.2 [3.7] degrees; P = .01), with all trunk motions greater than normative values. The box task required greater shoulder movements compared with the cup task for prosthesis users (mean [SD] flexion and extension; 51.3 [12.6] degrees vs 41.0 [9.4] degrees, P = .01; abduction and adduction: 40.5 [7.2] degrees vs 32.3 [5.1] degrees, P = .02; rotation: 50.6 [15.7] degrees vs 35.5 [10.0] degrees, P = .02). However, other than shoulder abduction and adduction for the box task, these values were less than those seen for participants with normal arm function.

CONCLUSIONS AND RELEVANCE

This study suggests that prosthesis users have an inherently different way of adapting to varying task demands, therefore suggesting that task selection is crucial in evaluating visuomotor performance. The cup task required greater compensatory visual fixations and prolonged grasp and release movements, and the box task required specific kinematic compensatory strategies as well as increased visual fixation. This is the first study to date to examine visuomotor differences in prosthesis users across varying task demands, and the findings appear to highlight the advantages of quantitative assessment in understanding human-prosthesis interaction.

Reliability of upper limb movement quality metrics during everyday tasks

BACKGROUND

Quantitative assessments of an individual's functional status commonly involve the use of movement quality metrics.

RESEARCH QUESTION

The purpose of this work was to quantify the reliability of movement quality metrics in healthy adults during a variety of unconstrained activities of daily living (ADLs).

METHODS

Nineteen participants performed six ADLs (lifting a laundry basket, applying deodorant, turning a doorknob, placing a pill in a pillbox, placing a pushpin in a bulletin board, and drinking water from a glass) during two separate sessions. The ADLs were divided into reaching and object manipulation phases. Movement quality for each phase was assessed using three measures of smoothness (log dimensionless jerk, spectral arc length, and number of submovements) and one measure of straightness (index of curvature). Within- and between-session reliability was quantified using intraclass correlation coefficients (ICCs) and minimum detectable changes in measured units and as a percentage of their mean value (MDC%).

RESULTS

Reliability was generally lower within-session than between-session and for object manipulation tasks compared to reaching tasks. The ICCs exceeded 0.75 for 5% of the within-session metrics and 73% of the between-session metrics. The average MDC% was 35% for the within-session metrics and 20% for the between-session metrics. Reliability was similar for most metrics when averaged across the tasks, but the number of submovements consistently indicated much lower reliability.

SIGNIFICANCE

Unconstrained ADLs can reliably be used to assess movement quality in functional settings that mimic real-world challenges. However, the specific movement quality metrics used in the assessment should be chosen carefully since some metrics perform dissimilarly when applied to the same data. In particular, it may be advisable to use the number of submovements in combination with other metrics, if it is to be used at all.

Shoulder and elbow joint position sense assessment using a mobile app in subjects with and without shoulder pain - between-days reliability

OBJECTIVES

To determine between-days reliability and the minimal detectable change for shoulder and elbow joint position sense assessment using a validated mobile app, in subjects with and without shoulder pain.

DESIGN

Reliability study.

SETTING

Clinical measurement.

PARTICIPANTS

Subjects with (n = 25) and without shoulder pain (n = 29).

MAIN OUTCOME MEASURES

Subjects were assessed by the same examiner in two sessions, with one-week interval. Active joint repositioning tests of shoulder flexion and scaption and elbow flexion were assessed at the target-angles of 50°, 70°, 90° and 110°. Intra-class correlation coefficient, standard error of measurement and minimal detectable change were calculated for constant, absolute, total and variable errors.

RESULTS

Good to excellent reliability was found for constant, absolute and total errors at the target-angle of 50° of scaption for healthy subjects; at 110° of shoulder flexion and all target-angles for elbow for both groups.

CONCLUSIONS

The mobile app is a reliable tool and may be useful for assessing shoulder joint position sense mainly at 110° of flexion and for elbow between 50° and 110° of flexion in subjects with and without shoulder pain. Minimal detectable changes were demonstrated and may help clinicians to follow-up rehabilitation and researchers to interpret findings of studies.