Reliability and Validity of Outcome Measures for Upper Limb Amputation

The Upper Extremity Functional Scale for Prosthesis Users (UEFS-P): subscales for one and two-handed tasks

PURPOSE

To develop a self-report measure of activity performance for upper limb prosthesis users that quantifies outcomes by level of amputation and prosthesis type.

MATERIALS AND METHODS

Telephone survey of 423 adults with major upper limb amputation (ULA) who used a prosthesis. Item generation, cognitive, and pilot testing were followed by field testing. Items were categorized as one- or two-handed. Factor and Rasch analyses evaluated unidimensionality, monotonicity, item fit, differential item functioning (DIF), and reliability. Test-retest reliability was evaluated with intraclass correlation coefficients (ICCs). Known group validity was assessed with ANOVAs.

RESULTS

Respondents with unilateral ULA utilized prosthesis for 24% of unilateral and 38% of bilateral tasks. Those with bilateral ULA utilized prostheses for 64% of unilateral and 46% of bilateral tasks. Factor analyses identified a One-handed Task factor (CFI = 0.963, TLI = 0.950, and RMSEA = 0.064) and a Two-Handed Task factor (CFI = 0.958, TLI = 0.953, and RMSEA = 0.053). Response categories were collapsed to address monotonicity. After DIF adjustment, person reliability was 0.49 and 0.82 for One-handed and Two-handed Task scales, respectively, and ICCs were 0.88 and 0.91. Both scales differed by amputation level (p < 0.001).

CONCLUSIONS

The Upper Extremity Functional Scale for Prosthesis Users (UEFS-P) measure of upper limb function of prosthesis users has promising psychometric properties.Implications for rehabilitationMeasurement of upper limb function in persons with amputation is challenging, given currently available measures which do not explicitly grade activity performance with a prosthesis.The Upper Extremity Functional Scale for Prosthesis Users (UEFS-P) builds upon the original Orthotics and Prosthetics User Survey (OPUS) UEFS Scale with modified instructions, a revised item set, response categories and scoring algorithm.The UEFS-P consists of two unidimensional scales, the One-handed Tasks scale and the Two-handed Tasks scale.The UEFS-P scales have clear advantages over existing self-report measures of upper limb function that ask about difficulty with performing functional activities without accounting for prosthesis use, and do not differentiate persons who use and do not use a prosthesis.

Comparison of patient-reported and functional outcomes after transition from traditional upper limb prosthetics to multiarticulating hands in the user with a unilateral transradial amputation

BACKGROUND

Multiarticulating hands (MAHs) have been commercially available for over 15 years. Despite this, their cost remains significantly higher than traditional electric hands, and they are not routinely available in many countries. The Scottish Specialist Prosthetic Service within the National Health Service has been prescribing MAHs since 2014. However, the benefits of MAHs provided in clinical settings are not well known.

OBJECTIVES

This study aimed to compare patient-reported and functional measures in unilateral transradial prosthetic users transitioning from a body-powered or traditional myoelectric prosthesis to a MAH.

STUDY DESIGN

This was a retrospective cohort analysis of individuals with a unilateral transradial amputation provided with a MAH.

METHODS

Of 38 users provided with MAHs, 20 had complete data sets of patient-reported and functional measures before and 6 months after provision. These included Disabilities of the Arm, Shoulder, and Hand; Southampton Hand Assessment Procedure Index of Function; health-related quality of life (EQ-5D-5L Health Index); Trinity Amputation and Prosthesis Experience Scales satisfaction; and Box and Block Test.

RESULTS

The mean age was 44 years (SD 16) (n = 20), and 75% were male. There were an 8-unit mean reduction in the Disabilities of the Arm, Shoulder, and Hand ( P = .01) and a 9.5-unit improvement in the Southampton Hand Assessment Procedure IOF ( P = .007) at 6 months after provision. Health-related quality of life did not change ( P = .581). Users reported a four-point improvement in their Trinity Amputation and Prosthesis Experience Scales ( P = .004) and transferred 3.3 blocks more completing the Box and Block Test ( P = .001).

CONCLUSIONS

The evidence clearly supports continued provision of MAHs to this group of moderate users: the more function the user achieves, the less of a disability they perceive to have.

The multi-grip and standard myoelectric hand prosthesis compared: does the multi-grip hand live up to its promise?

BACKGROUND

Multi-grip myoelectric hand prostheses (MHPs), with five movable and jointed fingers, have been developed to increase functionality. However, literature comparing MHPs with standard myoelectric hand prostheses (SHPs) is limited and inconclusive. To establish whether MHPs increase functionality, we compared MHPs with SHPs on all categories of the International Classification of Functioning, Disability, and Health-model (ICF-model).

METHODS

MHP users (N = 14, 64.3% male, mean age = 48.6 years) performed physical measurements (i.e., Refined Clothespin Relocation Test (RCRT), Tray-test, Box and Blocks Test, Southampton Hand Assessment Procedure) with their MHP and an SHP to compare the joint angle coordination and functionality related to the ICF-categories 'Body Function' and 'Activities' (within-group comparisons). SHP users (N = 19, 68.4% male, mean age = 58.1 years) and MHP users completed questionnaires/scales (i.e., Orthotics and Prosthetics Users' Survey-The Upper Extremity Functional Status Survey /OPUS-UEFS, Trinity Amputation and Prosthesis Experience Scales for upper extremity/TAPES-Upper, Research and Development-36/RAND-36, EQ-5D-5L, visual analogue scale/VAS, the Dutch version of the Quebec User Evaluation of Satisfaction with assistive technology/D-Quest, patient-reported outcome measure to assess the preferred usage features of upper limb prostheses/PUF-ULP) to compare user experiences and quality of life in the ICF-categories 'Activities', 'Participation', and 'Environmental Factors' (between-group comparisons).

RESULTS

'Body Function' and 'Activities': nearly all users of MHPs had similar joint angle coordination patterns with an MHP as when they used an SHP. The RCRT in the upward direction was performed slower in the MHP condition compared to the SHP condition. No other differences in functionality were found. 'Participation': MHP users had a lower EQ-5D-5L utility score; experienced more pain or limitations due to pain (i.e., measured with the RAND-36). 'Environmental Factors': MHPs scored better than SHPs on the VAS-item holding/shaking hands. The SHP scored better than the MHP on five VAS-items (i.e., noise, grip force, vulnerability, putting clothes on, physical effort to control) and the PUF-ULP.

CONCLUSION

MHPs did not show relevant differences in outcomes compared to SHPs on any of the ICF-categories. This underlines the importance of carefully considering whether the MHP is the most suitable option for an individual taking into account the additional costs of MHPs.

Comparison of compensatory shoulder movements, functionality and satisfaction in transradial amputees fitted with two prosthetic myoelectric hooks

The functionalities of myoelectric hooks, such as whether they allow wrist movements, as well as the volume and design of the devices, may impact how fitted transradial amputees use their upper limbs. The aim of the current study was to compare two prosthetic myoelectric hooks in terms of compensatory shoulder movements, functionality and user satisfaction. This monocentric, randomized, controlled, cross-over trial evaluated eight transradial amputees fitted with two prosthetic myoelectric hooks, the Greifer and the Axon-Hook, during two consecutive periods. At the end of each period, shoulder abduction (mean and percentage of time with shoulder abduction > 60°) and manual dexterity were assessed using the Box and Blocks Test (BBT) on both sides, and satisfaction was assessed with the Evaluation of Satisfaction with Assistive Technology questionnaire. For each patient, data obtained with the BBT on the amputated side were compared with those obtained on the non-amputated side. Shoulder abduction was significantly higher with the Greifer (60.9°± 20.3°, p = 0.03) than with the Axon-Hook (39.8°± 16.9°) and also than with the NA side (37.6 ± 19.4°, p = 0.02). Shoulder abduction on the NA side (37.6 ± 19.4°) was close to that of the Axon-Hook (39.8°± 16.9°). The percentage of time spent with shoulder abduction > 60° during the BBT was higher with the Greifer than with the Axon-Hook or with the NA side (53.3 ± 34.4%, 17.6 ± 27.0% and 18.4 ± 34.9%, respectively), but the differences were not significant (p = 0.15). A significant strong negative correlation was found between shoulder abduction and wrist position with the Axon-Hook (r = -0.86; p < 0.01), but not with the Greifer. Manual dexterity and satisfaction did not differ significantly between the two devices. These results revealed compensatory movements, such as shoulder abduction in transradial amputees equipped with hooks, themselves influenced by the prosthetic device settings.

Myoelectric prosthesis hand grasp control following targeted muscle reinnervation in individuals with transradial amputation

BACKGROUND

Despite the growing availability of multifunctional prosthetic hands, users' control and overall functional abilities with these hands remain limited. The combination of pattern recognition control and targeted muscle reinnervation (TMR) surgery, an innovative technique where amputated nerves are transferred to reinnervate new muscle targets in the residual limb, has been used to improve prosthesis control of individuals with more proximal upper limb amputations (i.e., shoulder disarticulation and transhumeral amputation).

OBJECTIVE

The goal of this study was to determine if prosthesis hand grasp control improves following transradial TMR surgery.

METHODS

Eight participants were trained to use a multi-articulating hand prosthesis under myoelectric pattern recognition control. All participated in home usage trials pre- and post-TMR surgery. Upper limb outcome measures were collected following each home trial.

RESULTS

Three outcome measures (Southampton Hand Assessment Procedure, Jebsen-Taylor Hand Function Test, and Box and Blocks Test) improved 9-12 months post-TMR surgery compared with pre-surgery measures. The Assessment of Capacity for Myoelectric Control and Activities Measure for Upper Limb Amputees outcome measures had no difference pre- and post-surgery. An offline electromyography analysis showed a decrease in grip classification error post-TMR surgery compared to pre-TMR surgery. Additionally, a majority of subjects noted qualitative improvements in their residual limb and phantom limb sensations post-TMR.

CONCLUSIONS

The potential for TMR surgery to result in more repeatable muscle contractions, possibly due to the reduction in pain levels and/or changes to phantom limb sensations, may increase functional use of many of the clinically available dexterous prosthetic hands.

Measuring embodiment: A review of methods for prosthetic devices

The development of neural interfaces to provide improved control and somatosensory feedback from prosthetic limbs has initiated a new ability to probe the various dimensions of embodiment. Scientists in the field of neuroprosthetics require dependable measures of ownership, body representation, and agency to quantify the sense of embodiment felt by patients for their prosthetic limbs. These measures are critical to perform generalizable experiments and compare the utility of the new technologies being developed. Here, we review outcome measures used in the literature to evaluate the senses of ownership, body-representation, and agency. We categorize these existing measures based on the fundamental psychometric property measured and whether it is a behavioral or physiological measure. We present arguments for the efficacy and pitfalls of each measure to guide better experimental designs and future outcome measure development. The purpose of this review is to aid prosthesis researchers and technology developers in understanding the concept of embodiment and selecting metrics to assess embodiment in their research. Advances in the ability to measure the embodiment of prosthetic devices have far-reaching implications in the improvement of prosthetic limbs as well as promoting a broader understanding of ourselves as embodied agents.

Benefits of the Cybathlon 2020 experience for a prosthetic hand user: a case study on the Hannes system

BACKGROUND

Cybathlon championship aims at promoting the development of prosthetic and assistive devices capable to meet users' needs. This paper describes and analyses possible exploitation outcomes of our team's (REHAB TECH) experience into the Powered Arm Prosthesis Race of the Cybathlon 2020 Global Edition, with the novel prosthetic system Hannes. In detail, we present our analysis on a concurrent evaluation conducted to verify if the Cybathlon training and competition positively influenced pilot's performance and human-technology integration with Hannes, with respect to a non-runner Hannes user.

METHODS

Two transradial amputees were recruited as pilots (Pilot 1 and Pilot 2) for the Cybathlon competition and were given the polyarticulated myoelectric prosthetic hand Hannes. Due to COVID-19 emergency, only Pilot 1 was trained for the race. However, both pilots kept Hannes for Home Use for seven weeks. Before this period, they both participated to the evaluation of functionality, embodiment, and user experience (UX) related to Hannes, which they repeated at the end of the Home Use and right after the competition. We analysed Pilot 1's training and race outcomes, as well as changes in the concurrent evaluation, and compared these results with Pilot 2's ones.

RESULTS

The Cybathlon training gradually improved Pilot 1's performances, leading to the sixth place with a single error in task 5. In the parallel evaluation, both pilots had an overall improvement over time, whereas Pilot 2 experienced a deterioration of embodiment. In detail, Pilot 1, who followed the training and raced the Cybathlon, improved in greater way.

CONCLUSION

Hannes demonstrated to be a valuable competitor and to perform grasps with human-like behaviors. The higher improvements of Pilot 1, who actively participated in the Cybathlon, in terms of functionality, embodiment and UX, may depend on his training and engagement in the effort of achieving a successful user-prosthesis interaction during the competition. Tasks based on Cybathlon's ones could improve the training phase of a prosthetic user, stimulating dexterity, prosthetic integration, and user perception towards the prosthesis. Likewise, timed races or competitions could facilitate and accelerate the learning phase, improving the efficiency and efficacy of the process.

Monitoring at-home prosthesis control improvements through real-time data logging

OBJECTIVE

Validating the ability for advanced prostheses to improve function beyond the laboratory remains a critical step in enabling long-term benefits for prosthetic limb users.

APPROACH

A nine week take-home case study was completed with a single participant with upper limb amputation and osseointegration (OI) to better understand how an advanced prosthesis is used during daily activities. The participant was already an expert prosthesis user and used the Modular Prosthetic Limb (MPL) at home during the study. The MPL was controlled using wireless electromyography (EMG) pattern recognition-based movement decoding. Clinical assessments were performed before and after the take-home portion of the study. Data was recorded using an onboard data log in order to measure daily prosthesis usage, sensor data, and EMG data.

MAIN RESULT

The participant's continuous prosthesis usage steadily increased (p = 0.04, max = 5.5 hr) over time and over 30% of the total time was spent actively controlling the prosthesis. The duration of prosthesis usage after each pattern recognition training session also increased over time (p = 0.04), resulting in up to 5.4 hr of usage before retraining the movement decoding algorithm. Pattern recognition control accuracy improved (1.2% per week, p < 0.001) with a maximum number of 10 classes trained at once and the transitions between different degrees of freedom increased as the study progressed, indicating smooth and efficient control of the advanced prosthesis. Variability of decoding accuracy also decreased with prosthesis usage (p < 0.001) and 30% of the time was spent performing a prosthesis movement. During clinical evaluations, Box and Blocks and the Assessment of the Capacity for Myoelectric Control (ACMC) scores increased by 43% and 6.2%, respectively, demonstrating prosthesis functionality and the NASA Task Load Index (NASA-TLX) scores decreased, on average, by 25% across assessments, indicating reduced cognitive workload while using the MPL, over the nine week study.

SIGNIFICANCE

In this case study, we demonstrate that an onboard system to monitor prosthesis usage enables better understanding of how prostheses are incorporated into daily life. That knowledge can support the long-term goal of completely restoring independence and quality of life to individuals living with upper limb amputation.

Real-World Testing of the Self Grasping Hand, a Novel Adjustable Passive Prosthesis: A Single Group Pilot Study

(1) Background: This study investigated the feasibility of conducting a two-week “real-world” trial of the Self Grasping Hand (SGH), a novel 3D printed passive adjustable prosthesis for hand absence; (2) Methods: Single-group pilot study of nine adults with trans-radial limb absence; five used body-powered split-hooks, and four had passive cosmetic hands as their usual prosthesis. Data from activity monitors were used to measure wear time and bilateral activity. At the end of the two-week trial, function and satisfaction were measured using the Orthotics and Prosthetics Users’ Survey Function Scale (OPUS) and the prosthesis satisfaction sub-scales of the Trinity Amputations and Prosthesis Experience Scale (TAPES). Semi-structured interviews captured consumer feedback and suggestions for improvement; (3) Results: Average SGH wear time over 2 weeks was 17.5 h (10% of total prosthesis wear time) for split-hook users and 83.5 h (63% of total prosthesis wear time) for cosmetic hand users. Mean satisfaction was 5.2/10, and mean function score was 47.9/100; (4) Two-week real-world consumer testing of the SGH is feasible using the methods described. Future SGH designs need to be more robust with easier grasp lock/unlock.

Usability Assessment of Body Controlled Electric Hand Prostheses: A Pilot Study

Poly-articulated hands, actuated by multiple motors and controlled by surface myoelectric technologies, represent the most advanced aids among commercial prostheses. However, simple hook-like body-powered solutions are still preferred for their robustness and control reliability, especially for challenging environments (such as those encountered in manual work or developing countries). This study presents the mechatronic implementation and the usability assessment of the SoftHand Pro-Hybrid, a family of poly-articulated, electrically-actuated, and body-controlled artificial hands, which combines the main advantages of both body-powered and myoelectric systems in a single device. An assessment of the proposed system is performed with individuals with and without limb loss, using as a benchmark the SoftHand Pro, which shares the same soft mechanical architecture, but is controlled using surface electromyographic sensors. Results indicate comparable task performance between the two control methods and suggest the potential of the SoftHand Pro-Hybrid configurations as a viable alternative to myoelectric control, especially in work and demanding environments.

Understanding the Relationship Between Patient-Reported Function and Actual Function in the Upper Limb Prosthesis User Population: A Preliminary Study

Objective

To understand how perceived function relates to actual function at a specific stage in the rehabilitation process for the population using upper limb prostheses.

Design

Quantitative clinical descriptive study.

Setting

Clinical offices.

Participants

A sample of 61 participants (N=61; mean age, 43.0±12.8y; 51 male/10 female) with upper limb amputation who use a prosthetic device and were in the definitive stage of a prosthesis fitting process.

Interventions

Not applicable.

Main Outcome Measures

A patient-reported outcome measure, the Disabilities of the Arm, Shoulder, and Hand questionnaire (DASH), and 2 performance-based outcome measures, Box and Blocks Test (BBT) and Capacity Assessment of Prosthesis Performance for the Upper Limb (CAPPFUL), were used as variables in multiple linear regression models.

Results

The multiple linear regression models, which controlled for prosthesis type and amputation level, did not show evidence that changes in the independent variable (DASH) are significantly associated with changes in the dependent variables (log(BBT) (B=−0.007; 95% confidence interval [CI], −0.015 to 0.001; P=.0937) and CAPPFUL (B=−0.083, 95% CI, −0.374 to 0.208; P=.5623)). In both models, individuals with elbow, transhumeral (above elbow), and shoulder disarticulation showed a significant negative association with the dependent variable (CAPPFUL or logBBT). In the CAPPFUL model, there was a significant negative association with individuals using a hybrid prosthesis (B=−20.252; 95% CI, −36.562 to −3.942; P=.0170). In the logBBT model, there was a significant positive association with individuals using body-powered prostheses (B=0.430; 95% CI, 0.089-0.771; P=.0157).

Conclusions

Although additional data and analyses are needed to more completely assess the association between self-reported measures and performance-based measures of functional abilities, these preliminary results indicate that patient-reported outcomes alone may not provide a complete assessment of an upper limb prosthesis users’ functional ability and should be accompanied by population-specific performance-based measures.

A soft neuroprosthetic hand providing simultaneous myoelectric control and tactile feedback

Neuroprosthetic hands are typically heavy (over 400 g) and expensive (more than US$10,000), and lack the compliance and tactile feedback of human hands. Here, we report the design, fabrication and performance of a soft, low-cost and lightweight (292 g) neuroprosthetic hand that provides simultaneous myoelectric control and tactile feedback. The neuroprosthesis has six active degrees of freedom under pneumatic actuation, can be controlled through the input from four electromyography sensors that measure surface signals from residual forearm muscles, and integrates five elastomeric capacitive sensors on the fingertips to measure touch pressure so as to enable tactile feedback by eliciting electrical stimulation on the skin of the residual limb. In a set of standardized tests performed by two individuals with transradial amputations, we show that the soft neuroprosthetic hand outperforms a conventional rigid neuroprosthetic hand in speed and dexterity. We also show that one individual with a transradial amputation wearing the soft neuroprosthetic hand can regain primitive touch sensation and real-time closed-loop control.

Assessing kinematic variability during performance of Jebsen-Taylor Hand Function Test

STUDY DESIGN

Clinical measurement; 22 subjects with no upper limb disability completed the Jebsen-Taylor Hand Function Test (JHFT).

INTRODUCTION

To realize the potential of 3D motion capture to augment evaluation of individuals with upper limb disability/impairment, it is important to understand the expected kinematic motion that characterizes performance during functional evaluation.

PURPOSE OF THE STUDY

To assess kinematic variability and establish kinematic patterns for the JHFT.

METHODS

Upper body joint kinematics were collected using a Vicon motion capture system. Average range of motion and maximum angle were calculated for all tasks. Intrasubject and intersubject variability were assessed by calculating Pearson's correlation coefficient, adjusted coefficient of multiple correlation (CMC_adj), and standard deviation for 10 joint angles at the wrist, elbow, shoulder, and torso.

RESULTS

The writing and picking up small objects tasks generally had high intrasubject variability, with most joint angles having median Pearson's correlation coefficients lower than 0.7. The CMC_adj values were generally greater than 0.5 for elbow, shoulder, and torso joints during can-lifting tasks, indicating high consistency in those kinematic trajectories across subjects. Low consistency across subjects in all joint angles was observed for writing (CMC_adj < 0.07; SD_max > 10°).

DISCUSSION

Kinematic patterns for the JHFT tasks were analyzed.

CONCLUSIONS

With kinematic patterns for the JHFT tasks analyzed, optimal patterns of activity performance can be defined, allowing for easier identification and adjustment of atypical motion. Results can be used to inform selection of tasks for kinematic evaluation and provide expected variability for comparison to patient populations, which is useful for regulatory review and clinical assessment.

Clinical evaluation of the revolutionizing prosthetics modular prosthetic limb system for upper extremity amputees

Individuals with upper extremity (UE) amputation abandon prostheses due to challenges with significant device weight-particularly among myoelectric prostheses-and limited device dexterity, durability, and reliability among both myoelectric and body-powered prostheses. The Modular Prosthetic Limb (MPL) system couples an advanced UE prosthesis with a pattern recognition paradigm for intuitive, non-invasive prosthetic control. Pattern recognition accuracy and functional assessment-Box & Blocks (BB), Jebsen-Taylor Hand Function Test (JHFT), and Assessment of Capacity for Myoelectric Control (ACMC)-scores comprised the main outcomes. 10 participants were included in analyses, including seven individuals with traumatic amputation, two individuals with congenital limb absence, and one with amputation secondary to malignancy. The average (SD) time since limb loss, excluding congenital participants, was 85.9 (59.5) months. Participants controlled an average of eight motion classes compared to three with their conventional prostheses. All participants made continuous improvements in motion classifier accuracy, pathway completion efficiency, and MPL manipulation. BB and JHFT improvements were not statistically significant. ACMC performance improved for all participants, with mean (SD) scores of 162.6 (105.3), 213.4 (196.2), and 383.2 (154.3), p = 0.02 between the baseline, midpoint, and exit assessments, respectively. Feedback included lengthening the training period to further improve motion classifier accuracy and MPL control. The MPL has potential to restore functionality to individuals with acquired or congenital UE loss.

Exploring augmented grasping capabilities in a multi-synergistic soft bionic hand

BACKGROUND

State-of-the-art bionic hands incorporate hi-tech devices which try to overcome limitations of conventional single grip systems. Unfortunately, their complexity often limits mechanical robustness and intuitive prosthesis control. Recently, the translation of neuroscientific theories (i.e. postural synergies) in software and hardware architecture of artificial devices is opening new approaches for the design and control of upper-limb prostheses.

METHODS

Following these emerging principles, previous research on the SoftHand Pro, which embeds one physical synergy, showed promising results in terms of intuitiveness, robustness, and grasping performance. To explore these principles also in hands with augmented capabilities, this paper describes the SoftHand 2 Pro, a second generation of the device with 19 degrees-of-freedom and a second synergistic layer. After a description of the proposed device, the work explores a continuous switching control method based on a myoelectric pattern recognition classifier.

RESULTS

The combined system was validated using standardized assessments with able-bodied and, for the first time, amputee subjects. Results show an average improvement of more than 30% of fine grasp capabilities and about 10% of hand function compared with the first generation SoftHand Pro.

CONCLUSIONS

Encouraging results suggest how this approach could be a viable way towards the design of more natural, reliable, and intuitive dexterous hands.

Virtual reality-based action observation facilitates the acquisition of body-powered prosthetic control skills

Background

Regular body-powered (BP) prosthesis training facilitates the acquisition of skills through repeated practice but requires adequate time and motivation. Therefore, auxiliary tools such as indirect training may improve the training experience and speed of skill acquisition. In this study, we examined the effects of action observation (AO) using virtual reality (VR) as an auxiliary tool. We used two modalities during AO: three-dimensional (3D) VR and two-dimensional (2D) computer tablet devices (Tablet). Each modality was tested from first- and third-person perspectives.

Methods

We studied 40 healthy right-handed participants wearing a BP prosthesis simulator on their non-dominant hands. The participants were divided into five groups based on combinations of the different modalities and perspectives: first-person perspective on VR (VR1), third-person perspective on VR (VR3), first-person perspective on a tablet (Tablet1), third-person perspective on a tablet (Tablet3), and a control group (Control). The intervention groups observed and imitated the video image of prosthesis operation for 10 min in each of two sessions. We evaluated the level of immersion during AO using the visual analogue scale. Prosthetic control skills were evaluated using the Box and Block Test (BBT) and a bowknot task (BKT).

Results

In the BBT, there were no significant differences in the amount of change in the skills between the five groups. In contrast, the relative changes in the BKT prosthetic control skills in VR1 (p < 0.001, d = 3.09) and VR3 (p < 0.001, d = 2.16) were significantly higher than those in the control group. Additionally, the immersion scores of VR1 (p < 0.05, d = 1.45) and VR3 (p < 0.05, d = 1.18) were higher than those of Tablet3. There was a significant negative correlation between the immersion scores and the relative change in the BKT scores (Spearman’s r_s = − 0.47, p < 0.01).

Conclusions

Using the BKT of bilateral manual dexterity, VR-based AO significantly improved short-term prosthetic control acquisition. Additionally, it appeared that the higher the immersion score was, the shorter the execution time of the BKT task. Our findings suggest that VR-based AO training may be effective in acquiring bilateral BP prosthetic control, which requires more 3D-based operation.

Comparison of DEKA Arm and Body-Powered Upper Limb Prosthesis Joint Kinematics

Objectives

To study the effects of advancements in upper-limb prosthesis technology on the user through biomechanical analyses at the joint level to quantitatively examine movement differences of individuals using an advanced upper-limb device, the DEKA Arm, and a conventional device, a body-powered Hosmer hook.

Design

Clinical measurement.

Setting

Laboratories at the United States Food and Drug Administration.

Participants

Convenience sample of participants (N=14) with no upper limb disability or impairment.

Interventions

All participants were trained on either an upper limb body-powered (n=6) or DEKA Arm (n=8) bypass device.

Main Outcome Measures

Participants completed the Jebsen-Taylor Hand Function Test (JHFT) and targeted Box and Blocks Test within a motion capture framework. Task completion times and joint angle trajectories for each degree of freedom of the right elbow, right shoulder, and torso were collected and analyzed for range of motion, mean angle, maximum angle, and angle path length during each task.

Results

Significant differences between devices were observed across metrics in at least one task for each degree of freedom. Completion times were significantly higher for DEKA users (eg, 30.51±19.29s vs 9.30±1.44s) for JHFT-simulated feeding. Some kinematic measures, such as angle path length, were significantly lower in DEKA users, with the greatest difference in the right elbow flexion path length during JHFT-Page Turning (0.29±0.14 units vs 0.11±0.04 units).

Conclusions

Results from this work elucidate the effect of the device on the user's movement approach and performance, as well as emphasizing the importance of capturing movement quality into the assessment of function for advanced prosthetic technology to fully understand and evaluate potential benefits.

Learning of Artificial Sensation Through Long-Term Home Use of a Sensory-Enabled Prosthesis

Upper limb prostheses are specialized tools, and skilled operation is learned by amputees over time. Recently, neural prostheses using implanted peripheral nerve interfaces have enabled advances in artificial somatosensory feedback that can improve prosthesis outcomes. However, the effect of sensory learning on artificial somatosensation has not been studied, despite its known influence on intact somatosensation and analogous neuroprostheses. Sensory learning involves changes in the perception and interpretation of sensory feedback and may further influence functional and psychosocial outcomes. In this mixed methods case study, we examined how passive learning over 115 days of home use of a neural-connected, sensory-enabled prosthetic hand influenced perception of artificial sensory feedback in a participant with transradial amputation. We examined perceptual changes both within individual days of use and across the duration of the study. At both time scales, the reported percept locations became significantly more aligned with prosthesis sensor locations, and the phantom limb became significantly more extended toward the prosthesis position. Similarly, the participant’s ratings of intensity, naturalness, and contact touch significantly increased, while his ratings of vibration and movement significantly decreased across-days for tactile channels. These sensory changes likely resulted from engagement of cortical plasticity mechanisms as the participant learned to use the artificial sensory feedback. We also assessed psychosocial and functional outcomes through surveys and interviews, and found that self-efficacy, perceived function, prosthesis embodiment, social touch, body image, and prosthesis efficiency improved significantly. These outcomes typically improved within the first month of home use, demonstrating rapid benefits of artificial sensation. Participant interviews indicated that the naturalness of the experience and engagement with the prosthesis increased throughout the study, suggesting that artificial somatosensation may decrease prosthesis abandonment. Our data showed that prosthesis embodiment was intricately related to naturalness and phantom limb perception, and that learning the artificial sensation may have modified the body schema. As another indicator of successfully learning to use artificial sensation, the participant reported the emergence of stereognosis later in the study. This study provides the first evidence that artificial somatosensation can undergo similar learning processes as intact sensation and highlights the importance of sensory restoration in prostheses.

Function, quality of life, and community integration of DEKA Arm users after discharge from prosthetic training: Impact of home use experience

BACKGROUND:

Research on adaptation to advanced upper limb prostheses is needed.

OBJECTIVES:

To (1) examine change in function, quality of life and community integration after prosthetic training, (2) determine whether change in outcomes varied by prosthesis complexity, and (3) compare patterns of change at 1 month for those who withdrew from the study and those who did not.

STUDY DESIGN:

Quasi-experimental time series.

METHODS:

Data were analyzed for 22 participants (18 completers). Performance and self-report outcome measures were collected after in-laboratory training (Part A) and every 4 weeks of home use (Part B). Outcomes from End of A to End of B were compared statistically. Outcomes across assessments and by configuration level were compared graphically. Changes in scores were compared graphically for completers and non-completers.

RESULTS:

Quality of life scores did not change between End of A and End of B, whereas scores improved for one activity measure, two measures of self-reported function, and three dexterity measures ( p < 0.05). Outcomes of community integration, self-reported function, four dexterity measures, and one activity measure varied by prosthesis level. For participants who withdrew early, dexterity and activity scores worsened, perceived disability increased, and prosthesis satisfaction decreased after 4 weeks of home use.

CONCLUSION:

Study completers adapted to the DEKA Arm.

CLINICAL RELEVANCE

Findings suggest that for the majority of upper limb amputees discharged from prosthetic rehabilitation, function continues to improve with home use. However, a minority experience a decline in function, greater perceived disability, and greater dissatisfaction after 4 weeks, suggesting a need for continued therapy after intensive prosthetic training ends.

Upper Extremity Amputation and Prosthetics Care Across the Active Duty Military and Veteran Populations

The hand and arm are exceptionally dexterous, exquisitely sensitive, and proficient in performing tasks and functions. Given the invaluable functions of the upper extremity in daily life, replacement of a missing limb through prosthetic substitution is challenging. Prosthetic and rehabilitation needs of injured Service members from recent military conflicts have brought upper extremity amputation to the forefront, which has led to an increase in attention and resource allocation. This article provides an overview of the care of the upper extremity amputee including surgical considerations, prosthetic design and fitting, and preprosthetic and post-prosthetic rehabilitation considerations.

The DEKA hand: A multifunction prosthetic terminal device-patterns of grip usage at home

BACKGROUND

Research is needed to understand how upper limb prosthesis users take advantage of multiple grip options.

OBJECTIVES

To quantify usage of DEKA hand grip patterns during home use and compare patterns of usage at home to test sessions.

STUDY DESIGN

Observational study design.

METHODS

Data were collected from 21 subjects. Engineering data on grip were downloaded at various intervals. Proportion of time in each grip was calculated for the first 4 weeks of home use, later months, and test sessions (testing use) and compared statistically across intervals. Exploratory analyses compared grip proportion by DEKA Arm level and prior prosthesis use.

RESULTS

Three most commonly used grips during home use were power, pinch open, and lateral pinch. There were no significant differences between grip use during the first month and later months. Power grip was used 55% of the time at home and 23% of the time in testing use. Pinch closed, lateral, and chuck grip were used less at home than in tests. Comparisons were by configuration level and prosthetic use and no significant differences were found.

CONCLUSION

Patterns of DEKA hand grip usage differed between home and test environments, suggesting that users relied on fewer grip patterns at home. Clinical relevance These findings have implications for prosthetic training with multi-articulating terminal devices.

Timed activity performance in persons with upper limb amputation: A preliminary study

STUDY DESIGN

55 subjects with upper limb amputation were administered the T-MAP twice within one week.

PURPOSE

To develop a timed measure of activity performance for persons with upper limb amputation (T-MAP); examine the measure's internal consistency, test-retest reliability and validity; and compare scores by prosthesis use.

INTRODUCTION

Measures of activity performance for persons with upper limb amputation are needed The time required to perform daily activities is a meaningful metric that implication for participation in life roles.

METHODS

Internal consistency and test-retest reliability were evaluated. Construct validity was examined by comparing scores by amputation level. Exploratory analyses compared sub-group scores, and examined correlations with other measures.

RESULTS

Scale alpha was 0.77, ICC was 0.93. Timed scores differed by amputation level. Subjects using a prosthesis took longer to perform all tasks. T-MAP was not correlated with other measures of dexterity or activity, but was correlated with pain for non-prosthesis users.

DISCUSSION

The timed scale had adequate internal consistency and excellent test-retest reliability.

CONCLUSIONS

Analyses support reliability and construct validity of the T-MAP.

LEVEL OF EVIDENCE

2c "outcomes" research.

Development and Psychometric Validation of Capacity Assessment of Prosthetic Performance for the Upper Limb (CAPPFUL)

OBJECTIVES

(1) To develop a performance-based measure for adult upper limb (UL) prosthetic functioning through broad (ie, overall performance) and functional domain-specific (eg, control skills) assessment of commonplace activities; (2) to conduct initial psychometric evaluation of the Capacity Assessment of Prosthetic Performance for the Upper Limb (CAPPFUL).

DESIGN

Internal consistency of CAPPFUL and interrater reliability for task, functional domain, and full-scale (sub)scores among 3 independent raters were estimated. Known-group validity was examined comparing scores by amputation level. Convergent validity was assessed between CAPPFUL and 2 hand dexterity or function tests; discriminant validity was assessed against self-reported disability.

SETTING

Six prosthetic rehabilitation centers across the United States.

PARTICIPANTS

Subjects (N=60) with UL amputation using a prosthesis.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Not applicable.

RESULTS

Interrater reliability was excellent for scoring on the task, domain, and full-scale scores (intraclass correlation coefficients=.88-.99). Internal consistency was good (α=.79-.82). Generally, subjects with higher UL amputation levels scored lower (worse) than subjects with lower UL amputation levels. CAPPFUL demonstrated strong correlations with measures of hand dexterity or functioning (r_s=-.58 to .72) and moderate correlation with self-reported disability (r=-.35).

CONCLUSIONS

CAPPFUL was designed as a versatile, low-burden measure of prosthesis performance for any UL functional prosthetic device type and any UL amputation level. CAPPFUL assesses overall performance and 5 functional performance domains during completion of 11 tasks that require movement in all planes while manipulating everyday objects requiring multiple grasp patterns. Psychometric evaluation indicates good interrater reliability, internal consistency, known-group validity, and convergent and discriminant validity.

Evaluation of Performance-Based Outcome Measures for the Upper Limb: A Comprehensive Narrative Review

Objective performance-based outcome measures (OMs) have the potential to provide unbiased and reproducible assessments of limb function. However, very few of these performance-based OMs have been validated for upper limb (UL) prosthesis users. OMs validated in other clinical populations (eg, neurologic or musculoskeletal conditions) could be used to fill gaps in existing performance-based OMs for UL amputees. Additionally, a joint review might reveal consistent gaps across multiple clinical populations. Therefore, the objective of this review was to systematically characterize prominent measures used in both sets of clinical populations with regard to (1) location of task performance around the body, (2) possible grips employed, (3) bilateral versus unilateral task participation, and (4) details of scoring mechanisms. A systematic literature search was conducted in EMBASE, Medline, and Cumulative Index to Nursing and Allied Health electronic databases for variations of the following terms: stroke, musculoskeletal dysfunction, amputation, prosthesis, upper limb, outcome, assessments. Articles were included if they described performance-based OMs developed for disabilities of the UL. Results show most tasks were performed with 1 hand in the space directly in front of the participant. The tip, tripod, and cylindrical grips were most commonly used for the specific tasks. Few measures assessed sensation and movement quality. Overall, several limitations in OMs were identified. The solution to these limitations may be to modify and validate existing measures originally developed for other clinical populations as first steps to more aptly measure prosthesis use while more complete assessments for UL prosthesis users are being developed.

LEVEL OF EVIDENCE

Level III.

The suitcase packing activity: A new evaluation of hand function

STUDY DESIGN

Prospective, repeated-measures study.

INTRODUCTION

Understanding individual hand function can assist therapists with the process of determining relevant treatment approaches and realistic therapeutic outcomes. At this point in time, a composite test that assesses both unilateral and bimanual hand function in relation to a functional activity is not available.

PURPOSE OF THE STUDY

To establish the reliability and validity of the suitcase packing activity (SPA).

METHODS

An expert panel established face and content validity. Eighty healthy, English-speaking volunteers aged between 18 and 45 years were randomly assigned to either 1 or 2 sessions (test-retest reliability). Relative agreement between 2 examiners using an intraclass correlation coefficient (ICC)_3,1 determined interrater reliability. Test-retest reliability was determined by using a repeated-measures analysis of variance and an ICC_3,2. Concurrent validity was evaluated against 2 well-established hand evaluations using separate tests of correlational coefficients.

RESULTS

Face and content validity were established across 4 focus groups. Our results demonstrate good to excellent interrater reliability (ICC_3,1 ≥ 0.93) and good to excellent test-retest reliability (ICC_3,2 ≥ 0.83). SPA scores were moderately correlated with the 2-hand evaluations.

DISCUSSION

Through evaluating hand function during participation in a goal-directed activity (eg, packing a suitcase), the SPA exhibits promise in usefulness as a future viable outcome measure that can be used to assess functional abilities following a hand injury.

CONCLUSION

The SPA is a valid and reliable tool for assessing bimanual and unilateral hand function in healthy subjects.

LEVELS OF EVIDENCE

Diagnostic level II.

Cognitive predictors of skilled performance with an advanced upper limb multifunction prosthesis: a preliminary analysis

Purpose The objectives were to 1) identify major cognitive domains involved in learning to use the DEKA Arm; 2) specify cognitive domain-specific skills associated with basic versus advanced users; and 3) examine whether baseline memory and executive function predicted learning. Method Sample included 35 persons with upper limb amputation. Subjects were administered a brief neuropsychological test battery prior to start of DEKA Arm training, as well as physical performance measures at the onset of, and following training. Multiple regression models controlling for age and including neuropsychological tests were developed to predict physical performance scores. Prosthetic performance scores were divided into quartiles and independent samples t-tests compared neuropsychological test scores of advanced scorers and basic scorers. Baseline neuropsychological test scores were used to predict change in scores on physical performance measures across time. Results Cognitive domains of attention and processing speed were statistically significantly related to proficiency of DEKA Arm use and predicted level of proficiency. Conclusions Results support use of neuropsychological tests to predict learning and use of a multifunctional prosthesis. Assessment of cognitive status at the outset of training may help set expectations for the duration and outcomes of treatment. Implications for Rehabilitation Cognitive domains of attention and processing speed were significantly related to level of proficiencyof an advanced multifunctional prosthesis (the DEKA Arm) after training. Results provide initial support for the use of neuropsychological tests to predict advanced learningand use of a multifunctional prosthesis in upper-limb amputees. Results suggest that assessment of patients' cognitive status at the outset of upper limb prosthetictraining may, in the future, help patients, their families and therapists set expectations for theduration and intensity of training and may help set reasonable proficiency goals.

Responsiveness of outcome measures for upper limb prosthetic rehabilitation

BACKGROUND

There is limited research on responsiveness of prosthetic rehabilitation outcome measures.

OBJECTIVES

To examine responsiveness of the Box and Block test, Jebsen-Taylor Hand Function tests, Upper Extremity Functional Scale, University of New Brunswick skill and spontaneity tests, Activity Measure for Upper Limb Amputation, and the Patient-Specific Functional Scale.

STUDY DESIGN

This was a quasi-experimental study with repeated measurements in a convenience sample of upper limb amputees.

METHODS

Measures were collected before, during, and after training with the DEKA Arm.

RESULTS

Largest effect sizes were observed for Patient-Specific Functional Scale (effect size: 1.59, confidence interval: 1.00, 2.14), Activity Measure for Upper Limb Amputation (effect size: 1.33, confidence interval: 0.73, 1.90), and University of New Brunswick skill test (effect size: 1.18, confidence interval: 0.61, 1.73). Other measures that were responsive to change were Box and Block test, Jebsen-Taylor Hand Function light and heavy can tests, and University of New Brunswick spontaneity test. Responsiveness and pattern of responsiveness varied by prosthetic level.

CONCLUSIONS

The Box and Block test, Jebsen-Taylor Hand Function light and heavy can tests, University of New Brunswick skill and spontaneity tests, Activities Measure for Upper Limb Amputation, and the Patient-Specific Functional Scale were responsive to change during prosthetic training. These findings have implications for choice of measures for research and practice and inform clinicians about the amount of training necessary to maximize outcomes with the DEKA Arm.

CLINICAL RELEVANCE

Findings on responsiveness of outcome measures have implications for the choice of measures for clinical trials and practice. Findings regarding the responsiveness to change over the course of training can inform clinicians about the amount of training that may be necessary to maximize specific outcomes with the DEKA Arm.

The lightweight Delft Cylinder Hand: first multi-articulating hand that meets the basic user requirements

Rejection rates of upper limb prostheses are high (23%-45%). Amputees indicate that the highest design priority should be reduction of the mass of the prosthetic device. Despite all efforts, the mass of the new prosthetic hands is 35%-73% higher than that of older hands. Furthermore, current hands are thicker than a human hand, they operate slower and do not provide proprioceptive force and position feedback. This study presents the Delft Cylinder Hand, a body powered prosthetic hand which mass is 55%-68% lower than that of the lightest current prosthetic hands, operates faster, has an anthropomorphic shape, and provides proprioceptive force and position feedback. The hand has articulating fingers, actuated by miniature hydraulic cylinders. The articulating fingers adapt to the shape of the grasped object. Its functional scores are similar to that of current prosthetic devices. The hand has a higher mechanical performance than current body-powered hands. It requires 49%-162% less energy from the user and it can deliver a higher maximum pinch force (30-60 N).