Social participation in persons with upper limb amputation receiving an esthetic prosthesis

A BIONIC HAND VS. A REPLANTED HAND

Objective

Evaluation of the hand function affected when replacing a malfunctioning hand by a bionic hand.

Design

Case report.

Subjects

One individual that wished for a better quality of life after unsatisfying hand function following a replantation.

Methods

A quantitative and qualitative evaluation of body functions as well as activity performance and participation before and after a planned amputation and prosthetic fitting is presented.

Results

Improvements were seen in the patient-reported outcome measures (PROMs) that were used regarding activity (Disability of the Arm, Shoulder and Hand [DASH] and Canadian Occupational Performance Measure [COPM]), pain (Neuropathic Pain Symptom Inventory [NPSI], Brief Pain Inventory [BPI], Visual Analogue Scale [VAS]), cold intolerance (CISS) and health related quality of life (SF-36), as well as in the standardised grip function test, Southampton Hand Assessment Procedure (SHAP). No referred sensations were seen but the discriminative touch on the forearm was improved. In the qualitative interview, a relief of pain, a lack of cold intolerance, improved appearance, better grip function and overall emotional wellbeing were expressed.

Conclusions

The planned amputation and subsequent fitting and usage of a hand prosthesis were satisfying for the individual with positive effects on activity and participation.

Clinical relevance

When the hand function after a hand replantation does not reach satisfactory levels, a planned amputation and a prosthetic hand can be the right solution.

Barriers and facilitators to community reintegration in adults following traumatic upper limb amputation: an exploratory study

PURPOSE

To explore barriers and facilitators to community reintegration experienced by people following traumatic upper limb amputation (ULA).

METHODS

An exploratory qualitative study was conducted with ten adults with major ULA due to trauma. Data from individual, semi-structured interviews was analysed using Braun and Clarke's reflexive thematic analysis.

RESULTS

Underlying and influencing community reintegration for participants, was a process of adjustment to the impacts of amputation on everyday function and re-establishing their identity. Participants felt social networks and peer support facilitated the return to social and community activities, as did drawing on personal attributes such as positivity, resilience and self-belief. Prosthetic devices were facilitative for community reintegration by minimising visible differences and unwanted attention through restored cosmesis and in the performance of functional tasks to fulfil social norms and meaningful roles despite issues with comfort and function. Despite the adaptation and evolution of abilities, perspectives and identities, the functional impact of ULA on everyday community activities was an ongoing challenge for all participants.

CONCLUSION

ULA has a significant and lifelong impact on an individual's ability to complete tasks and fulfil meaningful roles in the community. Recommendations based on the study's findings will inform clinicians to support community reintegration for people following traumatic ULA.

EMG feedback improves grasping of compliant objects using a myoelectric prosthesis

BACKGROUND

Closing the control loop in myoelectric prostheses by providing artificial somatosensory feedback is recognized as an important goal. However, designing a feedback interface that is effective in realistic conditions is still a challenge. Namely, in some situations, feedback can be redundant, as the information it provides can be readily obtained through hearing or vision (e.g., grasping force estimated from the deformation of a compliant object). EMG feedback is a non-invasive method wherein the tactile stimulation conveys to the user the level of their own myoelectric signal, hence a measurement intrinsic to the interface, which cannot be accessed incidentally.

METHODS

The present study investigated the efficacy of EMG feedback in prosthesis force control when 10 able-bodied participants and a person with transradial amputation used a myoelectric prosthesis to grasp compliant objects of different stiffness values. The performance with feedback was compared to that achieved when the participants relied solely on incidental cues.

RESULTS

The main outcome measures were the task success rate and completion time. EMG feedback resulted in significantly higher success rates regardless of pin stiffness, indicating that the feedback enhanced the accuracy of force application despite the abundance of incidental cues. Contrary to expectations, there was no difference in the completion time between the two feedback conditions. Additionally, the data revealed that the participants could produce smoother control signals when they received EMG feedback as well as more consistent commands across trials, signifying better control of the system by the participants.

CONCLUSIONS

The results presented in this study further support the efficacy of EMG feedback when closing the prosthesis control loop by demonstrating its benefits in particularly challenging conditions which maximized the utility of intrinsic feedback sources.

Nonlinear Mapping From EMG to Prosthesis Closing Velocity Improves Force Control With EMG Biofeedback

When using EMG biofeedback to control the grasping force of a myoelectric prosthesis, subjects need to activate their muscles and maintain the myoelectric signal within an appropriate interval. However, their performance decreases for higher forces, because the myoelectric signal is more variable for stronger contractions. Therefore, the present study proposes to implement EMG biofeedback using nonlinear mapping, in which EMG intervals of increasing size are mapped to equal-sized intervals of the prosthesis velocity. To validate this approach, 20 non-disabled subjects performed force-matching tasks using Michelangelo prosthesis with and without EMG biofeedback with linear and nonlinear mapping. Additionally, four transradial amputees performed a functional task in the same feedback and mapping conditions. The success rate in producing desired force was significantly higher with feedback (65.4±15.9%) compared to no feedback (46.2±14.9%) as well as when using nonlinear (62.4±16.8%) versus linear mapping (49.2±17.2%). Overall, in non-disabled subjects, the highest success rate was obtained when EMG biofeedback was combined with nonlinear mapping (72%), and the opposite for linear mapping with no feedback (39.6%). The same trend was registered also in four amputee subjects. Therefore, EMG biofeedback improved prosthesis force control, especially when combined with nonlinear mapping, which showed to be an effective approach to counteract increasing variability of myoelectric signal for stronger contractions.

Validation of Task-Specific Rating Scale for Open Balloon Catheter Arterial Embolectomy: An Assessor-Blinded Quasi-Experimental Pilot Study

Objective: To develop and validate a task-specific rating scale (TSRS) by comparing with the Global Rating Scale (GRS) for the evaluation of brachial artery embolectomy (BAE). Methods: Participants were divided into expert and novice groups who were oriented on the locally developed simulator model. The following day, an embolectomy procedure was performed independently by the participants and graded by two independent assessors using the GRS and TSRS. Validity was evaluated using Pearson's correlation coefficient (r), reliability by the interclass correlation coefficient (ICC), and agreement by Bland-Altman plots. A p-value <0.05 was considered significant. Results: Thirty-two participants were enrolled in this study. The overall TSRS was found to be a valid assessment tool (r=0.82; 95% confidence interval [CI]: 0.66, 0.91; p<0.001). Domain-specific analyses showed a moderate positive association between all domains (p<0.05), except for instrument handling (r=0.09; 95%CI: -0.27, 0.42; p=0.642). The ICC for overall scores showed excellent reliability for both instruments, GRS and TSRS, with values of 0.97 and 0.92, respectively. Conclusion: The TSRS was found to be a valid and reliable assessment tool for BAE; however, for some domains, such as instrument handling and time and motion, it has limited reliability.

A qualitative study of the long-term consequences and adaptation in daily life after replantation surgery at a young age

Introduction

Impaired functioning is seen in patients following replantation surgery to the thumb or fingers. Our aim was to explore long-term consequences and adaptation in daily life after a thumb and/or multiple finger amputation followed by replantation surgery during young age.

Methods

Semi-structured interviews were conducted with nine recruited individuals and analysed using content analysis. The participants were asked to describe their hand function, pain, appearance, emotional consequences, impact on daily life and strategies for overcoming daily challenges.

Results

The interviews revealed five main categories: memories of the injury and concerns for the future; hand function, pain and cold sensitivity; feelings about having a visibly different hand; adaptation to impairments and challenges in daily life; and key messages to healthcare professions and advice to future patients.The circumstances of the injury were well remembered. Pain at rest was rare but occurred when grasping. Cold sensitivity was a major issue. Appearance-related concerns varied from none to a major problem. Despite impaired hand function, solutions were found to challenges in daily life. Compensatory strategies, personal resources and support from others were important in this adaptation process.

Conclusions

Patients with replantation surgery after an amputation during young age adapt to challenges in daily life over time. Healthcare professionals should offer adequate support to enable emotional processing of trauma experience. Appearance-related concerns should be addressed to prevent distress. Information about alleviating strategies to overcome long-term problems with cold sensitivity should be emphasized.

EMG feedback outperforms force feedback in the presence of prosthesis control disturbance

Closing the prosthesis control loop by providing artificial somatosensory feedback can improve utility and user experience. Additionally, closed-loop control should be more robust with respect to disturbance, but this might depend on the type of feedback provided. Thus, the present study investigates and compares the performance of EMG and force feedback in the presence of control disturbances. Twenty able-bodied subjects and one transradial amputee performed delicate and power grasps with a prosthesis in a functional task, while the control signal gain was temporarily increased (high-gain disturbance) or decreased (low-gain disturbance) without their knowledge. Three outcome measures were considered: the percentage of trials successful in the first attempt (reaction to disturbance), the average number of attempts in trials where the wrong force was initially applied (adaptation to disturbance), and the average completion time of the last attempt in every trial. EMG feedback was shown to offer significantly better performance compared to force feedback during power grasping in terms of reaction to disturbance and completion time. During power grasping with high-gain disturbance, the median first-attempt success rate was significantly higher with EMG feedback (73.3%) compared to that achieved with force feedback (60%). Moreover, the median completion time for power grasps with low-gain disturbance was significantly longer with force feedback than with EMG feedback (3.64 against 2.48 s, an increase of 32%). Contrary to our expectations, there was no significant difference between feedback types with regards to adaptation to disturbances and the two feedback types performed similarly in delicate grasps. The results indicated that EMG feedback displayed better performance than force feedback in the presence of control disturbances, further demonstrating the potential of this approach to provide a reliable prosthesis-user interaction.

A Psychosocial Adjustment Measure for Persons With Upper Limb Amputation

BACKGROUND

Measurement of psychosocial adjustment after upper limb amputation (ULA) could be helpful in identifying persons who may benefit from interventions, such as psychotherapy and/or support groups. However, available measures of psychosocial adjustment after limb loss are currently designed for prosthetic users only.

OBJECTIVE

To create a measure of psychosocial adjustment for persons with ULA that could be completed by individuals regardless of whether a prosthesis is use.

METHODOLOGY

We modified items from an existing Trinity Amputation and Prosthesis Experience Survey (TAPES) measure and generated new items pertinent to persons who did not use a prosthesis. Item content was refined through cognitive interviewing and pilot testing. A telephone survey of 727 persons with major ULA (63.6% male, mean age of 54.4) was conducted after pilot-testing. After exploratory and confirmatory factor analyses (EFA and CFA), Rasch analyses were used to evaluate response categories, item fit and differential item functioning (DIF). Item-person maps, score distributions, and person and item reliability were examined. Test-retest reliability was evaluated in a 50-person subsample.

FINDINGS

EFA and CFA indicated a two-factor solution. Rasch analyses resulted in a 7-item Adjustment to Limitation subscale (CFI=0.96, TLI=0.95, RMSEA=0.128) and a 9-item Work and Independence subscale (CFI=0.935, TLI=0.913, RMSEA=0.193). Cronbach alpha and ICC were 0.82 and 0.63 for the Adjustment to Limitation subscale and 0.90 and 0.80 for the Work and Independence subscale, respectively.

CONCLUSIONS

This study developed the Psychosocial Adjustment to Amputation measure, which contains two subscales: 1) Adjustment to Limitation and 2) Work and Independence. The measure has sound structural validity, good person and item reliability, and moderate to good test-retest reliability.

The effect of calibration parameters on the control of a myoelectric hand prosthesis using EMG feedback

Objective.The implementation of somatosensory feedback in upper limb myoelectric prostheses is an important step towards the restoration of lost sensory-motor functions. EMG feedback is a recently proposed method for closing the control loop wherein the myoelectric signal that drives the prosthesis is also used to generate the feedback provided to the user. Therefore, the characteristics of the myoelectric signal (variability and sensitivity) are likely to significantly affect the ability of the subject to utilize this feedback for online control of the prosthesis.Approach.In the present study, we investigated how the cutoff frequency of the low-pass filter (0.5, 1 and 1.5 Hz) and normalization value (20%, 40% and 60% of the maximum voluntary contraction (MVC)), that are used for the generation of the myoelectric signal, affect the quality of closed-loop control with EMG feedback. Lower cutoff and normalization decrease the intrinsic variability of the EMG but also increase the time lag between the contraction and the feedback (cutoff) as well as the sensitivity of the myoelectric signal (normalization). Ten participants were asked to generate three grasp force levels with a myoelectric prosthetic hand, while receiving five-level vibrotactile EMG feedback, over nine experimental runs (all parameter combinations).Main results.The outcome measure was the success rate (SR) in achieving the appropriate level of myoelectric signal (primary outcome) and grasping force (secondary outcome). Overall, the experiments demonstrated that EMG feedback provided robust control across conditions. Nevertheless, the performance was significantly better for the lowest cutoff (0.5 Hz) and higher normalization (40% and 60%). The highest SR for the EMG was 71.9%, achieved in the condition (40% MVC and 0.5 Hz), and this was 24.1% higher than that in the condition (20% MVC and 1.5 Hz), which resulted in the lowest performance. The SR for the force followed a similar trend.Significance.This is the first study that systematically explored the parameter space for the calibration of EMG feedback, which is a critical step for the future clinical application of this approach.