1,720,976 research outputs found
State of the art of prosthesis simulators for the upper limb: A narrative review
No full textBackground: Research into prosthesis training and design puts a burden on the small population of people with upper-limb absence who can participate in these studies. One solution is to use a prosthetic hand simulator, which allows for attaching a hand prosthesis to an intact limb. However, whether the results of prosthesis simulator studies can be translated to people with upper-limb absence using a hand prosthesis is unclear. Objective: To review the literature on prosthetic hand simulators, provide an overview of current designs, and highlight the differences and similarities between prosthesis simulators and traditional prostheses. Methods: A Boolean combination of keywords was used to search 3 electronic databases: PubMed, Scopus and Web of Science. Relevant articles in English were selected. Results: In total, 52 papers were included in the review, and an overview of the state of the art was presented. We identified the key differences between prosthesis simulators and traditional prostheses as the position of the terminal device and the available degrees of freedom of the arm and (prosthetic) wrist. Conclusions: This paper provides an overview of prosthesis simulator designs over the past 27 years and an overview of the similarities and differences between prosthesis simulators and prostheses. The literature does not provide enough evidence to establish whether the results obtained from simulator studies could be translated to prostheses. A recommendation for future simulator design is to constrain pro- and supination of the forearm of anatomically intact participants and add a prosthetic wrist that can pro- and supinate. Additional research is required to find the ideal terminal device position for a prosthesis simulator with respect to the person's hand.Medical Instruments & Bio-Inspired Technolog
The reality of myoelectric prostheses: How do EMG skill, unpredictability of prosthesis response, and delays impact on user functionality and everyday prosthesis use?
No full textMyoelectric prostheses are designed to provide cosmesis and a degree of upper limb functionality for people with upper limb absence. However, self-reported rejection rates remain stubbornly high, with control of the prosthesis being commonly cited as one of the primary reasons. This observation may indicate that the significant engineering efforts aimed at improving prosthesis control may not have been addressing the most important issues. Surprisingly, there has been no empirical work outside of lab environments to understand the relative importance of key factors affecting prosthesis control. This thesis explores the impacts of three factors: (1) user skill in controlling an EMG signal, (2) unpredictability of prosthesis response introduced at the interface between the electrodes and the skin, and (3) the electromechanical delay in the prosthesis, on user performance, quantified in terms of: (1) functionality (kinematic and gaze), and (2), for the first time, everyday prosthesis use. Chapter 1 introduces the thesis, followed by Chapter 2, which contains a review of existing literature relating to the factors affecting control of myoelectric prostheses. Chapters 3 reports a protocol for the assessment of the impact of skill, unpredictability and delays on user functionality and real world use of a prosthesis. Chapter 4 introduces the first method for the visualisation of time series data from wrist worn accelerometers and presents the first time series data on everyday prosthesis use. Chapter 5 presents results of a study, which recruited 20 trans-radial myoelectric prosthesis users from 6 centres across the UK, drawing conclusions as to the relative impacts of each control factor on performance. Results suggest unpredictability introduced at the electrode-skin interface by the socket mounted electrodes may be the key factor affecting control. Additionally, the results show the delay to the onset of hand opening from a fully closed position to be approximately double the delay measured from any other starting hand aperture. Chapter 6 reports on upper limb activity in the 20 trans-radial prosthesis users and 20 anatomically intact participants. The results show that, by contrast to the anatomically intact participants, upper limb activity of prosthesis users is heavily biased towards the intact limb. Finally Chapter 7 summarises the main findings of the thesis, addressing limitations and suggesting future work
Evidencing the effectiveness of upper limb prostheses: a multi-stakeholder perspective on study requirements
No full textThe provision of upper limb prosthetic devices through the National Health Services (NHS) within the United Kingdom is driven by national policies. NHS England have recently published a new policy to provide multi-grip myoelectric hands. The policy highlighted that there was limited evidence to support its deployment and it will be reviewed should new information arise. The clear identification of the evidence gap provides an opportunity for the academic research community to conduct studies that will inform future iterations of this and other upper limb prosthetic related policies. This paper presents a summary of findings and recommendations based on two multi-stakeholder workshops held in June 2022 and July 2022, which explored the design requirements for policy-driven research studies. The workshops involved people from a broad range of stakeholder groups: policy, academia, NHS clinical and management, industry, and a person with upper limb absence. The workshop discussions focused on the research questions that NHS England identified in the policy evidence review: (1) Clinical Effectiveness; (2) Cost Effectiveness; (3) Safety; and (4) Patient Subgroups. The recommendations based on stakeholder discussions included the need to gather qualitative and quantitative research evidence, use goal-based outcome measures, and conduct longitudinal studies. Future research studies also need to address the complexities of conducting national and international policy-driven research, such as clinical resource capacity and participant involvement.</p
An approach to replicating clinical prosthetic sockets to support research
No full textResearch into upper-limb prostheses is often limited by access to prosthetic sockets, each custom-fitted by a prosthetist. Many technological advances in upper-limb prostheses come from engineering focussed labs. Unfortunately, with a global shortage of prosthetists, often, these labs cannot rely on access to a prosthetist to support experimental work, making it hard to undertake quality research reflective of clinical realities. We propose a process to replicate the internal shape of a clinical standard prosthetic socket and facilitate broader access to more representative research. Our proposed method uses a combination of silicone, alginate, and plaster. This proof-of-concept study demonstrates that the proposed new approach is feasible and accurate. This technique will facilitate improvements in the assessment of prosthetic technologies. The process is non-destructive, thus also opening opportunities for socket design and electrode placement research with the removal of confounding factors relating to socket shape. Improving access to prosthetic sockets for research purposes will undoubtedly have international impact
Replication of clinical prosthetic sockets for research purposes
No full textFor research in the field of prosthetics to be representative of clinical realities, studies require inclusion of clinical standard prosthetic sockets. This necessitates involvement of a prosthetist (clinical professional) in any study, which is to truly explore the effectiveness of existing or novel prosthetic technologies. Unfortunately, there is a global shortage of prosthetists. With many technological advances in upper-limb prosthetics coming from engineering focused labs, it is unsurprising that studies are frequently conducted with anatomically intact individuals. In this paper, we present a method to clone the shape of a clinical standard prosthetic socket for research purposes. The technique uses silicone to capture the socket shape; this is then converted into a plaster mold, which can be used to manufacture an identically shaped socket using standard clinical manufacturing techniques. The whole process can be achieved without the involvement of a prosthetist. To validate the proposed technique, molds from an original socket and socket clone were 3D scanned. The distance between the aligned meshes were measured using CloudCompare software. The mean distance between the points on the 2 meshes was 0.16 mm (standard deviation 0.38 mm). This proof-of-concept study demonstrates that the proposed new approach to cloning a clinical standard prosthetic socket is feasible and accurate. This technique will facilitate improvements in the assessment of prosthetic technologies. The process is nondestructive, thus also opening opportunities for socket design and electrode placement research with the removal of confounding factors relating to socket shape.</p
Real-World Testing of the Self Grasping Hand, a Novel Adjustable Passive Prosthesis: A Single Group Pilot Study
Full text link(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.Medical Instruments & Bio-Inspired Technolog
An evaluation of contralateral hand involvement in the operation of the Delft Self-Grasping Hand, an adjustable passive prosthesis.
Full text linkThe Delft Self-Grasping Hand is an adjustable passive prosthesis operated using the concept of tenodesis (where opening and closing of the hand is mechanically linked to the flexion and extension of the wrist). As a purely mechanical device that does not require harnessing, the Self-Grasping Hand offers a promising alternative to current prostheses. However, the contralateral hand is almost always required to operate the mechanism to release a grasp and is sometimes also used to help form the grasp; hence limiting the time it is available for other purposes. In this study we quantified the amount of time the contralateral hand was occupied with operating the Self-Grasping Hand, classified as either direct or indirect interaction, and investigated how these periods changed with practice. We studied 10 anatomically intact participants learning to use the Self-Grasping Hand fitted to a prosthesis simulator. The learning process involved 10 repeats of a feasible subset of the tasks in the Southampton Hand Assessment Procedure (SHAP). Video footage was analysed, and the time that the contralateral hand was engaged in grasping or releasing was calculated. Functionality scores increased for all participants, plateauing at an Index of Functionality of 33.5 after 5 SHAP attempts. Contralateral hand involvement reduced significantly from 6.47 (first 3 attempts) to 4.68 seconds (last three attempts), but as a proportion of total task time remained relatively steady (increasing from 29% to 32%). For 9/10 participants most of this time was supporting the initiation of grasps rather than releases. The reliance on direct or indirect interactions between the contralateral hand and the prosthesis varied between participants but appeared to remain relatively unchanged with practice. Future studies should consider evaluating the impact of reliance on the contralateral limb in day-to-day life and development of suitable training methods
A quantitative comparison between the mHand Adapt passive adjustable hand prosthesis and its predecessor, the Delft Self-Grasping Hand.
No full textIntroductionThe Delft Self-Grasping Hand (SGH) is an adjustable passive hand prosthesis that relies on wrist flexion to adjust the aperture of its grasp. The mechanism requires engagement of the contralateral hand meaning that hand is not available for other tasks. A commercialised version of this prosthesis, known as the mHand Adapt, includes a new release mechanism, which avoids the need to press a release button, and changes to the hand shape. This study is the first of its kind to compare two passive adjustable hand prostheses on the basis of quantitative scoring and contralateral hand involvement.Methods10 anatomically intact participants were asked to perform the Southampton Hand Assessment Procedure (SHAP) with the mHand. Functionality and contralateral hand involvement were recorded and compared against SGH data originating from a previous trial involving a nearly identical testing regime.ResultsmHand exhibited higher functionality scores and less contralateral hand interaction time, especially during release-aiding interactions. Additionally, a wider range of tasks could be completed using the mHand than the SGH.DiscussionGeometric changes make the mHand more capable of manipulating smaller objects. The altered locking mechanism means some tasks can be performed without any contralateral hand involvement and a higher number of tasks do not require contralateral involvement when releasing. Some participants struggled with achieving a good initial grip due to the inability to tighten the grasp once already formed.ConclusionThe mHand offers the user higher functionality scores with less contralateral hand interaction time and the ability to perform a wider range of tasks. However, there are some design trade-offs which may make it slightly harder to learn to use
Wear and use of prostheses in sport by adolescents with upper limb absence: a preliminary mixed-methods study
No full textBackground: there is minimal research on sports participation in adolescents with upper limb absence (ULA) and specifically on the impact of prosthesis provision. Objectives: this study explored using activity monitoring sensors and interviews to gain insight into levels of sport participation and associated prosthesis use in active adolescents with ULA.Study design: a mixed methods study using a convergent parallel design. Methods: semi-structured interviews and activity diaries were used to investigate sports and related activities undertaken during a 2-week period. Prosthesis wear/use were determined via accelerometers worn on the anatomical and prosthetic wrists throughout; interview data added context. For comparison, accelerometer data and activity diaries were captured from similar aged anatomically intact (AI) participants. Results: three adolescents with unilateral transradial ULA and 4 AI adolescents were recruited. Two ULA participants wore prostheses during sport (16.2% and 56.5% of the time). The third rarely wore their prosthesis. The ability to participate in sport has a powerful influence on participants’ lives, and prostheses were used when participants felt they offered specific benefits. In contrast to AI participants, who showed similar reliance on each of their arms throughout, when wearing a prosthesis, users were heavily reliant on the anatomical arm, including during periods playing sports.Conclusions: prosthesis use facilitated access to some sports, although they were only used by 2 out of 3 participants for short periods. The methods were acceptable to adolescent individuals with ULA.</p
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