Prosthetic Research Research Articles

Towards Instant Calibration in Myoelectric Prosthetic Hands: A Highly Data-Efficient Controller Based on the Wasserstein Distance.

Prosthetic hand control research typically focuses on developing increasingly complex controllers to achieve diminishing returns in pattern recognition of muscle activity signals, making models less suitable for user calibration. Some works have investigated transfer learning to alleviate this, but such approaches increase model size dramatically-thus reducing their suitability for implementation on real prostheses. In this work, we propose a novel, non-parametric controller that uses the Wasserstein distance to compare the distribution of incoming signals to those of a set of reference distributions, with the intended action classified as the closest distribution. This controller requires only a single capture of data per reference distribution, making calibration almost instantaneous. Preliminary experiments building a reference library show that, in theory, users are able to produce up to 9 distinguishable muscle activity patterns. However, in practice, variation when repeating actions reduces this. Controller accuracy results show that 10 non-disabled and 1 disabled participant were able to use the controller with a maximum of two recalibrations to perform 6 actions at an average accuracy of 89.9% and 86.7% respectively. Practical experiments show that the controller allows users to complete all tasks of the Jebsen-Taylor Hand Function Test, although the task of picking and placing small common objects required on average more time than the protocol's maximum time.

Prosthetic and robotic wrists comparing with the intelligently evolved human wrist: A review

AbstractBoth prosthetic and robotic research communities have tended to focus on hand/gripper development. However, the wrist unit could enable higher mobility of the end effector and thus more efficient and dexterous manipulation. The current state of the art in both prosthetic and robotic wrists is reviewed systematically, mainly concerning their kinematic structures and resultant capabilities. Further, by considering the biomechanical advantages of the human wrist, an evaluation including the mobility, stability, output capability, load capacity and flexibility of the current artificial wrists is conducted. With the pentagonal capability radar charts, the major limitations and challenges in the current development of artificial wrists are derived. This paper hence provides some useful insights for better robotic wrist design and development.

A Multi-Material, Anthropomorphic Metacarpophalangeal Joint With Abduction and Adduction Actuated by Soft Artificial Muscles

In recent years, the field of hand prosthetic research has seen anthropomorphic designs that make use of hybrid soft-rigid materials, combining the load-bearing capability of rigid skeletons with the robustness and mobility of soft materials. This approach generates potential for more advanced prosthetics, yet there are unexplored opportunities for leveraging soft actuation and joint interfaces towards creating more versatile joints. In this work, we present a multi-material metacarpophalangeal (MCP) joint that uses a rigid skeleton and soft ligaments, with the addition of novel soft actuators for active ab/adduction and soft cartilage-lubricant for smoother motion. To support the joint’s potential applications in more dexterous prosthetics, we perform experiments to demonstrate its (1) near linearity in positional control (2) positional repeatability (3) and force output repeatability. We also find that the addition of the novel cartilage-lubricant combination improves the joint’s dynamic response.

Developing a paediatric healthcare research network: key learnings from the 'Starworks' child prosthetics project

The context of child prosthetics is a complex and important area for research and innovation. Yet, like many areas of paediatric medical technology development, there are several barriers to innovating specifically for the unique needs of children (i.e., a relatively small patient population or ‘market’). As such, much child prosthetics technology is developed from the downsizing of adult prosthetics, leading to suboptimal outcomes for children and young people. Since 2016, the Starworks Child Prosthetics Research Network has been exploring this space, bringing children and their families together with key opinion leaders from the NHS, clinical Academia and leading National Research Centres with capabilities in child prosthetics with the aim of increasing research across the system. Above all else, Starworks is centred on the needs of children and their families, ensuring they have an equal voice in driving the ongoing research agenda. This article will share key learnings from the creation and development of the Starworks Network that may be applicable and/or adaptable across a wider paediatric medical technology research and innovation landscape. In particular it will discuss how it addressed three key aims of; (1) Addressing child-specific issues; (2) Building a sustainable network; and (3) Fostering impactful innovation.

A Multi-User Transradial Functional-Test Socket for Validation of New Myoelectric Prosthetic Control Strategies.

The validation of myoelectric prosthetic control strategies for individuals experiencing upper-limb loss is hindered by the time and cost affiliated with traditional custom-fabricated sockets. Consequently, researchers often rely upon virtual reality or robotic arms to validate novel control strategies, which limits end-user involvement. Prosthetists fabricate diagnostic check sockets to assess and refine socket fit, but these clinical techniques are not readily available to researchers and are not intended to assess functionality for control strategies. Here we present a multi-user, low-cost, transradial, functional-test socket for short-term research use that can be custom-fit and donned rapidly, used in conjunction with various electromyography configurations, and adapted for use with various residual limbs and terminal devices. In this study, participants with upper-limb amputation completed functional tasks in physical and virtual environments both with and without the socket, and they reported on their perceived comfort level over time. The functional-test socket was fabricated prior to participants' arrival, iteratively fitted by the researchers within 10 mins, and donned in under 1 min (excluding electrode placement, which will vary for different use cases). It accommodated multiple individuals and terminal devices and had a total cost of materials under $10 USD. Across all participants, the socket did not significantly impede functional task performance or reduce the electromyography signal-to-noise ratio. The socket was rated as comfortable enough for at least 2 h of use, though it was expectedly perceived as less comfortable than a clinically-prescribed daily-use socket. The development of this multi-user, transradial, functional-test socket constitutes an important step toward increased end-user participation in advanced myoelectric prosthetic research. The socket design has been open-sourced and is available for other researchers.

Unilateral below-knee prosthesis users walking on uneven terrain: The effect of adding a toe joint to a passive prosthesis

Lower limb prosthesis users cite uneven terrain as a challenging surface to walk on. We sought to determine whether adding a Flexible toe joint to a prosthetic foot would be preferred by unilateral below-knee prosthesis users relative to a Locked (non-articulating) toe joint for walking on uneven terrain. We also quantified lower limb joint kinetics for the Locked and Flexible toe joint configurations. Five of our nine participants preferred the Flexible toe joint when walking on uneven terrain, yet from a biomechanical standpoint, the reason for this is unclear. All participants exhibited reductions in prosthetic limb net positive hip joint work when walking with a Flexible toe joint (11%; p < 0.05). For other parameters (e.g., prosthetic side knee joint moments) we observed high inter-subject variation, which adds to a growing body of literature highlighting the need for subject-specific data analyses in lower limb prosthetics research.

Towards User-Centred Prosthetics Research Beyond the Laboratory.

The purpose of this study was to explore a range of perspectives on how academic research and clinical assessment of upper-limb prosthetics could happen in environments outside of laboratories and clinics, such as within peoples’ homes. Two co-creation workshops were held, which included people who use upper limb prosthetic devices (hereafter called users), clinicians, academics, a policy stakeholder, and a representative from the upper-limb prosthetics industry (hereafter called professionals). The discussions during the workshops indicate that research and clinical assessment conducted remotely from a laboratory or clinic could inform future solutions that address user needs. Users were open to the idea of sharing sensor and contextual data from within their homes to external laboratories during research studies. However, this was dependent upon several considerations, such as choice and control over data collection. Regarding clinical assessment, users had reservations of how data may be used to inform future prosthetic prescriptions whilst, clinicians were concerned with resource implications and capacity to process user data. The paper presents findings of the discussions shared by participants during both workshops. The paper concludes with a conjecture that collecting sensor and contextual data from users within their home environment will contribute towards literature within the field, and potentially inform future care policies for upper limb prosthetics. The involvement of users during such studies will be critical and can be enabled via a co-creation approach. In the short term, this may be achieved through academic research studies, which may in the long term inform a framework for clinical in-home trials and clinical remote assessment.

Identifying and linking prosthetic outcomes to the ICF framework: a step to inform the benefits measured in prosthetic health economic evaluations

Purpose Prosthetic research seems focused on measuring gait-related outcomes that may not adequately measure real-world benefits of prosthetic interventions. Systematically cataloguing a comprehensive range of outcomes is an important steppingstone towards developing a holistic way to measure the benefits of prosthetic interventions for future health economic evaluations. The purpose of this research was to identify and catalogue the outcomes measured in lower-limb prosthetic research using the International Classification of Functioning, Disability, and Health (ICF) framework and a custom clinical framework, and thereby describe the existing research focus and identify evidence gaps. Materials and methods A structured literature search identified systematic reviews of lower-limb prosthetic interventions. Reported outcomes were extracted from included studies and linked to the ICF- and clinical-frameworks. Results Of the 1297 extracted outcomes, 1060 were linked to the ICF framework. Most outcomes linked to second- (63.8%) or third-level categories (33.4%), such as Gait Pattern Functions (b770, 49.8%). Most of these outcomes (31.2%) describe temporospatial, kinematic or kinetic gait measures as categorised by the clinical framework. Conclusions Lower-limb prosthetic research is focused on laboratory-based measures of gait. There are evidence gaps describing participation in real-world activities – important outcomes to inform policy and investment decisions that determine the prosthetic interventions available for people with limb-loss. Implications for rehabilitation Cataloguing the outcomes used in prosthetic research to the International Classification of Functioning, Disability, and Health (ICF) allows important evidence gaps to be illuminated given the holistic description of function and disability. Establishing a comprehensive list of prosthetic outcomes, described using an internationally recognised framework with unified and consistent language, is an important steppingstone towards developing a core outcome set (COS) for prosthetic interventions and informing the benefits measured in future prosthetic health economic evaluations (HEEs). Being able to measure the benefits of a prosthesis that are most important to prosthesis users and funders has potential to fundamentally change future HEEs that influence funding policies, and ultimately the prostheses made available to people living with limb-loss.

Alpha-band activity in parietofrontal cortex predicts future availability of vibrotactile feedback in prosthesis use.

Prosthesis disuse and abandonment is an ongoing issue in upper-limb amputation. In addition to lost structural and motor function, amputation also results in decreased task-specific sensory information. One proposed remedy is augmenting somatosensory information using vibrotactile feedback to provide tactile feedback of grasping objects. While the role of frontal and parietal areas in motor tasks is well established, the neural and kinematic effects of this augmented vibrotactile feedback remain in question. In this study, we sought to understand the neurobehavioral effects of providing augmented feedback during a reach-grasp-transport task. Ten persons with sound limbs performed a motor task while wearing a prosthesis simulator with and without vibrotactile feedback. We hypothesized that providing vibrotactile feedback during prosthesis use would increase activity in frontal and parietal areas and improve grasp-related behavior. Results show that anticipation of upcoming vibrotactile feedback may be encoded in motor and parietal areas during the reach-to-grasp phase of the task. While grasp aperture is unaffected by vibrotactile feedback, the availability of vibrotactile feedback does lead to a reduction in velocity during object transport. These results help shed light on how engineered feedback is utilized by prostheses users and provide methodologies for further assessment in advanced prosthetics research.

Adherence rates of person-centered language in amputation research: A cross-sectional analysis.

Person-centered language (PCL) is the recommended method of addressing patients by the American Medical Association Manual of Style in medical research, thus requiring published manuscripts to be free of non-PCL. Although individuals, communities, and organizations have the autonomy to use non-PCL, it is imperative for medical researchers to use PCL in an effort to reduce the transfer of stigmatization into clinical practice. To determine current adherence to PCL related to individuals with limb or digit amputations in scientific journals. A cross-sectional analysis was performed by systematically searching PubMed from May 1, 2018 to April 30, 2020 for publications focused on amputations. Journals with less than 20 articles were excluded, and remaining publications were randomized, with the first 500 articles selected. Articles were screened for inclusion criteria, and data were extracted in masked, duplicate fashion, for predetermined non-PCL terms. A chi-squared test and logistic regression were used to quantify PCL adherence study characteristics. Of 500 articles, 81 were excluded, and 419 articles from 13 journals were examined-64.6% containing non-PCL. The most common non-PCL terms used were "amputee" in 148 articles and "limb loss" in 138 articles. PCL was significantly associated with article type, research funding, and journal requirements for PCL. Results indicate that one-third of research articles were PCL-adherent, which we speculate may contribute to the stigma that individuals with amputations experience. Our findings suggest that PCL adherence is higher among surgery research and lower among engineering and prosthetic research.

Increasing Voluntary Myoelectric Training Time Through Game Design.

In virtual prosthetic training research, serious games have been investigated for over 30 years. However, few game design elements are used and assessed for their effect on the voluntary adherence and repetition of the performed task. We compared two game-based versions of an established myoelectric-controlled virtual prosthetic training task with an interface without game elements of the same task [for video, see (Garske, 2022)]. Twelve limb-intact participants were sorted into three groups of comparable ability and asked to perform the task as long as they were motivated. Following the task, they completed a questionnaire regarding their motivation and engagement in the task. The investigation established that participants in the game-based groups performed the task significantly longer when more game design elements were implemented in the task (medians of 6 vs. 9.5 vs. 14 blocks for groups with increasing number of different game design elements). The participants in the game-based versions were also more likely to end the task out of fatigue than for reasons of boredom or frustration, which was verified by a fatigue analysis of the myoelectric signal. We demonstrated that the utilization of game design methodically in virtual myoelectric training tasks can support adherence and duration of a virtual training, in the short-term. Whether such short-term enhanced engagement would lead to long-term adherence remains an open question.

The Value of Health Economics and Outcomes Research in Prosthetics and Orthotics.

The demand has increased for evidence regarding the effectiveness and value of prosthetic and orthotic rehabilitation interventions. Clinicians and managers are under pressure to provide treatment recommendations and demonstrate effectiveness through outcomes. It is often assumed that rehabilitation interventions, including the provision of custom-made and custom-fit orthotic and prosthetic devices, are beneficial to patients. Assessing the value of orthotic and prosthetic services has become more critical to continue to ensure equitable access to needed services. Health economics and outcomes research methods serve as tools to gauge the value of prosthetic and orthotic rehabilitation interventions. The purpose of this article is to provide an overview of the current need of health economics and outcomes research in orthotics and prosthetics, to introduce common economic methods that assist to generate real-world evidence, and to discusses the potential value of economic methods for clinicians and clinical practice.

Value and Applicability of Large Administrative Healthcare Databases in Prosthetics and Orthotics Outcomes Research.

The goal of health economics and outcomes research is to improve healthcare decision making. In the absence of high-value clinical data, the availability and quality of administrative healthcare data could be vital in the generation of evidence for orthotics and prosthetics services. The purpose of this article is to provide a stronger understanding of administrative healthcare data analysis, an area that has been scarcely examined within prosthetics and orthotics despite the wealth of information available within such data. Examples of common datasets in this arena currently available are provided, as well as an overview of the limitations and advantages of studies utilizing such datasets.

With Signal Processing Support, Prosthetics Are Becoming Safer, More Natural, and Increasingly Sensitive: Ongoing Prosthetics Research Is Leading to Systems That Adapt to Users Rather Than Forcing Users to Accommodate the Prosthesis [Special Reports

Ongoing prosthetics research is leading to systems that adapt to users rather than forcing users to accommodate the prosthesis Market research and consulting firm Precedence Research forecasts that the prosthetics market will reach approximately US$13.2 billion by 2027, expanding at a compound annual growth rate of 4.8% from 2020 to 2027. A new generation of breakthrough technologies is helping to propel the growth of the prosthetics market. Significant progress is being made in multiple areas, including usability, safety, performance, and control. Signal processing is playing a major role in all of these key areas.

The Utilization of Consensus Techniques in Education and Research in Medical Professions

ABSTRACT Study Design This is a narrative review. Introduction Consensus techniques are an increasingly common research tool used to define levels of expert agreement on a topic where evidence is inconsistent or lacking. An assessment of commonly used consensus techniques can inform future education and research. Objective The aim of this study was to describe the use of various consensus techniques used in education and research in orthotics and prosthetics and closely related medical professions, to aid in choosing the most appropriate consensus technique for future research. Methods A systematic search of the literature was conducted using specific terms and keywords related to various consensus techniques, applications of consensus techniques in research and education, and medical disciplines related to orthotics and prosthetics. Studies were included if they described the use of a consensus technique for medical education or research and explained why the specific technique was used. Results Common consensus techniques were identified in the literature. To allow comparison of the techniques, the advantages, disadvantages, limitations, and previous applications of each were extracted from the literature. Conclusion Using the information from the literature, the most prevalent consensus techniques can be compared, aiding educators and researchers in choosing the technique most suitable for their topic of inquiry.

Using a Sweating Residuum/socket Interface Simulator for the Evaluation of Sweat Management Liners in Lower Limb Prosthetics.

Lab-based simulators can help to reduce variability in prosthetics research. However, they have not yet been used to investigate the effects of sweating at the residuum-liner interface. This work sought to create and validate a simulator to replicate the mechanics of residual limb perspiration. The developed apparatus was used to assess the effects of perspiration and different liner designs. By scanning a cast, an artificial residuum was manufactured using a 3D-printed, transtibial bone model encased in silicone, moulded with pores. The pores allowed water to emit from the residuum surface, simulating sweating. Dry and sweating cyclic tests were performed by applying compressive and tensile loading, while measuring the displacement of the residuum relative to the socket. Tests were conducted using standard and perforated liners. Although maximum displacement varied between test setups, its variance was low (coefficient of variation <1%) and consistent between dry tests. For unperforated liners, sweating increased the standard deviation of maximum displacement approximately threefold (0.04mm v 0.12mm, p<0.001). However, with the perforated liner, sweating had little effect on standard deviation compared to dry tests (0.04mm v 0.04mm, p=0.497). The test apparatus was effective at simulating the effect of perspiration at the residual limb. Moisture at the skin-liner interface can lead to inconsistent mechanics. Perforated liners help to remove sweat from the skin-liner interface, thereby mitigating these effects.

Focusing research efforts on the unique needs of women prosthesis users.

Women with lower limb loss represent a relevant and growing patient cohort with unique rehabilitation needs. These needs are emphasized in a growing body of literature and the most recent Veteran Affairs/Department of Defense clinical practice guidelines. Women with limb loss experience greater dissatisfaction with prosthetic fit, appearance, and types of footwear they can use. There is a lack of prosthetics solutions to accommodate the desire of women to wear different footwear varieties, including high heels. The choice to wear a variety of footwear is important to attire and hence community participation. Despite these recognized challenges, women are still underserved in prosthetics research, which limits available information to guide the rehabilitation process. This narrative review describes considerations of lower limb prosthesis prescription and use by women, and examples of current research to address these topics. Research efforts are beginning to explore factors that contribute to prosthetics prescription for women, and design creative prosthetics solutions to expand the range of available footwear options. Research is still needed to characterize the types of footwear women with limb loss prefer to use, and the effects of prosthesis designs, footwear, and lower limb loss on women mobility outcomes and community participation. Through targeted research initiatives, scientists and clinicians can be responsive to the specific needs of women to provide evidence-based guidelines for prosthetics prescription and improve the patient-centered care after limb loss.

TIPS for Scaling up Research in Upper Limb Prosthetics

Many research initiatives have been employed in upper limb prosthetics (ULP) in the last few decades. The body of knowledge is growing and inspired by new and interesting technology that has been brought to the market to facilitate functioning of people with upper limb defects. However, a lot of research initiatives do not reach the target population. Several reasons can be identified as to why research does not move beyond the lab, such as lack of research quality, disappointing results of new initiatives, lack of funding to further develop promising initiatives, and poor implementation or dissemination of results. In this paper, we will appraise the current status of the research in ULP. Furthermore, we will try to provide food for thought to scale up research in ULP, focusing on (1) translation of research findings, (2) the quality of innovations in the light of evidence-based medicine and evidence-based practice, (3) patient involvement, and (4) spreading of research findings by focusing on implementation and dissemination of results and collaboration in a national and international perspective. With this paper, we aim to open the discussion on scaling up research in the community of professionals working in the field of ULP.

Harmonization of Outcomes and Vision Endpoints in Vision Restoration Trials: Recommendations from the International HOVER Taskforce.

Translational research in vision prosthetics, gene therapy, optogenetics, stem cell and other forms of transplantation, and sensory substitution is creating new therapeutic options for patients with neural forms of blindness. The technical challenges faced by each of these disciplines differ considerably, but they all face the same challenge of how to assess vision in patients with ultra-low vision (ULV), who will be the earliest subjects to receive new therapies.Historically, there were few tests to assess vision in ULV patients. In the 1990s, the field of visual prosthetics expanded rapidly, and this activity led to a heightened need to develop better tests to quantify end points for clinical studies. Each group tended to develop novel tests, which made it difficult to compare outcomes across groups. The common lack of validation of the tests and the variable use of controls added to the challenge of interpreting the outcomes of these clinical studies.In 2014, at the bi-annual International “Eye and the Chip” meeting of experts in the field of visual prosthetics, a group of interested leaders agreed to work cooperatively to develop the International Harmonization of Outcomes and Vision Endpoints in Vision Restoration Trials (HOVER) Taskforce. Under this banner, more than 80 specialists across seven topic areas joined an effort to formulate guidelines for performing and reporting psychophysical tests in humans who participate in clinical trials for visual restoration. This document provides the complete version of the consensus opinions from the HOVER taskforce, which, together with its rules of governance, will be posted on the website of the Henry Ford Department of Ophthalmology (www.artificialvision.org).Research groups or companies that choose to follow these guidelines are encouraged to include a specific statement to that effect in their communications to the public. The Executive Committee of the HOVER Taskforce will maintain a list of all human psychophysical research in the relevant fields of research on the same website to provide an overview of methods and outcomes of all clinical work being performed in an attempt to restore vision to the blind. This website will also specify which scientific publications contain the statement of certification. The website will be updated every 2 years and continue to exist as a living document of worldwide efforts to restore vision to the blind.The HOVER consensus document has been written by over 80 of the world's experts in vision restoration and low vision and provides recommendations on the measurement and reporting of patient outcomes in vision restoration trials.

Hippocampal CA1 and CA3 neural recording in the human brain: validation of depth electrode placement through high-resolution imaging and electrophysiology.

Intracranial human brain recordings typically utilize recording systems that do not distinguish individual neuron action potentials. In such cases, individual neurons are not identified by location within functional circuits. In this paper, verified localization of singly recorded hippocampal neurons within the CA3 and CA1 cell fields is demonstrated. Macro-micro depth electrodes were implanted in 23 human patients undergoing invasive monitoring for identification of epileptic seizure foci. Individual neurons were isolated and identified via extracellular action potential waveforms recorded via macro-micro depth electrodes localized within the hippocampus. A morphometric survey was performed using 3T MRI scans of hippocampi from the 23 implanted patients, as well as 46 normal (i.e., nonepileptic) patients and 26 patients with a history of epilepsy but no history of depth electrode placement, which provided average dimensions of the hippocampus along typical implantation tracks. Localization within CA3 and CA1 cell fields was tentatively assigned on the basis of recording electrode site, stereotactic positioning of the depth electrode in comparison with the morphometric survey, and postsurgical MRI. Cells were selected as candidate CA3 and CA1 principal neurons on the basis of waveform and firing rate characteristics and confirmed within the CA3-to-CA1 neural projection pathways via measures of functional connectivity. Cross-correlation analysis confirmed that nearly 80% of putative CA3-to-CA1 cell pairs exhibited positive correlations compatible with feed-forward connection between the cells, while only 2.6% exhibited feedback (inverse) connectivity. Even though synchronous and long-latency correlations were excluded, feed-forward correlation between CA3-CA1 pairs was identified in 1071 (26%) of 4070 total pairs, which favorably compares to reports of 20%-25% feed-forward CA3-CA1 correlation noted in published animal studies. This study demonstrates the ability to record neurons in vivo from specified regions and subfields of the human brain. As brain-machine interface and neural prosthetic research continues to expand, it is necessary to be able to identify recording and stimulation sites within neural circuits of interest.