Clinical Research Directory

Regulatory Clearance of the Glide Control Strategy for Upper Limb Prostheses

The investigators will test the following hypothesis: Use of Glide results in improved functional performance, satisfaction, and usage metrics as compared to use of a standard Direct Control (DC) prosthesis. This study will compare the use of Glide \[Experimental\] prosthesis with a DC \[Standard\] prosthesis in a clinical setting and in unsupervised daily activity. We will follow a multiple baseline design, specifically an AB design. Each of the subjects will use the Experimental and Standard systems over a total of 24-weeks. The A phase is the baseline phase where the DC prosthesis will be used, and the B phase will be the treatment phase where the Glide prosthesis will be used. Participants will undergo an A phase of either 10-weeks, 12-weeks, or 14-weeks duration, with the remaining 14-, 12-, or 10-weeks of the study being dedicated to the B phase.

Assessing Ambulatory and Non-ambulatory Community Mobility in People With Lower Limb Amputation

Mobility is a fundamental aspect of daily life, enabling individuals to participate in social, occupational, and recreational activities. Community mobility, defined as movement in environments outside the home, is particularly important for quality-of-life. Following lower limb amputation (LLA), mobility limitations are common and persistent. With rehabilitation and prosthetic training, many regain the ability to ambulate but results vary as only 25 - 58% of patients regain ambulatory ability and less than half of those who become ambulatory achieve sufficient ability to walk in community settings. As a result, \~40% of people with LLA are ambulatory but also use wheeled mobility (e.g., wheelchair, scooter) for some or all of their community mobility tasks. To date, the complementary role of wheeled and ambulatory mobility in maximizing community mobility has been overlooked, with clinical research overwhelmingly focused on assessing and improving ambulatory ability despite its impracticality for many community settings.

Bio Leg: Advancing Mobility

Following transfemoral amputation, regaining functional mobility, particularly the ability to navigate curbs, ramps, long distances, and the ability to stand is challenging and often unattainable. Use of advanced prosthetic limb technology can dramatically influence mobility outcomes. The purpose of this study is to compare walking function in individuals with transfemoral amputations who are current users of the C-leg (current clinical standard) to function achieved when using the Bio Leg powered micro-processor prosthetic knee.

Influence Of A Slope Adaptive Foot On Participation Of Veterans With Lower-Limb Amputations

Veterans with below-knee amputations are limited by prosthetic feet that cannot adapt to sloped and uneven terrain. This limitation results in reduced mobility, reduced balance confidence, and a higher risk of falls among some individuals who use below-knee prostheses, which have been shown to negatively impact participation in daily and recreational activities. The investigative group has designed a novel Slope Adaptive Foot (SAF) that is mechanically passive, capable of slope adaption on every step of walking, and maintains high levels of energy storage and return. Pilot testing of the SAF with Veterans has generated excellent results to date, with comments suggesting potential improvements in participation. This study will evaluate the extent to which participation and fall-related health outcomes are influenced by using the SAF versus a typical hydraulic foot in a cross-over randomized controlled trial. Using mixed-methods, the investigators will also collect long-term data of Veterans using their preferred foot to inform the development of evidence-based education materials for use in clinical decision making.

A Unique Body-Powered Terminal Device With Enhanced Grasping Capabilities for Individuals With Upper Limb Loss

We have developed a novel terminal device for a prosthetic arm that eliminates the functional tradeoffs seen in body-powered voluntary open devices. The primary goal of this study is to validate the performance of the device against the commercial state-of-the-art in upper limb terminal devices.

Regenerative Peripheral Nerve Interface for Control of Lower Limb Prostheses

Individuals with an above-knee lower limb amputation are known to walk more slowly, expend more energy, have a greater risk of falling, and have reduced quality of life compared to individuals without amputation and those with below knee amputation. One of the driving factors behind these deficits is the lack of active function provided by above-knee prostheses with prosthetic knees and ankles. While many prosthetic devices have been developed for functional restoration after major lower extremity amputation, there remains no stable interface to facilitate reliable, long-term volitional control of an advanced robotic limb capable moving multiple joints. Moreover, there is no existing interface that provides useful sensory feedback that in turn enhances the functional capabilities of the prosthesis. To achieve both greater signal specificity and long-term signal stability, we have developed a biologic interface known as the Regenerative Peripheral Nerve Interface (RPNI). An RPNI consists of a peripheral nerve that is implanted into a free muscle graft that would otherwise go unused in the residual limb. As the nerve grows, it reinnervates the free muscle graft which undergoes a predictable sequence of revascularization and regeneration. The main questions it aims to answer are: 1. Can the amplitude, movement specificity and stability of sciatic nerve RPNI electromyography (EMG) signals be detected up to one year post RPNI surgery? 2. Do RPNIs contain information to enable control of a physical motorized prosthetic leg with multiple degrees of freedom? 3. Does stimulation of sciatic nerve RPNIs provides meaningful sensory feedback? Consenting participants with unilateral transfemoral amputation (TFA) will: 1. Undergo RPNI surgery and electrode implantation in the residual limb. 2. Attend regular follow-up visits following surgery to assess the health and signal strength of the RPNIs and their ability to use a prescribed prosthesis between 3- and 12-months following implantation. 3. Undergo explantation of electrodes following the conclusion of data collection.

Thermoregulation in Individuals With a Leg Amputation

The goal of this project is to understand the factors that affect skin temperature (e.g., tissue above amputation site, and opposite foot) in people with amputation and diabetes. This project will also test the effects of 'shock-absorbing' prosthesis on skin temperature responses.

Can an Array of Micro-electrodes Implanted in a Human Nerve Record Neural Signals and Provide Feedback?

The investigators will investigate the device feasibility of human peripheral nerves and muscles recording and stimulation using percutaneous Utah Slanted Electrode Arrays (pUSEAs) implanted into residual peripheral arm nerves and EMG electrodes implanted in the residual muscles of patients with limb amputations in order to determine the ability of the HAPTIX (Hand Proprioception and Touch Interfaces) System to control an upper-extremity prosthesis, and to provide a sense of cutaneous touch and muscle proprioceptive feedback to the amputee.

Assessment of a Hybrid Pump for Vacuum Suspension of Prosthetic Sockets for Persons With Lower Limb Loss to Characterize the Effects of Added Movement on Socket-reaction Torques

Prostheses can be suspended from the amputated limb using a variety of techniques, such as straps and suction. Suspending the prosthesis by creating a vacuum between the prosthetic socket and limb using a pump has benefits over other techniques including improved limb health and mobility. A new pump design will be tested by prosthesis users in the laboratory to verify its functionality during walking.

Investigation of Embodiment for Upper Limb Amputees

Today, prosthetic hands are numb. They provide no tactile or proprioceptive sensory information back to the user. The lack of sensory feedback has been shown to reduce the utility of a prosthesis by half. The prosthesis is seen as a tool, not as an incorporated part of the body schema. Only now are there chronically-implantable technologies which can provide physiologically appropriate sensory feedback to upper limb amputees to recreate tactile and proprioceptive percepts. These sensations are the building blocks to enable the embodiment of the device. Furthermore, newly developed outcome measures are now available which can detail the improved embodiment such neural interfaces can create. The investigator's mission is to enable the embodiment of artificial devices using peripheral nerve stimulation and thereby close the gap between the experience of our intact physiological systems and those using prosthetic remedies. This investigation of embodiment for upper limb amputees is organized into three main areas of work including 1) normative data collection, 2) device development, and 3) characterization of embodiment using peripheral nerve stimulation. The normative data collection will quantify the embodiment of conventional cosmetic, body-powered, and myoelectric prosthetic hand options using a modified Rubber Hand Illusion protocol (Specific Aim 1). This thrust will ask how does the amount of embodiment vary among conventional prosthetic hands as well as probe the relationship between agency and embodiment. The device development project entails the design of multi-modal sensors in order to study full-hand embodiment (Specific Aim 2). The ability to measure and then elicit sensation on the passive surfaces of the hand (palm, ulnar border, and dorsal surface) has never been explored. Here, a multi-modal sensor which can detect proximity, contact, and force will be integrated into a commercially available prosthetic hand in order to provide detailed measurements across the palm, ulnar border, and dorsal surfaces in order to study embodiment in more depth. Finally, the characterization of embodiment using peripheral nerve stimulation will take place over a multiple subject factorial experiment which quantifies the effects of quantity and spatial parameters of the peripheral nerve stimulation on the embodiment of prosthetic hands (Specific Aim 3). This study asks what somatosensory percepts from the hand are most critical for embodiment by varying the parameters of the peripheral nerve stimulation (quantity and spatiality) and measuring the level of embodiment in each case.

Deploying Digital Prosthetic Interface Technology and Exercise in Dysvascular Amputees

The study will test a new approach to the design and implementation of socket and liner technology in individuals who lost a lower limb secondary to diabetes mellitus type II (herein referred to as dysvascular amputees). The technology-based intervention will be combined with an exercise program designed to improve the health status of dysvascular amputees.

Transfemoral Osseointegrated Prosthesis Limb-Load Symmetry Training

This randomized controlled trial (n=25 enrolled, n=15 expected to complete) will 1) determine the feasibility of a 40-week limb-load biofeedback training intervention, 2) determine if there is an intervention signal of efficacy, and 3) identify functional movement priorities for people with transfemoral osseointegrated (OI) prostheses. A limb-load biofeedback training group (EXP (n=10)) will be compared to a standard of care attention-control group without limb-load biofeedback training (CTL (n=5)). Outcomes will be assessed at standard of care pre-habilitation end (Week 5), standard of care rehabilitation end (Week 24), and one year after OI Stage 2 surgery (Week 64).

Influence of Prosthetic Foot Stiffness on Transtibial Osseointegrated Bone-Anchored Limb Outcomes

A clinical trial utilizing cross-over study design in which individuals with transtibial amputation using either a bone-anchored limb or standard socket prosthesis will perform activities of daily living with varying prosthetic foot stiffness categories to complete the following 4 Specific Aims: 1) Determine the influence of prosthetic foot stiffness on dynamic bone-implant loading, 2) Determine how prosthetic foot stiffness influences function, pain, and multi-joint biomechanics outcomes, 3) Establish how prosthetic foot stiffness influences osseoperception and fall risk, and 4) Establish target ranges of optimal foot stiffness based on the sensitivity biomechanical outcomes to variability in foot stiffness.

Quantification of Motor Compensation Following Biomechanical, Proprioceptive and Physiological Alterations Post-lower Limb Amputation.

Lower limb amputation causes segmental loss that alters locomotor organization. The human body, designed to function in a multisegmental manner, must adapt to this new configuration where segments are missing, depending on the level of amputation. These adaptations are directly linked to the biomechanical, physiological and proprioceptive alterations caused by the loss of the amputated segments. Without mechanoreceptive afferents essential for regulating locomotion, the sensory system uses alternative information to maintain efficient locomotor function. The prosthesis partially compensates, but remains limited on the biomechanical and proprioceptive levels. Current prosthetic technologies, inspired by biomimicry, aim to imitate evolutionary solutions to restore walking, although current algorithms do not allow real-time modulation. This research aims to characterize post-amputation locomotor adaptations through biomechanical, physiological and proprioceptive exploration to develop a "locomotor characterization" model. The study authors hypothesize that the post-amputation alterations are exacerbated in contexts of continuous and discontinuous constraints (e.g., ascent/descent and destabilization), and that the addition of a prosthesis, although inspired by biomimicry, only restores partial compensation of locomotor functions.

Comparing the Attentional Demands and Functional Outcomes in People With Transradial Amputation

Different ways of controlling an upper-limb prosthesis can affect how easy it is to use and how helpful it is in everyday activities. One common method, called direct control, uses signals from two muscles and can make switching between movements difficult. Another clinically available option, called pattern recognition control, uses signals from several muscles to better understand the user's intended movement and may feel more natural to use. This study compares these two control methods to see how they affect function for adults with below-the-elbow limb loss.

Impact of Improving Footwear Options

Veterans with leg amputations have limited footwear options because their artificial feet do not change shapes for different shoes. Studies have shown that women with amputations receive more frequent prosthetics care than men, but are less satisfied with the fit, comfort, and appearance of their prostheses. The investigators' previous research indicates that women Veterans would like to be able to wear a broader variety of footwear, and those who perceive more footwear limitations tend to have poorer body image and community participation. A new prosthesis designed by the investigators' group allows Veterans with amputations to use their footwear of choice using 3D-printed artificial feet with a single ankle. The novel prosthesis will be tested in this project with women Veterans with amputations to determine the impact of improving footwear options on body image and community participation.

Evacuation Time and Tourniquet Use as Risk Factors for PTSD in Combat-Related Amputation

This study aims to evaluate the relationship between evacuation time, tourniquet use, and the development of post-traumatic stress disorder (PTSD) in patients with combat-related amputations. In the context of modern warfare, prolonged evacuation times and extended tourniquet application may contribute not only to physical injury but also to psychological trauma. The study will prospectively follow patients over 18 months to identify key predictors of PTSD and to assess their interaction.

Effect of PNF-Based Upper Extremity Strengthening With Core Stabilization on Fitness in Amputee Football Players

Amputee football (AF) is a disability-specific football in which amputees can participate. This study aims to determine the effect of PNF-based upper extremity strengthening exercises combined with core stabilization exercises on physical fitness parameters in amputee football players. In the study, amputee soccer players will be randomly divided into two groups training and control groups. In addition to the standard training programs in the off-season, the amputee athletes in the training group will receive PNF-based upper extremity strengthening training combined with core stabilization training by the same physiotherapist 3 days a week for 8 weeks. The amputee football players in the control group will be given upper extremity strengthening training with free weights in addition to core stabilization training 3 days a week for 8 weeks. The physical and demographic characteristics of the cases who signed the consent form will be recorded. Initial evaluations will be made before the start of the exercise training program and secondary evaluations will be made at the end of 8 weeks. Detailed information about the participants will be obtained with the Descriptive Characteristics Information Form. Single Leg Balance Test, Berg Balance Scale and Activity Specific Balance Confidence Scale will be used to obtain information about postural control and balance strategies of the participants. Pressure Feedback Unit will be used to measure the stabilization capacity of deep spinal muscles. Trunk muscle endurance tests developed by McGill will be used to assess the level of core stability. Isokinetic muscle strength of the upper extremity muscles will be measured with the ISOMED 2000 (2017-Germany) device. Hand grip strength will be measured with Jamar Hand Dynanometer. Closed Kinetic Ring Upper Extremity Test will be used to measure the strength, anaerobic power, and closed kinetic chain stability of the upper extremity. The Distance Triple Hop Test will be used to assess the strength, speed, balance, and control ability of a lower extremity with special emphasis on the distance traveled by the lower extremity. Sprint Test will be used to measure the running performance of amputee soccer players. The data will then be analyzed and interpreted with appropriate statistical methods.

Prosthetic Socket Fit Testing System

Ensuring a well fitting prosthetic socket is a major challenge in the care of people with amputation. Poor fit causes pain, skin issues, reduced mobility, and lower satisfaction, affecting daily activity and quality of life. Current prosthetic socket fit assessment relies on prosthesis user feedback, prosthetist experience or intrusive equipment. The investigators have developed a non-invasive prototype socket fit testing system that attaches externally to the end of any prosthetic socket and uses two air cylinders to apply resistance and track motion. During testing, socket motion is mapped to a cursor on a screen. Participants perform a test where they move their leg and socket to randomly presented targets. Movement duration and accuracy provide measures of how well the socket and leg move together. This pilot study will assess feasibility and validity of the socket fit testing system performance for above-the-knee prosthesis users.

Feasibility of Neural Feedback for Lower Limb Amputees

The purpose of this study is to evaluate the effectiveness of providing sensation of the missing limb to individuals with lower limb loss, including above and below knee amputees. The approach involves delivering small electrical currents directly to remaining nerves via implanted stimulating electrodes. These small electrical currents cause the nerves to generate signals that are then transferred to your brain similar to how information about the foot and lower limb used to be transferred to your brain prior to the amputation. Individuals also have the option to have recording electrodes implanted within muscles of the lower limb(s) in an attempt to develop a motor controller that would enable the user to have intuitive control of a robotic prosthetic leg.

Studies Into Touch in Healthy Humans to Provide Sensory Feedback in Prostheses

Our sense of touch is essential to explore our environment and experience life and is based on signals from receptors in the body that are sensitive to different types of stimulation. The TACTHUM projects aims to investigate the fundamental firing of mechanoreceptors in the body to various external stimuli, with an end-aim to better understand the human somatosensory system and to apply this knowledge to provide comprehensive sensory feedback in prosthetics. We have a vast system of peripheral receptors in the skin and muscles that provide us with exquisitely detailed information about our everyday interactions. When there is injury to a body part, such as in amputation, there is a significant loss of somatosensory input. Prosthetic devices have greatly developmed in the past few years, especially with the introduction of useful sensory feedback. However, there is a lot to discover both about the workings of the somatosensory system and how to recreate this to give feedback in a prosthetic device. The main objective of the TACTHUM project is to understand how to recover and apply useful somatosensory feedback in prostheses for amputees. There are a number of other sub-objectives, to: 1. Determine how tactile mechanoreceptors encode the texture of natural surfaces during passive and active exploration. 2. Investigate how our sense of touch varies with emotional state. 3. Explore what happens to our sense of touch when we explore surfaces at different temperatures. 4. Understand the origin of our perception of humidity. 5. Investigate differences in the encoding of tactile information with age. 6. Determine the perceptions generated by the stimulation of single tactile afferents. 7. Study changes in spontaneous activity and responses to tactile stimulation on the residual limb of amputees. To accomplish these objectives, we will primarily use the technique of microneurography, in vivo recordings from peripheral nerves, to gain direct information about the firing of peripheral neurons in humans. In conjunction with this, we will use a variety of mechanical and thermal stimuli to excite somatosensory fibers and register the activity of other physiological and perceptual measures. This will allow us to gain a fuller understanding of how the incoming somatosensory signals are interpreted and processed. Overall, we aim to explore how more naturalistic tactile interactions are encoded and how these can be translated to provide realistic prosthetic feedback.

TOE Study: Treatment and Gait Analysis fOllowing an Excised Lesser Toe

Summary of study The study will examine patients with Diabetes Mellitus (DM) who have had a lesser toe amputations (LTA) (toes 2nd3rd,4th or 5th). It is currently not understood how this affects the way patients walk and foot function. No previous studies have been undertaken to examine this and its potential for causing further ulceration risk. This study is a feasibility study. It is designed to see if it is possible to undertake a large, randomised trial. It will explore how participants are recruited, kept in the study and how easy it is to follow the study protocol. Aim of the study Establish the feasibility of a corresponding full scale investigation into to the effectiveness of a toe divider made from Otoform for patients with DM following an LTA. Study Design 1. Participants will be recruited from Mid Yorkshire NHS teaching Hospital. 2. Participants will be randomised to receive either standard care or an otoform toe divider. 3. Participants age, gender, medical history, medication and blood sugar levels will be recorded. 4. Vascular and neurological assessments, foot posture and toe deformities will be undertaken and recorded. 5. All participants will have pressures measured on the plantar aspects of both feet. 6. Follow up visits will be arranged every 6 weeks for12 months for all participants to monitor foot health and changes in walking pattern and pressure redistribution. 7. If an ulceration or other foot complication occurs, the participants will be removed from the study and appropriate treatment given (the rescue arm of the study).

Evaluation of Myoelectric Implantable Recording Array (MIRA) in Participants With Transradial Amputation

The purpose of this research study is to see how well a new type of myoelectric prosthesis works. A myoelectric prosthesis is a robotic limb for amputees that is controlled by sensing the activity of muscles in the body above the amputation level. This study involves a medical procedure to implant the Myoelectric Implantable Recording Array (MIRA) in the residual limb. The procedure will be performed under sedation by a physician. When muscles contract, they generate an electrical signal that can be sensed by MIRA and used to control the prosthetic limb. Myoelectric prosthetic limbs normally use electrodes that are placed on the surface of the skin to control different movements. However, MIRA is implanted under the skin, which could improve the ability to control the myoelectric prosthesis. After the MIRA is implanted, training will occur to learn how to control the prosthesis using the muscles in the residual limb. The device can stay implanted for up to one year. The device will be removed (explanted) by a physician.

Amputations in Childhood and Neuropathic Pain

This observational study aims to assess the presence of neuropathic pain in children and adolescents who underwent limb amputation during childhood. The study focuses on two types of neuropathic pain: phantom limb pain and residual limb pain. It also evaluates quality of life and functional autonomy in this population and explores potential associations between neuropathic pain, autonomy, quality of life, and age at amputation. Using a mixed retrospective and prospective design, data are collected from medical records and standardized questionnaires administered during routine follow-up visits at a specialized pediatric limb anomaly center. The study seeks to improve understanding of neuropathic pain after pediatric amputation and its impact on daily functioning.