A Novel Sensory Feedback Approach to Facilitate Both Predictive and Corrective Control of Grasping Force in Myoelectric Prostheses.

Reliable force control is especially important when using myoelectric upper-limb prostheses as the force defines whether an object will be firmly grasped, damaged, or dropped. It is known from human motor control that the grasping of non-disabled subjects is based on a combination of anticipation and feedback correction. Inspired by this insight, the present study proposes a novel approach to provide artificial sensory feedback to the user of a myoelectric prosthesis using vibrotactile stimulation to facilitate both predictive and corrective processes characteristic of grasping in non-disabled people.

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.

Feasibility of a Wireless Implantable Multi-electrode System for High-bandwidth Prosthetic Interfacing: Animal and Cadaver Study.

Background: Currently used prosthetic solutions in upper extremity amputation have limited functionality, owing to low information transfer rates of neuromuscular interfacing. Although surgical innovations have expanded the functional potential of the residual limb, available interfaces are inefficacious in translating this potential into improved prosthetic control. There is currently no implantable solution for functional interfacing in extremity amputation which offers long-term stability, high information transfer rates, and is applicable for all levels of limb loss.

Reactive Exercises with Interactive Objects: Interim Analysis of a Randomized Trial on Task-Driven NMES Grasp Rehabilitation for Subacute and Early Chronic Stroke Patients.

Unlabelled: Enriched environments and tools are believed to promote grasp rehabilitation after stroke. We designed S2, an interactive grasp rehabilitation system consisting of smart objects, custom orthoses for selective grasp constraining, and an electrode array system for forearm NMES. Motor improvements and perceived usability of a new enriched upper limb training system for sub-acute stroke patients was assessed in this interim analysis.

Relying on more sense for enhancing lower limb prostheses control: a review.

Modern lower limb prostheses have the capability to replace missing body parts and improve the patients' quality of life. However, missing environmental information often makes a seamless adaptation to transitions between different forms of locomotion challenging. The aim of this review is to identify the progress made in this area over the last decade, addressing two main questions: which types of novel sensors for environmental awareness are used in lower limb prostheses, and how do they enhance device control towards more comfort and safety.

Experimental Testing of Bionic Peripheral Nerve and Muscle Interfaces: Animal Model Considerations.

Man-machine interfacing remains the main challenge for accurate and reliable control of bionic prostheses. Implantable electrodes in nerves and muscles may overcome some of the limitations by significantly increasing the interface's reliability and bandwidth. Before human application, experimental preclinical testing is essential to assess chronic biocompatibility and functionality.

Energy Recuperation at the Hip Joint for Paraplegic Walking: Interaction Between Patient and Supportive Device.

For patients with lower limb paralysis, wearable robotic systems are becoming increasingly important for regaining mobility. The actuation of these systems is challenging because of the necessity to deliver high power within very limited space. However, not all patients need full support, as many patients have residual muscle function that can be applied for locomotion.

Elicitation of usability-related Requirements for Upper-Limb Rehabilitation Systems.

The increasing number of strokes coincides with the need for new effective rehabilitation systems. In this contribution the methods and results of a series of user surveys comprising methods of qualitative research are presented. The goal of these surveys was to elicit requirements health care professionals pose on rehabilitation devices for upper limb training to enable an effective, efficient and satisfying use in a rehabilitation environment.

A Hybrid Robotic System for Arm Training of Stroke Survivors: Concept and First Evaluation.

Objective: To develop and evaluate a hybrid robotic system for arm recovery after stroke, combining ElectroMyoGraphic (EMG)-triggered functional electrical stimulation (FES) with a passive exoskeleton for upper limb suspension.

Methods: The system was used in a structured exercise program resembling activities of daily life. Exercises execution was continuously controlled using angle sensor data and radio-frequency identification technology.

An Insulated Flexible Sensor for Stable Electromyography Detection: Applicationto Prosthesis Control.

Electromyography (EMG), the measurement of electrical muscle activity, is used in a variety of applications, including myoelectric upper-limb prostheses, which help amputees to regain independence and a higher quality of life. The state-of-the-art sensors in prostheses have a conductive connection to the skin and are therefore sensitive to sweat and require preparation of the skin. They are applied with some pressure to ensure a conductive connection, which may result in pressure marks and can be problematic for patients with circulatory disorders, who constitute a major group of amputees.

Ultra-Low-Power Digital Filtering for Insulated EMG Sensing.

Myoelectric prostheses help amputees to regain independence and a higher quality of life. These prostheses are controlled by state-of-the-art electromyography sensors, which use a conductive connection to the skin and are therefore sensitive to sweat. They are applied with some pressure to ensure a conductive connection, which may result in pressure marks and can be problematic for patients with circulatory disorders, who constitute a major group of amputees.

Lessons from Vienna: stakeholder perceptions of functional electrical stimulation technology and a conceptual model for practice.

Functional electrical stimulation (FES) is a technology that can be used on paralyzed muscles to allow them to move. It has been used in populations with muscle paralysis or weakness for exercise, such as spinal cord injury (SCI) and multiple sclerosis. In order to improve technology, it is vital to understand from a qualitative perspective, issues surrounding device development and implementation.

Capacitively coupled EMG detection via ultra-low-power microcontroller STFT.

As motion artefacts are a major problem with electromyography sensors, a new algorithm is developed to differentiate artefacts to contraction EMG. The performance of myoelectric prosthesis is increased with this algorithm. The implementation is done for an ultra-low-power microcontroller with limited calculation resources and memory.

Review of the actuators of active knee prostheses and their target design outputs for activities of daily living.

Active prosthetic knees have the capability to provide net positive work, which is required in daily activities like stair and ramp negotiation or sit-to-stand transfers. Adding this capability might help to increase user mobility, safety, and independence. This article summarizes the biomechanical knee requirements for different activities of daily living and critically compares them with the actuator characteristics of state-of-the-art active prosthetic knee joints.

A novel motion sensor-driven control system for FES-assisted walking after spinal cord injury: A pilot study.

This pilot study reports the development of a novel closed-loop (CL) FES-gait control system, which employed a finite-state controller that processed kinematic feedback from four miniaturized motion sensors. This strategy automated the control of knee extension via quadriceps and gluteus stimulation during the stance phase of gait on the supporting leg, and managed the stimulation delivered to the common peroneal nerve (CPN) during swing-phase on the contra-lateral limb. The control system was assessed against a traditional open-loop (OL) system on two sensorimotor 'complete' paraplegic subjects.

Long-term decoding of movement force and direction with a wireless myoelectric implant.

Objective: The ease of use and number of degrees of freedom of current myoelectric hand prostheses is limited by the information content and reliability of the surface electromyography (sEMG) signals used to control them. For example, cross-talk limits the capacity to pick up signals from small or deep muscles, such as the forearm muscles for distal arm amputations, or sites of targeted muscle reinnervation (TMR) for proximal amputations. Here we test if signals recorded from the fully implanted, induction-powered wireless Myoplant system allow long-term decoding of continuous as well as discrete movement parameters with better reliability than equivalent sEMG recordings.

Cardiorespiratory and Muscle Metabolic Responses During Conventional Versus Motion Sensor-Assisted Strategies for Functional Electrical Stimulation Standing After Spinal Cord Injury.

This is a case series study with the objective of comparing two motion sensor automated strategies to avert knee buckle during functional electrical stimulation (FES)-standing against a conventional hand-controlled (HC) FES approach. The research was conducted in a clinical exercise laboratory gymnasium at the University of Sydney, Australia. The automated strategies, Aut-A and Aut-B, applied fixed and variable changes of neurostimulation, respectively, in quadriceps amplitude to precisely control knee extension during standing.

Pilot study of the effect of low-cadence functional electrical stimulation cycling after spinal cord injury on thigh girth and strength.

Objective: To investigate the long-term effects of functional electrical stimulation (FES)-evoked cycle training cadence on leg muscle hypertrophy and electrically evoked strength.

Design: Open intervention study.

Setting: Laboratory setting.

Acquisition of myoelectric signals to control a hand prosthesis with implantable epimysial electrodes.

The acquisition of myoelectric signals from the Musculus deltoideus of a rhesus monkey is described. Such signals are aimed to be used as control signal for an active myoelectric hand prosthesis. For recording, implantable flexible, polyimide-based multi-site microelectrodes were placed epimysially on the muscle.

Practical and effective stomal sphincter creation: evaluation in pigs.

Purpose: Stoma creation frequently presents complications for which there is no satisfactory surgical solution. We reexamined the feasibility of managing stoma continence with an artificial sphincter, addressing the outstanding issues of geometry, electrode disposition, and fatigue resistance.

Methods: In 6 pigs, 1 rectus abdominis muscle was preconditioned with electric stimulation for 4 weeks by an implanted stimulator.

Functional electrical stimulation-supported interval training following sensorimotor-complete spinal cord injury: a case series.

Objective. To investigate the effect of interval training supported by Functional Electrical Stimulation (FES) on ambulation ability in complete spinal cord injury (SCI). Methods.

Functional electrical stimulation control of standing and stepping after spinal cord injury: a review of technical characteristics.

Objectives. To investigate the different approaches in the field of functional electrical stimulation (FES) control of gait and address fundamental perquisites to enable FES walking systems to become safer, more practical, and therefore clinically efficacious. Design.

Therapeutic stimulation of denervated muscles: the influence of pattern.

Muscular atrophy due to denervation can be substantially reversed by direct electrical stimulation. Some muscle properties are, however, resistant to change. Using a rabbit model of established denervation atrophy, we investigated whether the extent of restoration would vary with the stimulation protocol.

Effects of chronic electrical stimulation on long-term denervated muscles of the rabbit hind limb.

We investigated the extent to which activity induced by chronic electrical stimulation could restore the mass and contractile function of rabbit tibialis anterior (TA) muscles that had undergone atrophy as a result of prolonged denervation. Denervation was carried out by selectively interrupting the motor nerve branches to the ankle dorsiflexors in one hind limb. Stimulators were implanted, with electrodes on the superficial and deep surfaces of the denervated TA muscle.

Implantable stimulator featuring multiple programs, adjustable stimulation amplitude and bi-directional communication for implantation in mice.

We describe an implantable stimulator with adjustable output amplitude and bi-directional communication at a size of approximately 1 cm(3). The user selects from preset patterns of stimulation and adjusts the stimulation amplitude by sending coded flashes of light, and receives active confirmation of the chosen settings via a powerful LED in the device. These characteristics allow selectivity of motor nerve stimulation and minimize unwanted excitation of adjacent structures.