A portable, programmable, multichannel stimulator with high compliance voltage for noninvasive neural stimulation of motor and sensory nerves in humans.

Most neural stimulators do not have a high enough compliance voltage to pass current through the skin. The few stimulators that meet the high compliance voltage necessary for transcutaneous stimulation are typically large benchtop units that are not portable, and the stimulation waveforms cannot be readily customized. To address this, we present the design and validation of a portable, programmable, multichannel, noninvasive neural stimulator that can generate three custom bipolar waveforms at ± 150 V with microsecond temporal resolution.

Portable System for Home Use Enables Closed-Loop, Continuous Control of Multi-Degree-of-Freedom Bionic Arm.

Commercial prosthetic hands are frequently abandoned due to unintuitive control methods and a lack of sensory feedback from the prosthesis. Advanced neuromyoelectric prostheses can restore intuitive control and sensory feedback to prosthesis users and potentially reduce abandonment. However, not all advanced prosthetic systems are deployable for home use on portable systems with limited computational power.

Activities of daily living with bionic arm improved by combination training and latching filter in prosthesis control comparison.

Background: Advanced prostheses can restore function and improve quality of life for individuals with amputations. Unfortunately, most commercial control strategies do not fully utilize the rich control information from residual nerves and musculature. Continuous decoders can provide more intuitive prosthesis control using multi-channel neural or electromyographic recordings.

Portable Take-Home System Enables Proportional Control and High-Resolution Data Logging With a Multi-Degree-of-Freedom Bionic Arm.

This paper describes a portable, prosthetic control system and the first at-home use of a multi-degree-of-freedom, proportionally controlled bionic arm. The system uses a modified Kalman filter to provide 6 degree-of-freedom, real-time, proportional control. We describe (a) how the system trains motor control algorithms for use with an advanced bionic arm, and (b) the system's ability to record an unprecedented and comprehensive dataset of EMG, hand positions and force sensor values.

Intensity Discriminability of Electrocutaneous and Intraneural Stimulation Pulse Frequency in Intact Individuals and Amputees.

Electrical stimulation of residual nerves can be used to provide amputees with intuitive sensory feedback. An important aspect of this artificial sensory feedback is the ability to convey the magnitude of tactile stimuli. Using classical psychophysical methods, we quantified the just-noticeable differences for electrocutaneous stimulation pulse frequency in both intact participants and one transradial amputee.

Intuitive neuromyoelectric control of a dexterous bionic arm using a modified Kalman filter.

Background: Multi-articulate prostheses are capable of performing dexterous hand movements. However, clinically available control strategies fail to provide users with intuitive, independent and proportional control over multiple degrees of freedom (DOFs) in real-time.

New Method: We detail the use of a modified Kalman filter (MKF) to provide intuitive, independent and proportional control over six-DOF prostheses such as the DEKA "LUKE" arm.

A Modular Transradial Bypass Socket for Surface Myoelectric Prosthetic Control in Non-Amputees.

Bypass sockets allow researchers to perform tests of prosthetic systems from the prosthetic user's perspective. We designed a modular upper-limb bypass socket with 3D-printed components that can be easily modified for use with a variety of terminal devices. Our bypass socket preserves access to forearm musculature and the hand, which are necessary for surface electromyography and to provide substituted sensory feedback.

Improved Training Paradigms and Motor-decode Algorithms: Results from Intact Individuals and a Recent Transradial Amputee with Prior Complex Regional Pain Syndrome.

Working towards improved neuromyoelectric control of dexterous prosthetic hands, we explored how differences in training paradigms affect the subsequent online performance of two different motor-decode algorithms. Participants included two intact subjects and one participant who had undergone a recent transradial amputation after complex regional pain syndrome (CRPS) and multi-year disuse of the affected hand. During algorithm training sessions, participants actively mimicked hand movements appearing on a computer monitor.

Miniature electrical stimulator for hemorrhage control.

Noncompressible hemorrhage is currently the most common cause of preventable death in battlefield and in civilian trauma injuries. Tourniquets, specialized wound dressings, and hemorrhage-inhibiting biomaterials are not sufficiently effective in arrest of noncompressible hemorrhage and often cause collateral tissue damage. An effective, easy-to-use, portable device is needed to reduce blood loss in trauma patients immediately following injury and to maintain hemorrhage control up to several hours-until the injured is evacuated to a medical facility.

Thermal sensitivity of endothelial cells on synthetic vascular graft material.

Purpose: The goal is to identify thermal exposures capable of reducing or eliminating cell survival on expanded polytetrafluoroethylene (ePTFE), in an effort to develop a mild hyperthermia treatment of neointimal hyperplasia in ePTFE vascular grafts.

Materials And Methods: Viable and dead bovine aortic endothelial cells were quantified following different thermal exposure conditions: cells on collagen-coated ePTFE sheets or tissue culture polystyrene dishes were heated at 42° and 45°C to determine their thermal sensitivity on different surfaces, and cells cultured on collagen-coated ePTFE sheets were heated at 43-50°C for various durations, followed by incubation at 37°C for 0 and 20 h, respectively. Significant cell death was set to be 50%.

Modelling ultrasound-induced mild hyperthermia of hyperplasia in vascular grafts.

Background: Expanded polytetrafluoroethylene (ePTFE) vascular grafts frequently develop occlusive neointimal hyperplasia as a result of myofibroblast over-growth, leading to graft failure. ePTFE exhibits higher ultrasound attenuation than native soft tissues. We modelled the selective absorption of ultrasound by ePTFE, and explored the feasibility of preventing hyperplasia in ePTFE grafts by ultrasound heating.