Newswise — Full-text articles are available at http://www.rehab.research.va.gov/jour/11/486/contents486.html

Manuscripts featured in this issue include—

Two-degree-of-freedom powered prosthetic wrist, pg. 609

This article describes a novel prosthetic wrist with two degrees of freedom: wrist flexion/extension and pronation/supination. Unlike current powered wrists, this wrist has two motors and a differential that allow for the independent motions. The article also describes initial testing of the wrist for accuracy and usability with a single user.

Target Achievement Control Test: Evaluating real-time myoelectric pattern-recognition control of multifunctional upper-limb prostheses, pg. 619

Researchers describe the Target Achievement Control (TAC) Test, which evaluates user control and positioning of a multifunctional prosthesis. Tested with a group of five individuals with below-elbow amputations, the TAC provided valuable information about user myoelectric control and pattern-recognition control algorithms that cannot be obtained from existing performance measures or existing real-time virtual performance tests.

Comparison of electromyography and force as interfaces for prosthetic control, pg. 629

This study used a position-tracking task to compare the performance of three control interfaces—myoelectric, force, and position—for upper-limb prostheses. Researchers evaluated task performance based on tracking error, human-operator bandwidth, and information transmission rate. The results show that electromyography control is as effective as force control and that information transmission rates for myoelectric control were best at tracking frequencies higher than previously reported for position control.

Electromyogram pattern recognition for control of powered upper-limb prostheses: State of the art and challenges for clinical use, pg. 643

This review discusses the current challenges and best practices in electromyogram pattern recognition as a control source for powered upper-limb prostheses. It also identifies promising research that may affect transition of the technology to a clinically viable option. Topics discussed include electromyogram interface, signal processing, and performance evaluation.

Use of two-axis joystick for control of externally powered shoulder disarticulation prostheses, pg. 661

Researchers compare control of externally powered shoulder disarticulation prostheses using a two-axis joystick versus a traditional rocker potentiometer system. The findings show that the joystick had clear advantages over the potentiometer. All test subjects preferred the joystick, which provided fast, accurate, and intuitive control.

Evaluation of shoulder complex motion-based input strategies for endpoint prosthetic-limb control using dual-task paradigm, pg. 669

Selection of a control strategy for powered prostheses depends heavily on a user’s musculature condition, range of motion, sensor type, and learning ability. This study explores options for automatically optimizing an end-point based control strategy according to a user’s characteristics. Two novel self-adjusting control schemes for multiarticulated powered upper-limb prostheses are discussed. The results indicate that the residual motion-based strategy outperformed the myoelectric signal-based scheme.

Prosthetic sockets stabilized by alternating areas of tissue compression and release, pg. 679

Researchers introduce new compression/release stabilized (CRS) socket designs for individuals with transradial, transfemoral, and transhumeral amputations that promise users increased range of motion, stability, and higher lift capacity. CRS sockets contain several built-in depressions and oblong-shaped perforations that compress and displace tissue between the socket wall and the bone, reducing motion between the two and increasing stability. Researchers discuss the physics behind these new sockets and illustrate how to create each of them using the plaster cast technique.

Development and testing of new upper-limb prosthetic devices: Research designs for usability testing, pg. 697

This article defines and reviews key aspects of usability testing research for new devices, focusing on their relevance to upper-limb prosthetics. The article also compares usability testing to other types of study designs used in prosthetics research.

Using virtual reality environment to facilitate training with advanced upper-limb prosthesis, pg. 707

This article explores the use of virtual reality for upper-limb amputee rehabilitation and describes the system used with the DEKA Arm. A case example of a subject using the full DEKA Arm with powered shoulder is presented.

Myoelectric forearm prostheses: State of the art from a user-centered perspective, pg. 719

This study presents recommendations for future research on improving user acceptance of myoelectric forearm prostheses. Focused on user acceptance, these recommendations derive from a needs assessment and literature review in the main prosthetic subsystems (electromyographic sensing, control, and feedback). The findings show that many of the components required for a natural and intuitive prosthetic system are currently available or being developed and that more attention must be paid to integration of these components into new systems.

Electromyogram-based neural network control of transhumeral prostheses, pg. 739

Researchers evaluate the feasibility of using electromyographic signals from various muscles in the upper arm and shoulder to predict arm movements in five nondisabled male subjects. This study advances research on the use of electromyographic-based control of a prosthetic limb to allow coordinated, simultaneous flexion/extension and pronation/supination of the arm. The findings present the relative effectiveness of various muscle subsets in predicting arm movement trajectories. The findings also suggest that with further development, simultaneous and accurate control of these actions may allow more natural, coordinated movements for people with upper-limb prostheses.

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JRRD is a well-established and respected peer-reviewed journal sponsored by the Department of Veterans Affairs. The journal publishes original research, clinical studies, and reviews covering 28 rehabilitation disciplines. JRRD is widely distributed to both national and international audiences in print and electronic format. For more information about JRRD and its publishing policies, please visit www.rehab.research.va.gov/jrrd.

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