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Neural Systems and Rehabilitation Engineering, IEEE Transactions on

Issue 2 • Date June 2002

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Displaying Results 1 - 6 of 6
  • The optimal stimulation pattern for skeletal muscle is dependent on muscle length

    Page(s): 85 - 93
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (265 KB) |  | HTML iconHTML  

    Stimulation patterns can be optimized by maximizing the force-time integral (FTI) per stimulation pulse of the elicited muscle contraction. Such patterns, providing the desired force output with the minimum number of pulses, may reduce muscle fatigue, which has been shown to correlate to the number of pulses delivered. Applications of electrical stimulation to use muscle as a controllable biological actuator may, therefore, be improved. Although muscle operates over a range of lengths, optimized patterns have been determined only at optimal muscle length. In this study, the patterns with up to four pulses that produced the highest isometric FTI were determined at 10 muscle lengths for 11 rabbit tibialis anterior muscles. The interpulse intervals (IPIs) used ranged from 4 to 54 ms. At high muscle length, the optimal stimulation pattern consisted of an initial short IPI (doublet) followed by longer IPIs, in agreement with previous studies. However, at low length, the third pulse still elicited more than linear summation (triplet); furthermore, the relative enhancement of the FTI per pulse was considerably larger at low length than at high length, suggesting that optimal stimulation patterns are length dependent. View full abstract»

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  • Evaluation of command algorithms for control of upper-extremity neural prostheses

    Page(s): 94 - 101
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (243 KB) |  | HTML iconHTML  

    Five new command control algorithms were created to enable increased control over grasp force in upper-extremity neural prostheses. Most of these algorithms took advantage of the ability to lock or assign a steady command value to the hand neural prosthesis. Five able-bodied subjects tested the algorithms by using a shoulder controller that controlled a video-simulated hand to repeatedly complete a consistent evaluation task. A generalized estimating equations-based linear model was used to analyze the data. The algorithms were ranked via contrast analyses between the coefficient values from the linear model of the proportional control with lock algorithm, which is the algorithm presently used in neural prostheses, and each of the other algorithms. The algorithms that allowed adjustment of the command value after the hand was locked as well as algorithms that allowed a decrease in controller gain after the hand was locked performed better than the proportional control with lock algorithm. Algorithms that changed command as a function of time performed worse than the proportional control with lock algorithm. Further, the computer-based video simulator proved to be useful as a first-pass evaluation tool for neural prosthesis control. View full abstract»

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  • Web-based telerehabilitation for the upper extremity after stroke

    Page(s): 102 - 108
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (267 KB) |  | HTML iconHTML  

    Stroke is a leading cause of disability in the United States and yet little technology is currently available for individuals with stroke to practice and monitor rehabilitation therapy on their own. This paper provides a detailed design description of a telerehabilitation system for arm and hand therapy following stroke. The system consists of a Web-based library of status tests, therapy games, and progress charts, and can be used with a variety of input devices, including a low-cost force-feedback joystick capable of assisting or resisting in movement. Data from home-based usage by a chronic stroke subject are presented that demonstrate the feasibility of using the system to direct a therapy program, mechanically assist in movement, and track improvements in movement ability. View full abstract»

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  • The influence of weight and starting height on lifting mechanics in lower extremity amputees

    Page(s): 109 - 117
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (271 KB) |  | HTML iconHTML  

    This study compares the lifting mechanics of lower extremity amputees to controls and describes the influence of weight lifted and starting height on lifting style. Subjects included three individuals with transtibial amputation (TTA), two individuals with transfemoral amputation (TFA), and three able-bodied controls (CO). Amputee subjects performed six repetitions of six weights, randomly ordered, from two starting heights. TTA lifted from 30 cm and knee height, TFA from knee and thigh height, and controls from all three heights. Data were obtained from a work simulator, force plate, and a motion analysis system, with starting posture index, lateral sway index, lift duration, synchrony index, and hip moments and elbow moments as dependent measures. The results for each lifting height were analyzed using a mixed model repeated measures MANOVA to test for group and weight differences and post hoc tests were applied when appropriate. Results suggest that healthy lower extremity amputees who have had a number of years to adjust to their prosthesis and develop compensatory strategies can complete a repetitive lifting task at a performance level very similar to able-bodied controls. The most consistent, group differences detected were in the timing parameters: synchrony and duration. TTA and TFA tended to lift with less synchronization of hip and knee movements than able-bodied controls and to initiate the lift with their upper bodies. In contrast, able-bodied controls tended to move their upper and lower bodies more synchronously during the lift. TTA had longer lift durations than CO. In terms of stability and moments generated, TTA lifted very similarly to controls. TFA used a different lifting style that involved higher moments and more use of the upper body, particularly for lifts of heavier weights. TFA appeared to be less stable than CO, while TTA did not appear to be less stable than CO. View full abstract»

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  • The Hephaestus Smart Wheelchair system

    Page(s): 118 - 122
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (226 KB)  

    The Hephaestus Smart Wheelchair System is envisioned as a series of components that clinicians and wheelchair manufacturers will be able to attach to standard power wheelchairs to convert them into "smart wheelchairs." A prototype of the system has been developed and mounted on an Everest and Jennings Lancer2000 wheelchair. The prototype bases its navigation assistance behavior on the behavior developed for the NavChair Assistive Wheelchair Navigation System, but the underlying hardware and software are being designed to facilitate commercialization. This paper describes our design goals for the Hephaestus system and discusses the current status of the system prototype as well as plans for future work. View full abstract»

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  • Voice control of a powered wheelchair

    Page(s): 122 - 125
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (217 KB) |  | HTML iconHTML  

    Several researchers have described voice control mechanisms for a power wheelchair, but voice control has yet to become a commercially viable control alternative. One problem with voice control is that the voice's limited bandwidth renders it impossible to make frequent small adjustments to the wheelchair's velocity. One possible solution is to utilize voice control in combination with the navigation assistance provided by "Smart wheelchairs," which use sensors to identify and avoid obstacles in the wheelchair's path. This paper describes an experiment that compares the performance of able-bodied subjects using voice control to operate a power wheelchair both with and without navigation assistance. View full abstract»

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Aims & Scope

IEEE Transactions on Neural Systems and Rehabilitation Engineering focuses on the rehabilitative and neural aspects of biomedical engineering.

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Editor-in-Chief
Paul Sajda
Columbia University