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Neural Systems and Rehabilitation Engineering, IEEE Transactions on

Issue 1 • Date March 2007

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  • Table of contents

    Page(s): C1 - C4
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  • IEEE Transactions on Neural Systems and Rehabilitation Engineering publication information

    Page(s): C2
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  • Guest Editorial Special Theme on Virtual Rehabilitation

    Page(s): 1
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  • Use of Magnetorheological Fluid in a Force Feedback Glove

    Page(s): 2 - 8
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    Magnetorheological fluid (MRF) is a smart material that has the property of changing its viscosity when exposed to a magnetic field. By placing this fluid into a sealed cylinder with an electromagnet piston as a core, a controllable resistance motion dampener can be created. A novel exoskeleton mechanical power transmission system was designed, utilizing rapid prototype parts, to transmit these resistive forces to the user's fingertips. A first iteration force feedback glove was developed and tested on human subjects for overall usability. The eventual goal of the system is to provide an alternative force producing system for exercises and rehabilitation. The entire system is lightweight, low power, and easily portable View full abstract»

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  • A Virtual Reality Environment for Designing and Fitting Neural Prosthetic Limbs

    Page(s): 9 - 15
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    Building and testing novel prosthetic limbs and control algorithms for functional electrical stimulation (FES) is expensive and risky. Here, we describe a virtual reality environment (VRE) to facilitate and accelerate the development of novel systems. In the VRE, subjects/patients can operate a simulated limb to interact with virtual objects. Realistic models of all relevant musculoskeletal and mechatronic components allow the development of entire prosthetic systems in VR before introducing them to the patient. The system is used both by engineers as a development tool and by clinicians to fit prosthetic devices to patients View full abstract»

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  • AudioMUD: A Multiuser Virtual Environment for Blind People

    Page(s): 16 - 22
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    A number of virtual environments have been developed during the last years. Among them there are some applications for blind people based on different type of audio, from simple sounds to 3-D audio. In this study, we pursued a different approach. We designed AudioMUD by using spoken text to describe the environment, navigation, and interaction. We have also introduced some collaborative features into the interaction between blind users. The core of a multiuser MUD game is a networked textual virtual environment. We developed AudioMUD by adding some collaborative features to the basic idea of a MUD and placed a simulated virtual environment inside the human body. This paper presents the design and usability evaluation of AudioMUD. Blind learners were motivated when interacted with AudioMUD and helped to improve the interaction through audio and interface design elements View full abstract»

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  • Technical Feasibility of Teleassessments for Rehabilitation

    Page(s): 23 - 29
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    Background: technical feasibility was evaluated for conducting standard motor assessment instruments in a remote setting. Remote assessment was compared to co-located assessment for five clinical evaluation instruments: joint range-of-motion (ROM), manual muscle test (MMT), Berg sit-to-stand, Berg forward reach, and timed up and go (TUG). Methods: co-located and remote rooms were in the same building connected by broadband video and audio. Ten subjects without impairments participated, but were given simulated impairments to mimic the patient population commonly seen in rehabilitation clinics. One therapist performed all co-located testing while another performed all remote assessments. Measurements followed standard clinical methods. Data were analyzed using repeated measures ANOVA and paired t-tests. Results: no differences were found between co-located and remote assessments except for some cases using screen-based ROM measures. Remote ROM tests using snapshots and a virtual goniometer were preferred. A digital dynamometer added no additional information to a visually-based remote MMT assessment View full abstract»

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  • Technical and Patient Performance Using a Virtual Reality-Integrated Telerehabilitation System: Preliminary Finding

    Page(s): 30 - 35
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    Telerehabilitation is the provision of rehabilitation services at a distance by a therapist at a remote location. Integration with virtual reality (VR) is a relatively new addition to this field. This paper describes the technical and patient performance of a telerehabilitation application the remote console (ReCon) that is integrated with a VR system. The VR system consists of the Rutgers Ankle prototype robot, a local PC which is connected with a remote PC connected over the Internet. Six individuals in the chronic phase poststroke participated in a four week training program. They used the robot to interact with two VR simulations, while the therapist was in the same room during the first three weeks or in another room during the fourth week. Technical and patient performance was assessed in the transition from the third to the fourth week of training. Technical performance of the system was assessed based on bandwidth and lag of message transmission, which were found to be suitable for clinic-to-clinic communication. Patient performance (in terms of accuracy of ankle movement, exercise duration and training efficiency, mechanical power of the ankle, and number of repetitions) did not decrease during telerehabilitation in the fourth week. These preliminary findings over a short telerehabilitation intervention support the feasibility of remote monitoring of VR-based telerehabilitation without adverse effects on patient performance View full abstract»

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  • Telerehabilitation Using a Virtual Environment Improves Upper Extremity Function in Patients With Stroke

    Page(s): 36 - 42
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    In this paper, we describe our experience in designing a virtual environment-based (VE) telerehabilitation system, and the results of a clinical study of the first 11 subjects with stroke to use the system. Our telerehabilitation system allows a therapist to conduct interactive VE treatment sessions remotely with a patient who is located at home. The system, software architecture, and development experience are described. Results of the clinical study on subjects with stroke showed significant improvements in upper extremity function following 30 1-h VE treatment sessions as measured by three standard clinical tests: Fugl-Meyer test of motor recovery (FM) (p<0.0001), Wolf motor test (WMT) (p=0.0097, and shoulder strength (ShS) (p=0.0027). Grip strength (GS) showed a trend toward improvement (p=0.025). These changes were maintained, for the most part, at four-months follow-up (FM +7.6, WMT -18.4 s, ShS, +169%, GS, +53%) View full abstract»

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  • Telerehabilitation Using the Rutgers Master II Glove Following Carpal Tunnel Release Surgery: Proof-of-Concept

    Page(s): 43 - 49
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    Carpal tunnel syndrome is caused by the compression of the median nerve as it transits the carpal tunnel, with an incidence of about 1% of the population. If surgery is needed, the treatment involves decompression of the median nerve followed sometimes by musculoskeletal outpatient rehabilitation. This paper presents a proof-of-concept pilot clinical trial in which the Rutgers Masters II haptic glove was tested on five subjects, who were two weeks post-hand surgery. Subjects trained for 13 sessions, 30 min per session, three sessions per week, and had no conventional outpatient therapy. Computerized measures of performance showed group effects in hand mechanical energy (1200% for the virtual ball squeezing and DigiKey exercises and 600% for the power putty exercise). Improvement in their hand function was also observed (a 38% reduction in virtual pegboard errors, and 70% fewer virtual hand ball errors). Clinical strength measures showed increases in grip (by up to 150%) and key pinch (up to 46%) strength in three of the subjects, while two subjects had decreased strength following the study. However, all five subjects improved in their tip pinch strength of their affected hand (between 20%-267%). When asked whether they would recommend the virtual reality exercises to others, four subjects very strongly agreed and one strongly agreed that they would View full abstract»

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  • EEG-Based Synchronized Brain-Computer Interfaces: A Model for Optimizing the Number of Mental Tasks

    Page(s): 50 - 58
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    The information-transfer rate (ITR) is commonly used to assess the performance of brain-computer interfaces (BCIs). Various studies have shown that the optimal number of mental tasks to be used is fairly low, around 3 or 4. We propose an experimental validation as well as a formal approach to demonstrate and confirm that this optimum is user and BCI design dependent. Even if increasing the number of mental tasks to the optimum indeed leads to an increase of the ITR, the gain remains small. This might not justify the added complexity in terms of protocol design View full abstract»

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  • A Comparative Study on Generating Training-Data for Self-Paced Brain Interfaces

    Page(s): 59 - 66
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    Direct brain interface (BI) systems provide an alternative communication and control solution for individuals with severe motor disabilities, bypassing impaired interface pathways. Most BI systems are aimed to be operated by individuals with severe disabilities. With these individuals, there is no observable indicator of their intent to control or communicate with the BI system. In contrast, able-bodied subjects can perform the desired physical movements such as finger flexion and one can observe the movement as the indicator of intent. Since no external knowledge of intention is available for individuals with severe motor disabilities, generating the data for system training is problematic. This paper introduces three methods for generating training-data for self-paced BI systems and compares their performances with four alternative methods of training-data generation. Results of the offline analysis on the electroencephalogram data of eight subjects during self-paced BI experiments show that two of the proposed methods increase true positive rates (at fixed false positive rate of 2%) over that of the four alternative methods from 50.8%-58.4% to about 62% which corresponds to 3.6%-11.2% improvement View full abstract»

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  • Electrical Stimulation of the Paralyzed Orbicularis Oculi in Rabbit

    Page(s): 67 - 75
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    Dysfunction of the seventh cranial nerve often results in facial paralysis and loss of the ability to blink the eye, which can lead to corneal scarring, diminished vision, and potential loss of the eye. This study investigated the potential of electrical stimulation of the orbicularis oculi muscle as a means of restoring blink function. An animal model of orbicularis paralysis was created by sectioning the seventh cranial nerve in rabbit. Twenty paralyzed and five normal rabbits were acutely implanted with a subcutaneous stimulating electrode near the margin of the upper eyelid. Biphasic current controlled stimulation pulses were delivered between implanted contacts at the medial and lateral edges of the eyelid. Strength-duration curves for lid twitch threshold were generated, and quantitative measurements of lid closure were made for systematically varied parameters including pulse amplitude, pulse width, number of pulses delivered, and duration of paralysis prior to stimulation. Normal rabbits achieved a greater degree of lid closure due to electrical stimulation than rabbits that had been surgically paralyzed. Of rabbits that had been paralyzed, those demonstrating evidence of at least partial reinnervation achieved a greater degree of lid closure than those demonstrating persistent denervation. Trains of 10 ms biphasic pulses delivered at 50 Hz were found to be the most effective means of eliciting lid closure for the range of parameters tested View full abstract»

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  • Human Nerve Stimulation Thresholds and Selectivity Using a Multi-contact Nerve Cuff Electrode

    Page(s): 76 - 82
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    Testing of the recruitment properties and selective activation capabilities of a multi-contact spiral nerve cuff electrode was performed intraoperatively in 21 human subjects. The study was conducted in two phases. An exploratory phase with ten subjects gave a preliminary overview of the data and data collection process and a systematic phase with eleven subjects provided detailed recruitment properties. The mean stimulation threshold of 25 plusmn 17 nC was not significantly different than previous studies in animal models but much lower than muscle electrodes. The selectivity, defined as the percent of total activation of the first muscle recruited before another muscle reached threshold, ranged from 27% to 97% with a mean of 55%. In each case, the muscle that was selectively activated was the first muscle to branch distal to the cuff location. This study serves as a preliminary evaluation of nerve cuff electrodes in humans prior to chronic implant in subjects with high tetraplegia View full abstract»

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  • Methodology and Design Flow for Assisted Neural-Model Implementations in FPGAs

    Page(s): 83 - 93
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    Field programmable gate arrays (FPGAs) have previously been shown as high-performance platforms for neural-modeling applications. Implementations have traditionally been time-consuming and error-prone, requiring the neural modeler to work outside of their expert domain. This paper demonstrates a new approach to the development of neural models using an auto-generation toolkit. This design tool enables model construction-level alterations (e.g., adjustment of model population size or insertion/deletion of an ionic conductance) within hours and parameter changes on-the-fly. The approach is validated on a 40-neuron pre-Boumltzinger complex population model consisting of Hodgkin-Huxley style conductances and fully interconnected synapses. A total of 1880 parameters are on-the-fly user tunable on a free-running model. The resulting implemented model performs at a theoretical 8.7times real-time utilizing 90% of logic elements within a Xilinx Virtex-4 XC4VSX35-fg676-10FPGA View full abstract»

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  • Stochastic Estimation of Arm Mechanical Impedance During Robotic Stroke Rehabilitation

    Page(s): 94 - 103
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    This paper presents a stochastic method to estimate the multijoint mechanical impedance of the human arm suitable for use in a clinical setting, e.g., with persons with stroke undergoing robotic rehabilitation for a paralyzed arm. In this context, special circumstances such as hypertonicity and tissue atrophy due to disuse of the hemiplegic limb must be considered. A low-impedance robot was used to bring the upper limb of a stroke patient to a test location, generate force perturbations, and measure the resulting motion. Methods were developed to compensate for input signal coupling at low frequencies apparently due to human-machine interaction dynamics. Data was analyzed by spectral procedures that make no assumption about model structure. The method was validated by measuring simple mechanical hardware and results from a patient's hemiplegic arm are presented View full abstract»

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  • Linear Summation of Torque Produced by Selective Activation of Two Motor Fascicles

    Page(s): 104 - 110
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    Linear summation of torque was observed while applying selective activation to two different motor fascicles in the cat sciatic nerve. The excitatory stimulus was applied to two or more contacts housed in a four contact self-sizing spiral cuff electrode. To achieve a linear summation of torque, a delay between the two stimuli that was longer than the length of the facilitatory period but less than the length of the refractory period was used. Using a 900-mus delay between pulses, linear summation of two different torque outputs was successfully achieved in 125 out of 129 trials across five cats. These trials were performed using cuff electrodes that were in place for periods ranging up to 352 days. The results of these studies support the hypothesis that a single self-sizing spiral cuff with multiple contacts and a single lead may be used in place of several muscle-based electrodes each with its own separate lead View full abstract»

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  • The Optimal Controller Delay for Myoelectric Prostheses

    Page(s): 111 - 118
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    A tradeoff exists when considering the delay created by multifunctional prosthesis controllers. Large controller delays maximize the amount of time available for EMG signal collection and analysis (and thus maximize classification accuracy); however, large delays also degrade prosthesis performance by decreasing the responsiveness of the prosthesis. To elucidate an "optimal controller delay" twenty able-bodied subjects performed the Box and Block Test using a device called PHABS (prosthetic hand for able bodied subjects). Tests were conducted with seven different levels of controller delay ranging from nearly 0-300 ms and with two different artificial hand speeds. Based on repeted measures ANOVA analysis and a linear mixed effects model, the optimal controller delay was found to range between approximately 100 ms for fast prehensors and 125 ms for slower prehensors. Furthermore, the linear mixed effects model shows that there is a linear degradation in performance with increasing delay View full abstract»

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  • Graphical Tactile Displays for Visually-Impaired People

    Page(s): 119 - 130
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    This paper presents an up-to-date survey of graphical tactile displays. These devices provide information through the sense of touch. At best, they should display both text and graphics (text may be considered a type of graphic). Graphs made with shapeable sheets result in bulky items awkward to store and transport; their production is expensive and time-consuming and they deteriorate quickly. Research is ongoing for a refreshable tactile display that acts as an output device for a computer or other information source and can present the information in text and graphics. The work in this field has branched into diverse areas, from physiological studies to technological aspects and challenges. Moreover, interest in these devices is now being shown by other fields such as virtual reality, minimally invasive surgery and teleoperation. It is attracting more and more people, research and money. Many proposals have been put forward, several of them succeeding in the task of presenting tactile information. However, most are research prototypes and very expensive to produce commercially. Thus the goal of an efficient low-cost tactile display for visually-impaired people has not yet been reached View full abstract»

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  • Digital Emulation of Pulse Frequency Modulation for Neuroprosthetic Sensory Feedback

    Page(s): 131 - 135
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    Pulse frequency modulation (PFM) is a method of encoding information where the instantaneous frequency of a pulse train carries the signal's information. PFM is of particular interest to those working towards interfacing prosthetic devices directly with the human nervous system. In this paper, we consider the effects of directly implementing PFM with a digital microprocessor. We consider three digital PFM algorithms: two are deterministic, and the third has a probabilistic nature that has desirable time-averaged and ensemble behavior. For each algorithm, we analytically bound the error between the desired pulse frequency and the actual frequency output by the microprocessor. We aim to provide tools for the design and analysis of closed-loop neuroprosthetic systems containing PFM View full abstract»

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  • An Intelligent Powered Wheelchair to Enable Mobility of Cognitively Impaired Older Adults: An Anticollision System

    Page(s): 136 - 143
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    Older adults with cognitive impairments are generally prohibited from using powered wheelchairs, because of the high risk of collisions with people and objects. This paper describes and presents the preliminary results of a system that uses an infrared sensor to provide anticollision and a prompting system for a powered wheelchair that helps guide the user safely past obstacles. Trials with the prototyped system detected collisions and stopped the chair in 95% of trials with an object and generated no false alarms View full abstract»

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  • Force Control Strategies While Driving Electric Powered Wheelchairs With Isometric and Movement-Sensing Joysticks

    Page(s): 144 - 150
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    Innovations to control interfaces for electric powered wheelchairs (EPWs) could benefit 220 000 current users and over 125 000 individuals who desire mobility but cannot use a conventional motion sensing joystick (MSJ). We developed a digital isometric joystick (IJ) with sophisticated signal processing and two control functions. In a prior study, subjects' driving accuracy with our IJ was comparable to using an MSJ. However, we observed subjects using excessive force on the IJ possibly because its rigid post provides no positional feedback. Thus, this paper examines the time-series data recorded in the previous study to characterize subjects' force control strategies since weakness is a concern. Eleven EPW users with upper limb impairments drove an EPW using an IJ with two different control functions and an MSJ in a Fitts' law paradigm. Subjects relied upon positional feedback from the MSJ and used appropriate force. In contrast, subjects using the IJ with either control function applied significantly higher force than necessary (p<0.0001 and p=0.0058). Using higher average force was correlated with quicker trial times but not associated with accuracy. Lack of positional feedback may result in use of excess isometric force. Modifying control functions, adjusting gain, or providing additional training or feedback might address this problem View full abstract»

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  • Order form for reprints

    Page(s): 151
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  • 29th Annual International Conference of the IEEE Engineering in Medicine and Biology Society

    Page(s): 152
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  • IEEE Transactions on Neural Systems and Rehabilitation Engineering Information for authors

    Page(s): C3
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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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Meet Our Editors

Editor-in-Chief
Paul Sajda
Columbia University