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Neural Systems and Rehabilitation Engineering, IEEE Transactions on

Issue 5 • Date Oct. 2010

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  • [Front cover]

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  • IEEE Transactions on Neural Systems and Rehabilitation Engineering publication information

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  • Technology-Aware Algorithm Design for Neural Spike Detection, Feature Extraction, and Dimensionality Reduction

    Page(s): 469 - 478
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1022 KB) |  | HTML iconHTML  

    Applications such as brain-machine interfaces require hardware spike sorting in order to 1) obtain single-unit activity and 2) perform data reduction for wireless data transmission. Such systems must be low-power, low-area, high-accuracy, automatic, and able to operate in real time. Several detection, feature-extraction, and dimensionality-reduction algorithms for spike sorting are described and evaluated in terms of accuracy versus complexity. The nonlinear energy operator is chosen as the optimal spike-detection algorithm, being most robust over noise and relatively simple. Discrete derivatives is chosen as the optimal feature-extraction method, maintaining high accuracy across signal-to-noise ratios with a complexity orders of magnitude less than that of traditional methods such as principal-component analysis. We introduce the maximum-difference algorithm, which is shown to be the best dimensionality-reduction method for hardware spike sorting. View full abstract»

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  • Measurement of BOLD Changes Due to Cued Eye-Closure and Stopping During a Continuous Visuomotor Task via Model-Based and Model-Free Approaches

    Page(s): 479 - 488
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    As a precursor for investigation of changes in neural activity underlying lapses of responsiveness, we set up a system to simultaneously record functional magnetic resonance imaging (fMRI), eye-video, EOG, and continuous visuomotor response inside an MRI scanner. The BOLD fMRI signal was acquired during a novel 2-D tracking task in which participants (10 males, 10 females) were cued to either briefly stop tracking and close their eyes (Stop+Close) or to briefly stop tracking (Stop) only. The onset and duration of eye-closure and stopping were identified post hoc from eye-video, EOG, and visuomotor response. fMRI data were analyzed using a general linear model (GLM) and tensorial independent component analysis (TICA). The GLM-based analysis identified predominantly increased blood oxygenation level dependent (BOLD) activity during eye-closure and stopping in multisensory areas, sensory-motor integration areas, and default-mode regions. Stopping during tracking elicited increased activity in visual processing areas, sensory-motor integration areas, and premotor areas. TICA separated the spatio-temporal pattern of activity into multiple task-related networks including the 1) occipito-medial frontal eye-movement network, 2) sensory areas, 3) left-lateralized visuomotor network, and 4) fronto-parietal visuomotor network, which were modulated differently by Stop+Close and Stop. The results demonstrate the merits of using simultaneous fMRI, behavioral, and physiological recordings to investigate the mechanisms underlying complex human behaviors in the human brain. Furthermore, knowledge of widespread modulations in brain activity due to voluntary eye-closure or stopping during a continuous visuomotor task is important for studies of the brain mechanisms underlying involuntary behaviors, such as microsleeps and attention lapses, which are often accompanied by brief eye-closure and/or response failures. View full abstract»

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  • Highly Doped Polycrystalline Silicon Microelectrodes Reduce Noise in Neuronal Recordings In Vivo

    Page(s): 489 - 497
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    The aims of this study are to 1) experimentally validate for the first time the nonlinear current-potential characteristics of bulk doped polycrystalline silicon in the small amplitude voltage regimes (0-200 ) and 2) test if noise amplitudes ( 0-15 ) from single neuronal electrical recordings get selectively attenuated in doped polycrystalline silicon microelectrodes due to the above property. In highly doped polycrystalline silicon, bulk resistances of several hundred kilo-ohms were experimentally measured for voltages typical of noise amplitudes and 9-10 k for voltages typical of neural signal amplitudes (> 150-200 ). Acute multiunit measurements and noise measurements were made in n = 6 and n = 8 anesthetized adult rats, respectively, using polycrystalline silicon and tungsten microelectrodes. There was no significant difference in the peak-to-peak amplitudes of action potentials recorded from either microelectrode (p > 0.10). However, noise power in the recordings from tungsten microelectrodes (26.36 ±10.13 pW) was significantly higher (p <;; 0.001) than the corresponding value in polycrystalline silicon microelectrodes (7.49 ± 2.66 pW). We conclude that polycrystalline silicon microelectrodes result in selective attenuation of noise power in electrical recordings compared to tungsten microelectrodes. This reduction in noise compared to tungsten microelectrodes is likely due to the exponentially higher bulk resistances offered by highly doped bulk polycrystalline silicon in the range of voltages corresponding to noise in multiunit measurements. View full abstract»

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  • The Effects of Stimulating Lower Leg Muscles on the Mechanical Work and Metabolic Response in Functional Electrically Stimulated Pedaling

    Page(s): 498 - 504
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (459 KB) |  | HTML iconHTML  

    Functional electrical stimulation (FES) pedaling with the muscles of the upper leg has been shown to provide benefit to spinal cord injured (SCI) individuals. FES pedaling with electrical stimulation timing patterns that minimize the stress-time integral of activated muscles has been shown to increase the work individuals can perform during the exercise compared to existing FES stimulation timing patterns. Activation of the lower leg muscles could further enhance the benefit of FES pedaling by increasing the metabolic response to the exercise. For SCI individuals, the objectives of this study were to experimentally determine whether FES pedaling with the upper and lower leg muscles would affect the work generated and increase the physiological responses compared to pedaling with the upper leg muscles alone. Work, rate of oxygen consumption ( V̇O2), and blood lactate data were measured from nine SCI subjects (injury level T4-T12) as they pedaled using upper leg and upper and lower leg muscle groups on repeated trials. The subjects performed 6% more work with the upper and lower legs than with the upper legs alone, but the difference was not significant (p = 0.2433). The average rate of oxygen consumption associated with the upper leg muscles (441 ± 231 mL/) was not significantly different from the corresponding average for the upper and lower legs (473 ± 213 mL/) (p = 0.1176). The blood lactate concentration associated with the upper leg muscles (5.9 ± 2.3 mmoles/L) was significantly lower than the corresponding average for the upper and lower legs (6.8 ± 2.3 mmoles/L) (p = 0.0049). The results indicate that electrical stimulation timing patterns that incorporate the lower leg muscles do increase the blood lactate concentrations. However, there was not enough evidence to reject the null hypothesis that stimulating the lower leg muscles affected the work accomplished or increased the rate of oxygen consumption. In con- - clusion, incorporating the lower leg muscles in the exercise does not lead to negative effects and could result in enhanced exercise outcomes in the long term. View full abstract»

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  • The Rutgers Arm II Rehabilitation System—A Feasibility Study

    Page(s): 505 - 514
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    The Rutgers Arm II (RA II) is a new system that trains the shoulder/arm motor control, strengthening, arm speed of motion, endurance, and grasp strength in a single rehabilitation session. The system components are a tilted low-friction table, a forearm support with markers and wireless transmitter, a shoulder appendage to detect compensatory leaning, infrared vision tracking, a large display and a PC running custom virtual reality games. Three participants in the chronic stage post-stroke were trained on the RAII for four weeks (12 sessions) and had a follow-up evaluation after three months. The results of this study indicate that the participants were able to use the technology, and preliminary results are encouraging. One participant showed improvement in all timed Jebsen-Taylor test tasks, all participants had a larger shoulder range-of-motion and pinch strength of the affected hand post-training. Computerized measure of supported arm reach area increased in two participants post-training and in all participants at follow-up. Participants reported an improved ability to perform activities of daily living with the affected arm. There was good compliance by the participants, each of whom attended all sessions. The participants accepted the training length, even with some sessions lasting 1 h (excluding rest periods). The participants' subjective evaluation rated the system an average 3.7 out of 5 (see also the accompanying taped video interview of one of the participants). View full abstract»

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  • Construction of Age Model for the Evaluation of Swallowing Function Using Photo Sensors

    Page(s): 515 - 522
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2182 KB) |  | HTML iconHTML  

    For the realization of better in-home nursing environment, understanding the swallowing function and its process are quite essential to realize appropriate rehabilitation policies and dietary menus to prevent aspirations. However, the swallowing function is currently examined using mainly large-scale and expensive methods such as video fluoroscopic examination of swallowing, mesophagia fiber, palatal pressure measurement, CT, and cine MRI, which are difficult to be used at patients' homes. This paper proposes an age model, which applies a self organization map (SOM) to evaluate the swallowing function. As parameters to make the SOM, the lead time, the geniohyoid muscle, and the thyrohyid muscle are measured using photo sensors with a little invasiveness. To verify the effectiveness of our swallowing function map, the age of the subject determined by the map is compared with his/her actual age. As a result of the comparison, the root mean square error was 6.28 years. View full abstract»

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  • Electrical Stimulation of the Rectus Femoris During Pre-swing Diminishes Hip and Knee Flexion During the Swing Phase of Normal Gait

    Page(s): 523 - 530
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    Individuals who have suffered cerebral insults often exhibit stiff-knee gait, a condition characterized by reduced knee flexion during swing. We investigated the effect that an increment in normal rectus femoris (RF) activity can have on hip and knee joint angles during swing, as a first step to determining this muscle's involvement in stiff-knee gait. For this, we developed a protocol that electrically stimulated the RF during pre-swing or after toe-off in randomly selected strides of treadmill walking, consistent with the timing of RF activity during normal gait. Seven healthy young adults participated in the study. Pre-swing stimulation induced a significant ( p<;;0.05) reduction in peak knee flexion (avg 7.5° ) in all subjects, with an accompanying decrease in hip flexion in four of the subjects. RF stimulation after toe-off diminished peak knee flexion in three subjects and reduced hip flexion in four subjects. When compared to muscle-actuated gait simulations that were similarly perturbed, the induced motion measures were generally consistent in direction but exhibited greater variability across strides and subjects. We conclude that excess RF activity during pre-swing has the potential to contribute to stiff-knee gait, and that clinical treatment should consider the “counter-intuitive” function that the RF has in extending the hip. View full abstract»

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  • An Adaptive Mixed Reality Training System for Stroke Rehabilitation

    Page(s): 531 - 541
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    This paper presents a novel mixed reality rehabilitation system used to help improve the reaching movements of people who have hemiparesis from stroke. The system provides real-time, multimodal, customizable, and adaptive feedback generated from the movement patterns of the subject's affected arm and torso during reaching to grasp. The feedback is provided via innovative visual and musical forms that present a stimulating, enriched environment in which to train the subjects and promote multimodal sensory-motor integration. A pilot study was conducted to test the system function, adaptation protocol and its feasibility for stroke rehabilitation. Three chronic stroke survivors underwent training using our system for six 75-min sessions over two weeks. After this relatively short time, all three subjects showed significant improvements in the movement parameters that were targeted during training. Improvements included faster and smoother reaches, increased joint coordination and reduced compensatory use of the torso and shoulder. The system was accepted by the subjects and shows promise as a useful tool for physical and occupational therapists to enhance stroke rehabilitation. View full abstract»

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  • Robust Tracking of the Upper Limb for Functional Stroke Assessment

    Page(s): 542 - 550
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (452 KB) |  | HTML iconHTML  

    We present a robust 3-D parts-based (PB) tracking system designed to follow the upper limb of stroke survivors during desktop activities. This system fits a probabilistic model of the arm to sequences of images taken from multiple angles. The arm model defines shapes and colors of limbs and limb configurations that are more or less likely. We demonstrate that the system is 1) robust to cluttered scenes and temporary occlusions, 2) accurate relative to a commercial motion capture device, and 3) capable of capturing kinematics that correlate with concurrent measures of post-stroke limb function. To evaluate the PB system, the functional motion of seven stroke survivors was measured concurrently with the PB system and a commercial motion capture system. In addition, functional motion was assessed by an expert using the Fugl-Meyer Assessment (FMA) and related to recorded kinematics. Standard deviation of differences in measured elbow angles between systems was 5.7^; deviation in hand velocity estimates was 2.6 cm/s. Several statistics, moreover, correlated strongly with FMA scores. Standard deviation in shoulder velocity had a significant correlation coefficient with FMA score below -0.75 when measured with all systems. View full abstract»

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  • A Pneumatic Glove and Immersive Virtual Reality Environment for Hand Rehabilitative Training After Stroke

    Page(s): 551 - 559
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    While a number of devices have recently been developed to facilitate hand rehabilitation after stroke, most place some restrictions on movement of the digits or arm. Thus, a novel glove was developed which can provide independent extension assistance to each digit while still allowing full arm movement. This pneumatic glove, the PneuGlove, can be used for training grasp-and-release movements either with real objects or with virtual objects in a virtual reality environment. Two groups of stroke survivors, with seven subjects in each group, completed a six-week rehabilitation training protocol, consisting of three 1-h sessions held each week. One group wore the PneuGlove during training, performed both within a novel virtual reality environment and outside of it with physical objects, while the other group completed the same training without the device. Across subjects, significant improvements were observed in the Fugl-Meyer Assessment for the upper extremity ( p<;;0.001), the hand/wrist portion of the Fugl-Meyer Assessment ( p<;;0.001), the Box and Blocks test ( p<;;0.05), and palmar pinch strength ( p<;;0.05). While changes in the two groups were not statistically different, the group using the PneuGlove did show greater mean improvement on each of these measures, such as gains of 3.7 versus 2.4 points on the hand/wrist portion of the Fugl-Meyer Assessment and 14 N versus 5 N in palmar pinch. View full abstract»

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  • A Learning Model for the Automated Assessment of Hand-Drawn Images for Visuo-Spatial Neglect Rehabilitation

    Page(s): 560 - 570
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    Visuo-spatial neglect (often simply referred to as “neglect”) is a complex poststroke medical syndrome which may be assessed by means of a series of drawing-based tests. Based on a novel analysis of a test battery formed from established pencil-and-paper tests, the aim of this study is to develop an automated assessment system which enables objectivity, repeatability, and diagnostic capability in the scoring process. Furthermore, the novel assessment system encapsulates temporal sequence and other “dynamic” information inherent in the drawing process. Several approaches are introduced in this paper and the results compared. The optimal model is shown to produce significant agreement with the score for drawing-related components of the Rivermead Behavioural Inattention Test, the widely accepted standardised clinical test for the diagnosis of neglect, and, more importantly, to encapsulate data to enable an enhanced test resolution with a reduction in battery size. View full abstract»

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  • Impact of Visual Error Augmentation When Integrated With Assist-as-Needed Training Method in Robot-Assisted Rehabilitation

    Page(s): 571 - 579
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (924 KB) |  | HTML iconHTML  

    The paper investigates the impact of the integration of the visual error augmentation training method with the assist-as-needed training method in robot-assisted rehabilitation training of the upper extremity. A robot-assisted rehabilitation system is developed that integrates an assistive controller, which can provide robotic assistance to the participant as and when needed, with a visual error augmentation mechanism, which amplifies the tracking error to heighten the participant's motivation to improve tracking accuracy. A crossover study is designed to evaluate the impact of the integration of the visual error augmentation method with the assist-as-needed training method. Experimental results on unimpaired participants demonstrate improved performance has been achieved in the integrated training session. View full abstract»

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  • IEEE Transactions on Neural Systems and Rehabilitation Engineering information for authors

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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