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Neural Systems and Rehabilitation Engineering, IEEE Transactions on

Issue 6 • Date Dec. 2009

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  • [Front cover]

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

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  • An Empirical Bayesian Framework for Brain–Computer Interfaces

    Page(s): 521 - 529
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (504 KB) |  | HTML iconHTML  

    Current brain-computer interface (BCI) systems suffer from high complex feature selectors in comparison to simple classifiers. Meanwhile, neurophysiological and experimental information are hard to be included in these two separate phases. In this paper, based on the hierarchical observation model, we proposed an empirical Bayesian linear discriminant analysis (BLDA), in which the neurophysiological and experimental priors are considered simultaneously; the feature selection, weighted differently, and classification are performed jointly, thus it provides a novel systematic algorithm framework which can utilize priors related to feature and trial in the classifier design in a BCI. BLDA was comparatively evaluated by two simulations of a two-class and a four-class problem, and then it was applied to two real four-class motor imagery BCI datasets. The results confirmed that BLDA is superior in accuracy and robustness to LDA, regularized LDA, and SVM. View full abstract»

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  • Phase Stability Analysis of Chirp Evoked Auditory Brainstem Responses by Gabor Frame Operators

    Page(s): 530 - 536
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1258 KB) |  | HTML iconHTML  

    We have recently shown that click evoked auditory brainstem responses (ABRs) can be efficiently processed using a novelty detection paradigm. Here, ABRs as a large-scale reflection of a stimulus locked neuronal group synchronization at the brainstem level are detected as novel instance-novel as compared to the spontaneous activity which does not exhibit a regular stimulus locked synchronization. In this paper we propose for the first time Gabor frame operators as an efficient feature extraction technique for ABR single sweep sequences that is in line with this paradigm. In particular, we use this decomposition technique to derive the Gabor frame phase stability (GFPS) of sweep sequences of click and chirp evoked ABRs. We show that the GFPS of chirp evoked ABRs provides a stable discrimination of the spontaneous activity from stimulations above the hearing threshold with a small number of sweeps, even at low stimulation intensities. It is concluded that the GFPS analysis represents a robust feature extraction method for ABR single sweep sequences. Further studies are necessary to evaluate the value of the presented approach for clinical applications. View full abstract»

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  • Unmyelinated Aplysia Nerves Exhibit a Nonmonotonic Blocking Response to High-Frequency Stimulation

    Page(s): 537 - 544
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (915 KB) |  | HTML iconHTML  

    The application of high-frequency alternating current (HFAC) stimulation to reversibly block conduction in peripheral nerves has been under investigation for decades. Computational studies have produced ambiguous results since they have been based on axon models that are perhaps not valid for the nerves in which the phenomenon has been demonstrated. Though simulations based on the Hodgkin-Huxley unmyelinated nerve cable model have been used to understand the phenomena, the isolated response of an unmyelinated nerve to HFAC waveforms has not been experimentally investigated. To understand the effect of HFAC waveforms in homogenous nerves, experiments were conducted on purely unmyelinated nerves of the sea-slug Aplysia californica. Sinusoidal waveforms in the range of 5-50 kHz were used to block the propagation of action potentials through the nerves. The time for complete recovery from block was found to be dependent on the duration of application of the HFAC waveform but was independent of the frequency of the waveform tested. Unlike data from simulations and experiments on myelinated nerves, the minimum HFAC amplitude for blocking conduction in these unmyelinated nerves exhibited a unique nonmonotonic relationship with frequency, which may be advantageous in various neurophysiological applications. View full abstract»

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  • Selective and Graded Recruitment of Cat Hamstring Muscles With Intrafascicular Stimulation

    Page(s): 545 - 552
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1248 KB) |  | HTML iconHTML  

    The muscles of the hamstring group can produce different combinations of hip and knee torque. Thus, the ability to activate the different hamstring muscles selectively is of particular importance in eliciting functional movements such as stance and gait in a person with spinal cord injury. We investigated the ability of intrafascicular stimulation of the muscular branch of the sciatic nerve to recruit the feline hamstring muscles in a selective and graded fashion. A Utah Slanted Electrode Array, consisting of 100 penetrating microelectrodes, was implanted into the muscular branch of the sciatic nerve in six cats. Muscle twitches were evoked in the three compartments of biceps femoris (anterior, middle, and posterior), as well as semitendinosus and semimembranosus, using pulse-width modulated constant-voltage pulses. The resultant compound muscle action potentials were recorded using intramuscular fine-wire electrodes. 74% of the electrodes per implant were able to evoke a threshold response in these muscles, and these electrodes were evenly distributed among the instrumented muscles. Of the five muscles instrumented, on average 2.5 could be selectively activated to 90% of maximum EMG, and 3.5 could be selectively activated to 50% of maximum EMG. The muscles were recruited selectively with a mean stimulus dynamic range of 4.14 ?? 5.05 dB between threshold and either spillover to another muscle or a plateau in the response. This selective and graded activation afforded by intrafascicular stimulation of the muscular branch of the sciatic nerve suggests that it is a potentially useful stimulation paradigm for eliciting distinct forces in the hamstring muscle group in motor neuroprosthetic applications. View full abstract»

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  • Estimation of 2-D Center of Mass Movement During Trunk Flexion–Extension Movements Using Body Accelerations

    Page(s): 553 - 559
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (887 KB) |  | HTML iconHTML  

    Motions of the center of body mass (COM) and body segment acceleration signals are commonly used to indicate movement performance and stability during standing activities. The COM trajectory is usually calculated by video motion analysis, which has a time consuming setup and also is not readily available in all clinical settings. In this paper, we present a novel method to estimate the COM trajectory from the upper and lower limb accelerations, based on experimental data. We have modeled the relationships that exist between the 2-D hip and trunk acceleration data with the 2-D COM trajectory in the sagittal plane, during four trunk flexion-extension movement tasks and estimated the COM trajectory based on that model. The model accounted for between 93 ?? 9% to 97 ?? 3% of the resultant COM trajectory's variability, depending on the task. This corresponded to a range of absolute error between the true and estimated COM trajectories of 0.65 ?? 0.62 to 1.07 ?? 1.13 cm. The advantage of this model compared to our previous work on COM trajectory estimation is that it does not require any calibration and provides a reasonably accurate estimation of the COM trajectory, which can be used to study human balance performance in any clinical setting. View full abstract»

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  • Humans Can Integrate Force Feedback to Toes in Their Sensorimotor Control of a Robotic Hand

    Page(s): 560 - 567
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (586 KB) |  | HTML iconHTML  

    Tactile sensory feedback is essential for dexterous object manipulation. Users of hand myoelectric prostheses without tactile feedback must depend essentially on vision to control their device. Indeed, improved tactile feedback is one of their main priorities. Previous research has provided evidence that conveying tactile feedback can improve prostheses control, although additional effort is required to solve problems related to pattern recognition learning, unpleasant sensations, sensory adaptation, and low spatiotemporal resolution. Still, these studies have mainly focused on providing stimulation to hairy skin regions close to the amputation site, i.e., usually to the upper arm. Here, we explored the possibility to provide tactile feedback to the glabrous skin of toes, which have mechanical and neurophysiological properties similar to the fingertips. We explored this paradigm in a grasp-and-lift task, in which healthy participants controlled two opposing digits of a robotic hand by changing the spacing of their index finger and thumb. The normal forces applied by the robotic fingertips to a test object were fed back to the right big and second toe. We show that within a few lifting trials, all the participants incorporated the force feedback received by the foot in their sensorimotor control of the robotic hand. View full abstract»

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  • Application of Modified Regression Techniques to a Quantitative Assessment for the Motor Signs of Parkinson's Disease

    Page(s): 568 - 575
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (927 KB) |  | HTML iconHTML  

    Effective clinical trials for neuroprotective interventions for Parkinson's disease (PD) require a way to quantify an individual's motor symptoms and analyze the change in these symptoms over time. Clinical scales provide a global picture of function but cannot precisely measure specific aspects of motor control. We have used commercially available sensors to create a protocol called Advanced Sensing for Assessment of Parkinson's disease (ASAP) to obtain a quantitative and reliable measure of motor impairment in early to moderate PD. The ASAP protocol measures grip force as an individual tracks a sinusoidal or pseudorandom target force under three conditions of increasing cognitive load. Thirty individuals with PD have completed the ASAP protocol. The ASAP data for 26 of these individuals were summarized in terms of 36 variables, and modified regression techniques were used to predict an individual's score on the Unified Parkinson Disease Rating Scale based on ASAP data. We observed a mean prediction error of approximately 3.5 UPDRS points, and the predicted score accounted for approximately 76% of the variability of the UPDRS. These results demonstrate that the ASAP protocol can measure differences for individuals who are clinically different. This indicates that the ASAP protocol may be able to measure changes with time in the motor signs of an individual with PD. View full abstract»

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  • Nonlinear Neuromuscular Electrical Stimulation Tracking Control of a Human Limb

    Page(s): 576 - 584
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    A high-level objective of neuromuscular electrical stimulation (NMES) is to enable a person to achieve some functional task. Towards this goal, the objective of the current effort is to develop a NMES controller to produce a knee position trajectory that will enable a human shank to track any continuous desired trajectory (or constant setpoint). A nonlinear control method is developed to control the human quadriceps femoris muscle undergoing nonisometric contractions. The developed controller does not require a muscle model and can be proven to yield asymptotic stability for a nonlinear muscle model in the presence of bounded nonlinear disturbances (e.g., spasticity, delays, fatigue). The performance of the controller is demonstrated through a series of closed-loop experiments on human subjects. The experiments illustrate the ability of the controller to enable the leg shank to track single and multiple period trajectories with different periods and ranges of motion, and also track desired step changes with changing loads. View full abstract»

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  • A Combined sEMG and Accelerometer System for Monitoring Functional Activity in Stroke

    Page(s): 585 - 594
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    Remote monitoring of physical activity using body-worn sensors provides an alternative to assessment of functional independence by subjective, paper-based questionnaires. This study investigated the classification accuracy of a combined surface electromyographic (sEMG) and accelerometer (ACC) sensor system for monitoring activities of daily living in patients with stroke. sEMG and ACC data (eight channels each) were recorded from 10 hemiparetic patients while they carried out a sequence of 11 activities of daily living (identification tasks), and 10 activities used to evaluate misclassification errors (nonidentification tasks). The sEMG and ACC sensor data were analyzed using a multilayered neural network and an adaptive neuro-fuzzy inference system to identify the minimal sensor configuration needed to accurately classify the identification tasks, with a minimal number of misclassifications from the nonidentification tasks. The results demonstrated that the highest sensitivity and specificity for the identification tasks was achieved using a subset of four ACC sensors and adjacent sEMG sensors located on both upper arms, one forearm, and one thigh, respectively. This configuration resulted in a mean sensitivity of 95.0%, and a mean specificity of 99.7% for the identification tasks, and a mean misclassification error of <10% for the nonidentification tasks. The findings support the feasibility of a hybrid sEMG and ACC wearable sensor system for automatic recognition of motor tasks used to assess functional independence in patients with stroke. View full abstract»

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  • An Assessment of Robot-Assisted Bimanual Movements on Upper Limb Motor Coordination Following Stroke

    Page(s): 595 - 604
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    Robot-assisted training is increasingly being investigated in upper limb rehabilitation for individuals with stroke. Many studies have suggested that an appropriate synchronization of voluntary motor commands and limb movement is critical for long-term efficacy. Bimanual training is one method for enhancing this synchronization or motor coordination. The purpose of the study was to evaluate the potential efficacy of bimanual robot-assisted movements by comparing the relative timing of muscle activation and forces to those generated during unimanual robot-assisted movement. A secondary goal was to compare bimanual robot-assisted movement to bimanual voluntary movement, where both limbs moved independently without robotics. Subjects performed reaching tasks while attached to one or two robotic manipulators. A predefined movement trajectory was prescribed during unimanual robot-assisted movement; in bimanual robot-assisted movement the paretic limb trajectory mirrored the nonparetic limb. Relative to unimanual movements, during bimanual movements the timing of muscle activation and initial interface forces was more similar to the nonparetic limb. However, there were limited differences in these measures between bimanual voluntary and bimanual robot-assisted movements. Bimanual robot-assisted movements resulted in superior motor coordination compared to unimanual movements and could be beneficial for individuals with a restricted movement range. Bimanual movements without robotics were just as efficacious and may be preferred for individuals who can generate movement without assistance. View full abstract»

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  • Correction to Why is the Metabolic Efficiency of FES Cycling Low?

    Page(s): 605
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  • Erratum to “Influence of the Number and Location of Recording Contacts on the Selectivity of a Nerve Cuff Electrode”

    Page(s): 605
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  • Erratum to “Kinetic Trajectory Decoding Using Motor Cortical Ensembles”

    Page(s): 606
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    Summary form only given, as follows. The first footnote of the above-named work should have included the following sentence: "The first two authors contributed equally to this work." View full abstract»

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  • 32nd Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC'10)

    Page(s): 607
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  • Why we joined ... [advertisement]

    Page(s): 608
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  • 2009 Index IEEE Transactions on Neural Systems and Rehabilitation Engineering Vol. 17

    Page(s): 609 - 621
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  • IEEE Transactions on Neural Systems and Rehabilitation Engineering information for authors

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  • Table of contents

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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