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Background: Recent studies have shown that brain-machine interfaces (BMIs) offer great potential for restoring upper limb function. However, grasping objects is a complicated task and the signals extracted from the brain may not always be capable of driving these movements reliably. Vision-guided robotic assistance is one possible way to improve BMI performance. We describe a method of shared control where the user controls a prosthetic arm using a BMI and receives assistance with positioning the hand when it approaches an object. Methods: Two human subjects with tetraplegia used a robotic arm to complete object transport tasks with and without shared control. The shared control system was designed to provide a balance between BMI-derived intention and computer assistance. An autonomous robotic grasping system identified and tracked objects and defined stable grasp positions for these objects. The system identified when the user intended to interact with an object based on the BMI-controlled movements of the robotic arm. Using shared control, BMI controlled movements and autonomous grasping commands were blended to ensure secure grasps. Results: Both subjects were more successful on object transfer tasks when using shared control compared to BMI control alone. Movements made using shared control were more accurate, more efficient, and less difficult. One participant attempted a task with multiple objects and successfully lifted one of two closely spaced objects in 92 % of trials, demonstrating the potential for users to accurately execute their intention while using shared control. Conclusions: Integration of BMI control with vision-guided robotic assistance led to improved performance on object transfer tasks. Providing assistance while maintaining generalizability will make BMI systems more attractive to potential users. Trial registration: NCT01364480 and NCT01894802.

Background: Providing neurofeedback (NF) of motor-related brain activity in a biologically-relevant and intuitive way could maximize the utility of a brain-computer interface (BCI) for promoting therapeutic plasticity. We present a BCI capable of providing intuitive and direct control of a video-based grasp. Methods: Utilizing magnetoencephalography's (MEG) high temporal and spatial resolution, we recorded sensorimotor rhythms (SMR) that were modulated by grasp or rest intentions. SMR modulation controlled the grasp aperture of a stop motion video of a human hand. The displayed hand grasp position was driven incrementally towards a closed or opened state and subjects were required to hold the targeted position for a time that was adjusted to change the task difficulty. Results: We demonstrated that three individuals with complete hand paralysis due to spinal cord injury (SCI) were able to maintain brain-control of closing and opening a virtual hand with an average of 63 % success which was significantly above the average chance rate of 19 %. This level of performance was achieved without pre-training and less than 4 min of calibration. In addition, successful grasp targets were reached in 1.96 ± 0.15 s. Subjects performed 200 brain-controlled trials in approximately 30 min excluding breaks. Two of the three participants showed a significant improvement in SMR indicating that they had learned to change their brain activity within a single session of NF. Conclusions: This study demonstrated the utility of a MEG-based BCI system to provide realistic, efficient, and focused NF to individuals with paralysis with the goal of using NF to induce neuroplasticity.

After spinal cord injury (SCI), motor commands from the brain are unable to reach peripheral nerves and muscles below the level of the lesion. Action observation (AO), in which a person observes someone else performing an action, has been used to augment traditional rehabilitation paradigms. Similarly, AO can be used to derive the relationship between brain activity and movement kinematics for a motor-based brain-computer interface (BCI) even when the user cannot generate overt movements. BCIs use brain signals to control external devices to replace functions that have been lost due to SCI or other motor impairment. Previous studies have reported congruent motor cortical activity during observed and overt movements using magnetoencephalography (MEG) and functional magnetic resonance imaging (fMRI). Recent single-unit studies using intracortical microelectrodes also demonstrated that a large number of motor cortical neurons had similar firing rate patterns between overt and observed movements. Given the increasing interest in electrocorticography (ECoG)-based BCIs, our goal was to identify whether action observation-related cortical activity could be recorded using ECoG during grasping tasks. Specifically, we aimed to identify congruent neural activity during observed and executed movements in both the sensorimotor rhythm (10-40 Hz) and the high-gamma band (65-115 Hz) which contains significant movement-related information. We observed significant motor-related high-gamma band activity during AO in both able-bodied individuals and one participant with a complete C4 SCI. Furthermore, in able-bodied participants, both the low and high frequency bands demonstrated congruent activity between action execution and observation. Our results suggest that AO could be an effective and critical procedure for deriving the mapping from ECoG signals to intended movement for an ECoG-based BCI system for individuals with paralysis. © 2014 Collinger, Vinjamuri, Degenhart, Weber, Sudre

Brain-computer interface (BCI) technology aims to help individuals with disability to control assistive devices and reanimate paralyzed limbs. Our study investigated the feasibility of an electrocorticography (ECoG)-based BCI system in an individual with tetraplegia caused by C4 level spinal cord injury. ECoG signals were recorded with a high-density 32-electrode grid over the hand and arm area of the left sensorimotor cortex. The participant was able to voluntarily activate his sensorimotor cortex using attempted movements, with distinct cortical activity patterns for different segments of the upper limb. Using only brain activity, the participant achieved robust control of 3D cursor movement. The ECoG grid was explanted 28 days post-implantation with no adverse effect. This study demonstrates that ECoG signals recorded from the sensorimotor cortex can be used for real-time device control in paralyzed individuals.

Laboratory-based simulators afford many advantages for studying physiology and biomechanics; however, they may not perfectly mimic wheelchair propulsion over natural surfaces. The goal of this study was to compare kinetic and temporal parameters between propulsion overground on a tile surface and on a dynamometer. Twenty-four experienced manual wheelchair users propelled at a self-selected speed on smooth, level tile and a dynamometer while kinetic data were collected using an instrumented wheel. A Pearson correlation test was used to examine the relationship between propulsion variables obtained on the dynamometer and the overground condition. Ensemble resultant force and moment curves were compared using cross-correlation and qualitative analysis of curve shape. User biomechanics were correlated (R ranging from 0.41 to 0.83) between surfaces. Overall, findings suggest that although the dynamometer does not perfectly emulate overground propulsion, wheelchair users were consistent with the direction and amount of force applied, the time peak force was reached, push angle, and their stroke frequency between conditions. © 2012 Human Kinetics, Inc.

Rehabilitation engineers apply engineering principles to improve function or to solve challenges faced by persons with disabilities. It is critical to integrate the knowledge of biologics into the process of rehabilitation engineering to advance the field and maximize potential benefits to patients. Some applications in particular demonstrate the value of a symbiotic relationship between biologics and rehabilitation engineering. In this review we illustrate how researchers working with neural interfaces and integrated prosthetics, assistive technology, and biologics data collection are currently integrating these 2 fields. We also discuss the potential for further integration of biologics and rehabilitation engineering to deliver the best technologies and treatments to patients. Engineers and clinicians must work together to develop technologies that meet clinical needs and are accessible to the intended patient population. Copyright © 2011 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

This paper demonstrates a synergy-based brain-machine interface that uses low-dimensional command signals to control a high dimensional virtual hand. First, temporal postural synergies were extracted from the angular velocities of finger joints of five healthy subjects when they performed hand movements that were similar to activities of daily living. Two synergies inspired from the extracted synergies, namely, two-finger pinch and whole-hand grasp, were used in real-time brain control, where a virtual hand with 10 degrees of freedom was controlled to grasp or pinch virtual objects. These two synergies were controlled by electrocorticographic (ECoG) signals recorded from two electrodes of an electrode array that spanned motor and speech areas of an individual with intractable epilepsy, thus demonstrating closed loop control of a synergy-based brain-machine interface. © 2006 IEEE.

Movement-related field potentials can be extracted and processed in real-time with magnetoencephalography (MEG) and used for brain machine interfacing (BMI). However, due to its immense sensitivity to magnetic fields, MEG is prone to a low signal to noise ratio. It is therefore important to collect enough initial data to appropriately characterize motor-related activity and to ensure that decoders can be built to adequately translate brain activity into BMI-device commands. This is of particular importance for therapeutic BMI applications where less time spent collecting initial open-loop data means more time for performing neurofeedback training which could potentially promote cortical plasticity and rehabilitation. This study evaluated the amount of hand-grasp movement and rest data needed to characterize sensorimotor modulation depth and build classifier functions to decode brain states in real-time. It was determined that with only five minutes of initial open-loop MEG data, decoders can be built to classify brain activity as grasp or rest in real-time with an accuracy of 846%. © 2011 IEEE.

This paper presents Craniux, an open-access, open-source software framework for brain-machine interface (BMI) research. Developed in LabVIEW, a high-level graphical programming environment, Craniux offers both out-of-the-box functionality and a modular BMI software framework that is easily extendable. Specifically, it allows researchers to take advantage of multiple features inherent to the LabVIEW environment for on-the-fly data visualization, parallel processing, multithreading, and data saving. This paper introduces the basic features and system architecture of Craniux and describes the validation of the system under real-time BMI operation using simulated and real electrocorticographic (ECoG) signals. Our results indicate that Craniux is able to operate consistently in real time, enabling a seamless work flow to achieve brain control of cursor movement. The Craniux software framework is made available to the scientific research community to provide a LabVIEW-based BMI software platform for future BMI research and development. © 2011 Alan D. Degenhart et al.

In the presented work, standard and high-density electrocorticographic (ECoG) electrodes were used to record cortical field potentials in three human subjects during a hand posture task requiring the application of specific levels of force during grasping. We show two-class classification accuracies of up to 80% are obtained when classifying between two-finger pinch and whole-hand grasp hand postures despite differences in applied force levels across trials. Furthermore, we show that a four-class classification accuracy of 50% is achieved when predicting both hand posture and force level during a two-force, two-hand-posture grasping task, with hand posture most reliably predicted during high-force trials. These results suggest that the application of force plays a significant role in ECoG signal modulation observed during motor tasks, emphasizing the potential for electrocorticography to serve as a source of control signals for dexterous neuroprosthetic devices. © 2011 IEEE.

Objective: To quantify median nerve characteristics before and after strenuous wheelchair propulsion and relate them to symptoms of carpal tunnel syndrome (CTS). We hypothesized that persons with and without symptoms of CTS would have significantly different nerve characteristics at baseline and after propulsion. Design: A repeated-measures design was used to obtain ultrasound images of the median nerve at 3 levels of the wrist (radius, pisiform, and hamate) before and after wheelchair propulsion. Investigators were blinded to subject history related to CTS. Setting: The 2007 and 2008 National Veterans Wheelchair Games and the Human Engineering Research Laboratories. Participants: Fifty-four participants between the ages of 18 and 65 years with a nonprogressive disability who used a manual wheelchair as their primary means of mobility completed this study. Methods: Participants completed questionnaires regarding demographics and the presence and severity of symptoms of CTS. Ultrasound images of the median nerve were obtained before and after a 15-minute strenuous wheelchair-propulsion task. Main Outcome Measurements: Baseline values and post-propulsion changes were determined for median nerve cross-sectional area, flattening ratio, and swelling ratio. Differences in median nerve variables between symptomatic and asymptomatic groups were assessed. Results: No significant differences between symptom groups were identified at baseline; however, persons with symptoms of CTS showed a significantly different percent change from baseline compared with the asymptomatic participants for cross-sectional area at pisiform (P = .014) and flattening ratio at hamate (P = .022), and they showed a strong trend toward a difference in swelling ratio (P = .0502). For each of these variables, the change in the symptomatic group was in the opposite direction of the change in the asymptomatic group. Conclusions: We found several median nerve responses to wheelchair propulsion associated w

Used clinically since Penfield and Jasper's pioneering work in the 1950's, electrocorticography (ECoG) has recently been investigated as a promising technology for brain-computer interfacing. Many researchers have attempted to analyze the properties of ECoG recordings, including prediction of optimal electrode spacing and the improved resolution expected with smaller electrodes. This work applies an analytic model of the volume conductor to investigate the sensitivity field of electrodes of various sizes. The benefit to spatial resolution was minimal for electrodes smaller than 1mm, while smaller electrodes caused a dramatic decrease in signal-to-noise ratio. The temporal correlation between electrode pairs is predicted over a range of spacings and compared to correlation values from a series of recordings in subjects undergoing monitoring for intractable epilepsy. The observed correlations are found to be much higher than predicted by the analytic model and suggest a more detailed model of cortical activity is needed to identify appropriate ECoG grid spacing. © 2011 IEEE.

In this study we investigated the reliability of ultrasound in measuring median nerve characteristics including cross-sectional area (CSA), flattening ratio (FR), swelling ratio (SR), and mean grayscale. Generalizability theory was used to assess inter- and intrarater reliability using the dependability coefficient (Φ), normalized standard error of measurement, and normalized minimum detectable change (MDCNORM) for multiple study design protocols. Interrater reliability was generally moderate. Intrarater reliability was mostly good (Φ > 0.876) when using a single image, captured on one occasion, and being read once. Intrarater MDCNORM ranged from 3.8% to 6.2% for all CSA measures and SR. Using multiple images and/or readings at multiple occasions did not appreciably improve reliability measures. Ultrasound is a reliable tool for measuring median nerve characteristics. We recommend that a single evaluator capture all images for protocols aimed at quantifying median nerve ultrasound measures. We believe an appropriately designed protocol can utilize ultrasound to accurately assess changes in median nerve characteristics after activity. © 2010 Wiley Periodicals, Inc.

This article reviews neural interface technology and its relationship with neuroplasticity. Two types of neural interface technology are reviewed, highlighting specific technologies that the authors directly work with: (1) neural interface technology for neural recording, such as the micro-ECoG BCI system for hand prosthesis control, and the comprehensive rehabilitation paradigm combining MEG-BCI, action observation, and motor imagery training; (2) neural interface technology for functional neural stimulation, such as somatosensory neural stimulation for restoring somatosensation, and non-invasive cortical stimulation using rTMS and tDCS for modulating cortical excitability and stroke rehabilitation. The close interaction between neural interface devices and neuroplasticity leads to increased efficacy of neural interface devices and improved functional recovery of the nervous system. This symbiotic relationship between neural interface technology and the nervous system is expected to maximize functional gain for individuals with various sensory, motor, and cognitive impairments, eventually leading to better quality of life. © 2010 Elsevier Inc.

Objective: To investigate acute ultrasound changes of biceps and supraspinatus tendon appearance after an intense wheelchair propulsion task, and how these changes relate to demographic and biomechanical risk factors. Design: A survey. Setting: Research laboratory and research space at the National Veterans Wheelchair Games. Participants: A convenience sample of 60 manual wheelchair users were recruited through research registries and rehabilitation clinics as well as from participants at the 2007 and 2008 National Veterans Wheelchair Games. The subjects were between 18 and 65 years of age at least 1 year after injury and did not have progressive disabilities. Main Outcome Measures: Quantitative ultrasound (QUS) measures of biceps and supraspinatus tendon appearance, stroke frequency, resultant force, tendinopathy score, and duration of wheelchair use. Results: Biceps tendon appearance after an intense propulsion task was significantly related to chronic biceps tendinopathy, duration of wheelchair use, stroke frequency, and resultant force. The subjects with a higher stroke frequency or resultant force tended to have a brighter, more organized tendon appearance compared with the prepropulsion imaging session (baseline). The subjects with tendinopathy or a longer duration of wheelchair use were more likely to have a darker, diffuse tendon appearance immediately after the propulsion task. Supraspinatus tendon appearance after propulsion was only significantly predicted by baseline QUS measures. Conclusions: QUS has proven to be sensitive to risk factors for tendon pathology. Future studies can apply grayscale-based QUS to study the development and prevention of repetitive strain injuries, particularly on an individual basis. © 2010 American Academy of Physical Medicine and Rehabilitation.

OBJECTIVE: The primary aim of this study is to establish the validity of grayscale-based quantitative ultrasound (QUS) measures of the biceps and supraspinatus tendons. DESIGN: Nine QUS measures of the biceps and supraspinatus tendons were computed from ultrasound images collected from 67 manual wheelchair users. Shoulder pathology was measured using questionnaires, physical examination maneuvers, and a clinical ultrasound grading scale. RESULTS: Increased age, duration of wheelchair use, and body mass correlated with a darker and more homogenous tendon appearance. Subjects with pain during physical examination tests for biceps tenderness and acromioclavicular joint tenderness exhibited significantly different supraspinatus QUS values. Even when controlling for tendon depth, QUS measures of the biceps tendon differed significantly between subjects with healthy tendons, mild tendinosis, and severe tendinosis. Clinical grading of supraspinatus tendon health was correlated with QUS measures of the supraspinatus tendon. CONCLUSIONS: QUS is valid method to quantify tendinopathy and may allow for early detection of tendinosis. Manual wheelchair users are at a high risk for developing shoulder tendon pathology and may benefit from QUS-based research that focuses on identifying interventions designed to reduce this risk. Copyright © 2010 by Lippincott Williams & Wilkins.

Magnetoencephalography (MEG) enables a noninvasive interface with the brain that is potentially capable of providing movement-related information similar to that obtained using more invasive neural recording techniques. Previous studies have shown that movement direction can be decoded from multichannel MEG signals recorded in humans performing wrist movements. We studied whether this information can be extracted without overt movement of the subject, because the targeted users of brain-controlled interface (BCI) technology are those with severe motor disabilities. The objectives of this study were twofold: 1) to decode intended movement direction from MEG signals recorded during the planning period before movement onset and during imagined movement and 2) to localize cortical sources modulated by intended movement direction. Ten able-bodied subjects performed both overt and imagined wrist movement while their cortical activities were recorded using a whole head MEG system. The intended movement direction was decoded using linear discriminant analysis and a Bayesian classifier. Minimum current estimation (MCE) in combination with a bootstrapping procedure enabled source-space statistical analysis, which showed that the contralateral motor cortical area was significantly modulated by intended movement direction, and this modulation was the strongest ∼100 ms before the onset of overt movement. These results suggest that it is possible to study cortical representation of specific movement information using MEG, and such studies may aid in presurgical localization of optimal sites for implanting electrodes for BCI systems. Copyright © 2010 The American Physiological Society.

Rationale and Objectives: Ultrasound is a proven method for examining soft tissue structures, including tendons, and recently quantitative ultrasound has become more prevalent in research settings. However, limited reliability data have been published for these new quantitative ultrasound measures. The main objective of this study was to quantify the reliability and measurement error of multiple quantitative ultrasound imaging protocols for the biceps and supraspinatus tendons. Materials and Methods: Two examiners captured ultrasound images of the non-dominant long head of the biceps tendon and supraspinatus tendon from 15 able-bodied participants and five manual wheelchair users. Each examiner captured two images per subject under two different preparations, which included subject positioning and reference marker placement. Image processing (reading) was performed twice to compute nine quantitative ultrasound measures of grayscale tendon appearance using first-order statistics and texture analysis. Generalizability theory was applied to compute interrater and intrarater reliability using the coefficient of dependability (Φ) for multiple study design protocols. Results: Interrater reliability was generally low (0.26 < Φ < 0.82), and it is recommended that a single evaluator capture all images for quantitative ultrasound protocols. Most of the quantitative ultrasound measures (n = 14 of 18) exhibited at least moderate (Φ > 0.50) intrarater reliability for a single image captured under one preparation and read once. Conclusion: By following a protocol designed to minimize measurement error, one can increase the reliability of quantitative ultrasound measures. An appropriately designed protocol will allow quantitative ultrasound to be used as an outcome measure to identify structural changes within tendons. © 2009 AUR.

Cowan RE, Nash MS, Collinger JL, Koontz AM, Boninger ML. Impact of surface type, wheelchair weight, and axle position on wheelchair propulsion by novice older adults. Objective: To examine the impact of surface type, wheelchair weight, and rear axle position on older adult propulsion biomechanics. Design: Crossover trial. Setting: Biomechanics laboratory. Participants: Convenience sample of 53 ambulatory older adults with minimal wheelchair experience (65-87y); men, n=20; women, n=33. Intervention: Participants propelled 4 different wheelchair configurations over 4 surfaces: tile, low carpet, high carpet, and an 8% grade ramp (surface, chair order randomized). Chair configurations included (1) unweighted chair with an anterior axle position, (2) 9.05kg weighted chair with an anterior axle position, (3) unweighted chair with a posterior axle position (Δ0.08m), and (4) 9.05kg weighted chair with a posterior axle position (Δ0.08m). Weight was added to a titanium folding chair, simulating the weight difference between very light and depot wheelchairs. Instrumented wheels measured propulsion kinetics. Main Outcome Measures: Average self-selected velocity, push frequency, stroke length, peak resultant and tangential force. Results: Velocity decreased as surface rolling resistance or chair weight increased. Peak resultant and tangential forces increased as chair weight increased, as surface resistance increased, and with a posterior axle position. The effect of a posterior axle position was greater on high carpet and the ramp. The effect of weight was constant, but was more easily observed on high carpet and ramp. The effects of axle position and weight were independent of one another. Conclusion: Increased surface resistance decreases self-selected velocity and increases peak forces. Increased weight decreases self-selected velocity and increases forces. Anterior axle positions decrease forces, more so on high carpet. The effects of weight and axle position are independen

Koontz AM, Roche BM, Collinger JL, Cooper RA, Boninger ML. Manual wheelchair propulsion patterns on natural surfaces during start-up propulsion. Objectives: To classify propulsion patterns over surfaces encountered in the natural environment during start-up and compare selected biomechanical variables between pattern types. Design: Case series. Setting: National Veterans Wheelchair Games, Minneapolis, MN, 2005. Participants: Manual wheelchair users (N=29). Intervention: Subjects pushed their wheelchairs from a resting position over high-pile carpet, over linoleum, and up a ramp with a 5° incline while propulsion kinematics and kinetics were recorded with a motion capture system and an instrumented wheel. Main Outcome Measures: Three raters classified the first 3 strokes as 1 of 4 types on each surface: arc, semicircular (SC), single looping over propulsion (SL), and double looping over propulsion (DL). The Fisher exact test was used to assess pattern changes between strokes and surface type. A multiple analysis of variance test was used to compare peak and average resultant force and moment about the hub, average wheel velocity, stroke frequency, contact angle, and distance traveled between stroke patterns. Results: SL was the most common pattern used during start-up propulsion (44.9%), followed by arc (35.9%), DL (14.1%), and SC (5.1%). Subjects who dropped their hands below the rim during recovery achieved faster velocities and covered greater distances (.016≤P≤.075) during start-up on linoleum and carpet and applied more force during start-up on the ramp compared with those who used an arc pattern (P=.066). Conclusions: Classifying propulsion patterns is a difficult task that should use multiple raters. In addition, propulsion patterns change during start-up, with an arc pattern most prevalent initially. The biomechanical findings in this study agree with current clinical guidelines that recommend training users to drop the hand below the pushrim during recovery.

In this study human motor cortical activity was recorded with a customized micro-ECoG grid during individual finger movements. The quality of the recorded neural signals was characterized in the frequency domain from three different perspectives: (1) coherence between neural signals recorded from different electrodes, (2) modulation of neural signals by finger movement, and (3) accuracy of finger movement decoding. It was found that, for the high frequency band (60-120 Hz), coherence between neighboring micro-ECoG electrodes was 0.3. In addition, the high frequency band showed significant modulation by finger movement both temporally and spatially, and a classification accuracy of 73% (chance level: 20%) was achieved for individual finger movement using neural signals recorded from the micro-ECoG grid. These results suggest that the micro-ECoG grid presented here offers sufficient spatial and temporal resolution for the development of minimally-invasive brain-computer interface applications. ©2009 IEEE.

Impink BG, Boninger ML, Walker H, Collinger JL, Niyonkuru C. Ultrasonographic median nerve changes after a wheelchair sporting event. Objectives: To investigate the acute median nerve response to intense wheelchair propulsion by using ultrasonography and to examine the relationship between carpal tunnel syndrome (CTS) signs and symptoms and the acute median nerve response. Design: Case series. Setting: Research room at the National Veterans Wheelchair Games. Participants: Manual wheelchair users (N=28) competing in wheelchair basketball. Intervention: Ultrasound images collected before and after a wheelchair basketball game. Main Outcome Measures: Median nerve cross-sectional area, flattening ratio, and swelling ratio and changes in these after activity. Comparison of median nerve characteristics and patient characteristics between participants with and without positive physical examination findings and with and without symptoms of CTS. Results: Significant changes in median nerve ultrasound characteristics were noted after activity. The group as a whole showed a significant decrease in cross-sectional area at the radius of 4.05% (P=.023). Participants with positive physical examinations showed significantly different (P=.029) and opposite changes in swelling ratio compared with the normal group. Subjects with CTS symptoms had a significantly (P=.022) greater duration of wheelchair use (17.1y) compared with the asymptomatic participants (9y). Conclusions: Manual wheelchair propulsion induces acute changes in median nerve characteristics that can be visualized by using ultrasound. Studying the acute median nerve response may be useful for optimizing various interventions, such as wheelchair set up or propulsion training, to decrease both acute and chronic median nerve damage and the likelihood of developing CTS. © 2009 American Congress of Rehabilitation Medicine.

This paper presents a fuzzy logic model to decode the hand posture from electro-cortico graphic (ECoG) activity of the motor cortical areas. One subject was implanted with a micro-ECoG electrode array on the surface of the motor cortex. Neural signals were recorded from 14 electrodes on this array while Subject participated in three reach and grasp sessions. In each session, Subject reached and grasped a wooden toy hammer for five times. Optimal channels/electrodes which were active during the task were selected. Power spectral densities of optimal channels averaged over a time period of 1/2 second before the onset of the movement and 1 second after the onset of the movement were fed into a fuzzy logic model. This model decoded whether the posture of the hand is open or closed with 80% accuracy. Hand postures along the task time were decoded by using the output from the fuzzy logic model by two methods (i) velocity based decoding (ii) acceleration based decoding. The latter performed better when hand postures predicted by the model were compared to postures recorded by a data glove during the experiment. This fuzzy logic model was imported to MATLAB® SIMULINK to control a virtual hand. ©2009 IEEE.

Collinger JL, Boninger ML, Koontz AM, Price R, Sisto SA, Tolerico ML, Cooper RA. Shoulder biomechanics during the push phase of wheelchair propulsion: a multisite study of persons with paraplegia. Objectives: To present a descriptive analysis and comparison of shoulder kinetics and kinematics during wheelchair propulsion at multiple speeds (self-selected and steady-state target speeds) for a large group of manual wheelchair users with paraplegia while also investigating the effect of pain and subject demographics on propulsion. Design: Case series. Setting: Three biomechanics laboratories at research institutions. Participants: Volunteer sample of 61 persons with paraplegia who use a manual wheelchair for mobility. Intervention: Subjects propelled their own wheelchairs on a dynamometer at 3 speeds (self-selected, 0.9m/s, 1.8m/s) while kinetic and kinematic data were recorded. Main Outcome Measures: Differences in demographics between sites, correlations between subject characteristics, comparison of demographics and biomechanics between persons with and without pain, linear regression using subject characteristics to predict shoulder biomechanics, comparison of biomechanics between speed conditions. Results: Significant increases in shoulder joint loading with increased propulsion velocity were observed. Resultant force increased from 54.4±13.5N during the 0.9m/s trial to 75.7±20.7N at 1.8m/s (P<.001). Body weight was the primary demographic variable that affected shoulder forces, whereas pain did not affect biomechanics. Peak shoulder joint loading occurs when the arm is extended and internally rotated, which may leave the shoulder at risk for injury. Conclusions: Body-weight maintenance, as well as other interventions designed to reduce the force required to propel a wheelchair, should be implemented to reduce the prevalence of shoulder pain and injury among manual wheelchair users. © 2008 American Congress of Rehabilitation Medicine and the American Academy of Ph

Brose SW, Boninger ML, Fullerton B, McCann T, Collinger JL, Impink BG, Dyson-Hudson TA. Shoulder ultrasound abnormalities, physical examination findings, and pain in manual wheelchair users with spinal cord injury. Objectives: To investigate the presence of ultrasound (US) abnormalities in manual wheelchair users with spinal cord injury (SCI) using a quantitative Ultrasound Shoulder Pathology Rating Scale (USPRS). To investigate physical examination (PE) findings using a quantitative Physical Examination of the Shoulder Scale (PESS), and to obtain data about pain and other subject characteristics such as age, years with SCI, and weight. Design: Case series. Setting: National Veterans' Wheelchair Games 2005 and 2006. Participants: Volunteer sample of manual wheelchair users with SCI participating in the National Veterans' Wheelchair Games. Interventions: Not applicable. Main Outcome Measures: Presence of relationships between US findings, PE findings, pain, and subject characteristics. Results: The USPRS correlated with age, duration of SCI, and weight (all P<.01), and showed a positive trend with the total Wheelchair User's Shoulder Pain Index (WUSPI) score (r=.258, P=.073). Several US findings related to presence of PE findings for specific structures. The PESS score correlated with the WUSPI (r=.679, P<.001) and duration of SCI (P<.05). The presence of untreated shoulder pain that curtailed activity was noted in 24.5% of subjects, and this was related to increased WUSPI scores (P=.002). Conclusions: PE and US abnormalities are common in manual wheelchair users with SCI. The USPRS and PESS demonstrated evidence for external validity and hold promise as research tools. Untreated shoulder pain is common in manual wheelchair users with SCI, and further investigation of this pain is indicated. © 2008 American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation.