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Articles 1 - 30 of 33
Full-Text Articles in Engineering
A Pneumatically Actuated Manipulandum For Neuromotor Control Research, Aaron J Suminski, Kristina Ropella, Robert Scheidt
A Pneumatically Actuated Manipulandum For Neuromotor Control Research, Aaron J Suminski, Kristina Ropella, Robert Scheidt
Robert Scheidt
Functional magnetic resonance imaging (fMRI) techniques have great potential for identifying which neural structures are involved in the control of goal-directed reaching movements. However, fMRI techniques alone are not capable of probing the neural mechanisms involved in acquisition of novel motor behaviors because such studies require that the moving limb be perturbed in a controlled fashion. We outline a plan to design and develop a non-metallic, pneumatically actuated tool that, along with systems identification techniques and functional magnetic resonance imaging (fMRI), will characterize and quantify how the human central nervous system uses sensory information during practice-based motor learning.
Experimental Validation Of A Mr-Compatible Pneumatic Manipulandum For Imaging The Neural Correlates Of Motor Control, Aaron Suminski, Janice Zimbelman, Robert Scheidt
Experimental Validation Of A Mr-Compatible Pneumatic Manipulandum For Imaging The Neural Correlates Of Motor Control, Aaron Suminski, Janice Zimbelman, Robert Scheidt
Robert Scheidt
No abstract provided.
A Real-Time Haptic/Graphic Demonstration Of How Error Augmentation Can Enhance Learning, Yejun Wei, James Patton, Preeti Bajaj, Robert Scheidt
A Real-Time Haptic/Graphic Demonstration Of How Error Augmentation Can Enhance Learning, Yejun Wei, James Patton, Preeti Bajaj, Robert Scheidt
Robert Scheidt
We developed a real-time controller for a 2 degree-of-freedom robotic system using xPC Target. This system was used to investigate how different methods of performance error feedback can lead to faster and more complete motor learning in individuals asked to compensate for a novel visuo-motor transformation (a 30 degree rotation). Four groups of human subjects were asked to reach with their unseen arm to visual targets surrounding a central starting location. A cursor tracking hand motion was provided during each reach. For one group of subjects, deviations from the “ideal” compensatory hand movement (i.e. trajectory errors) were amplified with a …
Remapping Hand Movements In A Novel Geometrical Environment, Kristine Mosier, Robert Scheidt, Santiago Acosta, Ferdinando Mussa-Ivaldi
Remapping Hand Movements In A Novel Geometrical Environment, Kristine Mosier, Robert Scheidt, Santiago Acosta, Ferdinando Mussa-Ivaldi
Robert Scheidt
The issue of how the Euclidean properties of space are represented in the nervous system is a main focus in the study of visual perception, but is equally relevant to motor learning. The goal of our experiments was to investigate how the properties of space guide the remapping of motor coordination. Subjects wore an instrumented data glove that recorded the finger motions. Signals generated by the glove operated a remotely controlled endpoint: a cursor on a computer monitor. The subjects were instructed to execute movements of this endpoint with controlled motions of the fingers. This required inverting a highly redundant …
A Physiologically Based Clinical Measure For Spastic Reflexes In Spinal Cord Injury, Ela Benz, T. Hornby, Rita Bode, Robert Scheidt, Brian Schmit
A Physiologically Based Clinical Measure For Spastic Reflexes In Spinal Cord Injury, Ela Benz, T. Hornby, Rita Bode, Robert Scheidt, Brian Schmit
Robert Scheidt
Objective: To test the validity of the Spinal Cord Assessment Tool for Spastic reflexes (SCATS), a clinical tool intended to rate spastic motor behavior after spinal cord injury (SCI). Design: By using correlational analyses, the SCATS was validated using concurrent measurements of kinematics and electromyograms and traditional assessments of spasms and spastic hypertonia. Setting: Research laboratory (kinematics and electromyography) and outpatient medical clinic (traditional measures of spastic hypertonia). Participants: Eleven people with SCI were used for kinematic and electromyographic measurements. Seventeen people with SCI were used for comparison with other clinical scales. Interventions: Not applicable. Main outcome measures: Kinematic and …
Control Strategies For The Transition From Multijoint To Single-Joint Arm Movements Studied Using A Simple Mechanical Constraint, Robert Scheidt, W. Rymer
Control Strategies For The Transition From Multijoint To Single-Joint Arm Movements Studied Using A Simple Mechanical Constraint, Robert Scheidt, W. Rymer
Robert Scheidt
Changes were studied in neuromotor control that were evoked by constraining the motion of the elbow joint during planar, supported movements of the dominant arm in eight normal human subjects. Electromyograph (EMG) recordings from shoulder and arm muscles were used to determine whether the normal multijoint muscle activity patterns associated with reaching to a visual target were modified when the movement was reduced to a single-joint task, by pinning the elbow to a particular location in the planar work space. Three blocks of 150 movements each were used in the experiments. Subjects were presented with the unconstrained task in the …
Reach Adaptation And Final Position Control Amid Environmental Uncertainty After Stroke, Robert Scheidt, Tina Stoeckmann
Reach Adaptation And Final Position Control Amid Environmental Uncertainty After Stroke, Robert Scheidt, Tina Stoeckmann
Robert Scheidt
We characterized how hemiparetic stroke survivors and neurologically intact individuals adapt reaching movements to compensate for unpredictable environmental perturbations. We tested the hypotheses that like unimpaired subjects, hemiparetic stroke survivors adapt using sensory information obtained during only the most recent movements and that the reliability of target acquisition decreases as the degree of sensorimotor impairment increases. Subjects held the handle of a two-joint robotic arm that applied forces to the hand while reaching between targets in a horizontal plane. The robot simulated a dynamic environment that varied randomly in strength from one trial to the next. The trial sequence of …
Neural And Electromyographic Correlates Of Wrist Posture Control, Aaron Suminski, Stephen Rao, Kristine Mosier, Robert Scheidt
Neural And Electromyographic Correlates Of Wrist Posture Control, Aaron Suminski, Stephen Rao, Kristine Mosier, Robert Scheidt
Robert Scheidt
In identical experiments in and out of a MR scanner, we recorded functional magnetic resonance imaging and electromyographic correlates of wrist stabilization against constant and time-varying mechanical perturbations. Positioning errors were greatest while stabilizing random torques. Wrist muscle activity lagged changes in joint angular velocity at latencies suggesting trans-cortical reflex action. Drift in stabilized hand positions gave rise to frequent, accurately directed, corrective movements, suggesting that the brain maintains separate representations of desired wrist angle for feedback control of posture and the generation of discrete corrections. Two patterns of neural activity were evident in the blood-oxygenation-level-dependent (BOLD) time series obtained …
Temporal And Spatial Aspects Of Sensory Interactions During Human Fusional Response, Robert Scheidt, Andrew Kertesz
Temporal And Spatial Aspects Of Sensory Interactions During Human Fusional Response, Robert Scheidt, Andrew Kertesz
Robert Scheidt
Temporal and spatial aspects of sensory interactions during human fusional response were investigated using band-limited, 10th-derivative-of-Gaussian patterns confined to separate regions of the visual field. Experiments were performed to investigate the time course of sensory interactions using the horizontal sensory fusional amplitude (SFA) and the sensory fusional range (SFR) as measures of the interaction. The nature of sensory interactions across the spatial domain has been found to be a function of stimulus duration and time course. These interactions included both enhancements and reductions of SFAs as well as reductions and shifts in SFRs. Two functional components of sensory fusional interactions …
Separate Adaptive Mechanisms For Controlling Trajectory And Final Position In Reaching, Robert Scheidt, Claude Ghez
Separate Adaptive Mechanisms For Controlling Trajectory And Final Position In Reaching, Robert Scheidt, Claude Ghez
Robert Scheidt
We examined control of the hand's trajectory (direction and shape) and final equilibrium position in horizontal planar arm movements by quantifying transfer of learned visuomotor rotations between two tasks that required aiming the hand to the same spatial targets. In a trajectory-reversal task (“slicing”), the hand reversed direction within the target and returned to the origin. In a positioning task (“reaching”), subjects moved the hand to the target and held it there; cursor feedback was provided only after movement ended to isolate learning of final position from trajectory direction. We asked whether learning acquired in one task would transfer to …
Effects Of Wrist Tendon Vibration On Arm Tracking In People Poststroke, Megan Conrad, Robert Scheidt, Brian Schmit
Effects Of Wrist Tendon Vibration On Arm Tracking In People Poststroke, Megan Conrad, Robert Scheidt, Brian Schmit
Robert Scheidt
The goal of this study was to evaluate the influence of wrist tendon vibration on a multijoint elbow/shoulder tracking task. We hypothesized that tendon vibration applied at the wrist musculature would improve upper arm tracking performance in chronic stroke survivors through increased, Ia-afferent feedback to the central nervous system (CNS). To test this hypothesis, 10 chronic stroke and 5 neurologically intact subjects grasped the handle of a planar robot as they tracked a target through a horizontal figure-8 pattern. A total of 36 trials were completed by each subject. During the middle trials, 70-Hz tendon vibration was applied at the …
Effects Of Optimal Tactile Feedback In Balancing Tasks: A Pilot Study, Emmanouil Tzorakoleftherakis, Ferdinando Mussa-Ivaldi, Robert Scheidt, Todd Murphey
Effects Of Optimal Tactile Feedback In Balancing Tasks: A Pilot Study, Emmanouil Tzorakoleftherakis, Ferdinando Mussa-Ivaldi, Robert Scheidt, Todd Murphey
Robert Scheidt
In this study, we employ optimal control and tactile feedback to teach subjects how to balance a simulated inverted pendulum. The output of a Linear Quadratic Regulator (LQR) was converted to a vibratory teacher-signal and was provided as additional somatosensory feedback to the subjects. The LQR approach is consistent with an energy-saving strategy commonly observed during human motor learning. Our rationale for using the inverted pendulum as a criterion task is that this balance system requires the brain to solve many of the same problems encountered in simple tasks of daily living like transporting a glass of water to the …
Reorganization Of Finger Coordination Patterns During Adaptation To Rotation And Scaling Of A Newly Learned Sensorimotor Transformation, Xiaolin Liu, Kristine Mosier, Ferdinando Mussa-Ivaldi, Maura Casadio, Robert Scheidt
Reorganization Of Finger Coordination Patterns During Adaptation To Rotation And Scaling Of A Newly Learned Sensorimotor Transformation, Xiaolin Liu, Kristine Mosier, Ferdinando Mussa-Ivaldi, Maura Casadio, Robert Scheidt
Robert Scheidt
We examined how people organize redundant kinematic control variables (finger joint configurations) while learning to make goal-directed movements of a virtual object (a cursor) within a low-dimensional task space (a computer screen). Subjects participated in three experiments performed on separate days. Learning progressed rapidly on day 1, resulting in reduced target capture error and increased cursor trajectory linearity. On days 2 and 3, one group of subjects adapted to a rotation of the nominal map, imposed either stepwise or randomly over trials. Another group experienced a scaling distortion. We report two findings. First, adaptation rates and memory-dependent motor command updating …
Contributions Of Online Visual Feedback To The Learning And Generalization Of Novel Finger Coordination Patterns, Xiaolin Liu, Robert Scheidt
Contributions Of Online Visual Feedback To The Learning And Generalization Of Novel Finger Coordination Patterns, Xiaolin Liu, Robert Scheidt
Robert Scheidt
We explored how people learn new ways to move objects through space using neuromuscular control signals having more degrees of freedom than needed to unambiguously specify object location. Subjects wore an instrumented glove that recorded finger motions. A linear transformation matrix projected joint angle signals (a high-dimensional control vector) onto a two-dimensional cursor position on a video monitor. We assessed how visual information influences learning and generalization of novel finger coordination patterns as subjects practiced using hand gestures to manipulate cursor location. Three groups of test subjects practiced moving a visible cursor between different sets of screen targets. The hand-to-screen …
Simultaneous Robotic Manipulation And Functional Magnetic Resonance Imaging: Feasibility In Children With Autism Spectrum Disorders, Nicole Salowitz, Bridget Dolan, Rheanna Remmel, Amy Van Hecke, Kristine Mosier, Lucia Simo, Robert Scheidt
Simultaneous Robotic Manipulation And Functional Magnetic Resonance Imaging: Feasibility In Children With Autism Spectrum Disorders, Nicole Salowitz, Bridget Dolan, Rheanna Remmel, Amy Van Hecke, Kristine Mosier, Lucia Simo, Robert Scheidt
Robert Scheidt
An unanswered question concerning the neural basis of autism spectrum disorders (ASD) is how sensorimotor deficits in individuals with ASD are related to abnormalities of brain function. We previously described a robotic joystick and video game system that allows us to record functional magnetic resonance images (FMRI) while adult humans make goal-directed wrist motions. We anticipated several challenges in extending this approach to studying goal-directed behaviors in children with ASD and in typically developing (TYP) children. In particular we were concerned that children with autism may express increased levels of anxiety as compared to typically developing children due to the …
Persistence Of Motor Adaptation During Constrained, Multi-Joint, Arm Movements, Robert Scheidt, David Reinkensmeyer, Michael Conditt, W. Reymer, Ferdinando Mussa-Ivaldi
Persistence Of Motor Adaptation During Constrained, Multi-Joint, Arm Movements, Robert Scheidt, David Reinkensmeyer, Michael Conditt, W. Reymer, Ferdinando Mussa-Ivaldi
Robert Scheidt
We studied the stability of changes in motor performance associated with adaptation to a novel dynamic environment during goal-directed movements of the dominant arm. Eleven normal, human subjects made targeted reaching movements in the horizontal plane while holding the handle of a two-joint robotic manipulator. This robot was programmed to generate a novel viscous force field that perturbed the limb perpendicular to the desired direction of movement. Following adaptation to this force field, we sought to determine the relative role of kinematic errors and dynamic criteria in promoting recovery from the adapted state. In particular, we compared kinematic and dynamic …
Different Learned Coordinate Frames For Planning Trajectories And Final Positions In Reaching, Claude Ghez, Robert Scheidt, Hank Heijink
Different Learned Coordinate Frames For Planning Trajectories And Final Positions In Reaching, Claude Ghez, Robert Scheidt, Hank Heijink
Robert Scheidt
We previously reported that the kinematics of reaching movements reflect the superimposition of two separate control mechanisms specifying the hand's spatial trajectory and its final equilibrium position. We now asked whether the brain maintains separate representations of the spatial goals for planning hand trajectory and final position. One group of subjects learned a 30° visuomotor rotation about the hand's starting point while performing a movement reversal task (“slicing”) in which they reversed direction at one target and terminated movement at another. This task required accuracy in acquiring a target mid-movement. A second group adapted while moving to—and stabilizing at—a single …
A Quantitative And Standardized Robotic Method For The Evaluation Of Arm Proprioception After Stroke, Lucia Simo, Claude Ghez, Lior Botzer, Robert Scheidt
A Quantitative And Standardized Robotic Method For The Evaluation Of Arm Proprioception After Stroke, Lucia Simo, Claude Ghez, Lior Botzer, Robert Scheidt
Robert Scheidt
Stroke often results in both motor and sensory deficits, which may interact in the manifested functional impairment. Proprioception is known to play important roles in the planning and control of limb posture and movement; however, the impact of proprioceptive deficits on motor function has been difficult to elucidate due in part to the qualitative nature of available clinical tests. We present a quantitative and standardized method for evaluating proprioception in tasks directly relevant to those used to assess motor function. Using a robotic manipulandum that exerted controlled displacements of the hand, stroke participants were evaluated, and compared with a control …
Interaction Of Visual And Proprioceptive Feedback During Adaptation Of Human Reaching Movements, Robert Scheidt, Michael Conditt, Emanuele Secco, Ferdinando Mussa-Ivaldi
Interaction Of Visual And Proprioceptive Feedback During Adaptation Of Human Reaching Movements, Robert Scheidt, Michael Conditt, Emanuele Secco, Ferdinando Mussa-Ivaldi
Robert Scheidt
People tend to make straight and smooth hand movements when reaching for an object. These trajectory features are resistant to perturbation, and both proprioceptive as well as visual feedback may guide the adaptive updating of motor commands enforcing this regularity. How is information from the two senses combined to generate a coherent internal representation of how the arm moves? Here we show that eliminating visual feedback of hand-path deviations from the straight-line reach (constraining visual feedback of motion within a virtual, “visual channel”) prevents compensation of initial direction errors induced by perturbations. Because adaptive reduction in direction errors occurred with …
Computerized Biofeedback Knee Goniometer: Acceptance And Effect On Exercise Behavior In Post-Total Knee Arthroplasty Rehabilitation, Todd Kuiken, Hagay Amir, Robert Scheidt
Computerized Biofeedback Knee Goniometer: Acceptance And Effect On Exercise Behavior In Post-Total Knee Arthroplasty Rehabilitation, Todd Kuiken, Hagay Amir, Robert Scheidt
Robert Scheidt
Objective To assess device accuracy, patient acceptance, and effect of a computerized biofeedback knee goniometer (CBG), on patients’ compliance with active range of motion (AROM) exercises after total knee arthroplasty (TKA). Design Two-stage study: measurement validation on asymptomatic controls and an unblinded, multiple crossover trial. Setting Inpatient rehabilitation. Participants Asymptomatic controls (n=14) and post-TKA inpatients (n=11). Interventions For measurement validation, CBG-angle measurements were compared with manual, clinician-obtained angles. To assess motivational effect, the CBG was worn after TKA; on alternating days, it either monitored AROM silently (no feedback) or provided audiovisual feedback about reaching preset range of motion (ROM) goals …
Electroencephalogram Coherence In Children With And Without Autism Spectrum Disorders: Decreased Interhemispheric Connectivity In Autism, Audrey Carson, Nicole Salowitz, Robert Scheidt, Bridget Dolan, Amy Van Hecke
Electroencephalogram Coherence In Children With And Without Autism Spectrum Disorders: Decreased Interhemispheric Connectivity In Autism, Audrey Carson, Nicole Salowitz, Robert Scheidt, Bridget Dolan, Amy Van Hecke
Robert Scheidt
Electroencephalogram coherence was measured in children with autism spectrum disorders (ASD) and control children at baseline and while watching videos of a familiar and unfamiliar person reading a story. Coherence was measured between the left and right hemispheres of the frontal, parietal, and temporal-parietal lobes (interhemispheric) and between the frontal and parietal lobes in each hemisphere (intrahemispheric). A data-reduction technique was employed to identify the frequency (alpha) that yielded significant differences in video conditions. Children with ASD displayed reduced coherence at the alpha frequency between the left and right temporal-parietal lobes in all conditions and reduced coherence at the alpha …
Impedance Control And Internal Model Formation When Reaching In A Randomly Varying Dynamical Environment, C. Takahashi, Robert Scheidt, D. Reikensmeyer
Impedance Control And Internal Model Formation When Reaching In A Randomly Varying Dynamical Environment, C. Takahashi, Robert Scheidt, D. Reikensmeyer
Robert Scheidt
We investigated the effects of trial-to-trial, random variation in environmental forces on the motor adaptation of human subjects during reaching. Novel sequences of dynamic environments were applied to subjects' hands by a robot. Subjects reached first in a “mean field” having a constant gain relating force and velocity, then in a “noise field,” having a gain that varied randomly between reaches according to a normal distribution with a mean identical to that of the mean field. The unpredictable nature of the noise field did not degrade adaptation as quantified by final kinematic error and rate of adaptation. To achieve this …
Learning To Move Amid Uncertainty, Robert Scheidt, Jonathan Dingwell, Ferdinando Mussa-Ivaldi
Learning To Move Amid Uncertainty, Robert Scheidt, Jonathan Dingwell, Ferdinando Mussa-Ivaldi
Robert Scheidt
We studied how subjects learned to make movements against unpredictable perturbations. Twelve healthy human subjects made goal-directed reaching movements in the horizontal plane while holding the handle of a two-joint robotic manipulator. The robot generated viscous force fields that perturbed the limb perpendicular to the desired direction of movement. The amplitude (but not the direction) of the viscous field varied randomly from trial to trial. Systems identification techniques were employed to characterize how subjects adapted to these random perturbations. Subject performance was quantified primarily using the peak deviation from a straight-line hand path. Subjects adapted their arm movements to the …
Characterization Of Motor Adaptation And Limb Posture Regulation During Arm Reaching Movements Following Stroke, Robert Scheidt, Tina Stoeckmann
Characterization Of Motor Adaptation And Limb Posture Regulation During Arm Reaching Movements Following Stroke, Robert Scheidt, Tina Stoeckmann
Robert Scheidt
Whether attempting to pour water into a handheld glass, or simply trying to hold a young child's hand, many activities of daily living require interaction with unpredictable or uncertain mechanical environments. Here we describe a systems identification study that used a planar manipulandum to characterize how hemiparetic stroke survivors adapt reaching movements to novel mechanical environments. By analyzing trial-by-trial variations in hand path kinematics, we found that stroke survivors are less likely than neurologically-intact subjects to adjust motor commands for upcoming movements based on hand trajectory errors experienced on previous trials. This ability is most significantly compromised in subjects with …
Compensation For The Passive Dynamics Of A Five-Bar Neurorehabilitation Robot, Matthew Amans, Kyle Lillis, Robert Scheidt
Compensation For The Passive Dynamics Of A Five-Bar Neurorehabilitation Robot, Matthew Amans, Kyle Lillis, Robert Scheidt
Robert Scheidt
Summary form only given. We have designed a compensator for the passive dynamics of a five-bar neurorehabilitation robot. This model-based compensator was tuned off-line using a simplex search method to minimize the error between measured joint torques during passive movement of the robot arm and torques predicted by the model during the same movement. The simplex algorithm selected the three independent parameters of the equations of motion to minimize the squared difference between measured and estimated joint torques. These parameters are implemented in a real-time operating system (xPC; the Mathworks) controlling the robot. This system yields stable compensation of over …
Brief Report: Visuo-Spatial Guidance Of Movement During Gesture Imitation And Mirror Drawing In Children With Autism Spectrum Disorders, Nicole Salowitz, Petra Eccarius, Audrey Carson, Kirsten Schohl, Sheryl Stevens, Amy Vaughan Van Hecke, Robert Scheidt
Brief Report: Visuo-Spatial Guidance Of Movement During Gesture Imitation And Mirror Drawing In Children With Autism Spectrum Disorders, Nicole Salowitz, Petra Eccarius, Audrey Carson, Kirsten Schohl, Sheryl Stevens, Amy Vaughan Van Hecke, Robert Scheidt
Robert Scheidt
Thirteen autistic and 14 typically developing children (controls) imitated hand/arm gestures and performed mirror drawing; both tasks assessed ability to reorganize the relationship between spatial goals and the motor commands needed to acquire them. During imitation, children with autism were less accurate than controls in replicating hand shape, hand orientation, and number of constituent limb movements. During shape tracing, children with autism performed accurately with direct visual feedback, but when viewing their hand in a mirror, some children with autism generated fewer errors than controls whereas others performed much worse. Large mirror drawing errors correlated with hand orientation and hand …
Design And Validation Of A Real-Time Controller For A Two-Joint Neurorehabilitation Robot, Kyle Lillis, Matthew Amans, Robert Scheidt
Design And Validation Of A Real-Time Controller For A Two-Joint Neurorehabilitation Robot, Kyle Lillis, Matthew Amans, Robert Scheidt
Robert Scheidt
Summary form only given. Large-scale neurorehabilitation robots require sophisticated control and safety systems. We describe the design and testing of a controller for a two-joint manipulandum for neurorehabilitation research. Design requirements and implementation considerations are highlighted. Procedures for testing and validating the system are also described.
Neural Activity In Primary Sensorimotor Cortex Increases With Movement Extent (Not Force) During Goal-Directed Movement, Janice Zimbelman, Karyn Bratcher, Stephen Rao, Aaron J Suminski, Robert Scheidt
Neural Activity In Primary Sensorimotor Cortex Increases With Movement Extent (Not Force) During Goal-Directed Movement, Janice Zimbelman, Karyn Bratcher, Stephen Rao, Aaron J Suminski, Robert Scheidt
Robert Scheidt
No abstract provided.
Evaluation Of Position Based Cueing Strategies For Bilateral Robotic Assessment And Therapy After Stroke, Shantanu Karnik, Michelle Johnson, Robert Scheidt
Evaluation Of Position Based Cueing Strategies For Bilateral Robotic Assessment And Therapy After Stroke, Shantanu Karnik, Michelle Johnson, Robert Scheidt
Robert Scheidt
Stroke is the leading cause of disability in the United States. Hemiparesis, affecting the majority of the subjects, leads to other related process like learned non-use, which compromises the affected individual's functionality. Many current therapy techniques do not incorporate new research which point towards involvement of both arms in a synchronous, bimanual but decoupled environment to achieve maximum recovery. A novel method of robotic therapy, using position based cues, was tested on able-bodied individuals with strong handed preferences as a model for stroke survivors with severe arm bias due to learned non-use, to verify the effectiveness in assessing and changing …
Patterns Of Hypermetria And Terminal Cocontraction During Point-To-Point Movements Demonstrate Independent Action Of Trajectory And Postural Controllers, Robert Scheidt, Claude Ghez, Supriya Asnani
Patterns Of Hypermetria And Terminal Cocontraction During Point-To-Point Movements Demonstrate Independent Action Of Trajectory And Postural Controllers, Robert Scheidt, Claude Ghez, Supriya Asnani
Robert Scheidt
We examined elbow muscle activities and movement kinematics to determine how subjects combine elementary control actions in performing movements with one and two trajectory segments. In reaching, subjects made a rapid elbow flexion to a visual target before stabilizing the limb with either a low or a higher level of elbow flexor/extensor coactivity (CoA), which was cued by target diameter. Cursor diameter provided real-time biofeedback of actual muscle CoA. In reversing, the limb was to reverse direction within the target and return to the origin with minimal CoA. We previously reported that subjects overshoot the goal when attempting a reversal …