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SMPP Seminars Archived

2009

Mon, Oct 26, 12-1pm

Speaker: Kimberlee Jordan, PhD (Postdoctoral Candidate)

Title: Time dependent structure of variability in physiological time series

Abstract: Variability in human movement has historically been equated with noise in the sensorimotor apparatus, in part because the invariance of movement has traditionally held more interest to scientists that movement variance.  Traditional measures of movement variability, such as the Standard Deviation, Coefficient of Variation and Root Mean Square Error provide information regarding the amount of variability in a physiological time series.  In contrast, techniques such as Detrended Fluctuation Analysis (Peng et al., 1994) and Approximate Entropy (Pincus 1991) provide information regarding the time dependent structure of fluctuations in the time series.

Increasingly with the use of these techniques it is being recognized that the variability in many physiological time series is not random, and that the degree of predictability of the time series can be indicative of the health of the physiological system in question.

Using Detrended Fluctuation Analysis, the time series of interstride intervals of walking and running in healthy young females was examined.  Fluctuations in the interstride interval are not random but contain long range correlations.  The strength of the long-range correlations follows a U-shaped function that is centered on the preferred speed of locomotion.  Additionally, the discharge rate variability of motor units was examined and was also shown to contain long range correlations, the strength of which are affected by both aging and the gain of visual feedback.

Hosts: Drs. Zev Rymer and Mehdi Mirbagheri

Fri, Oct 23,  12-1pm

Speaker: Winfried Ilg, PhD

Title: On the locomotion, dynamic stability and rehabilitation of patients with cerebellar ataxia

Abstract: I will present the results of our studies examining (1) the influence of the cerebellum on locomotion and goal-directed leg movements, (2) the phenomenon of velocity-dependent dynamic stability, and (3) the benefits of rehabilitation training for patients with cerebellar disease.

Using a computational method for the quantification of spatio-temporal characteristics of intra-limb coordination patterns, we have been able to identify specific changes in the control and the adaptation of intra-limb coordination for gait in cerebellar patients, which are not predominantly induced by impairments on balance control. In addition, we could show in a study examining patients with focal cerebellar lesions,  that the intermediate zone of the cerebellum appears to be of particular importance for limb control on goal-directed leg placement and adaptive locomotion, whereas the medial zone is related to balance control.

Due to the well-known importance of the cerebellum for motor learning and motor adaptation, the benefit of physiotherapeutic training is under dispute for patients with degenerative ataxia.

Impairments of cerebellar patients in (short-term) practice- dependent motor learning have been shown for various motor tasks. Open questions are, whether such patients have lost the ability of practice-dependent motor learning or rather require longer-duration or higher-intensity training to learn. In a controlled clinical study on intensive coordination training, we found first evidence that patients suffering from degenerative cerebellar disease can improve multi-joint coordination and dynamic balance by intensive and continuous coordinative training and thus improve allday-relevant activities.

Host: Dr. Jim Patton

Fri, Oct 16, 12-1pm

Speaker: Erik Bruun Simonsen, PhD (University of Copenhagen)

Title: Inter-individual differences in H reflex modulation during human walking

Abstract: Based on previous studies, at least two different types of soleus Hoffmann (H) reflex modulation were likely to be found during normal human walking. Accordingly, the aim of the present study was to identify different patterns of modulation of the soleus H reflex and to examine whether or not subjects with different H reflex modulation would exhibit different walking mechanics and different EMG activity. Fifteen subjects walked across two force platforms at 4.5 km/h (+/-10%) while the movements were recorded on video. The soleus H reflex and EMG activity were recorded separately during treadmill walking at 4.5 km/h. Using a two-dimensional analysis joint angles, angular velocities, accelerations, linear velocities and accelerations were calculated, and net joint moments about the ankle, knee and hip joint were computed by inverse dynamics from the video and force plate data. Six subjects (group S) showed a suppressed H reflex during the swing phase, and 9 subjects (group LS) showed increasing reflex excitability during the swing phase. The plantar flexor dominated moment about the ankle joint was greater for group LS. In contrast, the extensor dominated moment about the knee joint was greater for the S group. The hip joint moment was similar for the groups. The EMG activity in the vastus lateralis and anterior tibial muscles was greater prior to heel strike for the S group. These data indicate that human walking exhibits at least two different motor patterns as evaluated by gating of afferent input to the spinal cord, by EMG activity and by walking mechanics. Increasing H reflex excitability during the swing phase appears to protect the subject against unexpected perturbations around heel strike by a facilitated stretch reflex in the triceps surae muscle. Alternatively, in subjects with a suppressed H reflex in the swing phase the knee joint extensors seem to form the primary protection around heel strike.

Host: Maria Knikou

Thu, Oct 15,  2-3pm

Speaker: Dr. Penelope McNulty, BHMS (Hons), PhD (Prince of Wales Medical Research Institute in Australia)

Title: The recruitment order of single motor units in human muscles.

Abstract: Single motor units are generally activated during voluntary contractions with a stereotypical progressive recruitment order from the slowest, weakest units to stronger, larger motor units. While this principle is generally accepted for voluntary contractions it is often assumed that recruitment order is reversed by electrical stimulation. We examined the recruitment order of single motor units in a series of studies during voluntary contractions and in response to electrical stimulation. The exceptions to the orderly recruitment of single motor unit during targeted voluntary contractions reported for diaphragm motor units could not be demonstrated in limb muscles. Single motor unit activity was recorded in first dorsal interosseous muscle using an intramuscular concentric needle electrode during tasks with either a constant velocity to different displacements, or a constant displacement at different velocities. The shuffle index allowed us to quantify the recruitment order variability of single motor units (n=114) at 14 recording sites in 8 subjects. Significant variability in the recruitment order of single motor units was seen both within and between tasks, similar to that reported for the diaphragm but no systematic shuffling of motor unit recruitment order was observed.

A combination of experimental data and mathematical modelling was used to investigate the recruitment order of electrically stimulated motor units in tibialis anterior (n=20) and brachioradialis (n=6) muscles. Detailed stimulus response curves showed that the experimental and modelled data were closely matched with correlation coefficients ranging from 95.3-99.8. Motor units were recruited during electrical stimulation following a complex pattern that neither follows a strict Henneman size principle nor a simple reverse of that order. It is important to understand the recruitment order of motor units so that we can interpret the data from disordered physiology.

We compared the results of our modelling study to the detailed stimulus response curves recorded in a similar manner from the tibialis anterior muscle of 16 spinal cord injury (SCI) patients. Some muscles demonstrated a gross reduction in motor unit numbers while others did not differ from the able bodied. Abnormalities were also noted in the recruitment pattern of motor units in SCI affected muscles. These results suggest that traditional methods of motor unit number estimations may not reflect the number or combination of changes that affect surviving motor units in chronic SCI.

Host: Dr. Zev Rymer

Mon, Oct 12, 12:30pm - 1:30pm

Speaker: James Sulzer (PhD Candidate)

Title: Improving knee flexion for people with stiff-knee gait after stroke

Abstract: The inability to adequately bend the knee during swing phase of walking, known as Stiff-Knee gait (SKG), commonly occurs after stroke. It is believed other compensatory, energy-consuming kinematics such as pelvic obliquity and hip abduction accompany the "stiff" knee to help clear the foot. Models have shown that improving knee flexion torque before the paretic limb leaves the ground will result in greater knee flexion angle during swing, thus greater foot clearance.  If these gait compensations are motivated by foot clearance, then assisting pre-swing knee flexion torque will reduce gait compensations.

To pursue this hypothesis, we needed a lightweight, backdrivable knee actuator.  After finding existing actuators insufficient, we developed a concept that remotely controlled deflection of a compliant spring through a sheathed cable.  This concept was developed into a knee flexion actuator capable of selectively applying torque during gait. Its performance characteristics made this device, known as SERKA (Series Elastic Remote Knee Actuator), optimally suited to our needs. 

We examined the effect of knee flexion assistance on gait compensations in nine stroke subjects, examining changes in peak knee flexion angle, hip abduction and pelvic obliquity. The results were compared to the controls ran earlier.  Stroke subjects significantly increased hip abduction during assistance instead of the predicted decrease, with no change in controls.   We infer that this is due to abnormal coordination, which may be a primary cause of gait impairment after stroke.  In conclusion, assistive technology and rehabilitation science must account for less visible neural issues when addressing people with neurological disabilities.   We hope this work inspires others to investigate underlying mechanisms of disease states and their modes of neural control en route to rehabilitation and assistive device development.

Wed, Oct 7,  12-1pm

Speaker: Emily Keshner, PT, EdD

Title: Does Visual-Vestibular Conflict Reveal an Internal Model for Spatial Orientation?

Abstract: Visual field motion has been linked to postural behavior and orientation in space is governed by an interaction between the visual and vestibular systems. The sensory reweighting model predicts that as the velocity of visual motion becomes less relevant to physical motion, then subjects would exhibit a lesser response to visual motion and an increased sensitivity to their physical inputs. We have found that even when visual field motion is inappropriate for self-motion, reorganized postural behaviors emerge to compensate for the visual disturbance. In this talk I will present results of experiments suggesting that sensory reweighting may be a local phenomenon, defined by the momentary sensory array, which allows us to modify the internal model for spatial orientation.

Host: Sandro Mussa-Ivaldi

Thu, Oct 1, 2-3pm

Speaker: Maxim Klesnikov

Title: Improving the Realism of Haptic Interaction For Teaching of Sensorimotor Skill

Abstract: Recently, haptic simulators have shown great potential in teaching sensorimotor skills.  This is especially true for areas where the traditional training technique is expensive, such as medical and dental training. This talk addresses two areas where improvement is needed to increase the realism of haptic interaction and the effectiveness in teaching of sensorimotor skills. The first part of the talk is about haptic rendering algorithms. Modern penalty-based haptic rendering algorithms do not produce realistic forces in certain situations. A new method for haptic rendering is implemented based on physics rather than on heuristics. At the same time the new method is fast enough to be executed in the allowed time frame. The second part of the talk deals with the problem of recording haptically augmented training videos. This provides a way to convey the information necessary to master a new skill from a teacher to a trainee. Several haptic playback schemes are proposed. The talk will conclude with the description of PerioSim, a haptic virtual reality simulator for sensorimotor skill acquisition in dentistry.

Hosts: Sandro Mussa-Ivaldi and Kevin Lynch

Thu, Sept 10,  2-3pm

Speaker: Daniel Corcos, PhD

Title: Translational Neuroscience and the Treatment of Parkinson's Disease

Abstract: Parkinson's disease is a progressive neurological disorder that is associated with motor and nonmotor impairments.  Long-term treatment with dopaminergic therapy is often associated with major negative side effects that result in further impairment.  The effective treatment of Parkinson's disease will benefit from markers that help to detect the disease early, diagnose the disease accurately, and develop new therapies that reduce the amount of dopaminergic medication required by patients.  The first part of this talk will outline a new biomarker for Parkinson's disease.  The second part will present preliminary data from a two-year study of progressive resistance exercise for individuals with Parkinson's disease.  The talk will conclude with the presentation of some recent data on the effects of five years of stimulating the subthalamic nucleus on the cardinal signs of Parkinson's disease.

Host: Sandro Mussa-Ivaldi

Wed, Sept  2,  12-1pm

Speaker: Kiyoshi Okawa (Honda R&D Co., Ltd.)

Title: Honda Walking Assist Device (Stride Management Assist)

Abstract: Walking dysfunction represents a serious threat to elderly. As early as 1999, the Fundamental Technology Research Center at Honda R&D Co., Ltd. began research on walking assist technology to help improve the progressive decline in lower extremity motor abilities in the elderly. An early test model created in 2000 weighed approximately 70-lbs and was bulky, but following numerous prototypes and thousands of hours of testing, by 2007 the weight had been reduced to just 6-lbs.  Many currently available research  devices for walking provide assistance through an increase in power at various joint axis, while the walk assist  device assists movement based on a cooperative control principle where only the hip joint axis is equipped with a small motor, which generates assist force. Due to its simple construction and light weight, the device can be used in any public or social environment without one feeling self-conscious or uncomfortable.

During its operation a user’s walking pace is monitored through hip angle sensors and this information is fed to a control computer which applies cooperative control and calculates the amount and timing of assist to be provided. The torque generated by the motors is transmitted to the thighs through the frames thus serving to lengthen the user’s stride and resulting in optimal and enjoyable walking assist. Further, as the walking stride is lengthened, muscle activity around the hip area and lower legs increases. When used continuously over a period of time, test results have shown that the user maintains a longer and smoother walking stride even when the device is not worn. The device has been successfully tested in providing walking assistance in the elderly in Japan. A wide range of applications is conceivable, but in Japan, it is hoped that the device will be useful in walking rehabilitation. Currently, the validity of this device in the rehabilitation and recovery of walking in individuals with stroke and other neurological dysfunctions is being investigated.

Hosts: Drs. Zev Rymer and Arun Jayaraman

Fri, Aug 28,  12-1pm

Speaker: Jungwha "Julia" Lee, PhD

Biostatistician, Biostatistics Collaboration Center, Department of Preventive Medicine, Feinberg School of Medicine, Northwestern University

Title: Statistical power analysis and sample size estimation

Fri, Aug 21, 12-1pm

SMPP postdoc grant proposal presentation

Speakers: Keith Gordon, Claire Honeycutt & Ann Simon

SMPP postdoctoral fellows will present their grant proposals covering specific aims, design and key methods (5 minute presentation plus 5 minute discussion per proposal). The main purpose of the meeting is to provide feedback on postdoc grants from a non-expert audience, and give postdocs an opportunity to defend their proposed study.

Fri, Aug 14,  12-1pm

SMPP postdoc seminar

Speaker: Kunlin Wei

SMPP postdoctoral fellows will present their grant proposals covering specific aims, design and key methods (5 minute presentation plus 5 minute discussion per proposal). The main purpose of the meeting is to provide feedback on postdoc grants from a non-expert audience, and give postdocs an opportunity to defend their proposed study.

Thu, Aug 6,  12-1pm

Speaker: Todd Murphey, PhD (Assistant Professor, Mechanical Engineering, Northwestern University)

Title: Variational Methods for Hand Analysis and Simulation

Abstract: I will discuss numerical modeling techniques for dynamically modeling a human hand. We use a strand-based method of modeling the muscles and tendons. Our technique represents a compromise between capturing the full dynamics of the tissue mechanics and the need for computationally efficient representations for control design and multiple simulations appropriate for statistical planning and optimization tools. We show how to derive a strand-based model in a variational integrator context. Variational integrators are particularly well-suited to resolving closed-kinematic chains, making them appropriate for hand modeling. We demonstrate the technique with a hand model comprised of 19 rigid bodies and 23 muscle strands engaged in a grasp of an object. Moreover, we can compute the linearization of the hand dynamics around nominal trajectories allowing us to compute locally optimal control laws in the linear quadratic regulator (LQR) sense. 

I will end with a discussion of future work, including the need for local robustness analysis, impact handling, surface friction representations, and system identification.

Mon, August 3, 4-5pm

Magnuson Auditorium (16th Floor)

Speaker: David Reinkensmeyer, PhD

Title: How do people respond to robot assistance during motor training?

Abstract: There has been a rapid increase in the last ten years in the number of research groups and companies that are developing robotic devices to partially automate motor rehabilitation following neurologic injuries like stroke and spinal cord injury.  A common approach is to design the robotic therapy device to physically assist the patient in making desired movements, mimicking the approach of "active assistance" sometimes used by rehabilitation therapists.  In this talk, I will show that the motor system responds to such assistance differently for different movement tasks.  For training of reaching movements, most clinical studies of robot therapy to date suggest that assistance neither hinders nor improves motor recovery.  Rather, its primary benefit may be to provide a more motivating training environment.  These findings bring into question the Hebbian-like conceptual framework of motor plasticity that is sometimes used to provide a scientific rationale for robot-assisted therapy.  For training of walking, robot assistance allows a patient to practice faster, more natural looking movements more safely, but there is evidence it sometimes hinders recovery.  This may be because the human locomotor system systematically "slacks" when given the opportunity.  In a third application we are currently developing - teaching children with a severe disability to drive a powered wheelchair - we recently found that robotic assistance enhanced motor learning in a pilot study with non-disabled children.  Understanding the neural mechanisms that elicit these differing responses - indifference, slacking, and enhancement - is essential for determining whether and how robots can actually be useful in rehabilitation practice.

Host: Sandro Mussa-Ivaldi

 

Fri, July 31, 12-1pm

Speaker: Matthieu Chardon

Title: Center for Innovation in Global Health Technologies: RIC's first steps in South Africa

Wed, July 29, 12-1pm 

The SMPP - Review of AMSE-SBC and RSS

Attendees of the recent ASME-SBC (Summer Bioengineering Conference) and RSS (Robotics: Science & Systems) meetings will provide us with an overview of major projects of interest which were presented at the conference.

Fri, July 24, 12-1pm

Speaker: Sun G. Chung MD, PhD (Department of Rehabilitation Medicine, Seoul National University Hospital)

Title: A Novel Approach to Painful Stiff Shoulders: Hydraulic Distension with Real-Time Pressure Monitoring

Abstract: The painful stiff shoulder (PSS) is one of the most common causes of shoulder pain, estimated to affect 2–10% of the general population. To relieve pain and restore motion resulted from the contracted and obliterated GHJ capsule, several types of treatment methods, such as home-based and supervised physical therapy, intra-articular  corticosteroid injections with or without hydraulic distension (HD), closed manipulations, and arthroscopic capsular release, have been utilized for PSS patients depending on the clinical phases. Intra-articular HD has been utilized to treat PSSs by distending and then rupturing the contracted GHJ capsules. To the speaker’s knowledge, no attempts had been made to distend the joint capsule as much as possible without rupturing it before the two recent reports were published by our group, which demonstrated that real-time monitoring of pressure during HD procedures could be used to distend the GHJ capsule with prolonged stretch. The biomechanical parameters derived from the pressure-volume profiles, such as the steeply rising, high intra-articular pressure could be considered as a predominant characteristic of the PSS comparing with other conditions that showed flat, low pressure profiles, suggesting the pressure-volume profiles might be utilized in evaluation of the capsular tightness of various shoulder problems. Two clinical trials using this technique will be presented along with the diagnostic implications of the technique, limitations and directions of future researches.  

Fri, July 17, 12-1pm

SMPP postdoc seminar

Speaker: Renee Theiss, PhD

Title: The Importance of Persistence: PICs and pharmacological targeting of cellular excitability in human spinal cord injury

Abstract: Persistent inward currents (PICs) are intrinsic conductances in neurons that underlie many essential aspects of cellular excitability.  The first half of this talk with be a crash course in excitable cells and electrophysiology, covering the electrochemical basis for neuronal signalling, ionic fluxes responsible for action potential generation, input-ouput functioning of spinal neurons, measurements of intrinsic currents and the difference between transient currents and persistent currents, and the pharmacological manipulation of sodium and calcium currents.  The second half of the talk will be a presentation of current studies investigating mechanisms of hyperexcitable reflexes, spasticity, and loss of strength in human chronic spinal cord injury as probed by targeting intrinsic cellular excitability through pharmacological agents that 1) decrease persistent sodium currents (riluzole) and 2) block persistent calcium currents (isradipine).

Results from these studies may provide a framework for developing additional therapeutic options to treat hyper-reflexia and spasticity after spinal cord injury.

Wed, July 15, 11:30am-12:30pm

The SMPP - Review of ICORR

Attendees of the recent ICORR (International Conference on Rehabilitation Robotics) meeting will provide us with an overview of major projects of interest which were presented at the conference.

Fri, July 10, 12-1pm

Speaker: Professor Pyung Chang

http://mecha.kaist.ac.kr/research_main.htm

Title: Robust Control of Motion and Impedance of Dual Arms for Asymmetric Bimanual Tasks: A Human-Inspired Approach.

Abstract:  Bimanual tasks consist of three categories: unimanual (unconstrained) task, asymmetric bimanual (partially constrained) task, and symmetric bimanual (fully constrained) task. Of the three, partially constrained tasks take majority. In this talk, an impedance control of dual arms is proposed for the asymmetric bimanual tasks (AMT).

Approaches conventional employed tend to achieve desired position and impedance through the re-spective control of each arm. In our approach, we have proposed a new framework for kinematics and dynamics of dual arms, called the relative task space, based on Guiard’s 1st hypothesis – constructed on the observation of human behavior and verified through experiments.

In the relative task space, not only the kinematics and dynamics of dual arms are expressed in terms of relative Jacobian, but the relative impedance behavior can also be defined. Compared to the conven-tional approaches, ours enables to simplify the control of relative position and impedance, making it far easier to describe and achieve the desired position and impedance for dual arms. Furthermore, the rela-tive impedance can be achieved with a single force-torque sensor, instead of two.

In addition to the relative task space, we have incorporated Time-delay control, a robust control tech-nique for nonlinear plants of companion form such as robot dynamics. TDC necessitates little knowl-edge of robot model, and is easy to design. Thanks to TDC, all model uncertainty has been eliminated and robust control of impedance has been realized with relatively little time and effort.

We have implemented the proposed control in a dual arm system consisting of two 6 DOF PUMA type robots, using only 3 DOF in each robot. In the experiments where respective control is performed for relative position and impedance, the proposed control achieved accurate position and impedance, thereby demonstrating its effectiveness.

Thu, July 9, 12-1pm

Speaker: Dr. Ela Bhatt

Title: Stroke Rehabilitation: Options, Feasibility and Outcomes

Abstract:  Introduction: Stroke is an important cause of disability. Deficits, like upper limb dysfunction and peripheral visual field loss from hemianopia, are associated with poor prognosis. Despite intensive rehabilitation, residual deficits linger. My research goals are to 1) develop new stroke interventions or modify existing ones to prevent residual deficits and, 2) combine existing interventions with latest neurostimulatory or neuromoduatory techniques to harness plastic potential of surviving networks. The actions towards these goals have progressed steadily.   

Aim 1: Methods, Procedures and Findings: Preliminarily, effectiveness of complex visuomotor learning as a new model for stroke rehabilitation was tested. In healthy, hand visuomotor training was shown to transfer to other joints. Functional Magnetic Resonance Imaging (fMRI) revealed plastic processes of cortical reorganization. It was thus theorized that visuomotor learning could be effective in stroke since skill could transfer between segments and cortical mechanisms of recovery could be potentiated. In chronic stroke, benefits of hand visuomotor learning were compared to repetitive movement. Visuomotor training improved motor skill, which transferred to Box and Block test, a measure of dexterity. However, motor skill and Box and Block scores were still below norms. Thus, complex learning could reduce disability, but resolution of function was incomplete. Exploration of aim 2 became important.

Aim 2: Methods, Procedures and Findings: I hypothesized that combining visuomotor training of the hand with neurostimulatory peripheral electrical stimulation of wrist/hand would lead to greater improvement than peripheral electrical stimulation delivered alone. Visuomotor skill improved to a greater degree in the visuomotor training + peripheral electrical stimulation group, while Box and Block scores improved in both groups without a relative difference. Improvement in the visuomotor training + peripheral electrical stimulation group was strongly associated with cortical mechanisms of recovery, such as shift of fMRI activation to the lesioned hemisphere. I was intrigued with the possibility of directly inducing these cortical mechanisms in the brain to gain even greater recovery; one method is the use of cortical neurostimulation/neuromodulation with Transcranial Magnetic Stimulation (TMS) and Transcranial Direct Current Stimulation (tDCS). I am comparing the effectiveness of rehabilitation + visual cortical neuromodulation versus rehabilitation alone in a double blind, randomized clinical trial for patients with hemianopia. Patients in the rehabilitation + cortical neuromodulation group have shown significant gain in visual field compared to the rehabilitation alone group. Functional questionnaire assessments have also demonstrated significant transfer to daily function in the rehabilitation + cortical neuromodulation group. FMRI in a patient from the combined group shows cortical reorganization of higher order visual and peri-lesional areas.

Conclusions: Complex skill training, associated with cortical plasticity, has greater efficacy than standard repetitive training in stroke. However, complex training itself or in combination with peripheral neurostimulation might not be efficacious enough to produce complete resolution of function. Based on current work in visual rehabilitation, directing adaptive plasticity using cortical neuromodulation might aid recovery further, above and beyond what is gained through standard or complex learning. Further exploration, across varying stroke deficits, is recommended.

Wed, July 8, 12-1pm

Jooeun Ahn, postdoctoral candidate

Title:  Feasibility of dynamic entrainment with ankle mechanical perturbation to treat human locomotor deficit

Abstract: Sensory-motor training will likely make important contributions to recovery after neurological impairments. Appropriate training of balance and mobility may reduce locomotor impairment, possibly by recruiting and entraining residual pattern generators in the lumbar cord. Human-interactive robots provide several advantages for delivering sensory-motor treatment and numerous studies have shown that upper-limb robotic therapy affords positive benefits for patients recovering after stroke. To treat the lower extremity, Anklebot, a machine that can simultaneously apply forces at the ankle in plantar- and dorsi-flexion, inversion and eversion is recently introduced.

Using Anklebot, I perturbed human gait by applying external torque to the human ankle at various frequencies. I observed that with a properly designed perturbation, 10 subjects out of 12 exhibited entrained gaits: their gait frequencies were adapted to the frequency of mechanical perturbation, and they synchronized their ankle actuation with the external torque supplied by the robot. This preliminary result suggests that a limit-cycle oscillator, a plausible element of the coupled system of central nervous system and musculo-skeletal periphery, plays a significant role in the neuromotor execution of human locomotion. Using simple mathematical models, I tested whether entrainment to mechanical perturbation may emerge without complete supra-spinal control. Analysis indicated that, with suitable control which is not necessarily supra-spinal, the mechanical perturbation from Anklebot can entrain human gait to faster cadence with limited basin of entrainment. The entrainment of human gait by periodic torque from a robotic aid may provide a novel approach to walking therapy that is uniquely supportive of normal biological function.

Mon, July 6, 4-5pm

RIC, Magnuson Auditorium (16th floor)

Speaker: Robert Kirsch, Ph.D

Fri, July 3,  12-1pm

SMPP postdoc grant proposal presentation

Speakers: Davide Piovesan,  Kunlin Wei & Inga Wang

SMPP postdoctoral fellows will present their grant proposals covering specific aims, design and key methods (5 minute presentation plus 5 minute discussion per proposal). The main purpose of the meeting is to provide feedback on postdoc grants from a non-expert audience, and give postdocs an opportunity to defend their proposed study.

Thu, July 2, 11:30am-12:30pm

Speaker: Anirban (Nir) Dutta

Title: Development of an Electromyogram-Based Controller for Functional Electrical Stimulation-Assisted Walking After Partial Paralysis

Abstract:   Paralysis can be caused by an injury to the spinal cord that may partially or completely interrupt communication between the brain and the muscles. If the paralyzed muscles below the level of injury remain innervated then they can be activated by applying small electrical currents in a process known as Functional Electrical Stimulation (FES). The electromyogram (EMG) is the time history of the electrical activity of a muscle that can be used to find its level of activation.

This dissertation investigated the use of EMG as a command source for FES-assisted ambulation after incomplete spinal cord injury (iSCI). The synergistic modulation of the volitional EMG was used to identify the intent to transition from step to step even when partially paralyzed muscles were too weak to produce enough moment at the joint to produce effective push-off.  This work has shown that:

  1. The controllability of the surface EMG from a partially paralyzed muscle from individuals with iSCI during a visual pursuit task was similar to able-bodied subjects.
  2. Surface EMG from the ipsilateral erector spinae and medial gastrconemius consistently performed well to identify the intent to step in able-bodied and iSCI subjects.
  3. Spatio-temporal gait parameters with EMG-triggering were at least as good as with standard switch-triggered FES for iSCI subjects in spite of the differences in their injury levels, degree of preserved volitional control, and muscle set chosen for stimulation.
  4. 4. EMG-triggering improved the coordination of the FES-assisted iSCI gait during stand-to-walk transitions to levels similar to able-bodied gait.
  5. Command sources can be selected objectively prior to implementing a fully implantable EMG-triggered FES system for walking.
  6. The optimal number of command sources, features, and signal processing techniques can be determined to further improve the accuracy of EMG-triggering.

More research is needed to optimize the implantation site for EMG recording electrodes and define the technical requirements for a clinically practical EMG-triggered system to facilitate ambulation after iSCI.

Host: Dr. Perreault

Fri, June 19

SMPP postdoc grant proposal presentation

Speakers: David Boothe, Maura Casadio, Winnie Wu & Jinsook Roh

Thu, June 18

Speaker: Andrew Pruzynski, PhD candidate from Queen's University, Canada

Title: What is the extent and origin of task-dependency in the long-latency response?

Host: Dr. Eric Perreault

Wed, June 17

Speaker: Ali Israr, PhD

Host: Sandro Mussa -ivaldi, PhD

Fri, June 5

SMPP postdoc grant proposal presentation

Speakers: Sangeetha Madhavan & Joe Towles

 

Fri, May 29

Speaker: Chandramouli Krishnan (postdoc candidate)

Title: Inter-limb Differences in Knee Strength: Role of Antagonist Activity, Voluntary Activation, and Muscle Physiology     

Host: Drs. Yasin Dhaher & Zev Rymer

Fri, May 22

Speaker: Dr. John Linehan

Professor in the Dept. of Biomedical Engineering at Northwestern University http://www.bme.northwestern.edu/faculty_staff/core/linehan.html

Thu, May 21 

Speaker: Leo Cohen, MD, Senior Investigator, Dr. Cohen's web page

Human Cortical Physiology & Stroke Neurorehabilitation Section Medical Neurology Branch, NINDS

Title: Novel interventional strategies in stroke rehabilitation

Thu, May 21 

Speaker: Virginia Chu, Stanford University

Title: Role of noise in motor learning     nonlinear systems.   

Host: Eric Perreault PhD

Fri, May 15

SMPP postdoc grant proposal presentation

Speakers: Sang Wok Lee  &   Nate Bunderson

Wed, May 6

Job Hunting 101 - academic job search do's and dont's

Fri, May 1

SMPP postdoc grant proposal presentation

Speakers: Randy Trumbower, Katharina Quinlan, Arun Jayaraman & Preeti Nair

Fri, April 24

Speaker: Andrea d'Avella, PhD

Department of Neuromotor Physiology, Santa Lucia Foundation, Rome, Italy

Title: Modular architecture for motor control

Fri, April 23

Speakers: Troy Turner & Ken Curley -- Invited speakers from TATRC, a DoD funding agency

Title: TATRC presentation

They will be speaking about their programs and how more investigators can learn to work with TATRC to obtain funding for their work in the area of prosthetics, neuroscience, and neuro-rehabilitation.

Host: Drs. Danielle Kerkovich, Todd Kuiken

Wed, April 22

Speaker: Megan Conrad, Marquette University

Title: Effects of Distal Manipulations on Arm Movements in Post-Stroke Hemiparesis

Host: Dr. Derek Kamper

Fri, April 17 

SMPP postdoc grant proposal presentation

Speakers: Gilles Hoffmann,    Heng Zhao,  Preeti Nair,  Mary Ellen Phillips-Stoykov

Thu, April 9

Lee Miller, PhD, Associate Professor, Department of Physiology

Northwestern University The Miller Laboratory of Limb Motor Control

Title: Voluntary control of paralyzed muscles: The development of brain-controlled functional electrical stimulation to restore hand use following spinal cord injury

Fri, April 2

The SMPP - The Neuro-Locomotion Lab

Speaker: George Hornby, PhD

Assistant Professor, Department of Physical Therapy, UIC & Research Scientist, SMPP, RIC

Title:  Repeated, Volitional, Fatiguing Contractions in Human SCI: General Findings, Potential Mechanisms, and Future Work

Thu, April 2

Speaker: Kevin Keenan, PhD, Assistant Professor, Human Movement Sciences, UW-Milwaukee

http://www3.uwm.edu/CHS/faculty/136~facultykkeenan.html 

Title: Hand function: assessing the neural control of finger forces and motions

Wed, April 1

SMPP postdoc grant proposal presentation

Na Jin Seo, Renee Theiss, Felix Huang, Peter Rauske

Wed, March 11

Speaker: Mark Latash, PhD, Penn State University

Title: Hierarchies of synergies and the equilibrium-point hypothesis

Host: Dr. Bob Scheidt

Fri, March 6

Gabriel Aguirre-Ollinger, PhD,Candidate at NU LIMS

Title: "Experiments in Lower-Limb Assist Using a 1-DOF Exoskeleton with Active Impedance"

Host: Yasin Dhaher, PhD

Fri, Feb, 27

SMPP postdoc grant proposal presentation

Paul Marasco, Jeremy Mogk  & Jon Shemmell

Thu, Feb, 26

The Spinal Neuron Laboratories

Director: Matthew Tresch

Tue, Feb 24

John Krakauer, MD, Associate Professor of Neurology

Co-director, Motor Performance Laboratory The Neurological Institute, Columbia University, New York, NY

Title: "Some new thoughts about motor recovery after stroke"

Fri, Feb 20

SMPP Postdoc Seminar: Craig Goehler, PhD

Title: Human-Robot Interactions: Breaking Down the Boundaries

Mon, Feb 16

Speaker: Michael Goldfarb, PhD

Professor of Mechanical Engineering, Director, Center for Intelligent Mechatronics from Vanderbilt University

Title: Some New Possibilities in the Design and Functionality of Upper and Lower Limb Prostheses

Fri, Feb 13

SMPP Postdoc Seminar: Winnie Wu, PhD

Title: In vivo fiber tension and sarcomere imaging measurement in a mouse stroke model

Thu, Feb 5

The Neuromuscular Control & Plasticity Lab Seminar

Lab Director: Eric Perreault

 

Fri, Jan 30

Speaker: Davide Piovesan, PhD (SMPP Postdoc Seminar)

Title: Comparative Analysis of Methods for Estimating Arm Segment Parameters and Joint Torqu es

Wed, Jan 21

Speaker: Karl Rosengren, PhD

Dr. Rosengren is a former professor at the University of Illinois at Urbana-Champaign (UIUC), and now a professor at Northwestern University.

Title: New Approaches to Quantifying Gait Differences Due to Development, Disability, and Injury

Host: Eric Perreault

Fri, Jan 16

Speaker: Anatol Feldman, PhD, DSci

Title: Common spatial frames of reference for action and perception

Fri, Jan 9

Speaker: Tasos Karakostas, MPT, PhD

Title: Surface electromyography: A tool towards the assessment of human motion

Host: Hyung-Soon Park

Wed, Jan 7

Immigration Issues (presentation by a legal firm)

The following individuals from the law firm Kempster Keller Lenz-Calvo will give a presentation on Non-Immigrant and Permanent Resident Options for RIC employees/candidates:
Martina Keller - partner
Theresa Corcoran - partner
Cheryl Lenz-Calvo - partner
David Kucinskas - legal assistant
 

Tue, Jan 6

Postdoc fellowship grant meeting

2008

December

Fri, Dec 19

The Neuro-Locomotion Lab

Speaker: T. George Hornby, PhD, PT

Assistant Professor, Department of Physical Therapy, University of Illinois at Chicago Research Scientist, SMPP, RIC

Title:  Repeated, Volitional, Fatiguing Contractions in Human SCI

Director: George Hornby

Thu, Dec 18

Speaker: Francis Suh, PhD

Bionics Research Team, Future Fusion Technology Laboratory, Korea Institute of Science and Technology, Seoul, Korea & Department of Biomedical Engineering, Tulane University, New Orleans, LA

Title: Soft Tissue Biomechanics in Orthopaedics and Ophthalmology

Fri, Dec 5

Speaker: Sangeetha Madhavan & Jon Shemmell

Title: Detecting ipsilateral connectivity from motor cortex to lower limb spinal motoneurons, and reorganizing cortical motor maps using paired electrical stimulation.

Mon, Dec 1

SMPP Graduate Student Seminar: Zachary Danziger

Title: Developing Learning Algorithms for Human-Machine Interfaces

November

Tue, Nov 25

The SMPP - Society for Neuroscience Review II

Members of SMPP will present interesting work that they learned at the annual meeting of the Society for Neuroscience.

Fri, Nov 21

Society for Neuroscience Review

Members of SMPP will present interesting work that they learned at the annual meeting of the Society for Neuroscience.

Thu,  Nov 20

Peter Konig, PhD 

Title: Integration of information in gaze control

Thu, Nov 13

Adrienne Harvey, PhD 

Title: Measuring mobility in the motion analysis centre: the Functional Mobility Scale (FMS) and beyond.

Host: Deb Gaebler    

October

Fri, Oct 31

Lanitia Gorman, PhD, Postdoctoral candidate

Title: Effects of Vibration on Spinal Circuitry Related to Spasticity and Walking Spinal cord injury (SCI) disrupts communication between the brain and spinal cord resulting in motor dysfunction.

Fri, Oct 24

Silvia Blemker, PhD

Title: Modeling muscle at multiple length scales with application to analyzing muscle design, injury, and disease Skeletal muscle has a beautiful hierarchical structure that enables thousands of muscle cells to work in concert and actuate movement.

Web: http://www.mae.virginia.edu/muscle

Fri, Oct 17

The Sitting Biomechanics Lab

Director: Mohsen Makhsous

Presenter: Sam Perlmutter (PhD student) 

Title: Sitting Balance and Trunk Control in Hemiparetic Stroke There is a lack of research regarding how the trunk is affected in post-stroke individuals.

 

 

Page Updated Friday, October 30, 2009