2013 Research Seminars - Rehabilitation Institute of Chicago

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2013 Research Seminars

Fri, Dec 20

Speaker: Dr. Elliott Rouse

Title: Joint impedance and the future of wearable robotics design and control

Abstract: Previous research in lower-extremity prostheses and exoskeletons has produced devices that are intelligent and can emulate biologically accurate joint kinetics and kinematics in the sagittal plane. However, these devices have been unable to improve the locomotory metabolic burden of the disabled—an unacceptable shortcoming affecting clinical impact. In this talk, I will present a strategy for the design and control of future wearable robotic technologies that may address this discrepancy. A powered knee prosthesis, developed in the Biomechatronics Group at the MIT Media Lab, will be discussed and how such work motivates the need for a new perspective. Namely, I propose a paradigm shift, where the joint mechanical impedance is considered in the design process in addition to the task dependent torque-angle profile. I will discuss how my previous work estimating joint impedance at Northwestern University/RIC provided novel insight into the mechanical impedance of the ankle during walking and highlight how such information can be used to improve future prosthesis design. Through the development of biologically inspired wearable robotic technology, I seek to not only to restore the performance of the disabled, but also eventually enable these individuals to outperform their able-bodied counterparts. 

Host: Dr. Kuiken


Fri, Dec 20, 2 - 3PM

Speaker: Dr. Sungshin Kim

Title: Computational models and model-based fMRI study in motor learning

Abstract:   In the last decade, computational models in motor learning have become  popular because it provides a theoretical framework not only to explain  but predict motor learning behaviors. However, the computational  approach sometimes has been criticized by dominating experimentalists in neuroscience due to its lack of the underlying neural mechanisms to  support the hypothetical models. In this talk, we combined the  computational modeling with a neuro-imaging method such as fMRI to  understand human motor memories in motor learning. First, we provided a unifying mechanism accounting for the spacing  and the contextual interference effects using multi-rate motor adaption  models: Model comparison and retention performance analyses showed how  varying learning schedule influence the dynamics of fast and slow motor  memories. Second, we searched neural correlates of motor memories  predicted by multi-rate motor adaptation models: We hypothesized that  different brain regions were correlated with activities of motor  memories with varying time scales. We could see the gradual shift of the correlated areas from the fronto-parietal to the cerebellar area with  slower time scales. In addition, using multi-voxel pattern analysis  (MVPA), we found results supporting separate representation of learning  opposing rotations in the cerebellum.

Host: Dr. Rymer

Fri, Dec 13

Speakers: Nina Suresh, Lynn Rogers, Derek Miller and Brian Jeon

Our next SMPP/CBM seminar will be Friday, December 13th and will be  presented by SMPP and CBM colleagues who will be sharing presentations  from recent conferences as a continuation of this week's seminar. Please come and learn about cutting-edge research in neuroscience, neural and rehabilitation engineering and motor control!

Fri, Dec 6

Speakers: Reva Johnson, Matt Perich, Lauren Smith and others TBD

The next SMPP/CBM seminar will be Friday, December 6th and will be presented by SMPP and CBM colleagues who will be sharing presentations from recent conferences. Please come and learn about cutting-edge research in neuroscience, neural and rehabilitation engineering and motor control. 

Fri, Nov 22 

Speaker: Dr. Mark Grabiner

Title: An evidence-based approach to the design of a task-specific fall prevention intervention

Abstract:   Exercise-based fall prevention interventions are demonstrably effective and decrease all-cause falls and risk of falls, on average, by about 30 percent.  However, because the population of older adults is increasing significantly and rapidly, this is insufficient to avoid unsustainable increases in the absolute number of falls by older adults, fall-related injuries, and related medical care costs.  The recent success of a trip-specific fall prevention intervention using perturbation training is both the basis for our hypothesis that task-specific perturbation training is a superior alternative to conventional exercise-based fall prevention interventions and the basis for the design of the fall-prevention intervention.  To test the hypothesis, we are designing and validating an integrated protocol focusing on preventable falls that occur as a result of trips, slips and failure to execute appropriate sideways directed stepping responses.  The categories may account for more than 60 percent of all-cause falls by older adults.  For each fall category, our approach is to first identify biomechanical/performance variables that are statistically significant and clinically modifiable determinants of laboratory-induced falls.  The effectiveness of a perturbation-based intervention designed with a focus on these determinants and, consequently, reduce the incidence of laboratory-induced falls is subsequently assessed.  A significant reduction in the incidence of laboratory-induced falls is the trigger for prospective study of the effect of the intervention on falls in the community.  The overall test of the hypothesis will be conducted by comparing the integrated protocol to conventional exercise-based protocol based on the number of all-cause falls and, more importantly, the number of falls that occur as a result of trips, slips and failure to execute appropriate sideways directed stepping responses, the number of fall-related injuries and associated costs of providing medical care, and the time- and cost effectiveness of delivering each of the interventions.

Host: Dr. Perreault

Tues, Nov 19

Speaker: Dr. Ilana Nisky

Title: Haptics in medical interventions and beyond: the human in the loop

Abstract:   Haptic interaction, involving all aspects of the sense of touch, allows us to communicate with the external world by exchanging information and energy with it. In the recent decades, the development of a variety of haptic and tactile devices has extended this ability to communication with computers. A particularly exciting application for these devices is medical intervention, including robotic rehabilitation and robot-assisted surgery (RAS), both involving interaction with a human user either at the patient side, the caregiver side, or both. Therefore, understanding the human sensorimotor system is extremely important for successful development and use of haptic devices. And because these applications involve interaction with robotic devices in rich environments and in purposeful tasks, they provide a fruitful ground for developing and testing novel theories about human motor control. In this talk, I will present three different research topics that exploit understanding of human sensorimotor system for medical applications. I will briefly discuss (1) isometric training for reach rehabilitation and (2) fingertip skin stretch for augmentation of stiffness perception. I will focus on (3) our efforts to understand the motor performance of surgeons during teleoperated RAS. This may lead to human-in-the-loop surgical teleoperator design, control, and training optimization, eventually improving patient outcome in surgical interventions. 

Host: Dr. Mussa-Ivaldi

Fri, Nov 15 

Speaker: Dr. Steven H. Collins

Title:  Prosthesis and exoskeleton emulators for rapid evaluation of human response to intervention

Abstract:   It is an exciting time in robotic prosthesis and exoskeleton design, with clever innovations emerging quickly. But will these technologies provide real benefits to their human users? It is surprisingly difficult to predict how humans will respond and adapt to wearable robotic devices, and many years of development are typically required before proposed designs can be tested on humans. What if we could test our ideas for device function quickly, without the overhead of designing product-like prototypes? We have developed a system for rapid emulation of robotic ankle prostheses and orthoses, which we have used in experiments that reveal quantitative relationships between device behavior and human performance, particularly in terms of energy cost and stability. Recent results include characterizing the trade-offs between ankle push-off work, motor size and metabolic energy cost, as well as the relationship between step-by-step adjustments in device behavior and gait stability for the human-robot system. We will discuss how this biomechanics-centered approach to the design of assistive robots will lead to empirically-verified design guidelines, facilitate new approaches in online adaptation, user-specialization, and clinical diagnosis, and speed the arrival of better wearable robots.

Host: Dr. Hargrove

Fri, Nov 8 **RESCHEDULED to Dec 8

Speaker: Dr. Sean Deeny (from the Rehabilitation Technologies & Outcomes Lab)

Title:  EEG Measures of Cognitive Workload and Cortical Dynamics During Myoelectric Prosthetic Limb Use

Abstract:   A primary goal in development of new myoelectric prosthetic technology is to reduce the cognitive workload or attentional demands of limb control.  Towards that end, the past decade has seen significant advances in prosthetic limb control strategies, prosthetic design, and even surgical techniques, all of which are intended to make prosthesis control as intuitive and functional as possible. However, there are currently no objective and quantitative outcome measures employed in the prosthetics literature to assess cognitive burden of using myoelectric prostheses, or to effectively measure and distinguish the cognitive, perceptual, or motor demands of prosthetic limb use.  We are exploring EEG measures of cortical resource allocation during myoelectric limb control for the purpose of evaluating and guiding new technological advances in “intuitive” prostheses.  We examined the efficacy of event-related potential (ERP) measures of cortical activation as a cognitive workload outcome tool during myoelectric virtual arm control, and compared the cognitive and physical workload of two methods of myoelectric control, direct control (DC) and pattern recognition control (PRC) in sixteen healthy participants with in-tact limbs.  For complicated (3 DOF) movements, PRC was faster and required less muscle activation (EMG), consistent with greater efficiency.  ERP measures of cognitive workload distinguished different levels of difficulty (viewing, 1 DOF, 3 DOF), and distinguished DC from PRC in the 3 DOF condition. We are currently adapting the paradigm to be testing in patients with upper limb and lower limb amputations, and exploring other EEG measures of cortical activation and cortico-cortical communication for future studies. 

Host: Dr. Jayaraman  

Fri, Nov 1

Speaker: Dr. Ning Lan, Ph.D.


Host: Dr. Rymer

Fri, Oct 25

Speaker: Dr. Aaron Batista

Title: Neural Constraints on Learning

Abstract:  Why are some skills and concepts easier to learn than others? Acquiring skills and mastering new concepts must require the generation of new activity patterns within populations of neurons, yet relatively little research has focused on how populations of neurons change during learning. Are differences in learnability due to constraints on the types of neural activity patterns that can be achieved? We studied this question using a brain-computer interface, which allowed us to directly specify the activity patterns we wanted the subjects to show. We identified a simple network principle that can predict which types of neural activity patterns the subjects are able to generate in a short time period. This work provides a novel network-level explanation for why learning some tasks may be easier than others. This principle may also operate in sensory and cognitive domains, and it may provide the balance between stability and flexibility that governs learning and cognition.

Host: Dr. Miller

Fri, Oct  18

Speaker: Dr. Patrick Crago

Title: Augmenting voluntary ability to reach and grasp following stroke

Abstract:  Restoring the ability of stroke survivors to reach and grasp with the affected limb should greatly increase performance of critical activities of daily living. New therapeutic interventions decrease impairments and increase function.  Nevertheless, people with moderate to severe impairments would also benefit from assistive technologies could offer significantly improved quality of life. Functional electrical stimulation (FES) is one such assistive technology.

The impact of FES for restoring upper extremity function post stroke has been limited due to flexion synergies elicited by voluntary reach that overpower stimulated reach and hand opening. The fundamental hypothesis of our new approach is to limit voluntary effort to reduce the expression of the synergies, enabling simultaneous FES to achieve larger net reach and hand opening. We also hypothesize that the residual voluntary effort can control the FES assistance.

We have completed a series of studies examining these principles in stroke survivors. One study demonstrated that reducing voluntary effort and increasing stimulation produced greater reach and hand opening in some subjects, but that the dependence was subject specific. A second study quantified the interaction between stimulated and voluntary effort to produce forward reaching force. While stimulation increased the net force, the increment due to stimulation decreased with increasing voluntary effort, demonstrating graded occlusion. A parallel modeling study replicated the force occlusion observed during simultaneous voluntary and stimulated contractions, and predicted that the voluntary component of the EMG will be also be reduced. The final study demonstrated the ability of stroke survivors to control an assistive force, applied by a haptic interface as a force at the wrist, by the EMGs produced by voluntary contractions in the same limb. Participants were able to control the assistance to reach and hold targets successfully.

The combined results of these studies support the proposed control of FES by residual voluntary movement to augment the ability to reach and grasp in stroke survivors, but also as a platform to explore further therapeutic approaches.

Host: Dr. Rymer

Fri, Oct 4

Speaker: Dr. Thomas J. Royston

Title: The Future of Palpation: Remote, Scalable and Quantifiable using Magnetic Resonance Elastography (MRE)

Abstract:   In this presentation I will give an overview of magnetic resonance elastography (MRE), explaining how it works, its history of development, current areas of research and future possibilities. A portion of the talk will go into more detail on our work at UIC in ultra high field, high resolution MRE, and its unique challenges.

Host: Dr. Perreault

Fri, Sept 27

Speakers: Debjani Mukherjee, Ph.D., Laura Pitts, Ph.D., Leora Cherney, Ph.D. and Teresa Savage, Ph.D., RN

Title:  Ethics in Action: Research Ethics Consultation in Neurodegenerative Disorders

Abstract:  In this “Ethics in Action” session, the concept of Research Ethics Consultation, an emerging research resource that exists at over 30 Clinical Translational Science Award institutions in the US, will be introduced by discussing a project that was brought to the RIC ethics team involving Neurodegenerative Disorders.

Fri, Sept 13 

Speakers: Alejandro Melendez, David Lipps, Sarah Wohlman, Carrie Peterson, Nicholas Fey

Abstract:  Members of SMPP and CBM who have recently attended conferences will present studies that captured their attention. Each speaker will present for about 10 minutes.

Fri, Aug 23

Speaker: Peter Cooman

Title: Controlling human arm movements generated by Functional Electrical Stimulation

Abstract:  Using a model-based approach, we designed and evaluated nonlinear combined feedforward-feedback algorithms to control arm movements in the presence of a wide range of perturbations: (1) manipulation of objects of unknown mass, (2) sensor noise, (3) muscle fatigue, (4) model uncertainty with respect to the true inertial properties of the arm and the true muscle dynamics, and (5) input time delays. These algorithms were developed specifically for use in FES neuroprostheses for individuals with paralysis due to spinal cord injury and other neurological disorders. An initial comparison of combined feedforward-feedback proportional-derivative (PD), adaptive control, and sliding mode control showed that input time delays quickly caused instability for all three controllers if feedback gains were chosen too high. Decreasing the feedback gains (i.e., shifting towards feedforward control) re-established stability, but greatly reduced performance as measured by the root-mean-square error between the specified movement intent and the simulated joint angles. Input time delays are unavoidable in FES applications, arising from the muscle dynamics and the relatively low stimulation frequency (i.e. 12Hz) typically used in upper extremity FES neuroprostheses. The destabilizing effects of time delay therefore cannot be ignored. Using a 2DOF musculoskeletal arm model, we designed and evaluated a nonlinear combined feedforward-feedback controller with time delay compensation. In the presence of a typical 80ms time delay, this controller achieved excellent tracking accuracy, both under ideal conditions (shoulder RMSE: 0.27º, elbow RMSE: 0.62º) and in the presence of a wide variety of perturbations expected under normal operating conditions (shoulder RMSE: 2.99º, elbow RMSE: 5.15º). We extended this time delay compensating controller to a more functionally relevant 5DOF arm model. This extended controller achieved stable, accurate tracking, even in the presence of time delay, measurement noise, muscle fatigue and additional loading - but only if the inertial properties of the arm were exactly known. Future research in gravity compensation and adaptation may further improve the robustness of the time delay compensating controller for the 5DOF arm model.

Host: Dr. Patton

Fri, Aug 16

Speaker: Dr. Frans van der Helm

Title: Force and position feedback mechanisms in neuromuscular control

Abstract:  The simultaneously modulation of the strength of the force and position feedback loops determines the postural control of the human limbs. Force feedback originates from the Golgi tendon organs, and position feedback from the muscle spindles. Position tasks require a high stiffness of the human limb (‘resist’), whereas force tasks require a low stiffness (‘give way’). Using closed-loop system identification mechanisms in combination with force perturbations, the quantitative contribution of the various feedback loops can be determined. In force tasks, the stiffness becomes lower than in passive conditions showing that the reflexive feedback is actively ‘giving way’. Remarkably, experimental results show a switch of the sign of position and force feedback gains between position and force tasks.

A theoretical model was developed which can explain the symptoms of dystonia, like preferred position and high resistance against displacement. The model assumes a-symmetric feedback gains between flexors and extensors, and the lack of positive force feedback gains settings. Experiments with CRPS patients with dystonia showed that they could significantly less modulate their force feedback strength.

It is concluded that Golgi tendon feedback has a similar important role for the stiffness behaviour of the human limbs as muscle spindles, and they should be simultaneously quantified in order to understand neuromuscular control.

Host: Dr.  Rymer 

Fri, July 12

Speaker: Dr. Carmit-Noa Shpigelman

Title: Online support applications to promote mental health of individuals with disabilities

Abstract:  What are the physical, social and emotional needs of individuals with disabilities? How can we use computer-mediated applications such as email, web forums, and social networks to connect between individuals with disabilities and support their needs? In my presentation, I will discuss these questions. I will present my interdisciplinary research that links between disability studies (mental health and inclusion), rehabilitation, education, and technologies. In my studies, I focus primarily on health promotion and empowerment of individuals with a wide range of disabilities (developmental, intellectual, sensory, emotional and/or behavioral disabilities). First, I will bring the voices of mothers with disabilities into the front of the public health discussion. I will present a research project that focuses on health barriers, needs and desires of mothers with physical and/or sensory disabilities. Then, I will present an innovative electronic mentoring program as an accessible environment to socially and emotionally support individuals with disabilities.

Host: Assaf Dvorkin 

Fri, July 5

Speaker: Tommi Raij, MD, Ph.D.

Abstract:  Neuronal activation trace lifetimes as an index of short-term plasticity across the cerebral cortex

Human neuroimaging (MEG/fMRI) data suggest a simple neurophysiological mechanism that may support functional hierarchical organization across the cerebral cortex. Specifically, in low-order sensory cortices neuronal activation traces decay rapidly, which may be perceptually advantageous, whereas activation traces in high-order areas can persist for tens of seconds, which may support abstract short-term memory, longer temporal integration windows, and greater plasticity in these regions.

Modeling-augmented TMS:  Research and clinical applications

Present transcranial magnetic stimulation (TMS) navigation systems underutilize the rich individual level anatomical information that can be extracted from structural MRI and diffusion MRI tractography. Employment of this information allows greatly improved TMS spatial accuracy and intensity estimates. Such methods also allow individual cortical surface estimates and averaging across subjects, which opens entirely new avenues for enhancing the scientific and clinical utility of TMS. To highlight such advances I will present data from (i) a paired-pulse TMS experiment that provides causal evidence of supratemporal auditory cortex feature-specific processing, and (ii) modulation of fear extinction in humans using imaging- and modeling-augmented TMS.

Host: Dr. Rymer

Fri, June 21

Speaker: John R. Hetling, Ph.D.

Title: Developing a New Electrophysiology-Based Diagnostic Device for Glaucoma 

Abstract:  Glaucoma is a leading cause of blindness in the world.  It is a slowly progressing disease, yet significant irreversible damage has typically occurred by the time of diagnosis.  Early detection is well correlated with better treatment outcomes making early detection a high priority.  This talk will describe the development of a new approach to measuring the health of the retina, multi-electrode electroretinography (meERG), with a focus on early detection of the localized damage associated with early-stage glaucoma.  Technology development, preliminary results from rat and human eyes, and commercialization efforts will be described. 

Host: Dr. Patton

Thurs, June 6

Speaker: Professor Dagmar Sternad

Title: Variability and Stability in Skill Learning: From Actions to Interactions

Abstract:  How does the brain coordinate our actions and interactions with objects and the environment? How do we throw or bounce a ball; how do we drink a cup of coffee without spilling it? Revealing the fundamental principles that underlie motor control and skill learning in the healthy nervous system is a necessary basis to understand neurological dysfunction and to develop intervention. Recent research of my lab has examined three interactive motor skills: the discrete task of throwing a ball to hit a target, the rhythmic task of bouncing a ball, and the continuous task of carrying a cup filled with coffee. Key concepts that drive our inquiry into changes with practice are variability and stability. Characteristic for our approach is to start with a mechanical model of the task and render it in a virtual environment. As such, the human interacts with a known task environment. Based on stability analyses of the dynamical model, we study how the neuro-mechanical system develops robust solutions to meet the task demands. Using the three skills as model examples, we show that developing skill means 1) exploiting solutions with dynamical stability, 2) finding the most error-tolerant strategy and channeling sensorimotor noise into task-irrelevant dimensions, and 3) optimizing safety margins and predictability of solutions. Based on these insights into healthy function, we started to test new intervention techniques that facilitate learning and relearning of motor tasks.

Host: Dr. Mussa-Ivaldi

Fri, May 3

Speaker: Hyunglae Lee

Title:  Quantitative Characterization of Human Ankle Mechanical Impedance

Abstract:  While all joints in the kinematic chain between the foot and trunk participate in lower extremity functions, the contribution of the ankle is significant for healthy people as well as for neurologically impaired patients. In this talk, quantitative characterization of ankle mechanical impedance for young healthy people is presented to better understand its roles in interaction with the environment and to provide a baseline for clinical studies in patients, especially those with neurological disorders. Ankle mechanical impedance, which is dynamic relationship between the angular displacement and the corresponding torque at the ankle joint, was studied in multiple degrees-of freedom(DOF) simultaneously, both in the sagittal and frontal planes. Multivariable studies using a wearable ankle robot, Anklebot, enabled assessment of several important ankle properties under different muscle active conditions, unavailable from single DOF studies: spatial ankle impedance structure, coupling between two DOF, and energetic passivity of the ankle.

Methods presented in this talk can be generally applicable to studies of multivariable joint mechanical impedance, both for multi-joint impedance and single joint multi-DOF impedance. Application to the human wrist joint and a preliminary study on stroke patients is also briefly addressed.

Host: Dr. Perreault

Fri, April 12

Speaker: Samuel Sober, Ph.D.

Title:  Neural, behavioral, and biomechanical approaches to vocal motor control and sensorimotor learning

Abstract: Our lab uses the songbird vocal control system to investigate how the brain generates behavior and learns from experience. The neural circuits governing the learning and production of song are easily accessible to measurement and manipulation, providing a rich system in which to study the interplay between sensory feedback, motor control, and neural plasticity.  However, although much is known about both song behavior and the functional anatomy of the songbird brain, we know very little about how the brain uses sensory feedback signals to rewire the neural circuits driving vocal behavior. In my talk I will present studies that employ a range of behavioral and physiological techniques to investigate sensorimotor learning and vocal control.  First, by developing a system for manipulating auditory experience in the singing bird, we have demonstrated that adult birds maintain vocal performance by a process of error correction and defined the computational rules governing vocal learning.  Shifting the pitch (fundamental frequency) of auditory feedback leads to compensatory changes in the pitch of song.  This result suggests that song is constantly evaluated relative to an auditory target and that the resulting error signals are used to correct vocal output.  Furthermore, quantitative analysis of learning across conditions (error size, animal age) suggests that songbirds use the statistics of their prior sensorimotor experience to constrain their behavioral responses to sensory errors, reflecting a robust strategy for optimizing behavior.  Second, neural recordings from premotor neurons in the songbird brain have revealed how premotor neurons contribute to the moment-by-moment control of vocal output and contribute to vocal plasticity during learning.  Third, studies using electromyographic (EMG) recordings, single-muscle electrical stimulation, and in vitro approaches allow us to quantify the mechanics of acoustic production.  Together, these approaches allow us to investigate the relationship between vocal learning, the neural encoding of motor commands, and the transformation of neural activity into vocal behavior by the motor periphery.

Host: Dr. Kording

Fri, April 5

Speakers: Debjani Mukherjee, Ph.D., Preya Tarsney, JD and Teresa Savage, Ph.D., RN

Title:  Ethics in Action: What does the ethics service at RIC do and what can it do for researchers?

Abstract:  In this session, the ethics team at RIC will discuss several services/initiatives that they have developed and discuss the underlying ethical principles and the process. Examples include clinical ethics consultation, an informed refusal policy, seminars on negotiation and on “vicarious traumatization.” Plenty of time will be left for discussion and an opportunity to suggest topics that would be beneficial for RIC researchers. This session will kick off a quarterly ethics lecture series that will ideally be driven by the interests and needs of the audience.

Fri, March 22

Speakers: Elsa Baehr, Ph.D. and Corey Feinberg, MA

Title:  Brainwave Biofeedback: A Non-Invasive Treatment for Multiple Disorders

Abstract:  This presentation will provide an introduction to brainwave biofeedback and its application towards the treatment of various disorders, with particular emphasis on treatment modalities involving stroke, head injury, and depression.  Other topics that will be discussed include: Quantitative EEG analysis (QEEG) as a diagnostic tool, live Z-score training protocols, and other recent developments in EEG-based brain imaging techniques such as sLORETA analysis and real-time 3D brain displays. 

The presentation will begin with a brief overview of brainwave biofeedback, the mechanisms behind it, and the history of how it came about.  It will then highlight brainwave biofeedback for the treatment various disorders; citing relevant literature and research regarding its use with those disorders.  Additionally during this segment of the presentation, Dr. Baehr will provide an in-depth look at its clinical application for the treatment of depression with specific details about the unique alpha asymmetry protocol and the research supporting it.  The remaining portion of the lecture will focus on some of the more recent advancements in EEG biofeedback technology for the purposes of brain mapping and brainwave entrainment.  Case studies will be presented and utilized as a means of better illustrating the brainwave biofeedback treatment process from the initial evaluation to the formation of lasting neurological changes encompassing symptom remediation.

Hosts: Drs Dvorkin and Stoykov

Fri, March 15

Speaker: Diane Morean, Ph.D.

Title:  Verb Recognition and Retrieval in Aphasia: Implications for the Lexical Conceptual Structure of Verbs

 Abstract:   The majority of people with aphasia experience word retrieval difficulties. Individuals with fluent anomic aphasia have more difficulty with nouns and individuals with nonfluent agrammatic aphasia have more difficulty with verbs, though this dissociation is not absolute. Two experiments were performed to explore the effects of the semantic complexity of verbs in aphasia, and to gain a better understanding of the lexical conceptual structure of verbs in the mental lexicon.  One experiment examined the effects of semantic weight on verb recognition of category exemplars in aphasia through lexical decision.  Another experiment examined the effects of semantic weight on verb retrieval of category exemplars in aphasia through a story completion task. Results are discussed with relevance to a proposed prototype model of verb typicality

Host: Dr. Cherney

Fri, March 8

Speaker: Mark Latash, Ph.D.

Title:  Less known aspects of feed-forward motor control

Abstract:  It has been known for years that animals (including humans) frequently act in an anticipatory fashion; a typical example is the phenomena of anticipatory postural adjustments (APAs). Over the past 8 years, we have been studying a group of phenomena called anticipatory synergy adjustments (ASAs); these phenomena represent consistent changes in indices of co-variation in multi-element redundant systems that are seen in preparation to a quick action. Recently, we performed a series of studies showing that this mode of feed-forward control can be used to prepare an action in an unknown direction as long as the timing of the action is known in advance (for example, think of the increased body sway of a tennis player getting ready for a quick serve or of a hiding predator watching an approaching prey). This feature distinguishes ASAs from APAs. The phenomenon of ASAs fits an earlier model with two types of variables participating in the control of an action: those that define desired time profiles of important performance variables and those that define stability properties of those time profiles. Host: Dr. Mussa-Ivaldi

Fri, Feb 22

Speaker: José L. Pons, Ph.D.

Title:  Hybrid Exoskeletal Robotics and Neuroprosthetics for motor restoration: research at GBio-CSIC

Abstract:  Wearable exoskeletal robotics can play a role in rehabilitation and functional compensation in a number of neurological conditions, e.g. hemiplegia post stroke, paraplegia or quadriplegia post SCI, which lead to sever motor impairments. However, in general, the musculoskeletal system after the insult is preserved and Motor Neuroprostheses (MNPs) can also be considered as valid technologies for rehabilitation and functional compensation. In view of the pros and cons of both technologies, our current approach at the Bioengineering Group of CSIC is to study the combination of neurorobots (NRs) and motor neuroprostheses for rehabilitation and functional compensation of motor disorders of neurological origin. In this concept, three players are to be combined for an optimal intervention, i.e. the patients with their latent motor capabilities, and the two technologies NRs and MNPs. The evaluation of latent capabilities of the patients becomes a crucial aspect for the orchestration of all three actors in promoting functional recovery or substitution. This seminar will address on-going work at CSIC towards the combined use of NRs and MNPs for motor restoration.

Host: Dr. Rymer

Fri, Feb 15

Speaker: Yi-Ning (Winnie) Wu

Title:  Home-based technology for children with impaired upper extremity

Abstract:  Cerebral palsy (CP) is one of leading causes of childhood disability. Children with CP have impaired motor or sensory function or both about one limb, one side of body or four limbs depending upon the lesion site and size of the brain.  Children with one side of body involved are categorized as hemiplegic CP. A child with hemiplegic CP often only uses the unimpaired arm for daily activities and disregard his/her less-able arm, which is potentially valuable. This observed developmental disregard is similar to the learned non-used seen in the adult stroke. Decreasing usage of impaired hand leads to further reduction in excitability of injured brain. This connection sets off a deleterious circle of decreasing brain excitability and hand mobility. Massed-practice of the impaired hand is thought to facilitate use-dependent neuroplasticity and promote functional recovery of hand use. However, solely relying on the conventional rehabilitation is not practical to reach the effective intensity of massed-practice because of limited clinic visits due to health care cost, time commitment, travel inconvenience, etc. To overcome the limitation, we have been developing a low-cost home-based therapy system which could deliver and monitor Massed-practice AT Home (MATH) beyond the clinical setting. Our system, consisting of a standard computer, a small hand-held controller, an arm rest, a camera and various video games, capitalizes on cheaper electronics, advanced software programming and using video games as motivators. In this talk, I will share the findings and experience based on our earlier home-based approach and the currently evolved approach. I will also present the preliminary data on how the children responded to our new system. Our system can potentially have great impact on the neurorehabilitation for both children and adults with movement disorders.

Host: Dr. Zhang

Fri, Feb 8

Speaker: Aaron Suminski, Ph.D.

Title:  Somatosensory Responses in the Motor Cortex and their implications for Brain-Machine Interfaces

Abstract: Historically, neurons in the primary motor cortex (MI) have been designated as “upper motor neurons” implying that they are little more than a pool muscle drivers sitting in the brain instead of in the spinal cord. This viewpoint underestimates MI as the exact computational and representational role it plays remains unclear after 50 years of extensive experimental and theoretical study. Moreover, a number of recent studies have documented interesting sensory or sensory-triggered responses in the motor cortex which may require us to revise our understanding of the functional role of the motor cortex.  In this talk, I will present recent experimental evidence demonstrating strong visual and somatosensory influences on the activity of MI neurons and discuss their utility for augmenting brain-machine interface control. 

Host: Dr. Miller

Thur, Jan 24

Speaker: Marije de Bruin, Ph.D.

Title:  Connecting the Dots: Musculoskeletal Adaptation in Cerebral Palsy

Abstract: In our daily life, we constantly and almost unconsciously use our hands during what seem to be uncomplicated tasks: making a sandwich, tying our shoelaces, shaking someone’s hand. It is not until we injure one of our arms, that we realize that tasks that would normally be performed effortless suddenly become very demanding. Patients with hemiplegic cerebral palsy (CP) cope with functional impairment due to movement limitations in one of their arms as a result of pathological motor control. Their inability to extend the wrist and elbow and rotate the forearm hinders them to do things unaffected people perform effortlessly. The impaired range of motion CP patients experience often develops into contractures that further limit functioning of the spastic hand and arm. Understanding why these contractures develop will affect the selection of patients suitable for surgical treatment as well as the choice for specific surgical procedures. In this seminar I will discuss the results of 5 years of research investigating the musculoskeletal adaptations from which movement limitations in CP may originate.

Host: Dr. Murray

Fri, Jan 18

Speaker: Philippe Archambault, Ph.D.

Title:  Use of data logging and virtual reality for the measurement and training of power wheelchair driving skills

Abstract: Power wheelchairs are fundamental as an aid to mobility for individuals with neurological or musculoskeletal impairments. However, both clinicians and users agree that, in general, an insufficient amount of training is provided to new power wheelchair users. I will be discussing two applications of technology aimed at improving the measurement and training of power wheelchair skills. 1) A data logger, with sensors fixed on the wheelchair, was developed in order to characterize wheelchair use both at the ecological (driving in real-life situations) and at the task performance level (joystick control, collision detection). 2) A virtual-reality power wheelchair simulator was designed in order to provide training experience to new users in a variety of situations. It is hoped that improving power wheelchair driving skills in new users will have a positive impact on their social participation.

Host: Dr. Mussa-Ivaldi