Fri, Sept 4
Speaker: Adeline Zbrzeski, PhD
Title: Closed-loop system development for research and rehabilitation devices
Abstract: The development of the future generation of microdevices and implants for rehabilitation requires combining the expertise of both electrical and biomedical engineering. These new systems for rehabilitation require several input sensors to control the rehabilitation support (stimulation of muscle or neural matter, deliver drugs, etc… ). The input data analysis should provide a control in reasonable time, using energy-efficient processing. The future generation of microdevices and implants for rehabilitation should also provide an adaptive control; therefore, the controller requires learning capabilities. Examples of closed-loop development are presented, through three research contexts: closed-loop system to alleviate Parkinson’s disease symptoms, smart prosthesis for upper limb amputees, and ventilation control using diaphragmatic pacing for people with spinal cord injury.
Fri, Aug 28
Speaker: Cindy Chestek, PhD
Title: Towards Restoration of Dexterous Finger Movement Using a Cortical Brain Machine Interface
Abstract: Brain machine interfaces or neural prosthetics have the potential to restore movement to people with paralysis by bridging gaps in the nervous system with an artificial device. Cortical implants can record from hundreds of individual neurons in motor cortex. Machine learning techniques can be used to generate useful control signals from this neural activity. Performance can now surpass typically used EMG control signals for artificial limbs, and animals can control computer cursors with brain activity 80-105% as well as they can with their native hand. One natural next step is to attempt to control more complex movements, such as grasping. We recorded 200 channels of single unit activity in motor cortex while an animal flexed and extended his fingers. There was a significant linear correlation of (rho=0.82) between finger flexion and neural firing rates. There was also substantial information about cutaneous sensation on the fingers in primary motor cortex. Using a classifier, one can determine which of five fingers is being brushed with 68% correct. We have also recently completed a 16 channel miniaturized neural recording device to demonstrate that reduced sampling rates of 2 ksps can achieve the same decoding performance as high bandwidth systems while using 89% less power, using “spiking band” features (Stark and Abeles, 2007). In future studies, to achieve order of magnitude improvements may require an order of magnitude increase in the number of neural units recorded. Towards that end, we have recently assembled 8 um carbon threads into a 3 x 8 array, and implanted 24 fibers into motor cortex at a pitch of 150 um, successfully recording single unit activity. There is a large portion of the paralyzed community whose primary need is for finger and grasp control, which has not previously been demonstrated in a real time experiment. If high perform
Tues, Aug 18
Speaker: Jim Schmiedeler, PhD
Title: Effects of Visual Feedback Manipulations on Lateral Weight Shifting Performance in Human Balance Training
Abstract: Balance disabilities commonly follow stroke. Accordingly, balance is often a significant focus of rehabilitation, particularly in the acute phase, since its restoration can make the critical difference between returning home and remaining in long-term care. The commoditization of accurate force sensing through its incorporation in modern gaming peripherals like the Nintendo Wii Balance Board has dramatically reduced the cost of providing quantitative visual feedback to therapists and patients during balance rehabilitation activities. With the cost barrier to adoption in clinics and even in patient homes dramatically reduced, optimizing visual feedback for balance training is more important than ever. This work has sought to better understand how different types of feedback affect subjects during standing balance activities and how that feedback can be manipulated to improve balance performance. First, the effects of visual feedback type, meaning direct center of pressure (COP) or lateral weight distribution, on both static balance and lateral weight shifting are examined. Lateral weight shifting performance is quantified in terms of shift duration and the strength of shift initiation, which provide complementary information. Second, the effects of filtering the direct COP feedback are investigated. Because of the inherent delay, increased filtering reduces differences between the presented COP and the subject’s center of mass early in the shift when the COP exhibits non-minimum phase behavior, but increases those differences later in the shift. Third, the effects of providing feedback that exaggerates deviations from a standard COP trajectory are examined. This approach was inspired by others’ work in reaching that demonstrated the potential of error augmentation techniques for movement rehabilitation. The present work differs, however, in that the nominal trajectory is a function of time and not exclusively a geometric path. Lastly, implications of each study for clinical practice are considered.
Fri, Aug 14
Speaker: Richard Lieber, PhD
Title: Mechanics and Biology of Skeletal Muscle Injury
Abstract: Forced lengthening of skeletal muscles (i.e., “eccentric contractions”) produce injury and, ultimately, muscle strengthening. Such contractions are common in everyday movements as well as sports activities. Because they are mechanically unique and have dramatic biological consequences, it is becoming increasingly popular to study the mechanics and biology of eccentric contraction-induced muscle injury. Current data suggests that the earliest events associated with injury are mechanical in nature and are based primarily on sarcomere strain. Unique biological events such as expression of genes and cytoskeletal remodeling are especially prevalent after eccentric contraction. Such strain results in relatively rapid breakdown or reorganization of cytoskeletal elements within the muscle cell can causes waves of muscle-specific gene expression. We developed transgenic animal models of muscle injury that mimic the effects seen in humans. In addition, the use of muscles with “knocked out” or modified cytoskeletal proteins give insights into load bearing and transmission in skeletal muscle. Ultimately, an improved understanding of the damage mechanism may improve our ability to provide rehabilitative and strengthening prescriptions that have a rational scientific basis.
Fri, July 31
Speaker: Kathleen Doherty
Title:ClinCard…Agony to Ecstasy
Tue, July 28
Speaker: Sunil Agrawal, PhD
Title: Tethered Pelvic Assist Device (TPAD) and Cable-driven Exoskeletons for Human Movement Training
Abstract: Robotics is emerging as a tool for training of human skills and functional movements. Robotics also provides the tools to probe the human neuromuscular system and to study how the human body would respond to simulated external conditions. While traditional exoskeletons are made of rigid links, our group at Columbia University Robotics and Rehabilitation (ROAR) Laboratory has designed light-weight cable-driven training devices - TPAD for active control of the pelvis, CAREX and C-ALEX for arm and legs, respectively. The talk will describe both the scientific challenges and human experiments conducted with these designs. These experiments were targeted at movement retraining of young healthy adults, fall prevention of the elderly, gait retraining of stroke patients with hemiparesis.
Host: Dr. Zhang
Fri, July 24
Speaker: Chandrasekaran Jayaraman
Title: Shoulder Pain and Manual Wheelchair Propulsion: A New Window into an Old Problem
Abstract: There are an estimated 2 million manual wheelchair users in the United States. Manual wheelchair users use their upper limbs for mobility and most day-to-day functional activities. Unfortunately, the human upper limb is not specialized for the repetitive loading required for wheelchair propulsion. This requirement predisposes manual wheelchair users for upper limb pathology. Indeed, up to 70% of manual wheelchair users report upper limb pain which is mainly manifested in the shoulder and wrist. Upper limb pain in wheelchair users is linked to difficulty performing activities of daily living (ADL), decreased physical activity and decreased quality of life. While research in this area have seen major advances in understanding wheelchair propulsion biomechanics and related rehabilitation practices, there are two main limitations, (1) there is limited information on biomarkers that relate wheelchair propulsion biomechanics and shoulder pain, and (2) absence of affordable technology to provide access to wheelchair propulsion training and feedback outside specialized research laboratory/clinical settings (i.e. home based).
In this talk I will focus on our recent research results which provide novel information about biomarkers relating shoulder pain and wheelchair propulsion. First I will present some of our recently published results which adopted approaches from human motor control theory to identify biomarkers that relate shoulder pain and manual wheelchair propulsion biomechanics. Building on these results, the second half of the talk will begin with a brief review of currently available technologies for clinical evaluation of manual wheelchair propulsion biomechanics, their limitations, and discuss preliminary data from a novel wearable device that has been developed for manual wheelchair users as a part of my doctoral research. This wearable technology enables users to self-monitor their day-to-day wheelchair propulsion activity through their mobile devices (via wireless integration of wearable sensor data). The goal of this technology is to increase user’s awareness on the repetitive usage of their arm and wheelchair propulsion metrics to minimize injury. Integration of such technology and novel research information into rehabilitation practices and home-based healthcare may pave the way for new interventions for tracking, treating, and/or preventing shoulder related overuse pathologies in the manual wheelchair population. I will conclude this talk with my future research goals, broader implication of these goals and areas of interest with ongoing research at the Center for Bionic Medicine -Rehabilitation Institute of Chicago.
Host: Arun Jayaraman
Tue, July 21
Speaker: Eric Sohn, PhD
Title: Understanding the pathology of dystonia by hardware emulation
Abstract: Movement disorders are neurological conditions that negatively affect speed, fluency, quality, and ease of movement arising from dynamical interactions among neural circuits and musculoskeletal structures. In this regard, investigating the neurological underpinning of the movement disorder is desirable despite the limitation posed by human studies due to practical and ethical reasons. The current emulation study is one of the alternative responses to overcome the limitations by utilizing a quantitative model that predicts how a disease process that affects the function of neurons causes specific abnormalities on neurological examination. We designed a platform with digital VLSI hardware for multi-scale hyper-time emulations of human motor nervous systems. The platform is constructed on a scalable, distributed array of Field Programmable Gate Array (FPGA) devices, which provides a unique benefit of accelerated emulation of a neurological system under tested circumstances. Using the platform, the first study proposes two plausible neurological mechanisms that lead to some of the known behavioral characteristics of dystonia. The emulation includes a joint with two Hill-type muscles, realistic muscle spindles, 2,304 Izhikevich-type spiking neurons, and physiologically realistic conduction delays. The second study investigates the general mechanism of constraint-induced therapy, a popular rehabilitative method in impaired biological systems, in a simplified two-layer neural structure with spike-based plasticity mechanism. Although our models are highly simplified and limited representation of sensorimotor nervous system, it helps us to find a sufficient mechanism that causes many features of movement disorders including dystonia, and the models also offer an explanation of how constraint as an intervention can help the biological system to escape from the suboptimal solution. These studies are part of the multi-year project conducted in Sanger Lab (www.sangerlab.net) of University of Southern California.
Fri, July 17 / Magnuson
Speaker: Adrian Owen, PhD
Title: When Thoughts Become Actions: Detecting Awareness in the Vegetative State
Abstract: In recent years, rapid technological developments in the field of neuroimaging have provided new methods for revealing thoughts, actions and intentions based solely on the pattern of activity that is observed in the brain. These methods are now being employed routinely to assess residual cognition, detect consciousness and even to communicate with some behaviourally non-responsive patients who clinically appear to be comatose or in a vegetative state. In this talk, I will compare those circumstances in which data from fMRI and EEG can be used to infer consciousness in the absence of a behavioural response with those circumstances in which it cannot. This distinction is fundamental for understanding and interpreting patterns of brain activity in various states of consciousness (including anaesthesia), and has profound implications for clinical care, diagnosis, prognosis and medical-legal decision-making after severe brain injury. It also sheds light on more basic scientific questions about how consciousness is measured and the neural representation of our own thoughts and intentions.
Fri July 10
Speaker: David Zembower, PhD and Tom Ferrone
Title: The Potential and Pitfalls of Collaboration. How to Protect Your Ideas When Working With Outside Companies
Abstract: Collaboration is a cornerstone of academic research. Working with collaborators at other academic institutions and researchers at commercial companies gives you access to new ideas, new technologies, and tools and infrastructure that help expand the scope and sophistication of your research. Our research reaches its full potential when it becomes a marketable product that’s available to help our patients in their daily lives. However, when your new product reaches the point of commercialization, who owns it? Did your collaborator at the other academic institution make a significant inventive contribution? Does the commercial company you worked with believe they own the invention? Is your invention patentable if you talked about it at a conference back in 2013? In this presentation we’ll discuss common mistakes that people make when disclosing their research ideas to people outside RIC, and present easy steps you can take to ensure your ideas and inventions were protected when it comes time go down that exciting path to commercialization.
Tue July 7
Speaker: Jiri Najemnik, PhD
Host: Dr. Kording
Mon July 6
Speaker: Steven Prawer, PhD
Title: Diamond and Carbon Based Bionics (The Diamond Bionic Eye)
Abstract: Diamond, nanodiamond, graphene and other carbon allotropes are emerging as a new class of materials with superior properties for use in bionics. In particular, these materials display excellent charge injection and recording properties making them particularly suitable for use as electrodes in brain-machine interfaces. In addition, diamond based materials have been shown to provide an outstanding, long-lasting hermetic encapsulation for sensitive electronic components implanted into the body.
Taking advantage of these properties has required the development of a suite of fabrication and characterization tools specifically designed to make devices from these materials. Many of the attractive properties such as chemical stability and extreme hardness (for diamond) mitigate against the use of more standard fabrication techniques used for silicon and other semiconductors. In this talk I will review the tool-box that we have developed to fabricate diamond based, high-density, hermetic electrode arrays, specifically for use in a high acuity retinal implant designed to restore vision to patients suffering from retinitis pigmentosa and macular degeneration. I will also review our progress in methods for making flexible electrodes based on graphene ‘ropes’ and solving the problem of how to insert these flexible electrodes into neural tissue. Looking towards the future, we envisage carbon allotropes as being the basis on which to build the next generation of brain-machine interfaces, which could not only provide unprecedented new insights into brain function, but also allow for the treatment of diseases such as epilepsy, chronic pain, Parkinson’s, and drug resistant depression, and the neural control of prosthesis for severely disabled.
Fri June 26
Speaker: Pyung Chang, PhD
Title: Robotic Rehabilitation Through the Control of Mechanical Impedance
Abstract: Robotics has been emerging as a promising tool for the diagnosis and therapy of human limb dysfunction and a key factor of robotic rehabilitation is the respective mechanical impedance of robot and human. In this talk, we will describe how robust control of robot impedance benefits rehabilitation of human limbs. To this end we will introduce a robust impedance control along with its application to the control of bimanual asymmetric tasks based on Guiard’s three principles. Then we will present how this control enables an accurate stochastic estimation of human wrists and arms. We will also show an active impedance control for both passive training and active training of human hands. Finally we will introduce our ongoing research at DGIST on robotic rehabilitation based on brain plasticity.
Tue June 23
Speaker: Gavin Buckingham
Title: Errors, Expectations, Perception, and Action
Abstract: In most circumstances, individuals are able to make relatively accurate predictions about how heavy an object will be, even if they have never lifted it before. These expectations of how heavy an object is are likely to have dramatic effects on both how the object is lifted and how heavy it feels to the lifter. In the context of weight illusions, I will first outline experiments showing how lifters' expectations of heaviness can reliably and persistently affect our perception of how heavy an object feels, and how they are distinct from the processes which allow us to rapidly adapt our fingertip forces to an object's veridical mass. Finally, I will describe experiments showing how observation of sensorimotor errors can supplement normal motor learning processes in experimental object lifting tasks and virtual reality surgical training.
Host: Daniel Wood
Fri June 19
Speaker: Leticia Vega
Title: Nitro Study Tracker (formerly eNOTIS) Basics & Features Session
NITRO Study Tracker
1.) FSM Participant Tracking Policy
2.) Document Storage
3.) Data Capture
4.) Scheduling & Calendar
5.) NITRO Recruit Tool
6.) NM Budget Highlights
Fri June 12
Speaker: Sandro Mussa-Ivaldi, PhD
Title: Human-Machine Interfaces: Brain and Body
Abstract: Since the beginning of the millennium (and well before then) the fancy of lay people, writers and scientists has been captured by the dream of extracting human intentions from neural activities and translating these in commands to robots and other devices. The frontier in brain-machine interfaces now is the establishment of adaptive bi-directional, closed loop interactions between neural and artificial systems, where decoding motor intention is coupled with encoding the state of the external system in patters of stimuli, as a form of artificial proprioception. The promise that so much fascinates the media is the possibility of "controlling by thought." But is this a biologically and clinically meaningful goal?
We will present a different perspective, where the external devices are controlled not directly by brain activities but by overt motions of the body. In this body/machine interface paradigm many of the encoding/decoding issues are identical to those encountered in the brain/machine communication. But the body-machine interface aims not only at controlling devices, but also at empowering paralyzed people to use their intact body skills, at recovering lost mobility and at developing new forms of motor dexterity. We will offer an overview of four key challenges in the current development of human-machine interfaces based on the reorganization of body motions that remain available to their paralyzed users.
Fri June 5
Speaker: Konrad Kording, PhD
Title: Motor cortex is pretty complicated
Abstract: I will review joint research with the Miller lab where we ask how uncertainty and reward affect motor cortices. Both have interesting effects on neural activity. I will also discuss the implications for the way I think about models.
Mon June 1
Speaker: Lorenzo Masia, PhD
Title: Robot Aided Rehabilitation for Proprioception and Design of an Assistive Upper Limb Exosuit
Abstract: Human Machine Interaction (HMI) has advanced the range of possibilities in manipulation tasks, providing additional empowering instruments for a wide spectrum of novel applications from Ergonomics (remotely operated systems or minimally invasive surgery MIS) to Clinical Rehabilitation (Robot Aided Rehabilitation).
After a short introduction on broadly used control schemes in HMI, I will briefly discuss the robotic solutions designed and developed in my previous experiences: driving through experiments for characterization of residual motor functions in stroke patients to better address rehabilitation strategies by using opportunely designed haptic devices. A special emphasis will be dedicated to proprioceptive impairment: loss of proprioception is likely to affect in a significant manner the capacity of stroke patients to recover functionality of the upper limb; clinical assessment methods currently in use are rather crude, with a low level of reliability and a limited capacity to discriminate the relevant features of the deficits. I will illustrate a new technique based on robotic technology, with the goal of providing a reliable, accurate, and quantitative evaluation of kinesthetic acuity which can be integrated in rehabilitation protocols.
The second part of the presentation will be on a new concept for actuation that combines an elastically compliant composite structure with conventional electromechanical elements. The proposed design is analogous to that used in Series Elastic Actuators, but with a distinctive feature in the compliant transmission which can provide different stable configurations. In other words, its elastic potential presents points of local minima that correspond to robust stable positions (multistability). This potential is known a priori as a function of the structural geometry, thus providing tremendous benefits in terms of control implementation. Such knowledge enables to overcome the complexities arising from the additional degrees of freedom associated with link deformations and uncovers challenges that go beyond those posed by standard rigid-link robot dynamics. It is thought that integrating a multistable elastic element in a robotic transmission can open new scenarios in the field of assistive robotics, as the system may help a subject to stand or carry a load without the need for an active control effort by the actuators: this new approach has the potential to provide tremendous benefits in terms of control implementation, enabling to overcome the complexities arising from the additional degrees of freedom associated with link deformations and uncovering challenges that go beyond those posed by standard rigid-link robot dynamics in assistive technology.
Hosts: Drs. Patton and Mussa-Ivaldi
Fri May 29
Speaker: Kathryn Nightingale, PhD
Title: Ultrasonic Elasticity Imaging with Acoustic Radiation Force
Abstract: Acoustic radiation force based ultrasonic elasticity imaging methods have become widely available in the clinical market over the past five years. To date, these methods have found success clinically in the context of hepatic fibrosis staging and breast lesion characterization, with many additional applications under investigation. Implementations are available that provide high resolution images of relative differences in tissue stiffness, as well as shearwave based approaches that provide quantitative estimates of the tissue stiffness. The quantitative methods assume that the tissues are linear, isotropic, elastic, homogeneous, and incompressible in order to reconstruct the underlying material stiffness. Our recent work in shear wave imaging focuses on understanding the sources of error in these systems, and developing methods that address some of the underlying assumptions, i.e. using 3D volumetric imaging to analyze material anisotropy and dispersion analyses to assess material viscoelasticity. In this talk, I will review the underlying physics of these tools and discuss the promise and limitations of these methods, and present examples of clinical applications.
Host: Dr. Rymer
Tue May 19
Speaker: Ravneet S Vohra, PT, PhD
Abstract: With a number of potential therapeutic interventions for Duchenne muscular dystrophy (DMD) under development, and some already in clinical trials, there is a need for non-invasive biomarkers. Recently, there has been increasing interest in non-invasive imaging modalities, particularly MRI, for diagnosis and assessment of disease progression for a number of neuromuscular diseases, including DMD. Indeed several MR investigations of dystrophic muscle have shown promise in monitoring disease progression in skeletal and cardiac muscle. In this talk, I will provide an overview of different MR imaging techniques to monitor the disease progression in skeletal muscles of human and animal models of DMD.
Host: Dr. Jayaraman
Fri May 15
Speaker: Claire Chambers
Title: Context effects in the perception of frequency shift
Abstract: A new experimental paradigm is presented for studying how recent sensory history (the context) affects a basic aspect of auditory perception, the comparison of successive frequency components. Stimuli were devised to include ambiguous transitions between frequency components, as it was hypothesized that such an ambiguity would make the task especially prone to reveal context effects. Using pairs of Shepard tones (Shepard, J. Acoust. Soc. Am., 1964), we show that frequency shifts are preferentially reported when they encompass a frequency regions that was stimulated during the context. This context effect is rapidly introduced, as a single tone as short as 20ms can produce a reliable bias. Yet it also has an enduring effect on perception, persisting over more than 30s. Using random chords pairs designed to include ambiguous frequency shifts, it then shown that the context effect is not specific to Shepard tones but rather reflects a generic process acting on the tonotopic representation of sounds. In a final experiment, we show that the context effect is modulated by both low-level (ear-of-entry) and high-level (selective attention) manipulations, suggesting an interplay between several processing stages in the underlying neural mechanism. Finally, we use a probabilistic perceptual model based on the notion of auditory grouping to account for our psychophysical results. Our findings show that one of the most ubiquitous and basic tasks of the auditory system, comparing successive frequency components, is not a fixed function of the physical stimulus. Rather, it is highly malleable and depends on the ongoing context.
Host: Dr. Kording
Speaker: Meena AbdelMaseeh
Title: New Approaches for the Analysis of Electromyographic Signals for Characterizing Neuromuscular Disorders and Myoelectric Control
Abstract: The focus of the first part of the talk is the use of intramuscular electromyographic (EMG) signals for assessing the neurophysiologic characteristics of neuromuscular disorders. The evaluation of patients with suspected neuromuscular disorders is typically based on qualitative visual and auditory assessment of needle electrode detected EMG signals; the resulting muscle characterization is subjective and highly dependent on the skill and experience of the examiner. Quantitative EMG techniques have been developed to identify motor unit potential trains (MUPTs) in EMG signals, and extract quantitative features capturing motor unit potential (MUP) morphology, morphological instability across MUPs of the same MUPT, and motor unit activation levels.
Following a brief introduction to the basic concepts of the decomposition-based quantitative EMG techniques, I will present new clinically useful representations and quantitative features that can be interpreted from an anatomical, physiological and pathological basis. I will then introduce a muscle categorization algorithm capable of estimating the likelihood of a muscle being affected with a specific disorder and inducing transparency rules integratable in the clinical assessment. The direct implication of these improvements is to increase the diagnostic power of quantitative EMG techniques. The availability of representations, quantitative features, and muscle categorizations that can be automatically obtained will motivate further utilization of quantitative EMG techniques for neuromuscular disorders assessment and other specialties such as senior care, rehabilitation, sport medicine, and pain management.
In the second part of the talk, I will describe a system for hand movement recognition using multi-channel EMG signals obtained from the forearm surface. In particular, methods for the extraction of activation trajectories underlying hand movements, and classifying the extracted trajectories using a metric based on multi-dimensional dynamic time warping will be discussed.
Host: Dr. Hargrove
Fri May 8
Speaker: Gerald E. Loeb, MD
Title: Biomimetic Machine Touch for Dexterous Robotic and Prosthetic Hands
Abstract: Machine vision has been applied successfully to industrial robots. Commercially available CCD video cameras capture images of objects being manipulated and computer algorithms extract information to make decisions about their handling. Is this a model for haptically enabled robots? No. Haptics is essentially collision management. No matter what tactile sensing modality is employed, the events that will be sensed depend on the mechanical properties of the appendage that contains the sensors and on the active movement that causes the collisions with an object. Humanlike dexterity is often seen as a desirable and challenging goal for haptic robots, so it seems reasonable to understand and perhaps to imitate those properties and movements. Key mechanical properties of glabrous fingertips include highly elastic and compliant skin that is deformed by mechanical interactions with objects. A flat region on the underlying bone called an apical tuft provides the equivalent of a vernier amplifier for tiny tilt angles. Fingerprint ridges convert simple sliding movements into coherent amplification of induced vibrations. Heating the fingertip above ambient results in thermal gradients indicative of the material properties of objects. All other surfaces of human limbs are covered by hairy skin, which provides highly sensitive contact detection to trigger evasive action and a tough surface that can absorb kinetic energy until such action takes effect. Dexterity also depends as much on speedy responses as on sophisticated signal processing, so humans rely first on simple, short-latency reflexes mediated by spinal cord rather than conscious perception by the distant brain. Conscious perception in the brain requires an iterative series of decisions about what exploratory movement will most likely resolve whatever uncertainty the human operator has about an object, based on prior experience and unfolding events. We have built robotic machines with tactile sensors, reflexive feedback and exploratory algorithms that mimic most of these human strategies and thereby achieve at least a modicum of humanlike haptic function. Much remains to be done but at least we are finally on the right track.
Host: Dr. Mussa-Ivaldi
Fri May 1
Speaker: Dominique Duncan, PhD
Title: Nonlinear Factor Analysis in Neurological Applications
Abstract: A novel approach to describe the variability of the statistics of intracranial EEG (icEEG) data is proposed that is an adaptation of the diffusion map framework. Diffusion maps, which extend principal components analysis and provide a nonlinear approach, provide dimensionality reduction of the data as well as pattern recognition that can be used to distinguish different states of a patient, for example, interictal and preseizure states. A new algorithm, which is an extension of diffusion maps, is developed to construct coordinates that generate efficient geometric representations of the complex structures in the icEEG data. Numerical results show that the proposed approach provides a distinction between interictal and preseizure states.
Furthermore, the algorithm is also applied to classify magnetic resonance images (MRI) of brains of patients with Alzheimer's Disease and those without Alzheimer's Disease. The method is adapted to the MRI and accounts for the variability in calibration of the MRI of different patients.
Additionally, the icEEG data of the epilepsy patients are used to test the existence of a relationship between distant parts of the default mode network (DMN), a resting state network defined by fMRI studies. Magnitude squared coherence, mutual information, cross-approximate entropy, and the coherence of the gamma power time-series were estimated, for one hour icEEG recordings of background activity from 9 patients, to evaluate the relationship between two test areas. These two test areas were within the DMN (anterior cingulate and orbital frontal, denoted as T1 and posterior cingulate and mesial parietal, denoted as T2), and one control area (denoted as C) was outside the DMN. The goal was to test if the relationship between T1 and T2 was stronger than the relationship between each of these areas and C. A low level of relationship was observed among the 3 areas tested. The relationships among T1, T2, and C did not demonstrate support for the DMN. The results obtained underscore the considerable difference between electrophysiological and hemodynamic measurements of brain activity and possibly suggest a lack of neuronal involvement in the DMN.
Host: Dr. Körding
Fri April 17
Speaker: Todd Kuiken, MD, PhD
Title: New Concepts for Attaching Prostheses to People
Abstract: The most challenging and important part of any prosthesis is how you attract the device to the person. The residual limbs of people with amputations have a nice rigid long bone, that is covered with multiple layers of compliant tissue. At the CBM we have been working on improving this human machine interface in many ways. Dr Kuiken will show preliminary work and early concepts on 4 different approaches to improving this interface.
Fri April 10
Speaker: Diane L. Damiano, PhD PT
Title: Activity-based neurorehabilitation for cerebral palsy: How well are we doing?
Abstract: This presentation will discuss the effectiveness of current activity-based neurorehabilitation strategies primarily aimed at improving mobility in children withcerebral palsy. It is now well-recognized that motor activity (or lack thereof) drives both muscle and brain plasticity. Intense motor training paradigms utilizing various types of devices have become increasingly common in CP rehabilitation with outcomes not always as anticipated. Emerging principles on the types, amounts and timing of activity that may best promote these processes will be discussed with respect to existing and novel strategies. Developmental and individual genetic factors and how these may affect responsiveness to motor training in CP will also be considered.
Host: Drs. Gaebler & Zhang
Fri April 3
Speaker: Alex Leow, PhD
Title: Multi-modal Connectomics of the Human Brain
Abstract: In this talk, I will provide an overview of multi-modal brain connectomics as a rapidly evolving field in computational neuroimaging. Using structural brain connectome as an example, we will first look at diffusion-weighted MR imaging developed in order to better understand the micro-architecture of white matter. Next, we will examine related techniques including diffusion tensor imaging (DTI), high angular resolution diffusion imaging (HARDI) and diffusion spectrum imaging (DSI). These techniques naturally lead to white matter tractography, based on which structural brain networks or “connectomes” can be built. This paves the way for the application of graph theory to probe the organizational properties of the human brain modelled as a graph. Most recent developments by our own group to investigate and further explore the translational implications of connectomics will be discussed. Case study topics may include the digital clock drawing test and virtual-reality connectome visualization.
Host: Dr. Patton
Tue March 31
Speaker: Michelle Ferrill
Title: Sentence Processing in Aphasia: Contributions of Word Level Deficits
Abstract: Although listeners rarely have difficulty understanding spoken language, the intricate complexity of language comprehension becomes all too obvious after an individual suffers neural trauma that results in aphasia. Individuals with one type of aphasia in particular, agrammatic Broca’s aphasia, have generally spared comprehension of sentences that follow the most common (canonical) word order in a language, but comprehension becomes impaired when sentences deviate from that order (e.g., Caramazza & Zurif, 1976; Grodzinsky, 2000; and many others). Revealing the underlying basis for this comprehension disorder would shed light on brain-language relations and would also allow for more effective treatment approaches. One hypothesis that has been supported by recent research implicates delayed lexical access during sentence comprehension (Love, Swinney, Walenski, & Shapiro, 2008; Ferrill, Love, Walenski, & Shapiro, 2012; see also Thompson & Choy, 2009). Our work suggests that this lexical access delay affects syntactic processes and thus contributes to the sentence comprehension deficits observe in this population. This talk will present findings from three studies: (1) a study which evaluated the time-course of lexical access during sentence processing in Broca’s aphasia via a method that measures real-time processing, that is, processing that is occurring as the sentence is ongoing; (2) a study that examined the relationship between these real-time lexical access patterns and patterns of brain damage in areas of the brain that have been linked to language; as well as (3) a study that attempted to exploit anticipatory processing cues to mitigate the lexical processing delay. Finally, a treatment study will be proposed that attempts to capitalize on sensitivity to certain types of processing cues in the listeners with Broca’s aphasia who have a comprehension disorder.
Host: Dr. Cherney
Fri March 20
Speaker: William S. Evans, MS, CCC-SLP
Title: Cognitive Control and Task Effects in Aphasia
Abstract: Executive control, attention, and language impairments often co-occur following stroke, and this observation has led to an increasing interest in the role of control processes in aphasia. This talk will present parts of my doctoral work, which explores relationships between cognitive control, task goals, and automatic linguistic processes in the post-stoke aphasia population. Results will be interpreted using the Ratcliff Diffusion Model, a classic forced-choice decision model that incorporates both accuracy and reaction time data to derive underlying parameters claimed to drive the decision process. Potential implications for aphasia rehabilitation will be discussed.
Host: Dr. Cherney
Fri March 13
Speaker: Luca Lonini, PhD
Title: Wearable sensors and machine learning: using novel outcome tools in rehabilitation
Abstract: The use of wearable sensors as a tool for continuous health monitoring is gaining interest due to their low cost and increasing memory storage and computing power. Machine learning algorithms are often used in this context to infer relevant information from the sensors data and inform clinicians on patients’ outcomes.
In this talk I will present two applications exploiting the synergy of these fields in physical rehabilitation: the first consists of measuring walking quality in spinal cord injury patients’ who are trained to use a robotic exoskeleton to walk; the second case is a comparative study of the effect of a computerized leg brace (C-brace) vs. a traditional stance-control orthoisis (SCO) on patients’ everyday activities.
Fri March 6
Speakers: Jessica Crujeiras, Nathalia Headley and Andy Kondrat
Title: Informed Consent in Research at RIC: Policy, Compliance, and Ethics
Fri Feb 27
Speaker: Katharine Polasek, PhD
Title: Referred Sensation from Surface Electrical Stimulation as a Potential Treatment for Phantom Limb Pain
Abstract: Phantom limb pain adversely affects a majority of amputees and most treatment options are unsatisfactory. The long term goal of this research is to develop a non-invasive therapy to treat phantom limb pain in individuals with amputations. This therapy will be based on the theory that a major contributor to phantom limb pain is lack of input from the missing limb. Our hypothesis is that sensation from the missing limb paired with appropriate visual feedback will lead to an overall decrease in painful sensations. Prior to testing in amputees, we needed to show that we could reliably evoke distal referred sensation through proximal stimulation. I will first talk about our testing on individuals with intact-limbs where we have been able to reliably evoke a tapping sensation in the hand or foot though surface electrical stimulation at the elbow or knee. At times we have evoked sensations in different hand locations but this has been more difficult to reproduce. To investigate what we are actually activating and see if we can determine a method to reliably produce sensations in different location we developed a computer model of surface electrical stimulation. This model will be used to predict the effect of electrode location, size and configuration on which part of the nerve is activated and help design an electrode configuration that can be adjusted to activate distinct distal locations. Future work will include using the rubber hand illusion to quantify the reality of the evoked sensations and experiments with individuals with amputations to evaluate the decrease in phantom limb pain due to periodic restoration of sensation.
Host: Carrie Peterson
Fri Feb 13
Speaker: Jinsung Wang, PhD
Title: Generalization of sensorimotor adaptation across different motor effectors
Abstract: Motor learning can generalize across different motor effectors. However, the extent of generalization across different effectors is typically smaller than the extent of generalization observed across different movement conditions within the same effector. While generalization of motor learning has been studied extensively, it remains unclear why generalization across different effectors is limited. Findings from our recent studies suggest that motor learning may involve two types of learning mechanisms: algorithmic learning, which is analogous to model-based learning, and instance-reliant learning, which is analogous to model-free learning. Based on the idea of instance-reliant learning, we attempt to explain why generalization of motor learning across motor effectors is limited, and also to demonstrate that providing effector-specific instances can increase the extent of interlimb generalization substantially.
Host: Dr. Patton
Fri Feb 6
Speaker: Lois Shepherd, JD
Title: Recent research ethics controversies and what they mean for comparative effectiveness (“outcomes”) research
Abstract: If a parent is asked to enroll her pre-mature infant in a study comparing different amounts of supplemental oxygen, what should she be told? In the controversial SUPPORT Trial, conducted from 2005-2009, investigators sought to determine the best oxygen saturation levels for infants in terms of reducing risks for eye disease, neurological injury, and death. The parents were told there was no predictable increase in risk from participation in the study because both oxygen levels targeted in the study were within the “standard of care.” Was this disclosure adequate? Was it accurate? These questions have split the bioethics community to an unprecedented degree. This session will discuss the SUPPORT Trial, basic principles of research ethics, and where research regulation is headed in relation to comparative effectiveness research.
Host: Max Shepherd
Tue Feb 3
Speaker: Amy Orsborn, PhD
Title: Designing neuroprostheses in closed-loop
Abstract: The ultimate goal for motor neuroprostheses is to provide high performance that can be maintained for long-term use in the varied activities of daily life. Leveraging the closed-loop, co-adaptive nature of neuroprostheses may be particularly beneficial for meeting these challenges. Neuroprostheses create artificial, closed-loop control systems where the subject can actively contribute to performance via learning. In this talk, I will discuss design strategies and research motivated by this closed-loop perspective. My work focuses on non-human primate models, where subjects control virtual objects using neural activity recorded from arrays implanted in motor cortex. I will first discuss closed-loop decoder adaptation (CLDA), which adapts the decoding algorithm as the user controls the prosthetic to improve performance. I will then show that CLDA can be combined with neural adaptation, and that incorporating both forms of adaptation may be useful for producing long-lasting flexible devices. I will also discuss new work exploring the potential importance of signal selection for neuroprosthetic performance. I will present a new method to simultaneously record neural activity across multiple spatial scales (electrocorticography, local field potentials, and action potentials). This method, combined with peripheral recordings like electromyography, will allow us to optimize signal selection for high-performance neuroprostheses.
Host: Dr. Miller
Fri. Jan 30
Speakers: Reva Johnson and Lauren Smith
Title 1: Sensorimotor Adaptation with Powered Upper-Limb Prosthesis Control
Abstract: Powered upper limb prostheses offer hope in restoring the abilities lost to amputation; however, the current lack of kinesthetic feedback requires users to devote constant visual attention. Providing additional sensory feedback is an intuitive solution, and many groups are working towards clinical implementation. However, we do not understand how amputees rely on sensory feedback during movements with a prosthesis, and how this use of feedback differs from movements with intact limbs. To help answer these questions, we studied how amputees and able-bodied subjects relied on feedback during trial-by-trial adaptation using different control signals: joint angle, joint torque, and EMG. Our results suggest that adaptation was not significantly affected by control signal or limb used, but depended primarily on mean error. Thus we can apply models of sensorimotor adaptation to powered prosthesis control and use them to clarify the most effective sensory feedback information.
Title 2: Intramuscular EMG for the Simultaneous Control of Multiple Degrees of Freedom in Upper-Limb Myoelectric Prostheses
Abstract: Clinically available myoelectric prostheses use surface EMG signals to control prosthetic joint movement, and have limited ability to provide simultaneous control of multiple degrees of freedom (DOFs). Instead, most patients are required to operate each DOF sequentially, unlike the coordinated multi-joint movements produced by intact limbs. Recent advances in implantable EMG recording devices have the potential to provide intramuscular EMG signals for clinical applications, which may allow for the use of simultaneous control approaches that have not been successfully implemented using surface EMG. Using fine wire EMG recordings from the forearm, we investigated the potential for using intramuscular EMG for the simultaneous control of a three-DOF wrist/hand system. We evaluated different methods for predicting intended wrist/hand movement from intramuscular EMG, how subjects used the simultaneous myoelectric control in a virtual task, and the potential for providing improved controllability compared to sequential control methods.
Fri Jan 23
Speaker: Tommaso Lenzi, PhD
Title: User-Adaptive Control of Powered Transfemoral Prostheses: Leveraging Robotics to Meet the Clinical Needs of the Amputee Population
Abstract: Robotic leg prostheses can actively regulate joint torque to emulate the full biomechanical functionality of the healthy limb, possibly restoring physiological gait efficiency and stability. However, proper emulation of the healthy limb depends on how well the prosthesis controller synchronizes the movement of the leg with the movement of the user. To this end, available control strategies rely on experimental, user-specific tuning that optimizes the leg behavior for the user’s preferred speed and cadence. Outside the tuned speed and cadence the prosthesis does not properly synchronize with the movement of the user, thus impairing walking ability. In addition, the tuning process is time consuming and requires expertise in robotics, which considerably limits the clinical viability of powered robotic legs. We have developed a new controller that automatically adapts to the user’s speed and cadence, providing physiological gait symmetry and joint energetics without need for tuning. The talk will describe the design, implementation, and preliminary validation of the new controller on transfemoral amputee patients.
Tue Jan 6
Speaker: Mingbo Cai
Title: Time perception - impact of expectation and duration cue combination
Abstract: Our perception of duration can be biased by many factors, including both stimulus history and stimulus properties. In this talk, I am going to present results from psychophysical experiments and modeling work to answer two questions: (1) is the influence of stimulus history on perceived duration due to the expectation of a stimulus or purely because of stimulus repetition? (2) How does the brain form a representation of duration when simultaneously presented stimuli provide conflicting cues of duration?
Host: Dr. Kording