Engineering for Neurologic Rehabilitation Program (ENRP)

ENRP at the Sensory Motor Performance Program (SMPP) of the Rehabilitation Institute of Chicago (RIC) is funded by a Medical Rehabilitation Infrastructure Award from the National Institute of Child Health and Human Development through the National Center for Medical Rehabilitation Research. Our program is part of a national network of research cores that provide access to collateral expertise, and focuses on access to neuroscience and engineering resources to augment rehabilitation research in the USA. Specifically, we focus on the application of neural engineering and robotic techniques to understand, diagnose, and treat neurologic disorders.

This program is built upon core facilities established in our center under the auspices of a previously funded R24 network grant  (Restoration of Function in Neurologic Impairment).

Researchers funded by the ENRP combine the design and problem-solving skills learned in engineering with medical and biological science to identify new avenues of investigation.  Specifically, researchers in SMPP and their collaborators are combining bioinformatics, medical imaging, physiological signal processing, biomechanics and biomaterials to investigate rehabilitation themes, and to train and nurture the development of investigators who plan to use such engineering applications to study neurologic disorders.

ENRP Cores

  1. The Robotics/Mechanics Core
  2. The Information Technology Core
  3. The Neuroscience Core

Current Collaborative Projects:

Sunil Agrawal, PhD , Steven Cramer, MD, Randy Powers PhD, Brian Schmit, PhD and Ying Wu, PhD have all joined with SMPP under the ENRP to form and expand our national network of researchers engineering solutions in neurologic rehabilitation for the temporary and permanently disabled.

1.     Sunil Agrawal, PhD    at the University of Delaware 

Support from this award mechanism has resulted in foundational work on the design of gait rehabilitation exoskeletons and preliminary subject training. Dr. Agrawal has developed a swing-assist passive exoskeleton with the Robotics/Mechanics core of the ENRP. This work is providing new pathways and insights into future studies.  Another device, the Gravity Balancing Orthosis (GBO) has also undergone evaluation.  The results from these studies show a spectacular improvement in the range of motion of the joints, symmetry of the gait, weight bearing on the affected leg of a stroke victim, see figure below.

Related Publications and/or Presentations:

  • S. K. Agrawal, S. Banala, A. Fattah, V. Sangwan, V. Krishnamoorthy, J. P. Scholz, W. L. Hsu, Assessment of Motion of a Swing Leg and Gait Rehabilitation with a Gravity Balancing Exoskeleton ,  IEEE Trans. on Neural Systems and Rehabilitation Engineering, Vol. 15, No. 3, 2007, 410-420).
  • Kalyan Mankala, S. K. Agrawal, “Passive Swing Assistive Exoskeletons for Motor-Incomplete Spinal Cord Injury Patients”, In Proceedings IEEE International Conference on Robotics and Automation, Rome, April 2007.

Resulting Grant Submissions:

  • Development and Evaluation of an Active Leg Exoskeleton for Gait Retraining after a Stroke, an NIH R01 submitted October 5, 2007.
  • Robotic Exoskeletons, FES, and Biomechanics: Treating Movement Disorder, an NIH R01 grant proposal submitted November 5, 2007.
  • An Upper Extremity Wearable Exoskeleton for Assistance and Training submitted to the National Science Foundation (Research to Aid Disabilities (RAPD) Program)  on September 15, 2007.
      • This research, supported through the ENRP, has enabled new directions of research in design and evaluation of upper and lower arm exoskeletons for training of motor impaired persons with stroke. ENRP has resulted in creation of a network of researchers to facilitate exchange of ideas and the development of next generation cutting-edge tools and methods.
  • 2.     Steven Cramer and his team at the University of California at Irvine
      • Steven Cramer and his team designed a hand-wrist assisting robotic device (HWARD) to help stroke patients improve their grasp and release abilities.  The design follows the neurobiological principles of motor learning – sensorimotor integration, environmental complexity, attention and movement repetition.  With support from the Engineering for Neurologic Rehabilitation Program and collaborative efforts with the Robotics/Mechanics core, Cramer’s group upgraded the HWARD robot including improvements to the user interface, software and clinical program.  There are now two modules, one emphasizing simple motor behaviors associated with primary motor cortex function and one emphasizing complex motor behaviors associated with premotor cortex function.

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    • In this figure, (A) Study design. (B) Subject’s posture, relationship to robot and relationship to computer monitor. (C) A subject’s hand in the robot. Arrowheads indicate the splint upon which the ulnar forearm rested.White asterisks indicate the three straps connecting the hand to the robot. (D) Example of virtual reality game, the ‘jewel match’ game, which required a subject to transfer different-shaped jewels from one rotating wheel to another. As the subject’s hand moved (long arrow), the virtual hand on the computer screen (short arrow) moved, in real time (C. D. Takahashi et al. Brain (2008).

Related Publications and/or Presentations:

  • C.D. Takahashi, L. Dcr-Yeghiaian, V.H. Le, S.C. Cramer, A Robotic Device for Hand Motor Therapy After Stroke, Proceedings of the 2005 IEEE, 9th Int’l Conference on Rehabilitation Robotics, pg 17 -20, June 28-July 1, 2005S.
  • C.D. Takahashi, L. Der-Yeghiaian, V. Le, R. Motiwala, and S. Cramer, Robot-based hand motor therapy after stroke , Brain. (in press).

Resulting Grant Submissions:

  • Over the next 12 months, Dr. Cramer’s group will evaluate the improved both modules in the HWARD in up to 20 with stroke patients to develop pilot data for application of funding from the NIH to study the efficacy of robotic hand rehabilitation for stroke victims.
  • The current project aims to examine how content of robotic therapy might be related to the stroke lesion location.  We expect that this approach will increase the effect size of robotic therapy for motor deficits after stroke.  Such developments are expected to support collaboration and application of robotic therapy nationwide. 

3.    Randy Powers of the University of Washington School of Medicine

  • Randy Rowers is working on a collaborative pilot project to develop and maintain a realistic compartmental model of the motoneuron in order to test hypotheses in the biophysical properties of motoneurons that may contribute to changes in motoneuron behavior following stroke.  Dr Powers and his team have developed a compartmental model that is capable of reproducing a number of features of normal motoneuron behavior and implemented this model using NEURON simulation language. Our hypothesis is that some of the deficits in motoneuron behavior following stroke result from alterations in voltage-sensitive channels mediating persistent inward currents (PICs) carried by sodium (Na) and calcium (Ca) ions. Two drugs that inhibit Na and Ca persistent inward currents are presently in use for therapy in human subjects.  Riluzole, now a standard treatment for ALS that is classically considered to reduce glutamate release, has now been demonstrated to block Na persistent inward currents at low micromolar concentrations. Isradipine, a blood pressure medicine that crosses the blood brain barrier, blocks the Ca persistent inward current at concentrations know to have minimal side effects.  Both of these agents are presently under study by Dr. Rymer and colleagues for control of spasticity in human spinal cord injured patients. A primary advantage of our approach is that we will be able to make accurate predictions of the impact of these agents on firing rate patterns in stroke subjects, thus providing a clear guide for a potentially important and effective therapeutic strategy.
  • Alterations in other intrinsic motoneuron properties may also contribute to the deficits in motor unit behavior in stroke.  One common feature of motor unit discharge in stroke is ‘negative rate modulation’, which is a decline in firing rate of an early recruited motor unit even as the firing rate of other motor units and whole muscle force is increasing. We have recently been able to replicate this behavior in a model by slow activation of a calcium-dependent potassium conductance known to exist on rat motoneuron dendrites. The figure below shows the change in firing rate (red trace) produced in  a motoneuron model by a triangular waveform of net excitatory synaptic conductance (black trace).   The initial, rapid increase in firing rate, which reflects the activation of the Ca PIC on the dendrite, is  followed by a decline in firing rate in spite of the continued increase in net excitation, reflecting outward current flow through calcium-activated potassium channels on the dendrites.  This firing rate profile is similar to that observed in low threshold units in spastic muscles. 

 

 

 

 

 

 

 

 

 

 

This figure illustrates the negative rate modulation in a compartmental motoneuron model.  Instantaneous firing rate (red trace) in response to a slowly increasing then decreasing excitatory synaptic conductance input (black trace).  The initial acceleration of firing rate reflects CaPIC activation, whereas the subsequent decline reflects slow activation of a dendritic calcium-activated potassium conductance.

Related Publications and/or Presentations:

  • The key features and behavior of the model were briefly described in a poster presentation at the 2006 Society for Neuroscience meeting that compared to behavior in the decerebrate cat (Cope et al., 2006).

Resulting Grant Submissions :

  • An NIH R01 submitted June, 2007
  • An NIH R01 submitted July, 2007.
  • 4.    Brian Schmit, PhD  of Marquette University School of Engineering
    • Brian Schmit is completing a longitudinal study of diffusion tensor imaging (DTI) in a rat model of spinal cord injury (SCI) with the Information Technology Core of the ENRP.  To date, Brian and his team have developed a fuzzy inference system for tissue classification in the human spinal cord, characterized DTI parameters in the human spinal cord and DTI imaging of the spinal cord in a rat model of injury and developed imaging sequences for magnetization transfer contrast (MTC) imaging of the spinal cord.  Future directions from these studies include expanding DTI imaging of the injured rat spinal cord.  The proposed study will examine the time-course of changes in diffusion parameters after injury and during healing.  This is part of a long-term plan to predict functional recovery from SCI using DTI measurements.

  • A longitudinal study was conducted using DTI measurements in a contusion model of the rat at the T8 segment.  Six groups of animals were tested (n= 7-12 in each group), including uninjured controls and 2, 5, 15, 20 and 25 weeks post injury.  Ex vivo images, obtained in the upper cervical spinal cord, using a 9.4T small animal MRI indicated substantial decreases in diffusivity distant from the injury, suggesting that DTI is sensitive to edema and other post-injury processes that cannot be detected using standard T2 weighted images (upper row).  Note that the longitudinal apparent diffusion coefficient (lADC) and transverse apparent diffusion coefficient (tADC) both decrease (turn blue), beginning 2 weeks post injury.  The fractional anisotropy (FA) changes only slightly, late in injury.

We are continuing to pursue a number of research directions related to DTI of the spinal cord.  First, we are looking to expand on our initial results in the rat model of SCI that suggest that DTI can be used to detect and monitor detailed characteristics of a spinal injury.  In particular, we are looking to establish the sensitivity of DTI to different severity of injury. 

Our initial work has also suggested that DTI can be used to monitor the progression of the response to injury.  As a result, we are currently preparing a study to monitor DTI of the spinal cord in two clinical conditions:

in acute traumatic SCI to determine whether DTI can be used for prognosis of functional recovery and

in patients with radiculopathy, to aid in prognosis and treatment planning.  A grant proposal for examining the use of DTI for SCI prognosis is currently being prepared.  We are also in the midst of preparing to translate this research to the clinic.  We are working with the Radiology Department at a local hospital in Milwaukee to routinely implement DTI scans in all acute traumatic SCI.  If successful, we anticipate that this technique will achieve widespread use.

Resulting Publications and/or Presentations:

Resulting Grant Submissions:

  • “Diffusion Tensor Imaging of the Injured Spinal Cord” research grant submitted to the VA Merit Review (6-15-06)
  • “Diffusion Tensor Imaging of Spinal Cord Injury”, Pre-Doctoral NRSA, (Benjamin Ellingson) submitted to the NIH (12-5-06)
  • “Diffusion Tensor Imaging in Spinal Cord Injury”, Research Grant submitted to the Craig H. Neilsen Foundation (1-12-07)
  • “RERC in Spinal Cord Injury: Motor Adaptations in Spinal Cord Injury”, RERC (Rehabilitation Engineering Research Center) submitted to NIDRR (3-16-07)
  • “Diffusion Tensor Imaging of the Injured Spinal Cord” research grant submitted to the VA Merit Review (12-15-07)
  • 5.  Ying Wu, PhD  of Northwestern University, Department of Electrical Engineering and Computer Science is  also working with IT core of the ENRP and W. Zev Rymer, PhD, MD  
    • Ying Wu of Northwestern University, Department of Electrical Engineering and Computer Science is also working with IT core of the ENRP and Dr. Rymer on a collaborative pilot project titled, “Vision-based Articulated Finger Motion Analysis for Hand Rehabilitation.”  Thus far, an integrated software platform has been built, a 3-D hand model is in place for rendering, animation and analysis, essential image analysis modules are ready, a new method for estimating the articulation of the hand is being tested using synthesized and real video. We believe vision-based motion analysis can be very useful in rehabilitation in a number of application scenarios. We plan to investigate such additional applications of the developed technology, as well as, the development of new vision-based motion analysis technologies.

Related Publications and/or Presentations:

Vision-based Articulated Finger Motion Analysis for Hand Rehabilitation, IEEE Conf. on Computer Vision and Pattern Recognition (CVPR), 2008

Resulting Grant Submissions:

“Video-based Non-invasive Measurement of Hand Articulation for Rehabilitation,” research grant submitted to National Science Foundation (NSF) RAPD program (2-28-2008)

    • We have been pursuing several new research directions incorporating video-based hand motion estimation and capturing. First, we are currently investigating a novel distributed and collaborative mechanism for estimating articulated hand motion. In this new approach, we have a network of correlated local motion estimators, each of which estimates a subset of the hand articulation. These local estimators are correlated. Through exchanging messages, their collaboration is expected to given computationally efficient solution to the estimation of the hand articulation. Second, we plan to develop a multiple camera system that gives multiple view image observations for motion recovery. Third, we plan to develop a method for tracking the articulated hand motion in continuous video. By taking advantage of the dynamics of the hand articulation, this will allow more accurate and more rapid motion recovery. We are submitting a grant proposal to National Science Foundation. We are currently improving the prototype video-based motion recovery system that we built, and expect more exciting results in real scenarios. We plan to submit a grant proposal to NIH in the near future.
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  • For more information about the ENRP program or to collaborate with members of the ENRP, SMPP or RIC, please contact the faculty advisor for the ENRP, Yasin Dhaher, PhD
    Sensory Motor Performance Program