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 Human Neuromechanics Laboratory (HNL)
Dr. Daniel Ferris, Dr. Riann Palmieri
1206A CCRB
401 Washtenaw Avenue
Ann Arbor, MI 48109-2214
Phone: (734) 615-1711
Research Overview
HNL in the News
Study: Muscles Respond to Getting on Your Feet After Spinal Cord Injury from the UM News Service (PDF version)
NSF CAREER Research Grant
SCRF Grant
Current Projects
Motor Adaptation During Human Locomotion
Pneumatically powered lower limb exoskeletons
Computer simulations of neuromechanical systems 
Self-Assisted Stepping for Neurologic Rehabilitation
CAREER: Biomechanics and energetics of human locomotion with powered exoskeletons
Members
HNL Photo Gallery
Photos (and stories!) from our trip to the International Society of Biomechanics XIXth Congress (July 2003) in Dunedin, New Zealand.
Links




Research Overview

Our research focuses on how the human nervous and musculoskeletal systems interact to produce coordinated movement, specifically locomotion. Studies span the range from basic to applied, and from experimental to theoretical.

 


Recent Grants


NSF CAREER Research Grant

The National Science Foundation has recently awarded Dr. Ferris with its highly competitive CAREER Research Grant. "The Faculty Early Career Development (CAREER) Program is a Foundation-wide activity that offers the National Science Foundation's most prestigious awards for new faculty members. The CAREER program recognizes and supports the early career-development activities of those teacher-scholars who are most likely to become the academic leaders of the 21st century. CAREER awardees were selected on the basis of creative, career-development plans that effectively integrate research and education within the context of the mission of their institution."
(quoted from the National Science Foundation web site). Details below.

SCRF Grant

Dr. Ferris has received funding from the Paralyzed Veterans of America Spinal Cord Research Foundation for research on neurologic rehabilitation. The $150,000 grant will be disbursed over two years, and will be used test the feasibility of self-assisted recumbent stepping as a gait rehabilitation therapy for spinal cord injured individuals. More information about this project, Self-Assisted Stepping for Neurologic Rehabilitation, can be found below.






Current Projects

Motor Adaptation During Human Locomotion



Keith Gordon (left) and Dr. Daniel Ferris try an orthoses on for size.

 


Idy Usoro attaches pneumatically driven muscles on the KAFO
(click on photo for a close-up)
 

The aim of the project is to determine if healthy human subjects alter their muscle activity patterns and/or limb kinematics when walking with powered ankle-foot orthoses.

ABSTRACT: Recent research suggests that locomotor training can improve human walking ability after neurological injury. When stroke and spinal cord injury patients practice stepping with manual assistance, they recover mobility more quickly due to task-specific motor learning. Although multiple studies support the efficacy of this rehabilitation method, there is considerable debate about the extent of motor adaptation possible in the human locomotor pattern. Some animal and clinical studies indicate that muscle activation patterns during locomotion are hardwired into the nervous system and incapable of substantial modification. This would suggest that there are limits to locomotor training as a therapeutic tool. The proposed research project will use powered ankle-foot orthoses to study human locomotor adaptation. The powered orthoses will exert a torque about the ankle joint, altering normal lower limb kinematics if muscle activity patterns are not modified. As a result, these studies will test the relative invariance of muscle activity patterns and lower limb kinematics during human locomotion. This will not only provide the opportunity to study human locomotor adaptation under controlled experimental conditions, it will also provide a means to test whether the nervous system controls lower limb movements during locomotion based on kinematics.

The overall objectives of the proposed research are 1) to determine the extent of motor adaptation possible in the human locomotor pattern and 2) to test an hypothesized neural control strategy for human walking. Healthy human subjects will walk while wearing carbon fiber ankle-foot orthoses that are powered by artificial pneumatic muscles and controlled via proportional myoelectrical control. The studies will test the hypothesis that subjects will modify their muscle activity patterns when walking with powered orthoses to maintain joint kinematics similar to normal walking. In addition to providing important insight into the neural control of human locomotion, the project will advance robotic technologies for assisting gait rehabilitation and controlling powered lower limb prostheses.

Pneumatically powered lower limb exoskeletons
  We are building carbon-fiber lower limb orthoses powered by artificial pneumatic muscles (i.e. McKibben muscles) and controlled by myoelectrical signals. One aim is to build a bilateral hip-knee-ankle-foot orthosis to assist gait rehabilitation after stroke or spinal cord injury (Christopher Reeve Paralysis Foundation grant). A second aim is to build smaller one-joint and two-joint orthoses for investigating basic principles of motor adaptation during human locomotion (NIH grant).
Computer simulations of neuromechanical systems

Simple mathematical equations can model the behavior of neural circuits that help control locomotion. We are coupling these mathematical neural oscillators with biomechanical models to test hypotheses about neuromechanical control. It is anticipated that these mathematical neural oscillators will eventually be implemented as an alternative control strategy for our lower limb exoskeletons.
Self-Assisted Stepping for Neurologic Rehabilitation
  Recent scientific evidence indicates that task-specific active exercise can greatly improve motor recovery after stroke or spinal cord injury. Traditional physical therapy techniques rely on patients performing motor tasks very slowly with therapists providing manual assistance. We believe that giving the patient control over the timing and amount of physical assistance can increase neuromuscular recruitment and promote greater activity-dependent plasticity. Allowing patients to provide their own 'self-assistance' should also enable them to perform task-specific active exercise at normal movement speeds. This is important because recent studies have demonstrated that faster movement speeds during rehabilitation lead to better functional gains in motor recovery. We are studying individuals with spinal cord injury and stroke as they perform a stepping motion on a commercially available exercise machine (NuStep TRS 4000, a recumbent stepper designed for cardiovascular exercise). The stepping machine has handles and pedals that are contralaterally coupled, allowing subjects to use their own arms to assist their lower limbs during stepping. The basic premise we are testing is that self-assisted rehabilitation will enhance motor recovery compared to externally-assisted rehabilitation.
CAREER: Biomechanics and energetics of human locomotion with powered exoskeletons
  This five-year CAREER Development project will examine the biomechanics and energetics of human locomotion with powered lower limb exoskeletons.  The Human Neuromechanics Laboratory at The University of Michigan has developed carbon fiber lower limb exoskeletons that can comfortably supply active torque assistance at the ankle, knee, and hip during walking and running. Artificial pneumatic muscles attached to a carbon fiber shell provide high power outputs while minimizing exoskeleton weight.  Myoelectrical signals from biological muscles control force in the artificial muscles in a physiologically appropriate manner.  Although the exoskeletons are limited to laboratory use because they require a large source of compressed air, they are ideal for studying human responses to powered locomotor assistance.

The objective of the research plan is to quantify the effects of powered assistance on the energetics of walking and running.  We will measure the metabolic efficiency of external power assistance at the ankle, knee, and hip during walking and running over a range of speeds and added loads.  The intellectual merit of these studies will be in two separate areas.  From a physiological perspective, the results will provide important insight into the mechanical factors that determine the metabolic cost of locomotion. There is considerable debate among biomechanists and physiologists as to the mechanical actions and functions of lower limb muscles during walking and running.  The exoskeleton allows us to selectively manipulate artificial flexor and extensor strength and then relate their force and work to changes in metabolic energy consumption.  From an engineering perspective, the results will provide much needed guidance for creation of future lower limb exoskeletons.  We will be able to quantify the biomechanical and metabolic benefit of adding external power to the ankle vs. knee vs. hip.  These data will be instrumental in performing cost-benefit analyses of actuator and exoskeleton design for gait rehabilitation and human performance augmentation.

The objective of the educational plan is to use exoskeleton research to introduce problem-based discovery learning into the curriculum of students preparing for health science careers (e.g. physician, physical/occupational therapist, prosthetist/orthotist). The plan includes: a) creating an upper division course on gait biomechanics that incorporates hands-on experimentation and testing related to exoskeletons for human augmentation and rehabilitation, b) recruiting and training female and minority undergraduate students for exoskeleton research projects in the Human Neuromechanics Laboratory, and c) creating an interactive web page on robotic exoskeletons that can be used as an educational resource for secondary and undergraduate students.  Thus, the broader impacts of these activities will be to enhance science and technology education of students at the college and high school level, increase participation of underrepresented groups in biomechanics research, and advance scientific and technological understanding of the public by broadly disseminating state of the art research on robotic exoskeletons.





Members

Faculty:

Keith Gordon and Dr. Ferris make adjustments
  Riann Palmieri, Ph.D. Co-Director
Research Assistant:
  Catherine Kinnaird, M.S. (kinnaird@umich.edu)
Graduate Student(s):
  Annie Barkowitz, B.S. (abarko@umich.edu)
 

Stephen Cain, B.S. (smcain@umich.edu)

  Antoinette Domingo, M.P.T. (adomingo@umich.edu)
Keith Gordon, M.A. (kegordon@umich.edu)
Helen Huang, M.S. (hjhuang@umich.edu)
  Pei-Chun Kao, M.S., P.T. (kaop@umich.edu)
  Kyla Russell, M.S. (kylar@umich.edu)
Greg Sawicki, M.S.M.E. (gsawicki@umich.edu)
Undergraduate Student(s):
  Alexis Ball (aaball@umich.edu)
  Zaineb Bohra (zbohra@umich.edu)
  Sarah Lucey (slucey@umich.edu)
  Jamie Lukos (jlukos@umich.edu)
  Kristin Roberts (krisrobe@umich.edu)
  Becca Stoloff (stoloreb@umich.edu)
  Theo Van Dam ( vtheo@umich.edu )
Julie Van Helden (jvanhel@umich.edu)
Collaborators:
David Gater, M.D., Ph.D., (dgater@umich.edu), UM Physical Medicine and Rehabilitation
Brent Gillespie, Ph.D. (brentg@umich.edu), UM Mechanical Engineering
Jessy Grizzle, Ph.D. (grizzle@umich.edu), UM Electrical Engineering and Computer Science
Art Kuo, Ph.D. (artkuo@umich.edu), UM Mechanical Engineering
Ammanath Peethambaran, M.S., C.O. (peeth@umich.edu), UM Orthotics and Prosthetics Center

 

 


HNL Photo Gallery

Click on a photo or description for a better view.






Links

Organizations:
  American Society of Biomechanics asb-biomech.org/
  The Christopher Reeve Paralysis Foundation www.apacure.com/index.cfm
  International Society of Biomechanics www.isbweb.org/
  Neural Control of Movement Society www-ncm.cs.umass.edu/
  Society For Neuroscience www.sfn.org/
  UM Biomedical Engineering www.bme.umich.edu/
Dr. Ferris' home page www.umich.edu/~ferrisdp/




 
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