Project B2:   Gait Restoration in Stroke and Incomplete SCI Patients Using the Lokomat Robotic Treadmill System

Principal Investigator:  Joseph Hidler, PhD
Co-investigator:  Edward Healton, MD, MPH
Research Assistant: Emily Olmstead, MS
Sub-contract/consultant: Anthony Ricamato, Ph.D. (Developmental Innovations)

Funding Source: Neuroscience Research Center (USAMRMC)

Abstract:
The overall goal of this study is to determine whether robotic-assisted gait training is superior to conventional rehabilitation treatments for facilitating the recovery of stable walking patterns in individuals following stroke and spinal cord injury.

The subject sample will consist of 80 patients, 40 with sub-acute hemiparetic stroke and 40 with incomplete spinal cord injury, randomly assigned to one of 2 experimental groups for each patient population (4 total groups total).  One group of stroke subjects (n=20) and one group of SCI subjects (n=20) will receive one hour of conventional rehabilitation, consisting of a standardized regimen of lower extremity strengthening exercises and full weight bearing ambulation as tolerated, with appropriate physical assistance and feedback as necessary. The other 2 groups will receive body-weight supported treadmill training (BWSTT) with robotic-assistance using the Lokomat® System (Hocoma, Inc., Zurich, Switzerland).  The Lokomat is an exo-skeletal robotic orthosis that attaches to a person’s legs and assists the subject in achieving normal gait patterns while walking on a treadmill.  During training sessions, patients will receive bio-feedback of their performance, allowing for goal-directed therapy.  Both groups will be trained for 24 sessions, with 1 hr allocated for all training paradigms. 

The re-acquisition of natural gait patterns and lower limb motor function will be evaluated at bi-weekly intervals and will be based on numerous measures, including the speed and variability of unassisted walking, step lengths and cadence, postural balance, assessment of spasticity, and various strength measures.  Using these criteria, we will determine the form of therapy which best promotes the restoration of walking capabilities in patients with incomplete SCI and stroke.

Progress and Outcomes (2004):

In anticipation of receiving DOD IRB approval to run the project, we continued to develop the necessary infrastructure for running the protocol outlined above.  Specifically, our first main goal was to develop electronic subject training logs which document all subject outcome measures digitally.  For this study, we utilize 14 different outcome assessments (e.g. Berg Balance, SF-36 Quality of Life, etc.) which encompass 212 data entries.  In order to minimize errors in managing data, we wanted to design a program that would record and store these outcome assessments.

Working with Dr. Tony Ricamato of Developmental Innovations of Chicago IL, we created a software program using the VB.net framework that links into an Access database that stores and manages all data obtained during the trial for each subject.  The software contains digital versions of 14 clinical scales used to evaluate each subject’s improvements in motor function and quality of life.  The software contains error checking and automatic calculations of performance which will be used to determine which intervention is more effective.

Our second main goal was to investigate how walking in the Lokomat affected normal muscle activation patterns (EMGs) utilized during gait.  This information is critical because when we train subjects in the Lokomat, we are interested in observing how their muscles fire.  And if the Lokomat changes normal muscle patterns, then comparing EMG profiles to those observed during healthy over-ground walking would be inappropriate.  Therefore, because this project is cost-shared with other funding sources separate from the Department of Defense, we have run a small number of related experiments on healthy subjects comparing EMG profiles while they walked in the Lokomat with those demonstrated on the treadmill.  In parallel with this work, we have developed an analytical technique for quantifying the magnitude and phase characteristics of EMG patterns during gait.

IRB approval was granted for this project in May 2004 and as such, we are currently running 3 stroke subjects in the study.  With this IRB approval, we now anticipate running at least 3 subjects in parallel for the remainder of the study. 

Publication and Presentations:

A number of presentation and publications resulting from the work affiliated with this project include:

Journal Papers

J. M. Hidler and A. Wall, “Changes in muscle activation patterns during robotic-assisted walking” In review.

A. Ricamato and J. M. Hidler, "Quantification of dynamic properties of EMG patterns during gait.” In review.

 Conference Proceedings

J. Hidler, “Robotic-Assessment of Walking in Individuals with Gait Disorders”, IEEE Engineering in Medicine and Biology Society, submitted.

A. Wall and J. Hidler, “Alterations in EMG patterns during robotic-assisted walking”, Northeast Bioengineering Annual Conference, April 2004.

Abstracts 
             

A. Ricamato and J. Hidler, “A Tool to Quantify the Temporal and Spatial Properties of EMG Patterns during Gait”, ISEK Annual Conference, Accepted for June 2004.

A. Lichy, J. Hidler, J. Cisper, and A. Wall.  “Changes in muscle activation patterns during robotic assisted gait training.” APTA Annual Conference, Accepted for July 2004.

Invited Presentations

“Contemporary Issues Surrounding Robotic-Assisted Locomotor Training”, Neural Prosthesis Seminar Series, Cleveland FES Center, Cleveland, Ohio, May 2004.

“Advances in the understanding and treatment of stroke impairment using robotic devices”, CME Symposium - Stroke Rehabilitation: Outstanding Outcomes and Best Practices, National Rehabilitation Hospital, Washington, DC, May 2004.

“Emerging technologies for understanding and treating motor-impairment in stroke and spinal cord injury”, Neurosurgery Lecture Series, Washington Hospital Center, Washington DC, April 2004.

“Loss of differential muscle control leads to weakness and discoordination in individuals with acute hemiparetic stroke”, IEEE Engineering in Medicine and Biology Society, Cancun, Mexico, September 2003.

Progress and Outcomes (2003):
During year 1, we have had 3 main goals for this project.  First, we have submitted a full IRB report detailing the NRC project to the National Rehabilitation Hospital Research Review Committee, Medstar Research Institute IRB committee, and the DOD IRB.  The IRB has been approved by the first two institutions, and is now being reviewed by the DOD. 

Our second goal for year 1 has been to develop the necessary instrumentation for the Lokomat that will be used to provide each subject bio-feedback of their performance during training, as well as allow us to quantify the stepping patterns of the subjects during training.  Specifically, DOD funds have been used to modify the leg attachment cuffs on the Lokomat to contain 6-degrees of freedom load cells which precisely monitor the interaction forces between the subject and the Lokomat during training.  Using these instrumented cuffs, we can show the subjects their functional deficits during training, which may assist them in correcting abnormal gait patterns.  A comprehensive software package has been developed to read in these forces, and then graphically display them to the subject in a user-friendly, intuitive manner.  The result is a much more advanced training system that we believe will allow for much more targeted therapy, and ultimately better outcomes in patients with stroke and spinal cord injury.

Our third goal was to setup the infrastructure necessary for conducting a comprehensive clinical trial.  DOD funds were used to contract Developmental Innovations, a Chicago based software consulting company, to develop electronic journals each subject will maintain during their training.  This will allow us to monitor outside activities that may influence their outcomes.  The electronic journals are programmed for the PocketPC using XML, and a separate software program has been design to upload the subjects responses to the patient database.  Subjects will respond to a variety of questions daily, such as “how much walking did you do today”, with their answers being stored on the PocketPC.  This will allow us to precisely monitor all activities that may influence the subject’s re-acquisition of stable walking patterns.  We also developed an electronic database that will be used to store subject information, as well as all outcome measures collected throughout the training (e.g. walking speed, Berg Balance Test results, etc).  The development of this electronic database will ensure smoother, more accurate data management, and will prevent any data loss in the event of a computer failure.

In order to generate pilot data, NRH has supported a small number of related experiments investigating the effects of training conditions on stepping patterns.  Specifically, we are interested in determining the training conditions, particularly walking speed and level of body-weight support, in which the subject’s step optimally.  This will provide us critical information for the this DOD project as we can be sure we train subjects at the correct conditions.  Abstracts related to these human trial pilot studies supported by NRH are included in this report.  In addition, using the instrumented leg attachment cuffs developed with DOD funds, we were able to conduct a series of pilot experiments supported by NRH which are outlined in the attached abstracts.

We have also conducted some related pilot studies investigating muscle synergy patterns in stroke patients, again using NRH sources.  This technique, which quantifies the motor control strategies stroke patients utilize while exerting isometric forces, will be used as an outcome measure in the DOD study, allowing us to quantify increases in strength and coordination as a result of the gait therapy (both Lokomat and conventional).  Abstracts for this work have been included in this progress report.

Publication and Presentations (2003):

PUBLICATIONS
J. Hidler, M. Carroll, E. Federovich, and C. Lacsamana, “Loss of Differential Muscle Control Leads to Weakness and Discoordination in Individuals with Acute Hemiparetic Stroke”, IEEE Engineering in Medicine and Biology Society, accepted.

J. M. Hidler, J. Cisper, and A. Wall, “Changes in Muscle Activation Patterns During Robotic-Assisted Gait Training.” American Society of Biomechanics, accepted.

J. Hidler, M. Zajacek, M. Carroll, E. Healton, and J. Dewald, “Reductions in differential control strategies at the hip and knee joints in acute stroke subjects”, Biomedical Engineering Conference, Washington, DC, 2002.

J. M. Hidler, M. Oursler, A. Lichy, and A. Ricamato, "Optimal training conditions for facilitating stepping patterns in individuals with incomplete spinal cord injury."  Society for Neuroscience, submitted.

M. Oursler and J. M. Hidler, "Effects of walking speed and  body-weight support on walking ability in individuals with spinal cord injury "  APTA Annual Conference, 2003.

J. M. Hidler, E. Healton, and M. Oursler, "Modulation of muscle activation patterns and reflex excitability with changes in walking speed and loading in individuals with spinal cord injury"  ASIA Conference, 2003.

J. M. Hidler, M. Oursler, G. Cooper, and E. Healton, "Robotic-assisted gait training for restoring motor function in the lower limbs following spinal cord injury."  KMRREC Conference, Parsippany, New Jersey, 2002.

PRESENTATIONS
Segmental control of walking: locomotor capacity of the spinal cord, Woodway USA Gait Training Workshop, Washington, DC, November 10, 2002.

Robotic-assisted treadmill training for restoring walking capability in spinal cord injured patients, National Institutes of Health, Rehabilitation Medicine Department Grand Rounds, September 6, 2002.