The Role of Movement Errors for Modifying Spatiotemporal Gait Asymmetry

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Background:  How did this project come to fruition?

My interest in research began during my undergraduate education at the University of Delaware.  During my junior and senior year, I was an undergraduate research aid in the infant motor behavior lab, a lab that was part of the department of physical therapy and the Ph.D. program for biomechanics.  During those 2 years, I observed data collections of infants using a Vicon motion analysis camera system, labelled markers after data collection, and processed the data using MATlab programs.  I loved and appreciated my experiences, but I felt I had more to learn about conducting research and the process of turning an idea into results.

During the spring semester of my first year of physical therapy graduate school, I found my opportunity to fulfill my curiosity about research in a fellow blue hen faculty member.  Dr. Mike Lewek, who received his MPT and Ph.D. in Biomechanics from UD, is the faculty advisor for the interdisciplinary human movement science lab and had a new project idea and needed a student to assist him.  I seized the opportunity and assisted him with data collection of a few subjects.  By the fall semester of second year, he had received approval and funding for the project.  With guidance, support and confidence from Mike, I took the project on as my own with his advisory.  From there, data collection for 20 subjects took place between November 2010 through December 2011.  Marker labelling, data analysis, and statistical analysis followed and a powerpoint presentation was put together and given as a research platform presentation at the APTA Combined Sections Meeting in Chicago in February 2012.

 

The Premise of the Research Study

Mike specializes in biomechanical, neurophysiologic, and motor learning aspects of locomotor training following stroke.  The interdisciplinary human movement science lab contains a split-belt treadmill, GaitRite mat, and 8-camera Vicon motion analysis system, as well as other equipment and technology, used to conduct research in gait retraining for individuals in the chronic phases post stroke.  Most recently, Mike has used the split belt treadmill to provide feedback to individuals during gait retraining.  By employing motor learning principles and the idea of motor adaptation, this pilot study was created.  The literature supporting treadmill gait retraining, motor adaptation, and error augmentation versus minimization is summarized in the following document.

Literature Review

The basis behind the study was to use the split-belt instrumented treadmill and a novel, responsive ‘closed loop’ control system to either assist or augment imposed spatiotemporal gait asymmetries during the training period by adjusting the speed of each belt on a step by step basis based on the participant’s current asymmetry.  The purpose was to compare the effects error augmentation, error minimization, or a control condition on the imposed spatiotemporal gait asymmetries during and immediate following treadmill walking.  Our unofficial hypothesis was that the augmentation condition training would produce greater variability in errors but during the post-training period, the subject would show improvements in spatiotemporal gait asymmetries.

After analyzing the data for all 20 subjects for all three conditions, 6 participants were eliminated due to errors in data collection.  Our results revealed:

• Statistically significant improvement in asymmetry during training in the minimization condition compared to the control condition.
• Ratio of asymmetry during training int he minimization group < 1.05, falling in the range of typical symmetry for unimpaired individuals.
• Statistically significant improvement in the percentage of symmetrical steps during training in the minimization condition compared to the other 2 conditions.
• Statistically significant increase in variability during training in the augmentation condition compared to the other 2 conditions.
• Statistically significant increase in asymmetry and decrease in the percentage of symmetrical steps in the minimization condition comparing baseline to post-adaptation training.
• Statistically significant increase percent of symmetric steps and an overall improvement in asymmetry (although not significant) and from baseline to post-adaptation training in the augmentation condition
• Positive correlation between the amount of variability during training and the change in asymmetry from baseline to post-training.

For more information regarding the specifics of the research study, please view the powerpoint presentation (pdf).

CSM presentation_Kyle Rascoe

Based on this pilot study, Dr. Lewek is currently conducting a study using the principle of error augmentation in a training protocol for individuals in the chronic phases post stroke.  Our hope is to have the full research article for this pilot study published in the near future.

 

The Experience of Presenting at the APTA Combined Sections Meeting

While I was on my third clinical rotation, Mike drafted and submitted an abstract based on our very first subjects (collected in May 2010) to the APTA to present at the Combined Sections Meeting (CSM).  In August 2011, we learned that the abstract had been submitted and I was going to give a platform presentation as part of the research section.  We completed data collection in early December 2011 and immediately began processing and analyzing the data and putting the presentation together.  The final draft of the presentation was completed just 3 days prior to the presentation in Chicago.  The presentation was 12 minutes, with three minutes for questions.  Everything went off without a hitch and I got the thumbs up from Mike.  Just a week later, I gave the presentation again at UNC Human Movement Science (HMSC) Day, a symposium to explore current research in the field of human movement science and biomechanics from head researchers and students.  This is the evaluation form that I provided to my committee members to evaluate my presentations.

Presentation Evaluation Form

Presenting at CSM and HMSC day was an extremely unique experience.  At CSM, I was the only current student presenting in the research section platform presentations.  Before I even presented, I felt very accomplished and proud of the work I had done.  I had done all of the preparation and practicing I could do, so I spent the morning of the presentation relaxing and giving myself plenty of time to get ready and get to where I needed to be.  Surprisingly, I did not get nervous until the presenter right before me was answering questions.  However, it took me about three quarters of the way through the presentation to really relax and own it.  I wished I was able to relax and calm my nerves earlier, but unfortunately, I can’t control everything like I’d like to.  I was proud to finish my presentation without any major hiccups and even more that I was able to answer the two questions that I had properly.

If I could provide any advice to future students presenting at an APTA national conference, first and foremost, give yourself plenty of time to create the presentation and prepare properly.  Second, give a mock presentation to a group of individuals who are similar to the intended audience.  It was essential for me that I had not only practiced to myself, my husband, and my adviser, but that I also practiced standing in front of a group of people, advancing the slides, and referencing the powerpoint properly.  Although I did this in the very early drafts of the presentation, it was something I was glad I had done by the time the national conference presentation day arrived.  Third, make sure you know where you are presenting, how to get there, and take a look at the layout of the room before the day of the presentation.  This helps to calm nerves and give you a sense of the number of people attending, whether you will have a microphone, and how close you will be to the audience.  This very much calmed my nerves because I felt prepared and nothing was going to surprise me.  Lastly, have confidence in yourself and your project.  As my dad told me “you know more than everyone else in the room about your topic”.  You are the expert, speak slow and tell them what you know and what you did.

 

I want to give a special thanks to Mike Lewek for taking me under his wing and giving me the opportunity to do this.  I also want to thank him for the endless hours he spent walking me through every detailed step of the research process over the past 2 years.  This experience has been invaluable!  I also want to thank Nicole Davis, the undergraduate research aid who assisted in data collection and processing.