The Complex Assessment of Military Performance for mTBI Assessment: Patrol Exertion Task Evaluation, Further Research, and Resource Tools

 

Background:

Before coming to PT school, I had the wonderful opportunity to shadow at Intrepid Spirit, a brain injury focused, interdisciplinary clinic at Fort Bragg. I chose to pursue this as a shadowing experience because my parents, who both served in the United States Air Force, often discussed different types of injuries service members sustained on a regular basis compared to the general public. In addition, I have lived in Fayetteville, NC for most of my life and this is where Fort Bragg Army Base is located. I have met many friends and community members affected by concussion and TBI related to military service. They often have long-lasting symptoms that restrict them from participating in some of their job-related duties, as well as leisure activities at home. Intrepid Spirit provides specific programming and treatment to get service members back to full active duty following traumatic brain injury and concussion. This shadowing experience sparked an interest in TBI and military populations, which was followed by excitement when I learned that UNC’s own, Karen McCulloch (Kmac), has been leading research initiatives on this very topic. I was thrilled to have the opportunity to aid in her research as a part of my capstone on a population that has been an interest of mine for some time.

 

Statement of Need:

Active-duty military service members (ADSM) are at increased risk for sustaining mild traumatic brain injury (mTBI) due to the nature and general hazards of their occupational training and duties.¹ After sustaining mTBI, it is often that symptoms like exertional headache, dizziness, cognitive impairments such as: impaired memory, recall, and reaction time, and exercise intolerance interfere with high level mobility, balance, and cognitive activities required of ADSM. These symptoms may last for weeks, months, or even years and can impact how and when the service member (SM) is able to return to duty safely.¹ Traditional post-concussive testing often lacks the necessary rigor and challenge needed to properly assess whether these impairments are interfering with the ADSM’s abilities; prompting the creation of tools such as the Complex Assessment of Military Performance (CAMP) test battery, specifically designed to capture full details of impairments and aid in clinical decision-making of appropriate time to return to active duty.¹

Historically, the Department of Defense has been utilizing best evidence from sports concussion literature to guide return to active duty.¹ The literature around sports concussion often relies on subjective symptom reports during rest and activity, outcome measures related to gaze and postural stability, and cognitive testing; however, culture in the military often produces an environment where underreporting of symptoms may be common, making subjective report measures less reliable.¹ Also, many combat-ready service members operate at very high levels of endurance and athletic ability, where traditional outcome measures may be limited by a ceiling effect.¹ The Traumatic Brain Injury Center of Excellence developed 5-stage progression for return to duty which guides interventions. However, this group also recommends an exertional test before resuming activities. Research is currently working to assess the reliability and validity of exertional tests that meet the demands and specific needs of the active-duty military population, while also identifying possible impairments in mobility, the autonomic nervous system, and/or cognitive domains, but more research is needed to determine what is most appropriate and clinically relevant.² Measures and tasks that analyze dual-tasks, high levels of attentional demand, and relatable activities to service members at appropriate performance levels are needed to assess safe return to active duty.¹

 

Purpose:

Without effective, specific, relatable, reliable, and ecologically valid tests for return to duty, ADSM may experience long-term symptoms, impaired or limited performance during occupation-specific duties, and be at an increased risk for future concussions or injuries due to these impairments.³ This capstone focuses on analyzing healthy control data for the Patrol Exertion Task in order to determine reliability and performance trends for healthy individuals which will serve as appropriate comparison measures for scores of service members affected by mTBI/concussion. The other aspect of this capstone was to aid in the creation of deliverables for the resource website to be accessed by researchers and clinicians interested in and using this clinically. Collectively, this information also aims to narrow the research gap and help determine effectiveness of this specific exertional task for ADSM who have sustained an mTBI. 

 

The Patrol Exertion Task: 

The Patrol Exertion Task (PET) is a virtual foot patrolling scenario conducted with the ADSM carrying a simulated weapon while viewing a virtual video and repeatedly stepping onto a 12” step maintaining an exercise level of heart rate 65-85% of age adjusted maximal heart rate.⁴ During the 10-minute task, there are reaction time challenges to audible tones, target identification tasks, and memory requirements while heart rate, rate of perceived exertion, and presence of symptoms are tracked.⁴ In this case, healthy control subjects from multiple military bases participated in the study. They viewed one virtual scenario video during initial testing, and one month later viewed a different, but similar virtual scenario video for final testing. The data analyzation was aimed at determining test-retest reliability, and identifying performance differences between initial and final virtual scenario videos, as well as differences in testing performance parameters. This also provides necessary healthy control data which may be used in the future for comparison to affected individuals in this population.

Current Evidence on the Patrol Exertion Task-

• PET targets attention, reaction time, visual scanning, and exertion.⁵
• Past testing on exertional tasks measuring reaction time and requiring high attentional demands revealed decreased reaction times and more inaccuracies in the mTBI group compared to healthy controls.¹
• Discriminative validity of the Patrol Exertion Task- the task was able to effectively discriminate between a group of service members who were deemed the health control group and a group of service members who had residual symptoms following mTBI in the categories of reaction time and self-report visual clarity during stepping task. There were significant differences in these categories between groups. However, there was insignificant differences in accuracy of target identification and rate of perceived exertion.¹
• The Polar H10 monitors were found to record HR data that is accurate and reliable compared to EKG. Polar H10 monitors are also less costly and potentially more accessible than an EKG.²
• Current outcome measures for post-mTBI like the Buffalo Concussion Treadmill Task and the Buffalo Concussion Bike test are standardized and validated, but also costly and time-consuming for clinical use.²
• Factors measured relating to executive function were able to distinguish between healthy controls and mTBI groups during PET, with symptom reports related to visual clarity and slower reaction times.⁵
• Initial RPE Reliability ICC: 0.98 (95% CI)⁵
• RPE End Reliability ICC:1.0 (95% CI)⁵
• Did not demonstrate correlation >/= 0.3 with neurocognitive measures included in the AAMP, an earlier version of CAMP⁵
• Small correlation with Simple Reaction Time test (SRT) at baseline, moderate with SRT at end for vision clarity and reaction time tasks.⁵
• More data to come! (Check out the abstract.)

 

Products:

During the fall semester, I performed a review of literature on the topic of mTBI in active-duty military populations which provided the appropriate background knowledge needed to perform data analysis on specific tasks in the CAMP battery. Data analysis took place on the healthy control data currently being collected at three military bases. The below products result from the data analysis performed. 

The abstract was submitted to the Novel Clinical Assessments and Interventions for mild Traumatic Brain Injury Poster section at the Military Health System Research Symposium 2022. We are waiting to hear if it has been accepted. The abstract was also submitted and accepted to be presented as a poster at the Human Movement Science Symposium at UNC-CH. 

MHSRS2022 Abstract

 

This is the poster that will be presented at the Human Movement Science Symposium. It will also be presented with updated data as more is received, if accepted, at the Military Health System Research Symposium. 

PET_PosterPresentation

 

This PPT serves as a preliminary guide to future creation of an instructional video on the Portable Warrior Test of Tactical Agility (POWAR-TOTAL) task, another item included in the CAMP battery. The purpose of this video will be to help clinicians who are implementing the tool clinically to better understand the instructions and have more success with implementation as a result. It is planned to be posted to the website as a resource once complete. 

Instructional Video Guide

 

Evaluation Component:

The PowerPoint that serves as a preliminary guide for an instructional video is a work in progress that I thought would benefit from an evaluative tool for the purpose of continuing refinement. This way, we can make sure that the video serves the purpose it was created for accurately and effectively. The plan is to present the video to small, diverse groups once it is in its more final stages, followed by the evaluation. The video can then be adapted accordingly to more specifically meet the needs of the audience. 

Guard_InstructionalVideoFeedbackForm

 

Self-Assessment:

This project began with reviewing the literature and realizing the nuances and specifics of mTBI in military populations. This gave me a better understanding of the necessity for a tool kit like the CAMP battery for active duty service members following mTBI. The necessity served as a purpose for me to work out of my comfort zone and into data analysis of research, because there is a need for targeted care in this population. I began this capstone project with little experience analyzing raw data for the purpose of drawing conclusions and creating an abstract. I have often thought of myself as someone who was interested in reading the research, but not necessarily participating in it. However, I think I held this thought because I was intimidated by the whole research process. Therefore, my personal objectives centered around gaining experience with data analyzation, abstract writing, and poster presentation creation; as well as, expanding my knowledge on mTBI in military populations and the CAMP battery. What I expected to be the most difficult part of the project, which was data analysis, ended up being easier than drawing conclusions from the data. Drawing conclusions requires specific knowledge on what the task is intended to measure, what the measurement implies, and, further, what the score implies about the subject. My advisor and committee helped me to be specific and realize the amount of background knowledge needed to draw conclusions from data that are helpful to making the tool better clinically. This includes but is not limited to, changing certain aspects of the instructions or tool so that they are more effective at capturing the measurements and picture of the possible symptoms. Overall, with the guidance of my advisor and committee members, I was able to achieve my personal objectives and discover a better appreciation for the behind the scenes work to the many research articles I consume, and will consume, throughout my physical therapy career. The time and work it takes to assess the feasibility, reliability, validity, accuracy, and relatability of tools and measures is much more than what I naively assumed. I reflect on times of being frustrated about not finding reliable evidence to support why a certain outcome measure is indicated for certain populations. I can now see clearly why this may be the case. It takes someone with the right funding, tools, time, and skills to take an interest in that specific topic with the intent to produce research. Therefore, I have a better appreciation for those who lead, fund, and participate in research and hope to continue participation in research in some aspect throughout my career. 

 

Acknowledgements:

Without the help of my advisor, Kmac, and the rest of my committee, I would not have been able to participate in such a fascinating learning experience. Thank you all so much for your support throughout this process.

 

To Karen McCulloch, PT, PhD, FAPTA, thank you for the guidance, expertise, and assistance throughout this experience as they were immensely appreciated and essential to the success of this project. I am also so thankful for your words of encouragement and support. Thank you for providing the opportunity to work on this project and, hopefully, present the information at MHSRS. I could not have done this without your help!

 

To Courtney Harrison, MS, your knowledge and assistance were very helpful to my many questions about data, research, and the like. I appreciate your feedback and guidance so much!

 

To Amy Cecchini, PT, DPT thank you for being so responsive, helpful, and uplifting with your feedback and edits. My project is more guided and organized because of your advice.

 

 

 

Bibliography

1. Scherer MR, Weightman MM, Radomski MV, et al. Measuring Soldier Performance During the Patrol-Exertion Multitask: Preliminary Validation of a Postconcussive Functional Return-to-Duty Metric. Arch Phys Med Rehabil. 2018;99(2S):S79-S85. doi:10.1016/j.apmr.2017.04.012
2. Prim JH, Davila MI, McCulloch KL. A pilot study on exertional tasks with physiological measures designed for the assessment of military concussion. Concussion. 2021;6(1):CNC88. doi:10.2217/cnc-2020-0018
3. Quatman-Yates CC, Hunter-Giordano A, Shimamura KK, et al. Physical therapy evaluation and treatment after concussion/mild traumatic brain injury. J Orthop Sports Phys Ther. 2020;50(4):CPG1-CPG73. doi:10.2519/jospt.2020.0301
4. Guard M, Harrison C, Cecchini A, Krok CM, McCulloch KL. The Complex Assessment of Military Performance for mTBI Assessment: Patrol Exertion Task TestRetest Reliability. In: Novel Clinical Assessments and Interventions for mild Traumatic Brain Injury. ; 2022.
5. Weightman MM, Radomski M, Finkelstein M. The Assessment of Military Multitasking Performance: Validation of a Dual-task and Multitask Protocol. 2015.