Ocular Motor Function and Related Brain Morphology, Network, and Circuitry Metrics in Military Veterans with Mild Traumatic Brain Injury
Abstract
Rationale: Vision is essential to safe and effective daily task performance such as reading, self-care, walking, and balance. A major physical function that provides accurate vision is based on both eyes moving together, including quick eye movements to refocus on separate visual points and tracking eye movements to pursue the same visual point. These eye movements are controlled by multiple brain areas and connections between those areas. Due to combat and training operations, military service personnel are frequently exposed to repeated physical and blast events that make them vulnerable to repeated traumatic brain injury (TBI). The majority of TBIs are considered mild TBI (mTBI), also referred to as concussion. Post-9/11 military Veterans frequently have a history of mTBI, with well more than half of those mTBI events related to blast exposure. Eye movement problems are common and often chronic following mTBI, making it difficult to diagnose. Prior studies have attempted to determine if eye movement problems are worse in Veterans with mTBI due to blast compared to Veterans with mTBI that was not due to blast, however, the results from those studies are not conclusive or in agreement. The proposed study aligns well with the FY21 VRP IIRA Level 1 eye injury or visual dysfunction as related to a military-relevant traumatic event Focus Area and pathobiology underlying TBI-associated visual dysfunction topic by aiming to determine: what type of eye movements (e.g., quick-refocusing, tracking-pursuing) are abnormal in Veterans with extended history (e.g., > 3 months) of mTBI; what brain area and connection imaging measures are found in Veterans with extended history of mTBI; and are eye movement and brain imaging measure findings in Veterans with blast as primary reason of mTBI different compared to Veterans with mTBI where blast was not the mechanism of main injury. Objective: The research team s short-term objective is to conduct a study that recruits male and female U.S. military Veterans. Based on eligibility, participants will be placed into one of two groups: Veterans with extended history (> 3 months) of mTBI and Veterans without history of mTBI (e.g., healthy control). Specific Aims: The primary aim of the study is to compare eye movement measures in Veterans with extended history of mTBI and in Veterans without history of mTBI. To be as accurate as possible when measuring eye movement, two measures of eye movements, a rapid number naming test and a computerized eye tracker system, will be used to measure quick and tracking types of eye movement on all participants. Based on these innovative approaches, the research team believes that eye movement control in Veterans with extended history of mTBI will be significantly worse compared to Veterans without history of mTBI. Additionally, advanced brain imaging techniques will be used to compare brain structure and connection function in Veterans with extended history of mTBI and Veterans without history of mTBI. The research team predicts that brain structure and connections that have previously been found to relate to eye movement control will be significantly different in Veterans with extended history of mTBI compared to Veterans without history of mTBI. The investigators will also explore eye movements and brain structure and connections in Veterans with extended history of mTBI where blast was the reason for the worse mTBI and compare the findings to Veterans with extended history of mTBI where blast was not the mechanism of main injury. The design and methods of the study will lead to robust and unbiased results, demonstrating a significant advantage over existing methodologies in prior eye movement-related research involving Veterans with mTBI. Short-term and long-term outcomes of the proposed study: More immediately, the results from the current study will assist in a significant advancement in clinical standard of care testing
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Dec 28, 2022
- Source ID
- W81XWH2210954
Entities
People
- Jeffrey Hebert
Organizations
- United States Army
- University of Colorado Denver