A complete understanding of the functional and structural impairments driving persistent post-concussive symptom (PCS) expression in approximately one-third of those who suffer from mild traumatic brain injury (mTBI) is essential for the development of effective treatment strategies and improving quality of life. While traditional outcome measures, such as neuropsychological testing and structural magnetic resonance imaging, are sensitive to the severe functional impairments and widespread tissue damage frequently seen after moderate-to-severe injuries, more advanced measures that are sensitive to the subtle changes in cognitive function and tissue microstructure that may underlie persistent PCS are necessary for the assessment of recovery from mTBI. Toward this end, the current study investigates the utility of eye-tracking analysis and high-definition fiber tractography (HDFT) as advanced measures of functional and microstructural outcome in 11 adults with chronic mTBI and varying levels of PCS (ages 20-60; mean time post-injury = 9.53 ± 6.74 years) in comparison to 10 healthy adults (ages 20-54). Performance on neuropsychological and eye-tracking tasks of processing speed, attention, and working memory, and HDFT-derived quantitative measures of the microstructural integrity of the forceps major, inferior fronto-occipital fasciculus, middle longitudinal fasciculus, and superior longitudinal fasciculus were compared between groups, and the results were used to define discriminatory functions for mTBI classification. The relationships between neuropsychological and eye-tracking measures of cognitive function and HDFT-derived measures of tract integrity were explored, as was the utility of these functional and structural measures for predicting persistent PCS in chronic mTBI. The results suggest that eye-tracking analysis may be more specific to cognitive impairments resulting from mTBI than neuropsychological testing, and HDFT is highly sensitive and specific to the subtle microstructural changes that persist chronically in this population. Furthermore, white matter integrity assessed using HDFT is more strongly associated with impairments in processing speed, attention, and memory indicated through eye-tracking analysis relative to performance on neuropsychological tests. Finally, although the predictive utility of eye-tracking and HDFT for the experience of persistent PCS was not demonstrated in the present sample, the possibility that these data are confounded by symptom exaggeration, comorbid mental health impairment, or lack of self-awareness for functional deficits cannot be ruled out, and future research using large, homogenous sample of mTBI is necessary to validate the present findings.
| Identifer | oai:union.ndltd.org:BGMYU2/oai:scholarsarchive.byu.edu:etd-9657 |
| Date | 03 August 2020 |
| Creators | Lindsey, Hannah M. |
| Publisher | BYU ScholarsArchive |
| Source Sets | Brigham Young University |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Theses and Dissertations |
| Rights | https://lib.byu.edu/about/copyright/ |
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