Date of Award

12-2023

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Program

Biomedical Sciences

Track

Neuroscience

Research Advisor

Ansley Grimes Stanfill, PhD

Committee

Brandon C. Baughman, PhD; Matthew Ennis, PhD; Max L. Fletcher, PhD; Jack W. Tsao, M.D.

Keywords

Cognition;Concussion;Post Concussion Syndrome;Psychology;Traumatic Brain Injury

Abstract

Mild Traumatic Brain Injury (mTBI), commonly referred to as a concussion, is a prevalent injury in the United States, with several million occurring every year. Many of these injuries take place while playing a sport, particularly in those activities that have higher rates of impact with another person, such as hockey, soccer, or football. While most recover quickly from an mTBI, some individuals may have longer term effects. Recent literature has provided some evidence for long-term dysfunction in head injured individuals, with these dysfunctions appearing as changes in cognition or psychological well-being. Some of the most frequently reported cognitive symptoms were difficulty with attention, insomnia, confusion, and memory loss. On the psychological side, depression, anxiety, insomnia, and agitation are often reported. In order to further examine such symptoms, a sample of 56 retired National Football League players participating in a medical monitoring program were assessed for their long-term cognitive and psychological functioning. In the first set of analyses, a neurocognitive battery was used to assess cognition on a set of three self-reported outcome measures: Number of Concussions, Number of Losses of Consciousness, and Number of Undiagnosed Concussions. The battery was composed of tests divided into one of five areas of cognition: Complex Attention and Processing Speed, Learning and Memory, Visual-Perceptual Processing, Language, or Executive Function. These results were assessed with descriptive statistics, linear regression, and an ANOVA for confirmation of significance (p≤0.01). The results in Complex Attention and Processing Speed, Learning and Memory were not associated with any of the three outcome measures. In Visual-Perceptual Processing, the Number of Concussions was found to be associated with the results on the Block Design test (p=0.003). The Number of Concussions was also found to be significantly associated with the Category Test, a measure of Executive Function (p=0.003). Three tests were found to be significantly associated with the Number of Losses of Consciousness (Boston Naming Test, p=0.006, Controlled Oral Word Associations: FAS Letter Fluency Test, p=0.001, and Similarities p=0.01). Of note, these reported results were all significant after the removal of any participant that failed 2 or more Performance Validity Tests, but showed a normal T-score mean and standard deviation. This may indicate that only a few participants are experiencing any long-term cognitive deficits; an increased sample size should be recruited for confirmation of these results. In the second set of analyses, two psychological tests were administered: the Minnesota Multiphasic Personality Inventory – version 2 RF (MMPI-2RF) and the Mini-International Neuropsychiatric Interview – Plus version (MINI+). The first test is made up of 9 areas of that measure a range of personality and psychological health issues. The second test conducts a brief psychological examination, looking for clinically relevant Axis I and II psychological disorders, falling into 22 diagnoses. As in the previous study, these data were analyzed with descriptive statistics and any individual with Symptom Validity Scale failures was removed from the final analysis. For the MMPI-2RF, a linear regression was conducted, as well as post hoc corrections with Tukey and ANOVA for confirmation of significance (p≤0.01). One significant outcome was found in the Somatic-Cognitive area, Head Pain Complaint (p=0.003). Two significant results were found on Internalizing scale, one in the outcome measure Number of Losses of Consciousness (BRF, p=0.01) and one in the outcome measure Number of Undiagnosed Concussions (SFD, p=0.01). A final significant result was seen on the PSY-5 scales (psychopathology), Introversion/Low Positive Emotion (p=0.01). Each of these results indicates a decreased interest in interpersonal relationships and gives an impression of lowered ability to self-regulate anxious emotions. A similar vein of significant results were found on the MINI+, with Anxiety (Dx2, p=0.001) and Panic Disorder (Dx16, p=0.007) appearing in the outcome measure Number of Concussions. Taken together, these results may indicate a relationship between anxiety and antisocial tendencies and those suffering from multiple head injuries. This work aimed to elucidate a relationship between concussions and cognitive and psychological health. The state of the science review in chapter two found several gaps in the literature and some of the issues in long-term study of concussion, such as the differences between symptoms in individuals with single versus multiple injuries. In chapters two and three, evidence was found for a small subpopulation with multiple recovery issues over time, though the overall population had normal recovery from their injuries. Of the three outcome measures studied, the Number of Concussions was most often associated with both cognitive and psychological symptoms over time. These chapters set a working model for future subjects to contribute to our growing body of knowledge. Future directions for this work include increasing the number of participants, more thoroughly studying the differences between single and multiple injury, and increasing the types of testing to include imaging work and anatomical differences in head injured individuals.

Declaration of Authorship

Declaration of Authorship is included in the supplemental files.

ORCID

0000-0002-6464-4775

DOI

10.21007/etd.cghs.2023.0644

Additional Files
2023-030-Somerville-DOA.pdf (260 kB)
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