Award Date


Degree Type


Degree Name

Doctor of Philosophy (PhD)



First Committee Member

Daniel N. Allen

Second Committee Member

Bradley Donohue

Third Committee Member

Kimberly Barchard

Fourth Committee Member

Jennifer Keene

Number of Pages



Sport concussion is among the most common injuries for an athlete to experience during sport participation. Because of the complex pathophysiological process that affects the brain during and after concussion, symptoms can be heterogeneous in presence and severity. Although most acute symptoms (e.g., headache, slowed processing speed, loss of consciousness, irritability, depression, anxiety) resolve within seven to 10 days for most athletes, there is evidence that higher initial symptom burden and other genetically based differences can lead to longer symptom duration and complicated recovery post-concussion. Because structural changes that commonly occur as a result of concussion (e.g., diffuse axonal injury) are not readily visible on frequently utilized neuroimaging, best practice guidelines suggest the use of serial cognitive testing with symptom reporting as evidence-based concussion management. As such, neurocognitive tests are now routinely administered at the beginning of the sport season for use as a within-athlete comparison following concussion to determine the course of action for return-to-play decisions. The Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) is the most commonly utilized computer-based assessment for the management of concussion in sport. Although it is routinely administered, there are a number of psychometric and practical limitations that necessitate further exploration of ImPACT and its utility in clinical sport concussion care. This dissertation had three primary aims, with the overarching objective of investigating the psychometric properties of ImPACT in order to find ways to improve clinical care with this assessment. The three aims were, broadly, (1) to examine the base rates of underperformance for athletes with neurodevelopmental disorders in a naturalistic sample, (2) to determine the underlying factor structure of ImPACT, and (3) to further understand the subgroups that characterize the heterogeneity in post-concussion cognitive performance. Results from aim #1 found that athletes with neurodevelopmental disorders were classified as invalid more often than healthy athletes, suggesting a potential bias in the standard and two novel performance validity criteria. Aim #2 found support for a four-factor structure underlying ImPACT’s scores. Of note, the five composite structure currently utilized by ImPACT was not supported. Finally, aim #3 identified four unique subgroups of athletes whose post-concussion cognitive performance, symptom severity reporting, and decline from baseline to post-concussion differed. Findings have important implications for clinical management of sport concussion and provide an initial step towards advancing our understanding of the measurement of cognitive performance before and after sport concussion.

Controlled Subject

Brain--Concussion--Complications; Psychological tests


Clinical Psychology | Medical Neurobiology | Neuroscience and Neurobiology | Neurosciences

File Format


File Size

2100 KB

Degree Grantor

University of Nevada, Las Vegas




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