Prevalence of Undiagnosed Concussion in Adolescent Athletes Based on Neuropsychological Declines Open Access

Herzog, Mackenzie Marie (2014)

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Prevalence of Undiagnosed Concussion in Adolescent Athletes Based on Neuropsychological Declines

Background: The effect of repeated impacts to the head during athletics, especially those at a subclinical level, is not well understood. We define undiagnosed concussion as traumatic brain injury that is not detected or reported. Reliable Change Index (RCI) for ImPACT can be used to identify athletes who have sustained a probable undiagnosed concussion, based on score declines in composite scores or symptom scale that indicate clinically significant change.

Hypothesis/Purpose: The purpose is to determine the prevalence of undiagnosed concussion based on neuropsychological score declines among adolescent athletes without diagnosis or report of a clinical concussion. In addition, we will compare the prevalence of undiagnosed concussions amongst sports.

Study Design: Cohort Study

Methods: Adolescent athletes, who had 2 baseline ImPACT tests 8 months to 2 years apart, without diagnosis or report of concussion, were retrospectively identified and included in this IRB-approved study. Athletes were aged 12-18 years and underwent initial baseline ImPACT test between 2010-2012. Athletes with impulse control composite scores >30 were excluded. Sports included football, boys' lacrosse, boys' soccer, girls' soccer, and wrestling. Clinically significant change was assessed using previously published 95% RCIs for high school athletes. Athletes who showed declines in test scores >95% RCI from test to retest were considered to have a potential undiagnosed concussion.

Results: Of 290 athletes, 42 (14.5%) showed cognitive function declines indicative of undiagnosed concussion. Football players had almost 2 times the risk of having undiagnosed concussion as participants in all other sports, when controlling for history of ADD/ADHD (RR=1.84; 95%CI: 1.11,3.06; p=0.004). Time between tests, age, hours of sleep, or years active in sport were not associated with undiagnosed concussion.

Conclusion: This study found that 14.5% of included adolescent athletes sustained a potential undiagnosed concussion, with football players having double the risk of other athletes. To our knowledge, this study is the first to attempt to identify the prevalence of undiagnosed concussion among adolescent athletes by assessing declines in neuropsychological test scores in the absence of clinically detected concussion. Findings demonstrate that the burden of sports-related concussion among adolescent athletes is potentially greater than the reported incidence rates.

Table of Contents

Table of Contents

Chapter 1: Manuscript for Submission for Publication pg. 1

Introduction pg. 1

Materials and Methods pg. 4

Results pg. 9

Discussion pg. 10

Significance pg. 17

References pg. 18

Tables pg. 21

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