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Abstract
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INTRODUCTION: Repetitive brain trauma (RBT) in American football has become a topic of recent interest. The objective of this study was to assess the interrelationships among neuroimaging findings with neurocognitive test performance and symptom endorsement in a cohort of retired professional (National Football League [NFL]) football players.
METHODS: Magnetic resonance imaging (MRI) scans were performed in 45 retired NFL players. Three neuroimaging parameters were recorded by blinded, board-certified neuroradiologists: (1) the absence or presence of small or large cavum septum pellucidum; (2) a global mean score of fractional anisotropy (FA); and (3) the presence or absence of microhemorrhages (microbleeds). The subjects underwent a battery of 9 paper-and-pencil neuropsychological tests (yielding 12 separate scores), a computerized neurocognitive test, and multiple (4) symptom and depression scales. The associations among the 3 independent neuroimaging results with these outcome measures were assessed using Pearson, Spearman Rank, and Point-Biserial Correlations.
RESULTS: Data from 45 retired NFL players (average age: 46.7 years) were analyzed. The retirees reported an average of 6.9 (±6.2) concussions and 13.0 (±7.9) sport-related "dings" in the NFL. Assessment of cavum septum pellucidum yielded a negative finding in 10 subjects (22%), while 32 (71%) had a small, and 3 (7%) had a large one. Four (9%) of the subjects had microhemorrhages present and average FA mean was 0.459 (±0.035). Number of sport-related "dings" was correlated with an increased risk of microhemorrhages (r = 0.305, P =.042). The majority (50.8%) of the correlations obtained among the 3 neuroimaging parameters and the neurocognitive/symptom scores were below the threshold of a "small" effect size (r < 0.10). The remaining (49.2%) correlations fell somewhere between "small" and "medium" effect sizes (0.1 < r < 0.3). However, all correlations were statistically nonsignificant.
CONCLUSION: The current results demonstrate minimal and statistically nonsignificant correlations among neuroimaging, neurocognitive, and symptom scores in a cohort of NFL retirees. The results indicate that, in this cohort, neuroimaging findings do not relate directly to neurocognitive test performance and clinical symptom burden. Although an often-accepted paradigm, associating the severity of structural brain changes with neurocognitive performance and symptom presentation after chronic RBT is complex, may involve other moderating variables, and requires further study.
Language: en |