45 Mild traumatic brain injuries (mTBI) that result from participation in sports are a major 46 public health issue affecting 1.6 to 3.8 million individuals annually. The injury has been 47 postulated as transient and void of long term consequences when rapidly diagnosed and 48 properly managed. Emerging evidence however, has suggested an increased risk for late 49 life cognitive dysfunction in those with previous injuries. The purpose of this 50 investigation was to evaluate young adults with

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... nd without a history of concussion using 51 a standard clinical assessment and highly sensitive electrophysiological measures for 52 persistent changes in cognitive functioning. Ninety participants (19.7+1.3 yrs: 44 53 without mTBI and 46 with previous mTBI) were evaluated using the ImPACT and event-54 related brain potentials (ERPs) that were recorded during a three stimulus oddball task. 55 Those with a history of concussion reported an average of 3.4 years post-injury. No 56 significant differences were found between groups on the ImPACT. Significant 57 decrements in the N2 and P3b amplitudes of the stimulus-locked ERP were noted for 58 those with a history relative to those without a history of concussion. Although the 59 previously concussed participants performed equal to those without injury on the clinical 60 cognitive assessment, these findings support the notion that sport mTBI can no longer be 61 thought of as a transient injury resulting in short-lived neurological impairment. It is not 62 clear if these persistent deficits will manifest into clinical pathologies later in life. 63 64 65 Key Words: mild traumatic brain injury, electroencephalogram (EEG), event-related 66 potentials (ERP), P3, N2, novelty oddball 67 Page 2 of 30 Journal of Neurotrauma The persistent effects of concussion on neuroelectic indices of attention (