Use of computer-based neuropsychological testing to identify impairments in high school players without concussion symptoms

A group of individuals was identified by Talavage et al. who exhibit neurological changes similar to or greater than individuals who are diagnosed with a concussion but do not demonstrate any clinical signs or symptoms of concussion (i.e., functional impairment). If not diagnosed, those individuals continue to play and continue to take blows to the head putting them at risk for long-term brain injury. Therefore, the identification of these functionally impaired individuals is of the utmost importance. The objective of this study was to evaluate the reliability of using the ImPACT neuropsychological testing battery to identify individuals who demonstrate neuropsychological impairment but who do not have clinical signs or symptoms. A prospective study at a single mid-western high school of 11 high school male football players (aged 15-19 years) was conducted. Participants who exhibited neurocognitive deficits were flagged by ImPACT as having a statistically lower score in either the visual memory composite or the verbal memory composite score. The reported change in the visual memory composite score from the ImPACT was not able to identify either the functionally or clinically impaired groups. The change in the verbal memory composite score relative to baseline was able to identify the clinically impaired group (p-value=0.0106) but not the functionally impaired group. The ImPACT results were also analyzed using a worst change score which was computed by identifying the greatest change in either the verbal or visual memory composite score. The worst score was able to predict both the clinically impaired group (p-value=0.0461) and the functionally impaired group (p-value=0.0288). A linear regression was run on the verbal memory composite score, the visual memory composite score, and the worst score for all non-concussed participants. ImPACT was able to correctly identify concussed individuals and gave no false positives with non-concussed individuals but there was no single score that was able to consistently identify individuals with functional impairments relative to the non-impaired group. A regression analysis of regional fMRI activity as a function of the ImPACT score found moderate correlation in the frontal and temporal lobes with the worst score. In conclusion, no single ImPACT generated metric can correctly indentify functional impairments