The purpose of this research was to determine if cortical metrics-a unique set of sensory-based assessment tools-could be used to characterize and differentiate concussed individuals from nonconcussed individuals. Cortical metrics take advantage of the somatotopic relationship between skin and cortex, and the protocols are designed to evoke interactions between adjacent cortical regions to investigate fundamental mechanisms that mediate cortical-cortical interactions. Student athletes, aged 18 to 22 years, were recruited into the study through an athletic training center that made determinations of postconcussion return-to-play status. Sensory-based performance tasks utilizing vibrotactile stimuli applied to tips of the index and middle fingers were administered to test an individual's amplitude discrimination, temporal order judgment, and duration discrimination capacity in the presence and absence of illusion-inducing conditioning stimuli. Comparison of the performances in the presence and absence of conditioning stimuli demonstrated differences between concussed and nonconcussed individuals. Additionally, mathematically combining results from the measures yields a unique central nervous system (CNS) profile that describes an individual's information processing capacity. A comparison was made of CNS profiles of concussed vs. nonconcussed individuals and demonstrated with 99% confidence that the two populations are statistically distinct. The study established solid proof-of-concept that cortical metrics have significant potential as a quantitative biomarker of CNS status.
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