Introduction: Tests of memory and speed of cognitive and motor responses have been the primary foci in sports-related concussion assessment. This study sought to assess the construct validity of neuropsychological tests within C3 Logix.
Method: Results of both baseline C3 Logix and the Immediate Post-Concussion Assessment and Cognitive Test (ImPACT) computerized tests from 86 Division I collegiate athletes were submitted to a two-factor confirmatory analysis using structural equation modeling. The two factors of Speed and Memory have been confirmed in previous studies of ImPACT.
Results: Results confirmed the two-factor model of ImPACT, whereas C3 Logix did not conform to a pure two-factor model. Instead, along with additional error terms, a cross-loading was required between Speed and Memory factors in order to obtain the best model fit (χ2 = 22.91, p= 0.12, CFI = 0.94, TLI = .90, RMSEA = 0.07 (90% CI [0.00, 0.13], SRMR = .06)): all factor loadings exceeded 0.30.
Conclusions: The final model suggested C3 Logix employs three pure indicators of Speed and one indicator of both Speed and Memory. The lack of a pure indicator of Memory in C3 Logix raises a concern about its specificity and ultimately, its sensitivity to a sports-related concussion.