A-222 Normative Reference Values for Crystallized-Fluid Discrepancy Scores for the NIH Toolbox Cognition Battery

Abstract

Abstract Objective: To translate NIH Toolbox Cognition Battery (NIHTB-CB) Crystallized-Fluid discrepancy scores into research and clinical practice with adults by providing normative data for discrepancy scores for both age-adjusted standard scores and demographic-adjusted T-scores. Method: We included adult participants from the NIHTB-CB standardization sample who completed all seven neuropsychological tests and who denied having neurodevelopmental, medical, psychiatric, or neurological conditions (n=730; M=47.4 years-old, SD=17.6, range: 18-85; 64.4% women; 63.1% White). Descriptive statistics were calculated for the Fluid and Crystallized composite scores and the Crystallized-Fluid discrepancy score, along with the correlation between the two composite scores. Percentiles were calculated for the discrepancy score, with stratifications by gender, education, and Crystallized composite for the age-adjusted standard scores (SSs) and only the Crystallized composite for the demographic-adjusted T-scores (T). Results: Crystallized-Fluid discrepancy scores ranged from -40 to 44 (M=-0.63, SD=14.89, Mdn =-1, interquartile range=-11-10) for age-adjusted SSs and from -29 to 27 (M=-0.39, SD=10.49, Mdn=-1, IQR=-8-7) for demographic-adjusted T-scores. Using age-adjusted SSs and demographic-adjusted T-scores, Crystallized-Fluid discrepancy scores of SS=15 and T=11 were at the 16th percentile (1 SD below the mean) and discrepancy scores of SS=21 and T=15 were at the 7th percentile (1.5 SDs below the mean). Conclusions: Crystallized-Fluid discrepancy scores might prove to be, with future research, a useful within-person interpretive approach for detecting decline from pre-injury or pre-disease levels of cognitive functioning. These normative reference values assist clinicians and researchers in determining the frequency at which given Crystallized-Fluid discrepancy scores occurred among healthy adults in the normative sample.