Robust Demographically-Adjusted Normative Data for Unsupervised, Self-Administration of the Cogstate Brief Battery

Existing normative data for the Cogstate Brief Battery (CBB) are non-robust, non-regression-based, and only adjust for age. The aims of the present study were to examine the effects of age, gender, education, and ethnocultural group on individual subtests of the unsupervised, self-administration of the CBB; to develop robust, demographically-adjusted normative data for the CBB; and to compare participants’ rates of impairment based on the new robust, demographically-adjusted CBB normative data versus the existing, non-robust, age-adjusted CBB normative data. A sample of 14,920 ethnoculturally diverse, cognitively unimpaired, community-dwelling adult participants completed the unsupervised, self-administered CBB through their participation in the longitudinal Brain Health Registry study. Results revealed significant independent effects of age, gender, education, and ethnocultural group on performance for all four CBB subtests, with the exception of gender not demonstrating an independent effect on performance on the One Card Learning (visual learning) subtest. Following development and application of robust, demographically-adjusted normative equations, demographic variables showed minimal, nonsignificant effects on all robust CBB T-scores and T-score composites. In comparison to impairment rates based on robust CBB T-scores, impairment rates based on non-robust, age-adjusted CBB z-scores showed significantly different rates of impairment in at least four CBB outcome measures for each individual demographic group. The present study offers potential for increasing the clinical utility of a remotely administered, brief cognitive test battery. The advantages of remote cognitive assessment, including increased access, repeated screening, cost efficiency, large-scale research potential, and increased generalizability, cannot be overstated. Prior to this study, U.S.-based normative data on the CBB did not exist, let alone robust, demographically-adjusted normative equations specifically for the self-administration format of the CBB. As such, this study represents an important methodological step forward by allowing users of the CBB to administer the battery for both research and clinical purposes. Importantly, users of demographically-adjusted norms are advised to consider the sociocultural makeup of the normative samples they are applying to patient data whenever possible, and to thoroughly assess the sociocultural context from which their patients present, all to assist in making clinical interpretations that account for the whole person