A critical need in the neuropsychology field is development and validation of efficient, scalable assessments of cognition. The Mobile Toolbox (MTB), a novel suite of mobile device-compatible, app-based cognitive assessments, was developed to address this need. The goals of this study were (1) To collect longitudinal normative data for the MTB assessments in a large, ethnoculturally and educationally diverse cohort; (2) To assess the feasibility and usability of remote assessment using MTB.

Participants were recruited from the UCSF Brain Health Registry (BHR), an online cohort (N>100,000) that collects longitudinal cognitive, functional, behavioral, and health data using online neuropsychological tests and self- and study-partner report surveys. BHR participants who opted to learning about additional research opportunities were sent automated email invitations to enroll in the MTB study. Those who indicated study interest were provided instructions within the BHR online portal for downloading the MTB app. All participants had the opportunity to complete a single baseline administration of MTB (Word Meaning, Sequences, Spelling, Arranging Pictures, Arrow Matching, Faces and Names, Shape-Color Sorting, Number Match). Those who completed the baseline assessment within three days were invited to continue into the longitudinal study, where they complete MTB assessments at a single, short-term timepoint (day 7, 14, or 21; study arms sequentially assigned), and then at 6-month intervals. Enrollment across demographic groups was monitored, and study invitations were sent to specific demographic groups, with the goal of enrolling a sample of 800 participants in the longitudinal study: equal distribution across eight, 10-year age bands (ages 18-80+); 60% with <16 years of education; 10% non-Latinx Black, 15% Latinx, and 5% non-White other ethnocultural identity.

Between January-June 2022, 48,110 BHR participants were invited to the MTB study. Of those, 8294 (17%) expressed interest, 3401 (7%) completed the baseline assessment, 850 (1.8%) were assigned to the longitudinal study, and 782 (1.6%) completed a short-term longitudinal assessment. Study staff received 797 help tickets submitted by participants asking for email support to complete MTB. The baseline cohort had and average age of 64 years and an average of 16.6 years of education, 76.2% female, 2.1% non-Latinx Black, 7.1% Latinx, 86.8% non-Latinx White, and 4% from other ethnocultural groups. The longitudinal cohort had an average age of 62.3 years and an average of 16.1 years of education, 80% female, 2.8% non-Latinx Black, 8.5% Latinx, 83.5% non-Latinx White; and 5% other ethnocultural group. Compared to those invited to the study, those who enrolled in the longitudinal study were older, had higher educational attainment, and were more likely to be female and self-identify as non-Latinx White (p<0.05 for all).

Efficient enrollment and task completion of a large cohort in a novel, app-based mobile cognitive assessment is feasible in a completely remote setting. Most participants were able to complete MTB without individual support, indicating good usability. This approach can be scaled up to efficiently assess cognition in many research and healthcare settings. A remaining challenge is achieving robust ethnocultural and educational diversity.