Comparison of PC and iPad administrations of the Cogstate Brief Battery in the Mayo Clinic Study of Aging: Assessing cross-modality equivalence of computerized neuropsychological tests.

Objective: Computerized neuropsychological assessments are increasingly used in clinical practice, population studies of cognitive aging and clinical trial enrichment. Subtle, but significant, performance differences have been demonstrated across different modes of test administration and require further investigation. Method: Participants included cognitively unimpaired adults aged 50 and older from the Mayo Clinic Study of Aging who completed the Cogstate Brief Battery and Cogstate's Groton Maze Learning Test (GMLT) on an iPad or a personal computer (PC) in the clinic. Mode of administration differences and test-retest reliability coefficients were examined across 3 cohorts: a demographically matched test-retest cohort completing PC and iPad administrations the same day (N = 168); a test naïve cohort comparing baseline PC (n = 1820) and iPad (n =605) performance; and a demographically matched longitudinal cohort completing 3 Cogstate visits over 15 months on either the PC (n =63) or iPad (n =63). Results: Results showed a small but statistically significant and consistent finding for faster performance on PC relative to iPad for several Cogstate Brief Battery measures. Measures of accuracy generally did not differ or differences were very small. The GMLT showed faster performance and higher total errors on iPad. Most Cogstate variables showed no difference in the rate of change across PC and iPad administrations. Conclusions: There are small, but significant, differences in performance when giving the same cognitive tests on a PC or an iPad. Future studies are needed to better understand if these small differences impact the clinical interpretation of results and research outcomes.