Biases in online vs. paper-pencil number line tasks in older adults

Digital and web-based at-home tests are increasingly important in neuropsychological assessments, providing various advantages (e.g., automated response recording, time, and cost savings). Extensive comparability between paper-based and online testing has been demonstrated, particularly for adults. However, there is limited evidence on possible testing mode effects (i.e., differences between paper-based and online testing) in older adults (>60 years), who often exhibit minor digital adoption (e.g., affecting visual, perceptual, cognitive, and physical abilities) due to typical age-related changes. In the present study, the effects of test mode were compared between web-based at-home and supervised paper-based testing in a between-participant design using the pseudoneglect in line bisection and number line estimation tasks in 77 neurologically healthy adults (36 female) aged 60 and above. Line bisection is a clinically frequently used test after stroke, and pseudoneglect is an unconscious but systematic neuropsychological phenomenon observed in this test. Results showed that the pseudoneglect was present in both testing environments in all (number) line bisection tasks, while the pseudoneglect did not differ between the groups in mean or variance. However, web-based at-home online testing resulted in a larger skew (i.e., more S-shaped curvature) of estimation in all number line estimation tasks. This bias can be explained by the amended response format (pencil vs. computer mouse). In conclusion, we consider only online line bisection tasks in older adults to be directly comparable to paper-pencil testing, with all the advantages of online data acquisition.