B – 155 Test Complexity and Speed-Accuracy Dynamics Influence Practice Effects on Repeated Digital Self-Administered Cognitive Tasks

Objective Observe whether practice effects occur among cognitively unimpaired adults in digital, self-administered cognitive tasks at three-month intervals across four timepoints. Method Participants included 448 cognitively unimpaired adults (average age 63.9 years, 33.5% male, 90.9% white, 67.4% college graduates) enrolled in the Framingham Heart Study. Inclusion criteria included smartphone ownership, Wi-Fi access, and English fluency. Participants self-administered three subtests from the Digital Automated Neurobehavioral Assessment (DANA) battery —Simple Reaction Time (SRT), Go/No-Go (GNG), and Code Substitution (CS)—at four tri-monthly timepoints. Outcomes included response time (RT), accuracy (ACC), and cognitive efficiency (CE: ACC divided by RT, scaled). Repeated measures ANOVA and η2 were used to evaluate changes in each outcome over time. Results All three tests showed significant improvements (p < .001) in response time and cognitive efficiency across timepoints. When considering both significance and small effect size (η2 ≥0.01), SRT showed effects only for accuracy, while GNG and CS showed effects for response time and cognitive efficiency, but not accuracy. The largest changes for all tests occurred between T1-T2; GNG and CS continued to improve across subsequent timepoints, while SRT plateaued after T2. Conclusion Distinct speed-accuracy dynamics appeared to influence practice effects based on task complexity. Effects were larger on more complex tasks (CS, GNG) and driven primarily by improved response speed, not accuracy. Meanwhile, improvements on the simpler task (SRT) were smaller and more driven by accuracy. Findings demonstrate practice effects specific to the present tasks, sample characteristics, and test-retest intervals. Speed-accuracy dynamics and task complexity shape longitudinal cognitive performance.