Objective: Prior work suggests that inclusion of a familiarization session (an initial completion of a task prior to baseline assessment) in interventional study designs may reduce the likelihood that any increases in performance from baseline to follow-up testing sessions are due to practice effects or increased familiarity with the test administration procedure, thereby increasing the fidelity to detect therapeutic interventions. This study examined the utility of a familiarization session as a means of mitigating practice effects on subsequent administrations of the Adaptive Tracking Task (ATT). The ATT is a novel tablet-based measure developed by Cambridge Cognition which requires the participant to track a moving target using their index finger. The speed of the target is adjusted throughout task completion depending on performance, to ensure adaptation to the participant’s ability, thereby providing a more individualized and sensitive assessment of visuomotor coordination and vigilance than is available by traditional tasks. Tasks such as the ATT are invaluable when assessing conditions with known attention and psychomotor speed impairments (e.g., Parkinson’s Disease).

Participants (n = 26, mean age = 29.7 (SD = 9.3), 54% male) were recruited online via Prolific (www.prolific.co) and completed the ATT at three time points (Familiarization/Visit 1, Visit 2 and Visit 3) approximately one month apart. The primary outcome variable was the mean ‘difficulty multiplier’, which is a calculation adjustment of the participant’s accuracy on target relative to current target speed, within a pre-specified smoothing window, averaged over the entire testing session.  This task consists of two separate phases; during Phase 1, the target continuously moves across the screen in a fixed pattern with a predictable trajectory, while during Phase 2 the target continuously moves across the screen in a random pattern with an unpredictable trajectory.

Participants showed a modest (though statistically non-significant) improvement in their Phase 1 mean difficulty multiplier from familiarization (Visit 1) to Visit 2 (t (50) = -.98, p = .33). No such improvement was observed from Visit 2 to Visit 3 (t(49) = -.31, p = .76). Similarly, participants showed a modest but non-significant improvement in their Phase 2 mean difficulty multiplier from familiarization to Visit 2 (t(50) = -1.22, p = .23), while no such improvement was observed from Visit 2 to Visit 3 (t(49) = .35, p = .73).

Both with regards to Phase 1 and Phase 2, a familiarization session may allow for stabilization in ATT performance across subsequent sessions. Interventional trials incorporating the ATT, such as those aimed at treating motor disease-related conditions, would benefit from inclusion of a familiarization session to reduce familiarity/practice effects and enhance detection of treatment effects.