Reaction time as a performance validity measure in older adults with and without early-stage Alzheimer's disease

Performance validity assessment is important in evaluating older adults with and without cognitive impairment. Performance validity tests (PVTs) such as the Test of Memory Malingering (TOMM) may inaccurately classify Alzheimer's disease (AD) patients as testing invalid despite genuine effort. We explored an alternative PVT using reaction time (RT).

Healthy older controls (OCs; N = 20) and AD patients (N = 20) completed an auditory oddball task and the TOMM. Over two counterbalanced sessions, OCs performed honestly and simulated dementia; AD patients completed one honest session.

RT differed between OC honest and simulating conditions and between AD and OCs in both conditions. Using a composite reflecting RT differences between true positives and false alarms, simulators took more time generating false alarms than true positives compared to AD patients (p = 0.021; r = 0.364). The composite did not differ between OC honest and AD groups. The RT composite showed comparable specificity to the TOMM in classifying AD patients (80% vs. 75% for TOMM Trial 2 and 65% for Trial 1).

The RT composite performed similarly to the TOMM without relying as heavily on episodic memory. It warrants investigation as a complement to memory-based PVTs. Future studies should replicate these findings in larger, education-matched samples.