Performance change while learning novel cognitive tasks as a potential identifier of preclinical Alzheimer's disease.

BACKGROUND

In healthy older adults (OA), the effects of amyloid-β (Aβ) deposition on cognitive functions involved in learning are unclear.

OBJECTIVE

This study aimed to determine how age, practice, and neuropsychological test performance are associated with performance change during the learning of three cognitive tasks, and if Aβ deposition impacts performance change in OA.

METHODS

Fifty-five OA and 28 young adults completed neuropsychological tests, and Aβ deposition was assessed in OA. Participants learned three cognitive tasks: stop-go normal task (SGNT), stop-go reverse task (SGRT), and -back task (NBT). Performance change was analyzed as change in accuracy and reaction time from the first to second and the first to third practice trials using linear mixed effect models. The basic model included age group and performance change, with neuropsychological test covariates. The second basic model mimicked the first but included Aβ deposition, instead of age group.

RESULTS

In the basic model, more practice resulted in a larger performance change for SGNT and SGRT, but not NBT. In the second basic model, after two NBT practice trials, performance change increased with greater amounts of Aβ deposition and worse information processing speed but, after three practice trials, decreased with greater amounts of Aβ deposition and worse information processing speed. Across the three tasks, greater Aβ deposition tended (non-significant trend) to be associated with smaller improvements after more practice.

CONCLUSIONS

These results suggest that the ability to learn a cognitive task is maintained with age but is negatively impacted by Aβ deposition.