Working Memory Precision and Associative Binding in Mild Cognitive Impairment.

Abstract

To better understand working memory (WM) deficits in Mild Cognitive Impairment (MCI), we examined information precision and associative binding in WM in 21 participants with MCI, compared to 16 healthy controls, using an item-location delayed reproduction task. WM, along with other executive functions (i.e. Trail Making Task (TMT) and Stroop task), were measured before and after a 2-h nap. The napping manipulation was intended as an exploratory element to this study exploring potential impacts of napping on executive functions.Compared to healthy participants, participants with MCI exhibited inferior performance not only in identifying encoded WM items but also on item-location associative binding and location precision even when only one item was involved. We also found changes on TMT and Stroop tasks in MCI, reflecting inferior attention and inhibitory control. Post-napping performance improved in most of these WM and other executive measures, both in MCI and their healthy peers.Our study shows that associative binding and WM precision can reliably differentiate MCIs from their healthy peers. Additionally, most measures showed no differential effect of group pre- and post-napping. These findings may contribute to better understanding cognitive deficits in MCI therefore improving the diagnosis of MCI.