Dynamic working memory performance in individuals with single-domain amnestic mild cognitive impairment

Abstract

Previous studies have observed poorer working memory performance in individuals with amnestic mild cognitive impairment than in healthy older adults. It is unclear, however, whether these difficulties are true only of the multiple-domain clinical subtype in whom poorer executive functioning is common. The current study examined working memory, as measured by the self-ordered pointing task (SOPT) and an n-back task, in healthy older adults and adults with single-domain amnestic mild cognitive impairment (aMCI). Individuals with single-domain aMCI committed more errors and required longer to develop an organizational strategy on the SOPT. The single-domain aMCI group did not differ from healthy older adults on the 1-back or 2-back, but had poorer discrimination on the 3-back task. This is, to our knowledge, the first characterization of dynamic working memory performance in a single-domain aMCI group. These results lend support for the idea that clinical amnestic MCI subtypes may reflect different stages on a continuum of progression to dementia and question whether standardized measures of working memory (span tasks) are sensitive enough to capture subtle changes in performance.

Keywords:

• Mild cognitive impairment
• Working memory
• Dynamic working memory
• Memory span
• Cognition

We sincerely thank Kashfia Alam, Brian Mainland, Magdalena Lysenko, Sandra Priselac, and Sarah Waters-Schulte for their assistance in data collection and Patricia Ebert for her contributions to this project.

Notes

¹ The significant linear within-subjects contrast observed for the trial by group interaction remained when gender and age were each analyzed as a covariate.

² The significant group by trail pair interaction remained when gender and age were each analyzed as a covariate.

³ The significant linear within-subjects contrast observed for the task by group interaction remained when gender and age were each analyzed as a covariate.