Prospective Memory in Healthy Aging, Subjective Cognitive Decline and Mild Cognitive Impairment

: A Magnetic Resonance Imaging Study

Abstract

Prospective memory (PM) is defined as remembering when an action needs to take place following a cue (event-based or time-based). Alzheimer’s Disease (AD) patients have an impairment in PM and almost 50% of patients with mild cognitive impairment (MCI) are expected to develop AD. Recent research has focused on a potential pre-MCI stage named Subjective Cognitive Decline (SCD) in which subjects perform similar to healthy individuals in standard tests yet declare a decline in their everyday memory functioning. We propose that PM might provide a more valuable insight into individual’s everyday memory functioning, which is not necessarily reflected in standard tests. Furthermore, neuroimaging studies show that atrophy in specific brain regions (e.g. rostral prefrontal cortex) is linked with impairment in PM. This study aimed to investigate the role of PM tasks as an early marker of functional decline in preclinical AD populations and explore potential links with cortical thickness as a proxy of brain structure. 84 participants including healthy controls (HC) (n=26), people with SCD (n=29) and patients with MCI (n=29) were tested using cognitive assessments including three event-based PM tests from the Rivermead Behavioural Memory Test-3 and the Nottingham Extended Activities of Daily Living Scale (NEADL). Most participants also underwent structural MRI to examine cortical thickness. Findings showed PM performance to be correlated with NEADL scores, suggesting a decline in PM reflects a decline in independent functioning. Furthermore, PM was found to be correlated with average whole brain cortical thickness. In group-based analyses, patients with MCI performed significantly worse than HC and SCD groups in all aspects of PM. These findings suggest that PM tasks could provide good insight into everyday functioning in individuals at risk of developing dementia. Thus, PM tasks could be implemented into clinics to provide a useful guide to ‘everyday’ functional decline in incipient AD.

Date of Award	25 Sept 2018
Original language	English
Awarding Institution	University of Bristol
Supervisor	Risto Kauppinen (Supervisor) & E J Coulthard (Supervisor)