Prospective memory in the early stages of Alzheimer’s disease: Clinical implications and its relation to metamemory Prospective memory in the early stages of Alzheimer’s disease: Clinical implications and its relation to metamemory

Prospective memory, which is the timely execution of an intended action, is a multi- componential process that relies on multiple cognitive operations and conjoint functions of a distributed neural network. This cognitive construct has received growing attention because of its sensitivity to the early cognitive decline in Alzheimer’s disease (AD) and its functional relevance in real life. However, insufficient research has been conducted to develop practical tools for clinical assessment and to disentangle the underlying neuropsychological mechanisms. We thus performed four serial studies to examine the sensitivity of the screening methods and to investigate the role of the metamemory in prospective memory impairment of patients in the early stages of AD. In the first study, we evaluated the psychometric properties of the Taiwanese version of the Prospective and Retrospective Memory Questionnaire (PRMQ) in healthy adults. The results verified the internal reliability and construct validity of the PRMQ, where a general episodic memory factor and a specific prospective memory factor were fitted. In the second study we assessed the clinical utility of the informants’ ratings on the PRMQ. The results confirmed the internal reliability, criterion-related validity, and incremental validity of the informant form of the PRMQ. The informant-rated PRMQ also demonstrated good sensitivity and specificity in identifying patients diagnosed with dementia. In the third study, we examined if single-trail prospective memory tasks were capable of detecting subtle cognitive change in old adults who reported subjective cognitive decline (SCD) with normal performances on conventional cognitive tests. The results showed that a time-based prospective memory task, which additionally relies on self-initiated internal control, was a distinctively sensitive measure to detect this risk group of AD. In the fourth study, we measured metamemory functioning and observed its relation with prospective memory performance in patients with amnesic mild cognitive impairment (MCI). The results showed that the MCI patients performed poorly on the prospective memory test and evinced less costs of speed when performing concomitant activities. However, their metacognitive knowledge and prospective monitoring of prospective memory abilities were compatible to those of the controls. The present thesis highlights the significance and feasibility of prospective memory assessment in clinical practice, especially for the early detection of AD. Based on the present findings, we thus recommend using the PRMQ and time-based prospective memory tasks for the initial evaluation. Furthermore, since poor metacognitive control did contribute to the prospective memory impairment in patients with MCI, it thus appears necessary to highlight the role of the theoretical elements of metamemory in developing neurorehabilitation programs that aid individuals with prodromal AD. Nevertheless, longitudinal studies are needed to verify the prognostic value of prospective memory tests.