Subjective memory complaints as a predictor of mild cognitive impairment and Alzheimer\u2019s disease

Samuel L Warren,Edwina Reid,Paige Whitfield,Ahmed A Moustafa

doi:10.1007/s44202-022-00031-9

Abstract

While there is a multitude of studies on mild cognitive impairment (MCI; more than 80,000 articles), subjective memory complaints (SMC) have received less attention as a prodromal stage of Alzheimer’s disease (AD; less than 2000 articles). In this perspective review article, we argue that SMC should also be considered as another risk factor for the development of AD, and perhaps a pre-MCI condition. This recognition of SMC could help clinicians to identify individuals at risk of developing dementia and could provide protective treatment for them. Accordingly, in this perspective article, we review key studies that outline the nature of SMC, discuss how SMC is measured, explore SMC in MCI, introduce some approaches to SMC treatment, and we discuss future directions for SMC research. Overall, we argue that, like MCI, there should be more research on SMC as a risk factor for developing AD. Consequentially, we aim to highlight the need for further research on SMC and the condition’s role as a potential neuroprotector against AD (e.g., early-stage marker).

Highlights

Alzheimer’s disease (AD) is a neurodegenerative disorder with an insidious onset that progresses through cognitive, functional, and behavioural impairment [1, 2]
Miley-Akerstedt et al [32] found that individuals with subjective memory complaints (SMC) and no objective cognitive decline had more years of education, more sleep problems, and a lot to do in their daily lives when compared to those who had SMC and objective memory problems
We have outlined the concept of SMC, discussed current measures for SMC, discussed SMC in mild cognitive impairment (MCI), and touched on some approaches to SMC treatment

Summary

Introduction

Alzheimer’s disease (AD) is a neurodegenerative disorder with an insidious onset that progresses through cognitive, functional, and behavioural impairment [1, 2]. Researchers often focus on pre-dementia conditions, such as mild cognitive impairment (MCI), to observe AD progression and identify at-risk individuals. A search for MCI returns approximately 80,000 results in the PubMed database while the term SMC nets less than 2000 results In this perspective article, we review key papers associated with SMC and the prediction of MCI or AD. Each article was found using online databases (e.g., PubMed) and was included via reviewer consensus if the paper discussed SMC as a predictor or prodromal stage of MCI or AD. This perspective review aims to discuss SMC as a precursor to dementia and argue that it is a critical area of AD research. We aim to highlight the current literature on SMC, discuss how SMC is a risk factor or transitional stage for MCI and AD, and stress avenues for future research

What is SMC?

Measuring SMC

SMC in MCI

SMC treatment

Findings

Conclusions and future directions