Losing the Life: A Review on Autobiographical Memory in Alzheimer's Disease

Abstract

Alzheimer's disease (AD), the most common type of dementia among older adults, is a progressive and neurodegenerative brain disease. AD is characterized by progressive memory impairments, but not other types of dementia. Autobiographical memory (AM) is defined as episodes recollected from individuals' life, and it is one of the memory systems impaired in AD. One consequence of AM decline in AD is difficulties in the retrieval of recent AMs rather than past ones. AM contains both episodic and semantic components, and it is crucial for self-concept. The aim of the present study is to review the current understanding of AM in people with AD. In the introduction part of the review, AD and its cognitive correlates are presented in detail, with how AM performance is important for the self. In the second part of the review, AM deteriorations in patients with AD are discussed. Factors, such as emotion and olfaction, affecting AM are mentioned along with the neural substrates. In this regard, the effect of the emotional dimension (e.g., valence) on the formation and retrieval of AMs is discussed and how AM is studied with olfactory stimuli is presented, respectively. Studies on the link between AM and emotion have shown that there is a positive shift of AM in AD, indicating that patients with AD remember their AMs more positively. In addition, olfactory stimuli evoke more AMs than verbal and visual stimuli. The conclusion section of the current review is devoted to some recommendations that might guide future research. For instance, stage-by-stage investigation of AM in AD and the comparison of them in relation to relevant variables could be one way of providing detailed findings on the nature of AM in AD.