Differences on autobiographical memory in healthy aging and Alzheimer’s disease

Abstract

AbstractBackgroundAutobiographical memory (AM) refers to memories from one’s past that are characterized by a sense of subjective time and autonoetic consciousness which involves a feeling of re‐experiencing or reliving the past. Cognitive aging research indicates age‐related deficits in episodic AM, whereas semantic AM is unimpaired in healthy older adults. Regarding research involving subjects with dementia had showed that episodic memories deteriorate rapidly in Alzheimer's disease (AD), whereas semantic memories are preserved until moderate stages. This study aims to compare healthy older adults and AD patients, on the type of AM in order to identify differences between the groups.MethodThirty patients with initial AD, and 46 healthy older participants matched on age and education took part in the present study. Participants underwent a neurological and neuropsychological assessment. To evaluated AM, Autobiographical Memory Interview (AMI) was applied. AMI is a semi‐structured interview, applicable to subjects from 18 years old, that evaluates the two components of AM: semantic and episodic. For the study, MANOVA was performed to determine whether there were differences between groups on AM components.ResultThe multivariate contrasts revealed a main effect of group (Λ = .701; F(2, 73) = 85.57; p < .001). Therefore, post hoc Tukey tests were performed for each dependent variable, and significant differences were obtained on all the measures studied. Healthy older people obtained higher score than AD on the episodic AM (F(1, 75) = 8.14; p < .001) and on semantic AM (F(1, 75) = 164.5; p < .001).ConclusionAutobiographical recall in AD is mainly characterized by a substantial loss of episodic and semantic information, leading to a decontextualization of autobiographical memories and a shift from mentally reliving past events to a general sense of familiarity. This decline is exacerbated by anterograde and retrograde amnesia, leaving AD patients with limited access to memories that shape self‐consciousness, self‐knowledge, and self‐images.