The impact of time and repeated exposure on famous person knowledge in amnestic Mild cognitive impairment and Alzheimer’s disease

Objective: Famous people knowledge has been shown to be impaired early in Alzheimer’s disease (AD) and amnestic mild cognitive impairment (aMCI). However, the question of whether recently acquired knowledge is more impaired than remotely acquired knowledge remains a matter of debate. The aim of this study was to investigate the patterns of semantic memory impairment in aMCI and AD by investigating two factors that may influence the retrieval of such knowledge, namely remoteness and frequency of repetition of information over time. Method: Three groups (19 controls, 20 aMCI and 20 AD patients) were compared on a test assessing general and specific biographical knowledge about famous people, where the period of acquired fame (remote vs recent) and the type of fame (enduring vs transient) were controlled for. Results: Global performance of aMCI and AD patients was significantly poorer than that of controls. However, different patterns of recall were observed as a function of time and type of fame. A temporal gradient was found in both patient groups for enduring names but not for transient ones, whereby knowledge about remote enduring famous persons was better recalled. Patients were more impaired at questions assessing specific biographical knowledge (unique to an individual) than more general knowledge. Conclusions: Tests of famous people knowledge offer a unique opportunity to investigate semantic deficits in aMCI and AD, because they make it possible to estimate the time at which memories were acquired, as well as the type of fame. Results are discussed in light of memory consolidation models. Keywords