Does retrieval frequency account for the pattern of autobiographical memory loss in early Alzheimer's disease patients? Maria Stefania De Simone a,n , Lucia Fadda a,b , Roberta Perri a , Marta Aloisi a , Carlo Caltagirone a,b , Giovanni Augusto Carlesimo a,b a Laboratory of Clinical and Behavioral Neurology, IRCCS Santa Lucia Foundation, Rome, Italy b University “Tor Vergata” Rome, Italy article info Article history: Received 4 August 2015 Received in revised form 18 November 2015 Accepted 28 November 2015 Available online 30 November 2015 Keywords: Alzheimer's disease Autobiographical memory interview Multiple trace theory Retrieval frequency Cortical reallocation theory abstract Episodic autobiographical memory (ABM) has been found to be impaired from the early stage of Alz- heimer's disease (AD). Previous works have focused on how ABM decreases over the lifespan, but no study has deeply investigated whether the extent of episodic autobiographical amnesia is mediated by the retrieval frequency of the episodic trace itself. The aim of the present study was to determine whether the frequency of trace retrieval has an effect on the quality of autobiographical incidents recall and whether the extent of this contribution changes over time. For this purpose, the episodic component of ABM was assessed in patients in the early stage of AD through a questionnaire which allowed eval- uating memory of past personal incidents as a function of both their age of acquisition and retrieval frequency. We found that both AD patients and healthy controls took advantage of greater retrieval frequency across all time segments, because of their better memory performance on frequently retrieved episodes than less frequently retrieved ones. Although in the AD group the retrieval frequency effect (i.e., higher scores on the episodes rated as more frequently retrieved) was found in all time segments, the extent of its beneficial effect on memory performance was temporally-graded and inversely related to the time course. Our findings provide new evidence that the combined action of both age of memory and retrieval frequency could provide a valuable framework for predicting patterns of ABM loss, at least in early AD patients. In line with the Multiple Trace Theory, we speculated that retrieval frequency protects episodic trace recall against hippocampal damage by reinforcing the neural representation of personal context-rich memories, which consequently are easier to access and recall. Furthermore, the age of memory should change the amplitude of this beneficial effect as a function of the remoteness of the trace. & 2015 Elsevier Ltd. All rights reserved. 1. Introduction Autobiographical memory (ABM) is commonly defined as memory for the events and facts of one's own life and has a fun- damental role in the self, emotions and experience of personhood over time (Conway and Pleydell-Pearce, 2000). In the literature, ABM has been conceptualized as involving two main components: personal episodic and semantic autobiographical memory (Ko- pelman, 1989). The former contains information about personal incidents that happened to an individual in a specific space and time of his own past; they critically involve a sense of autonoetic consciousness that allows re-experiencing or reliving the past (Levine, 2004). Conversely, personal semantic memory includes general information or facts about one's life such as addresses, friends' names or anniversaries, which can be retrieved in the absence of any recollection, e.g., from a “database” (Tulving, 1999). In a neurobiological perspective, two predominant theoretical positions are adopted to explain how these types of auto- biographical memory are stored and retrieved. The Cortical Re- allocation Theory, also known as the Standard Consolidation Model (SCM) (Alvarez and Squire, 1994; Squire, 2004), suggests a time-limited involvement of the medial temporal lobe (MTL) structures, i.e., the hippocampus and parahippocampal cortices, in the storage and recovery of both episodic and semantic traces; hence, over time the consolidation process leads to the formation of a permanent memory stored in the neocortex that is capable of sustaining the memory trace alone and mediating its retrieval (Alvarez and Squire, 1994). By contrast, the most recent Multiple Trace Theory (MTT) Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/neuropsychologia Neuropsychologia http://dx.doi.org/10.1016/j.neuropsychologia.2015.11.024 0028-3932/& 2015 Elsevier Ltd. All rights reserved. n Corresponding author. E-mail address: ms.desimone@hsantalucia.it (M.S. De Simone). Neuropsychologia 80 (2016) 194–200