Episodic future thinking in amnesic mild cognitive impairment

Results from behavioral studies of amnesic patients and neuroimaging studies of individuals with intact memory suggest that a brain system involving direct contributions from the medial temporal lobes supports both remembering the past and imagining the future (Episodic Future Thinking). In the present study, we investigated whether amnesic Mild Cognitive Impairment (aMCI) affects EFT. Amnesic MCI is a high-risk factor for Alzheimer's disease and is characterized by a selective impairment of episodic memory, likely reflecting hippocampal malfunctioning. The present study assessed, for the first time, whether the reduction of episodic specificity for past events, evident in aMCI patients, extends also to future events. We present data on 14 aMCI patients and 14 healthy controls, who mentally re-experienced and pre-experienced autobiographical episodes. Transcriptions were segmented into distinct details that were classified as either internal (episodic) or external (semantic). Results revealed that aMCI patients produced fewer episodic, event-specific details, and an increased number of semantic details for both past and future events, as compared to controls. These results are discussed with respect to the constructive episodic simulation hypothesis, which suggests that reminiscence and future thinking are the expression of the same neurocognitive system. (C) 2010 Elsevier Ltd. All rights reserved.