Recollection and familiarity in aging individuals with mild cognitive impairment and Alzheimer's disease: a literature review.

Memory impairment is a central cognitive symptom in mild cognitive impairment (MCI) and Alzheimer Disease (AD). Recognition tasks are often used to characterize and define the nature of memory deficits. Dual-process theories posit that familiarity and recollection are independently involved in the recognition of previously encountered material and both contribute to successful recognition. Recent evidence indicates that there is a double dissociation in the neuronal substrates of those two processes. More precisely, it has been suggested that perirhinal and entorhinal areas are selectively involved in familiarity-based recognition, while the hippocampus is associated with recollection. Interestingly, these regions are among the first to be targeted by neurofibrillary tangles, one of AD's neuropathological hallmarks. Impairment in recognition performance can occur in the very early stages of AD, such as MCI. To define the nature of recognition impairment in these clinical populations, we reviewed the current literature on familiarity and recollection performance in individuals with MCI and AD. Together with clinical features, methodological factors are taken into consideration in the interpretation of findings.