Episodic memory in Alzheimer's disease: decline in recollection and familiarity?

the retrieval of information from long-term memory is supported by recollection and familiarity. Alzheimer's disease is consistently found to affect recollection. As for familiarity, however, no consensus has been reached so far. Some studies are in favor of an early impairment of familiarity, while others are in favor of a preservation of familiarity in the mild and moderate stages of the disease. This lack of consensus can be partly explained by methodological differences between studies. We discuss three methodological dimensions: the type of recognition test, the type of paradigm for estimating familiarity and recollection, and the nature of the material used. These differences reveal the complex nature of familiarity which would be underlied by different mechanisms that may be selectively altered or preserved in the disease.