Mild cognitive impairment: Is it Alzheimer's disease or not?

In conclusion, the field of MCI research has been very active in recent years. We contend that MCI represents a transitional state between aging and very early dementia particularly AD. We feel that this is a necessary condition and the current criteria for MCI are useful in characterizing the features of this transition. The research in the field has been somewhat variable but there is a good deal of consistency among various studies attesting to the utility of this construct and its applicability in clinical and research practices. Some of the variability in the literature can be explained by methodological difference including the types of populations recruited and the implementation of given sets of criteria. We agree that some, perhaps many persons with MCI are expressing the early pathology of AD. But MCI is considerably more variable than just a pre-AD, and any slowly progressive condition that develops gradually over many years is likely to have a prodrome in which it can be documented in a milder form that does not meet criteria for the clinically-obvious syndrome.