Is mild cognitive impairment a distinct clinical entity?

Mild cognitive impairment is a syndrome characterized by significant cognitive deficits in the absence of dementia. Persons with mild cognitive impairment have a high risk of developing Alzheimer's disease and other dementias. However, opinion on whether mild cognitive impairment is a prodromal phase of Alzheimer's disease and should be treated is divided. The first part of this article will address some of the controversies in mild cognitive impairment on which most researchers have now reached an agreement. Second, we will discuss some of the remaining major controversies in the field, and suggest some avenues for future research. The article will focus around two questions: Is mild cognitive impairment a distinct clinical entity and should it be treated as Alzheimer's disease?