 - Treatment naïve, this means not having received any prior established specific treatment for MCI due to AD or mild dementia due to AD including no prior use of an acetylcholinesterase inhibitor or memantine. A maximum of two months of prior cumulative treatment with an acetylcholinesterase inhibitor or memantine is allowed if the acetylcholinesterase inhibitor or memantine was discontinued due to intolerance, and if this was done at least two months prior to baseline. Use of Souvenaid will be allowed if Souvenaid was discontinued at least twomonths prior to baseline, or if the subject is on stable dose for at least six months prior to baseline and is willing to continue during the study on the same dose and frequency. 