"Effect of Vitamin E and Memantine on Functional Decline in Alzheimer Disease"
JAMA  
http://jama.jamanetwork.com/article.aspx?articleid=1810379 
"Conclusions and Relevance  Among patients with mild to moderate AD, 2000 IU/d of alpha tocopherol compared with placebo resulted in slower functional decline. There were no significant differences in the groups receiving memantine alone or memantine plus alpha tocopherol. These findings suggest benefit of alpha tocopherol in mild to moderate AD by slowing functional decline and decreasing caregiver burden."