Multicenter Vitamin E Trial in Aging Persons With Down Syndrome

Inclusion Criteria: * presence of clinically determined Down syndrome (karyotypes optional) * appropriately signed and witnessed consent form * age of 50 years or older at the start of the protocol * medically stable * medications stable more than 1 month * involvement/cooperation of informant/caregiver Exclusion Criteria: * medical/neurological condition (other than Alzheimer disease) associated with dementia * inability to adequately perform the Brief Praxis Test, as demonstrated by a score \<20 * in the presence of dementia, modified Hachinski score \> 4 at Screening Visit * major depression within 3 months * history of coagulopathy (inherited or acquired) * current use of anticoagulants * use of experimental medications within 2 months * regular use of vitamin E greater than 50 units per day during the previous 6 months * allergy to vitamin E