[1] Univ Texas, Hlth Sci Ctr, San Antonio, TX 78229 USA
[2] Univ Helsinki, Cent Hosp, Helsinki, Finland
[3] A Murphy Vet Adm Hosp, San Antonio, TX USA
[4] McGill Ctr Studies Aging, Alzheimers Dis Res Unit, Montreal, PQ, Canada
[5] Univ British Columbia, Div Neurol, Vancouver, BC V5Z 1M9, Canada
[6] Dalhousie Univ, Queen Elizabeth II Hlth Sci Ctr, Geriatr Med Res Unit, Halifax, NS, Canada