[1] Northwestern Univ, Feinberg Sch Med, Cognit Neurol & Alzheimers Dis Ctr, Chicago, IL 60611 USA
[2] Advocate Lutheran Gen Hosp, Adult Down Syndrome Ctr, Park Ridge, IL USA
[3] Northwestern Univ, Feinberg Sch Med, Dept Psychiat & Behav Sci, Chicago, IL 60611 USA
[4] Northwestern Univ, Feinberg Sch Med, Dept Neurol, Chicago, IL 60611 USA