The ability to design a proxy for consent to treatment and for voting with Alzheimer's disease: preliminary results of a multicenter study.

Span Backwards plus Attention and Calculation, Color Trails 1 plus 2, ADAS-Cog, Attention and Calculation, Letter Fluency plus Category Fluency, and Color Trails 2. Several neuropsychological tests’ score distributions did not overlap completely (examples: Category Fluency, Digit Span Backwards, Color Trails 1), with worst and best scores uniquely associated with fast decliners and improvers respectively. Measures with restricted or narrow ranges did not have unique values, examples: MMSE and Attention and Calculation. Conclusions: Consistent with the known relationship between severity and rate of decline in AD, in the blinded data fast decliners and improvers were different at screening on verbal fluency, working memory, and complex information processing speed. Further analyses will focus on the smaller placebo group. These measures have potential use in strategic subject selection to fulfill the NINCDS-ADRDA requirement of supplementing theMMSE for confirming cognitive impairment, documenting progressivity (another NINCDS-ADRDA diagnostic criterion neglected in trials), and identifying improvers at screening for exclusion, and should be considered in protocol design.