Effects of Oral Rivastigmine on Cognitive Domains in Mild-to-Moderate Alzheimer’s Disease

Rivastigmine has beneficial effects on cognitive functioning in Alzheimer's disease (AD). Effects of cholinesterase inhibitors, particularly rivastigmine, on AD Assessment Scale-cognitive subscale (ADAS-cog) domains and individual items have rarely been analyzed. Results from 4 randomized, double-blind, placebo-controlled, 26-week rivastigmine capsule trials in patients with mild-to-moderate AD were pooled and ADAS-cog domains and individual items were evaluated. Data were available from 878, 1053, and 863 patients in the 1 to 4 mg/d, 6 to 12 mg/d, and placebo groups, respectively. Rivastigmine-treated groups were superior to placebo on total ADAS-cog and memory domain scores (P < or = .0001). Rivastigmine 6 to 12 mg/d was also significantly better versus placebo on language (P < .001) and praxis (P < .001); greatest treatment responses were seen on memory items (P < .0001). Although rivastigmine was associated with dose-dependent improvements in all cognitive domains, largest effects were on memory items. Evaluation of ADAS-cog domain scores provides insight into test items most likely to respond to treatment.