Nine patients with possible or probable dementia of the Alzheimer type were tested on nine cognitive tests prior to (two times) and during continuous intravenous administration of five different doses of the muscarinic cholinergic agonist arecoline (1, 4, 16, 28, and 40 mg/day). The present analysis examined whether improvement on cognitive testing for each patient during arecoline treatment was most likely to occur at the same dose for all tests or whether different test scores improved at different doses of arecoline. Results indicated there were significant differences among tests in the dose at which most patients showed improved cognitive performance. These differences may have therapeutic significance, as verbal ability tended to improve at low doses of arecoline, whereas attention and visuospatial ability tended to improve at higher doses of arecoline.