The existence of cognitive plateaus in Alzheimer's disease

In a patient sample predating the widespread use of cholinesterase inhibitors, we found that approximately one fifth of individuals with AD demonstrated periods of prolonged cognitive stability. This significant interindividual variability must be considered when providing prognostic information to families and when assessing individual patient responses to pharmacotherapy. We advise caution when assessing results of potentially disease-modifying agents at the individual patient level.