Abstract: Methods of using DAS-431 under conditions where it is administered at a dose that results in improved cognitive performance but without significant side effects are provided. Symptoms can be ameliorated during the period of treatment and, frequently, for substantially longer periods thereafter. In addition, the DAS-431 is provided at a level which does not negatively affect responsiveness to subsequent doses of DAS-431. Few adverse effects are observed, and the treatments can result in long term relief, so as to avoid frequent repetitive treatment.