[Methodological aspects and discrepancies in the clinical trials in Alzheimer's disease]

Authors review the main methodological aspects concerning clinical trials in Alzheimer's disease, especially in those points referring to patients' selection, design, duration of treatment, assessment of response, concomitant treatment and ethical questions. Published studies in last years present important discrepancies in design, duration of treatment and concomitant treatments. In author's opinion, the optimum design for to assess the real efficacy is a double-blind parallel design and duration of treatment should be at least one year, with a follow-up without treatment of at least two months. Allowed and prohibited concomitant treatments should be clearly specified in protocols.