Methodological Problems of Clinical Trials in Multi-Infarct Dementia

Abstract

In about 30% of the cases suffering from MID an unequivocal diagnosis can be made only on the basis of histopathological evidence. The imperfect diagnosis has a relevant impact on the methodology to be followed in therapeutic trial. The following points have to be considered in a therapeutic trial: (1) distribution of the patients expected to come to the observation, (2) the expected effectiveness of the treatment, (3) the likelihood of obtaining statistical significant results and (4) the required size of the study. The diagnostic inaccuracy gives rise to a decrease in the chance of yielding a statistically significant result and on the other hand produces an increase in the required number of subjects to be submitted to the trial.