A new method for quantifying the cognitive impairment. Its application in patients with vascular dementia.

Seven-three patients diagnosed with vascular dementia (VD) left to their natural evolution have been observed during a period of time of one year. The objective of this study is to find an index to quantify the degree of loss of cognitive capabilities in patients affected by VD, as well as to define the minimum loss of punctuation in this index, that can only be caused by an unfavourable evolution of the disease. This index, which we call Percentual Variation Index (PVI), is based on the evolution of the punctuations of the Cognoscitive Mini-Exam (CME) after a follow-up of one year. Our definition states that in order to consider patients as having cognitive impairment of vascular origin, they must lose more than 10% of their basal CME score in one year. This method could be useful in assessing the therapeutic efficacy of drugs used in treating such illnesses.