<P>PROBLEM TO BE SOLVED: To provide a system and a method for predicting decrease of cognitive ability in the future. <P>SOLUTION: Decrease of cognitive ability in the future is predicted by using data of quantitative electroencephalogram and/or quantitative magnetoencephalogram. Thereby the system includes an input section which receives input data corresponding to brain activity of an individual and a processor connected to the input section to analyze the input data for obtaining a set of selected properties. In the system and the method, the processor compares a set of the selected properties with at least a part of an item corresponding to brain activity of a plurality of the individual in a database; the item in the database is distributed into a plurality of categories which respectively corresponds to a degree of decreased cognitive ability of the individual and one of tendencies of decreased cognitive ability in the future concerning the item, and the processor decides a category which most closely corresponds to a set of the selected properties on the basis of the comparison. <P>COPYRIGHT: (C)2007,JPO&INPIT 
SYSTEM AND METHOD FOR PREDICTING DECREASE OF COGNITIVE ABILITY