Provided are a cognitive function evaluation apparatus, which can be used with healthy people and people with severe movement disorders, a cognitive function evaluation method, a cognitive function evaluation system, and a program. The apparatus according to the present invention is for evaluating cognitive function and is provided with a processing unit, which: analyzes brain waves arising from multiple stimulus events comprising targets and non-targets; estimates the number of stimulus events selected as targets from among the multiple stimulus events and determines the discrimination score or decoding accuracy; and evaluates cognitive function on the basis of the values of one or more of the discrimination score, the decoding accuracy, the time course of either the discrimination score or the decoding accuracy, and decoding speed. It is also possible to determine discrimination score or decoding accuracy for each different degree of difficulty for two or more stimulus event groups that differ in the degree of difficulty in discriminating between stimulus events and to evaluate cognitive function on the basis of the relationship between one or more of the discrimination score, decoding accuracy, the time course of either the discrimination score or the decoding accuracy, and the decoding speed, and said degree of difficulty.
COGNITIVE FUNCTION EVALUATION APPARATUS, METHOD, SYSTEM, AND PROGRAM