Abstract: A mentation test method that can test mentation of a human such as conjecture of brain's mentation age, discrimination of early stage of dementia and prediction of onset of dementia in addition to diagnosis of prediction probability of onset of dementia and screening of mental functions of senile dementia patients, decision of the effect of rehabilitation of the aftereffects of cerebrovascular disfunction, investigation of the therapeutic effects of medicines and side effects such as sleepiness, testing of degree of intoxication, testing of peripheral attention visual field, testing of cerebral dominant hemisphere, testing of various psychoneurosis such as schizophrenia and cerebrovascular disorder (syndrome and diagnosis, and decision of the effects of rehabilitation and treatment), and check of the degree of fatigue.