[Clinical characteristics of senile dementia in Japan]

Senile dementia encountered in Japan is characterized with a higher frequency of vascular dementia as compared to that in North America and Europe. This clinical impression is well substantiated by the statistics from the epidemiologically established cities and townships such as Rochester, Minnesota and Framingham, Massachusetts in the United States and Hisayama, Fukuoka in Japan. However, the difference in incidence between vascular dementia and Alzheimer disease in Japan has narrowed down, and it is possible that the ratio between those two disease entities in Japan may approach that in North America and Europe in the future. In addition, there are qualitative differences in vascular dementia in Japan in that the most frequent vascular dementia in Japan is caused by multiple lacunar infarcts and that one half of those patients develop dementia insidiously without a single ischemic event clinically. Those characteristics make the use of some of commonly utilized diagnostic criteria for vascular dementia inapplicable, and make it necessary to develop a comprehensive and flexible criterion for vascular dementia which is universally applicable in the world.