Few self-rating questionnaires have been developed for use in screening for dementia due to technical difficulties. We were required to develop a self-rating questionnaire for dementia for the first-stage screening of a 1995 dementia prevalence study in the Nagasaki Prefecture. In our pilot study, we drafted a questionnaire of 43 items and applied it to 399 subjects in attendance at educational programs for senior citizens, and residing in institutions for senior citizens and in nursing homes for the aged. 185 subjects (71 males, 114 females ; average age, 77.3 years) successfully completed the questionnaire, including 39 subjects with medically diagnosed dementia. We conducted a discriminant analysis on these subjects\u27 responses to the original 43 items, and extracted 13 items which most contributed to discrimination of dementia. The sensitivity of discrimination by the final questionnaire was 0.82, and the specificity was 0.89. In the prevalence study of dementia in Nagasaki Prefecture, we could re-examine the validity of the questionnaire. The high sensitivity and moderate level of specificity of the questionnaire was considered reasonable for use in screening dementia
