A comparative study of the performance of screening tests for senile dementia using receiver operating characteristics analysis.

The discriminability of three types of test for the detection of senile dementia was assessed within a French sample of 155 normal elderly and 120 persons with mild or moderate senile dementia using Receiver Operating Characteristics (ROC) analysis. Results suggest that despite differences in the content of the three instruments, they are equally discriminant. Methods involving direct cognitive examination were found to lose discriminability in relation to milder forms of dementia, whereas an informant questionnaire was found to perform equally as well on cases of mild and moderate dementia. The informant questionnaire was also found to produce lower refusal rates and to be less influenced by the place of residence of the elderly person. The problem of selecting cut-off points according to the range of predicted prevalence rates of dementia for the general population is also discussed.