[What is dementia? 8. Alzheimer's disease early diagnosis: a public health point of view].
It is justified to develop early diagnosis for Alzheimer disease and related disorders in order to offer professional support to patients and informal caregivers. On the other hand, the usefulness of screening cases, which have no repercussion on daily life, is not proven considering the difficulty to discriminate early stages from age-related intellectual performance decline. Taking into account a general population point of view, we assume that there is a risk to evolve from early diagnosis to screening. This trend is increased by the fear of the general population, which sees Alzheimer disease as a new plague, the movement towards medicalization in the general population, and the pressure of the pharmaceutical industry. The definition of thresholds for screening, diagnosis and therapy is a central issue. Improving the sensitivity of a test by lowering the threshold leads to a reduction of specificity and a rise of the false positive rate. It is necessary to evaluate the negative impact of labelling normal persons as Alzheimer disease's patients. In the present situation, it would not be sensible to leave the responsibility of the diagnosis to primary care professionals and to give up the validation process performed by the expert or reference centres.
Colvez
Alain
A
Inserm U500, Epidémiologie des maladies chroniques et du vieillissement, Montpellier. colvez@montp.inserim.fr
D000544:Alzheimer Disease / Q000175:diagnosis*; D003937:Diagnosis, Differential; D005189:False Positive Reactions; D006801:Humans; D008403:Mass Screening; D011634:Public Health; D012307:Risk Factors; D012680:Sensitivity and Specificity