Diagnostic misconceptions? A closer look at clinical research on Alzheimer's disease.

The current focus on early intervention trials in Alzheimer's disease research raises particular ethical issues. These arise out of problems of validating study results and translating them into general practice for one thing and out of unwanted effects of an uncertain diagnosis for diagnosed people for another. The first addresses the demands of scientific research compared to those of medical practice, questioning how the medical value of clinical trials is evaluated. The second relates the scientific and medical value of early intervention trials to the normative value of an uncertain diagnosis. Are people who are diagnosed with a potential early form of AD in clinical studies patients proper-although they would not have been diagnosed with the given "disease" in non-research-oriented medical settings? The very problem of framing this question in terms of diagnostic misconceptions connects conceptual with ethical issues of research into preclinical stages of neurodegenerative diseases.