Consent for the diagnosis of preclinical dementia states: A review.

It is now possible to detect the pathology of Alzheimer's disease (AD) many years before symptoms and signs otherwise become manifest. Biomarkers of disease include evidence of amyloid and tau in the cerebrospinal fluid and neuroimaging which (for instance) allows amyloid in the brain to be visualized. There is, thus, a preclinical state in which it is possible to identify Alzheimer's pathology long before there is clinical evidence of disease. Much research focuses on this preclinical state because it seems likely that treatments will be more effective before the disease is established. This means that researchers can discover Alzheimer's pathology some years before the person is at risk of developing the condition. In memory clinics, too, people may present with early (prodromal) symptoms which do not yet amount to a dementia syndrome (e.g. mild cognitive impairment), yet biomarker evidence that dementia is highly likely to develop. This is problematic because people will be required to consent to the disclosure of findings that indicate an uncertain risk of an alarming disease. We carried out a scoping review of the issues that arise in connection with a "diagnosis" of preclinical dementia. We identified four themes in the literature: stigma; ethical issues; psychological burden; and language. We shall discuss these themes and related issues that emerge to do with meaning, medicalization, virtues and values. More research is now required to understand these issues in detail, where the emphasis should be on the breadth of research, which must be biopsychosocial and ethical.