Disclosure of Alzheimer’s Disease Biomarker Status in Subjects with Mild Cognitive Impairment

Abstract

Biomarkers for Alzheimer’s disease (AD) pathology now give the opportunity to diagnose AD in subjects with mild cognitive impairment (MCI). AD biomarker assessment in this population is currently not part of routine clinical care, but it is nevertheless performed with increasing frequency. This raises several practical and ethical issues. The disclosure of AD biomarker status may have a stronger impact on subjects with MCI than on demented subjects. In addition, AD biomarker scores may often be near the threshold for an abnormal score or may be conflicting with other AD biomarker scores because of the early disease stage. Moreover, the prognosis of MCI subjects with abnormal AD biomarkers remains uncertain for individual patients. In this editorial, we will comment on the interpretation of AD biomarker scores in subjects with MCI and present an approach to disclose them. Current diagnostic work-up of subjects with MCI MCI refers to objective cognitive impairment that is not severe enough to warrant a diagnosis of dementia. The diagnosis is based on a clinical examination including administration of rating scales or neuropsychological tests. MCI is a syndromal diagnosis that can be caused by somatic, psychiatric or neurological conditions. A total of 30–80% of subjects have AD as the underlying pathology depending on the definition of MCI and the age of the subject [1]. The diagnostic work-up of subjects with MCI typically consists of blood analysis and computed tomography or MRI in order to identify causes of MCI that may be treatable such as metabolic or vascular disorders. The majority of the patients with MCI are told that they have an increased risk for AD, and almost 90% are invited for follow-up [2].