Literature evidence on counselling and disclosure in early AD detection

The pathology of Alzheimer’s disease (AD) starts years before cognitive deficits emerge and can be detected and characterized by biomarkers already in early stages (Jack et al. 2018). These early stages of Alzheimers’ disease comprehend asymptomatic persons and persons with subjective and mild cognitive impairment (SCI / MCI, in the following text summarized as prodromal dementia). There is great scientific interest in the prediction and early diagnosis of Alzheimer's dementia aiming to apply therapeutic interventions as early as possible. Additionally the social and individual interest is expected to increase in the coming years: With the advent of biomarker blood tests probably also lay people may request risk assessment of developing Alzheimers’ dementia in the near future. The use of biomarkers raises unresolved ethical, social and medical questions, for example how a valid risk assessment can be carried out, how patients and their relatives deal with their knowledge with regard to life planning and life quality, but also touches on practical questions, for example whether an increased risk of dementia has to be communicated to insurance carriers when an insurance policy is taken out. Against this background, it makes sense for people who are interested in biomarker diagnostics to seek comprehensive advice beforehand so that they can make an informed decision for or against such diagnostics. The aim of this scoping review is to gain an overview of the current body of literature regarding counselling and risk disclosure before and in the course of a biomarker diagnosis of early stages of Alzheimer's disease. In order to examine the literature focusing on counselling and risk disclosure in the context of early Alzheimer diagnosis, we will perform a scoping review. Scoping reviews are increasingly used in the context of health research with the aim of mapping the breadth and depth of a field and thus to provide greater conceptual clarity about the specific field or topic (O’Brien et al. 2016; Levac et al. 2010). The method of the scoping review aims at identifying available research conducted on a specific topic area, examining the extent and range of research activity as well as clarifying key concepts and definitions in that field (Munn et al. 2020; Levac et al. 2010). The first step for guiding the scoping review, encompassed the definition of a broad research question, namely what guidelines or recommendations currently exist regarding counselling of biomarker-based early AD detection and risk disclosure of Alzheimer's dementia. In a next step for the identification of relevant studies, we developed a list of distinctive keywords (search strings) for relevant aspects of the topic and started identifying relevant articles by systematically searching identified databases. The final search was carried out in four databases: PubMed, PsycINFO, LIVIVO and Web of Science. The period of literature search was set to 01.01.2005 and 31.12.2020 (last read out 11.01.2021), thus considering the last 15 years. Furthermore, the reference lists of all publications included in this review will be hand searched for additional studies. To reduce individual bias, three researchers will independently review the applied approach (Pham et al. 2014) carried out this analysis. We will include publications that investigated or commented on the process of counselling and disclosure in the context of early AD detection in individuals at risk of developing Alzheimer’s dementia, such as individuals with SCD or MCI and those with biological risk, such as a biomarker-evidence for amyloid-pathology or with genetic susceptibility. To be included in this review, articles have to be published in a peer-reviewed journal with full text availability and written in English or German. If eligibility is unclear, full text review will be undertaken of studies deemed potential eligible by title/abstract screening. Data synthesis will be assisted by an evaluation matrix developed for the purpose of this review. Categories and codes will be predefined based on the research question and will be further developed during the data extraction process.