Biomarkers for early Alzheimer's diagnosis

The development of new drugs targeting key aspects of Alzheimer’s disease pathology in the brain means that obtaining an accurate diagnosis during life – already important to inform prognosis and optimise management – has never been more important.

These newer therapies have maximum benefits when given early in the disease course, and many experts believe that they will have maximum impact when given to people who are developing brain evidence of Alzheimer’s disease before symptoms even start.

Access to these new treatments, should they become available on the NHS, requires evidence for Alzheimer’s pathology. Until recently, this could only be obtained through expensive or invasive tests, including PET scanning or lumbar puncture, which are not available outside a handful of specialist centres.

Professor Schott’s work towards developing biomarker-based blood tests addresses these issues by offering the potential for faster, more affordable diagnosis.

The research project was conducted using blood and cerebrospinal fluid (CSF) samples from a sub-group of the 1946 cohort. This cohort ­– formed of 5,362 people from across the UK, recruited as newborns in 1946 for lifelong observation – has participated in studies on education, mental health, fertility, cardiovascular health and menopause. In 2016, 502 members of the cohort agreed to be part of Professor Schott’s study, which involved them having detailed cognitive assessments and brain scans.

The research funded by the foundation’s grant supported the development of several breakthroughs:

• the researchers were able to show that a blood test to measure b-amyloid (a key brain protein associated with Alzheimer’s disease) was about 80% as accurate a PET brain scan, suggesting that blood screening might be useful as a first-stage diagnostic tool;
• a number of blood tests were able to predict the progression of Alzheimer’s as measured using MRI brain scans two years on; and
• the researchers were able to validate a diagnostic test using CSF, work that has informed the interpretation of diagnostic tests now used in NHS clinical practice.