A Blood Test for Dementia? A Cohort Study to Assess the Diagnostic Utility of Plasma Neurofilament Light Chain Protein in All-cause Dementia

Problem: There is no "gold-standard test" to detect all forms of dementia. People can present with subtle changes that are missed on standard cognitive screening tests, which are not designed for people whose first language is not English or from diverse cultural and educational backgrounds. State-of-the art brain imaging is only available to Australians living in large urban centres, further entrenching health care inequities. The lack of validated diagnostic tests and pathways causes diagnostic delays, increases patient and caregiver stress. Therapies are on the horizon for many forms of dementia - not only Alzheimer's disease - meaning that the lack of identification of simple dementia diagnostic biomarkers represents a critical knowledge gap.

Mission: New technologies now allow us to test abnormal brain protein levels in a routine peripheral blood test, record a voice sample to analyse its acoustics and reveal brain disease, and perform "mail-out" genetic tests using a simple saliva sample. The levels of a brain derived blood protein, neurofilament light chain (NfL), will be estimated and natural language processing and acoustic analysis will be measured in all patients presenting with cognitive complaints to a single healthcare network servicing 1 million ethnically and culturally diverse Australians. Researchers will investigate the utility of early genetic testing for those at high risk of a genetic cause for their disease. They will use these data to develop diagnostic pathways, leveraging existing collaborations to develop future screening programs. Early to mid-career researchers will be supported to translate new technologies into clinical practice in the shortest practicable time-frame.

Significance: Accessible and cost effective tests will inform new pathways to dementia diagnosis. This will transform the dementia landscape, shortening time to diagnosis, increasing diagnostic certainty, and allowing more Australians access to appropriate care, education, and future therapies.