Exploring whether a saliva test could support a diagnosis of Alzheimer’s disease

Lead Investigator: Dr Geraint Phillips 

Institution: University of Exeter

Grant type: Clinician and Healthcare Professional Training Fellowship

Start date: March 2026

Duration: 48 months

Amount: £345,029.30

Summary sentence:

Dr Geraint Phillips’ research aims to understand whether a saliva sample collected at home could be used to support a diagnosis of Alzheimer’s disease.

Short description (100 words):

Amyloid, one of the key proteins associated with Alzheimer’s disease, is also detectable in the saliva. Higher levels of salivary amyloid are found in people with Alzheimer’s disease compared to people who do not have the disease. Biomarkers are biological ‘red flags’ for diseases that can be tracked and measured.

Dr Phillips’ research aims to understand the potential of salivary amyloid, collected at home, as a biomarker for Alzheimer’s disease. Saliva samples will be collected from older adults participating in the PROTECT study and will be assessed against other blood-based biomarkers of dementia and memory test scores.

Salivary amyloid as a biomarker of Alzheimer’s diseases could provide a community-based screening option for the early detection of dementia in the future.

Long description (250 words):

Identifying dementia earlier offers patients the opportunity to benefit from support and treatment to help with symptoms and the opportunity to take part in research. The abnormal buildup of amyloid in the brain is a hallmark of Alzheimer’s disease. 

Amyloid can also be measured in the saliva, with higher levels found in people with Alzheimer’s disease and mild cognitive impairment (MCI) compared to people without the disease. 

Interestingly, amyloid remains stable in saliva for 7 days without the need for freezing which offers the possibility of self-collecting and posting saliva samples from home to the laboratory.

Dr Phillips’ research study aims to:

1. Assess whether self-collecting saliva samples at home is feasible.
2. Compare amyloid levels in saliva between samples collected in-person and remotely.
3. Examine whether salivary amyloid levels correlate with other blood-based Alzheimer's disease associated proteins and memory test scores.

Older adults, with and without cognitive decline, will be recruited through the UK-based PROTECT cognitive ageing study.

Participants will complete paper-based memory tests and provide an initial saliva sample in-person, before self-collecting and posting another saliva sample from home to the laboratory. Levels of amyloid in their saliva will be compared against previously collected blood-based dementia biomarkers and annual memory test scores.

The use of salivary amyloid as a potential biomarker of Alzheimer’s disease and cognitive decline could revolutionise dementia care by providing earlier, more accurate, community-based screening and diagnostic programmes.