Retinal scans could help doctors tell similar brain diseases apart, with research suggesting they may help detect conditions including ALS and Alzheimer’s.
There is currently no objective diagnostic test for amyotrophic lateral sclerosis, or ALS, a progressive condition that affects the nerve cells controlling movement, or for frontotemporal lobar dementia with TDP-43, known as FTLD-TDP.
In these conditions, the protein TDP-43 forms deposits in the spinal cord and brain respectively.
A team developing what it describes as a fast, non-invasive and affordable diagnostic tool said it could support earlier diagnosis, helping patients access interventions known to slow disease progression and aiding the development of more targeted treatments.
Dr Melanie Campbell, professor emeritus of physics and optometry at the University of Waterloo, said: “This is a major step towards earlier and more accurate diagnosis.
“Right now, FTLD and ALS are diagnosed only after symptoms appear, which often means the disease is already advanced.
“Being able to detect these conditions earlier could transform how we treat them.”
Researchers at the University of Waterloo used polarised light to image protein deposits in donated retinal samples from patients with Alzheimer’s and compared them with samples from patients with FTLD-TDP and ALS.
By analysing the light patterns, the team was able to accurately distinguish between deposits of amyloid beta, a protein associated with Alzheimer’s, and TDP-43, which is linked to FTLD and ALS, and predict the severity of disease in the brain.
The data were then fed into two artificial intelligence models to test whether they could learn to tell the two deposit types apart.
One model, known as Random Forest, correctly predicted the disease 86 per cent of the time, while a second model, convolutional neural networks, reached 96 per cent.
Campbell said: “We hope that within a few years, this technology will evolve into a simple eye test capable of detecting and distinguishing multiple brain diseases, giving patients in smaller, underserved communities access to this type of testing.
“A fast, accessible diagnostic tool could make a profound difference for patients and families.”
