Study finds an innovative and non-invasive way to diagnose Alzheimer's disease

A new study published in the journal PLOS ONE has revealed that Alzheimer disease can now be diagnosed in a new and non-invasive way.

Reduced blood capillaries in the back of the eye may be a new and non-invasive way to diagnose early cognitive impairment, the precursor to Alzheimer's disease, according to the study.

Scientists detected these vascular changes in the human eye non-invasively, with an infrared camera and without the need for dyes or expensive MRI scanners.

The back of the eye is optically accessible by a new type of technology (OCT angiography) that can quantify capillary changes in great detail and with unparalleled resolution, making the eye an ideal mirror for what is going on in the brain.

"Once our results are validated, this approach could potentially provide an additional type of biomarker to identify individuals at high risk of progressing towards Alzheimer's," said Dr Amani Fawzi, a researcher.

"These individuals can then be followed more closely and could be prime candidates for new therapies aimed at slowing down the progression of the disease or preventing the onset of dementia associated with Alzheimer disease," said Fawzi.

It's known that patients with Alzheimer have decreased retinal blood flow and vessel density but it had not been known if these changes are also present in individuals with early Alzheimer or forgetful mild cognitive impairment who have a higher risk for progressing to dementia.

Weintraub and her team recruited 32 participants who had cognitive testing consistent with the forgetful type of cognitive impairment, and age, gender, race, matched them to subjects who tested as cognitively normal for their age.

All individuals underwent eye imaging with OCT angiography. The data was analysed to identify whether the vascular capillaries in the back of the eye were different between the two groups of individuals.

Now the team hopes to correlate these findings with other more standard (but also more invasive) types of Alzheimer's biomarkers as well as explore the longitudinal changes in the eye parameters in these subjects.

"Ideally the retinal findings would correlate well with other brain biomarkers. Long-term studies are also important to see if the retinal capillaries will change more dramatically in those who progressively decline and develop Alzheimer's dementia," said Fawzi.