Retinal imaging detects biomarker for Alzheimer’s: Novel yes, but practical?

Does the news release adequately discuss the costs of the intervention?

Not Satisfactory

High up in the release it says:

“Accumulations of neurotoxic beta-amyloid protein can be detected with positron emission tomography, or PET scans, and analysis of cerebrospinal fluid, but these are invasive, inconvenient and costly, making them impractical for routine screening and follow-up evaluation.”

We love this kind of comparison but we expect those comparisons to be backed up. What makes these other diagnostic tools “invasive, inconvenient, and costly”? How much do they cost? How much does this type of diagnostic cost? Remember, the study was done on deceased people’s brains and retinas. So you can’t get much more invasive than that.

Does the news release adequately quantify the benefits of the treatment/test/product/procedure?

Not Satisfactory

In a news release of more than 1,000 words, we would expect some data to back things up. Instead, this release offers just two numbers by way of quantification, and both of them are couched in relative terms that, to any reader other than the authors of the study, may be meaningless. The release says:

“Among key findings, the researchers report a 4.7-fold increase in retinal plaque burden in patients with Alzheimer’s, compared to controls, and they provide observations regarding geometric distribution and layer location of amyloid pathology in the retina. … The demonstration of a fully automated calculation quantifying retinal autofluorescence that showed a 2.1-fold increase in patients with Alzheimer’s, compared with controls.”

In a study that compared the brains of 23 deceased people with Alzheimer’s to 13 people without, what do these numbers mean?

Because the research is very preliminary, and given there is no treatment for Alzheimer’s pathology and most people with dementia who are in their 80s have multiple cognitive issues, it’s difficult to see how identifying amyloid — or even multiple types of pathology — is going to benefit patients.

Does the news release adequately explain/quantify the harms of the intervention?

Not Satisfactory

There is a reference to how other ways of detecting Alzheimer’s are “invasive” but there is nothing in the release about the possible harms associated with this diagnostic tool. A false-positive diagnosis of dementia or Alzheimer’s would be one such harm.

Does the news release seem to grasp the quality of the evidence?

Not Satisfactory

The release explains how the study was conducted with a good amount of detail. We would have liked to have seen a better explanation, though, of how this type of lab study on dead tissue has been extrapolated to indicate any sort of findings — positive or negative — about a diagnostic tool for living patients.

To fully understand the presence of retinal plaque researchers would also need to test people with other diseases that are also known to have amyloid, such as Parkinson’s and Lewy body dementia, and also people with various eye disease such as glaucoma, which might change the results. The release states researchers also did a feasibility trial in 16 patients to test the ability to identify beta-amyloid in the eye using autofluorescence imaging, but we’re given none of the results from this part of the study.

Does the news release compare the new approach with existing alternatives?

Not Satisfactory

As noted, there is a passing reference to other types of diagnostic tools but no true comparisons.