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Akhila Satish Headshot

An Advancement and Missed Opportunity for Alzheimer's

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Last week a paper was published in Nature Medicine that drew significant media buzz. The paper was titled "Plasma phospholipids identify antecedent memory impairment in older adults." You may know it better by the headlines "New blood test for Alzheimer's disease" or "Alzheimer's can be predicted three years in advance."

As a scientist, the discord between the popular mainstream media's presentation of this paper and the actual scientific paper was jarring. Firstly, there is a sharp contrast between the precise language of the Nature title and the more attention-seeking, market-sensitive language of the mainstream-media headlines. Secondly, the mainstream-media headlines are relatively misleading. There is no blood test available on the market today; there are still large scientific gaps that we need to fill before the technique can be used to predict Alzheimer's in a diverse population.

The typical quick reader of these headlines will leave with the impression that science is ahead of where it actually is. There is a confidence exuded by the media that is not echoed within the paper. This kind of approach to scientific news does everyone, from patients to scientists, a huge disservice. It is particularly troubling with a disease as prevalent as Alzheimer's, which is predicted to impact one out of every six women over the age of 65 and one out of every 11 men over the age of 65.

A few caveats are stated within the news articles: USA Today, NPR, and CNN all explained that there is still research to be done. According to CNN:

If any of these tests work out -- and that's still an if -- it would take years to make it to doctors' offices, since the test would need to be validated by other labs and with larger groups of people.

However, there is a wide gap between delivering the facts and explaining how the science works.

In this particular paper, the approach to a disease like Alzheimer's was impressive -- and is important for the public to understand. We really do not completely understand how Alzheimer's is triggered, and we can only diagnose it after it has developed past a point. As a result, the authors chose to assay blood from patients with and without cognitive impairments over a period of time, and see if they could find a predictive change in the lipid composition. If I lost you at "lipid composition," think of it like this: Lipids make up the walls of cells, including neurons (brain cells). If those walls change, it may correlate with neurodegeneration, or neurons dying prematurely. So it's smart to think of testing lipid levels in patients with Alzheimer's, and even smarter to think of running a five-year study in which you could track patients with initial cognitive impairments and patients who developed those over time. Identifying lipids as predictive is useful not only for earlier intervention but for identifying potential therapeutic targets. If the public fully understood the merit of this kind of study, setting up a second trial may be an easier, quicker and more thoughtful process.

The second trial is necessary for several reasons. This is the first study of its kind, and it took five years to run. The last paragraph of the Nature paper itself states:

This biomarker panel requires external validation using similar rigorous clinical classification before further development for clinical use. Such additional validation should be considered in a more diverse demographic group than our initial cohort.

In other words, for certain data analysis, they had as few as 41 patients, and depending on the genetic background of participants, they may not be able to make assumptions of predictability for everyone. This is important and is often overlooked when clinical trials are discussed. Scientists desperately need participants from a variety of genetic backgrounds -- and larger numbers of participants to build a test that is accurate and meaningful.

The public's appreciation of the scientific methodology and merit behind the paper are critical to the furthering of research like this. Within science, authors are careful and precise. We understand that there is a fine line between prediction and causation, between statistical significance and repeatability. Every paper that is peer-reviewed is vetted through critical, careful eyes. The claims are brought down to the facts, and the holes punctured quickly.

That process doesn't exist for science in the media world. It's particularly telling that in Nature's social-media indexing for this particular article, they show less than 100 direct Tweets to the paper. CNN's news article had over 500 comments, and it doesn't appear as though the majority had read or understood the actual paper.

As a scientist and as a patient, this is alarming. I understand the need for science to be scientific -- precise, complex and detail-oriented. As a patient, I want to understand things in a way that is relevant to me -- clear, evidence-based and friendly. No matter how empowered I am as a patient, if I don't have access to accurate, complete information, I am still fumbling in the dark. If scientists don't turn the light on for patients and take the lead with scientific education, they will lose out on a population that is eager and energized and wants to meet the same research goals.