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CNN overstates evidence linking neck pulse measurements to increased dementia risk

Rating

2 Star

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Five-minute neck scan can spot dementia 10 years earlier, say scientists

Our Review Summary

The story focuses on research presented a conference that found increased intensity of “forward compression waves” (FCWs) in the carotid artery was associated with an increased risk of dementia later in life.

The story didn’t tell readers this was an observational study–cause-and-effect couldn’t be established. Also, there is no discussion of the risks of this kind of screening test, notably the risk of false positives and false negatives.

 

Why This Matters

The study does not, as the headline states, allow doctors to “spot dementia 10 years earlier.” This is an important distinction. Identifying important risk factors for dementia can be valuable, in part because it gives patients opportunities to make lifestyle changes that may reduce that risk. On the other hand, telling readers that a test can spot dementia “10 years earlier” makes it sound as if the outcome is a foregone conclusion.

Criteria

Does the story adequately discuss the costs of the intervention?

Not Satisfactory

Cost isn’t discussed. Various online estimates for carotid ultrasounds put them at $200-$800.

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

Not Satisfactory

Here’s what the story says: “People with the most intense pulses, which pointed to a greater and more irregular blood flow, were up to 50% more likely to suffer reduced cognitive functions.”

First, we need to point out that it wasn’t a pulse researchers were measuring, but something known as forward compression waves (FCW) in the neck arteries.

The story doesn’t include vital data-driven information for readers, such as:

  • What was considered high FCW? How did they determine what was considered high? How many people in the group fell into that group?
  • How many people per group (for ex., low or high FCW–or however they grouped people) had cognitive decline?
  • How was cognitive decline measured? Did people with the highest FCW have the worst cognitive decline?
  • Did researchers account for other possible risk factors, such as family history and smoking?

Also the story never makes it clear that, based on these observational study results, we don’t really know if doctors can “spot dementia 10 years earlier” just because of FCW. Nor that we have no know way of knowing to what extent identifying this risk allows patients to take action to improve their FCW score and therefore improve cognitive outcomes.

Some useful reading:

Observational studies: Does the language fit the evidence? Association vs. causation

Absolute vs relative risk

Does the story adequately explain/quantify the harms of the intervention?

Not Satisfactory

The biggest risk with a screening test like this is incorrect results–false positives and false negatives, which the story never explains. There is significant harm that can result if a person thinks they are at high risk of dementia when they aren’t, or thinks they’re at low-risk when they’re high risk. These are otherwise known as a test’s sensitivity and specificity and they should have been discussed, especially how these unknowns will guide next steps for future research.

Does the story seem to grasp the quality of the evidence?

Not Satisfactory

The story never explains that the study is observational, so cause-and-effect conclusions can’t be drawn. It hints at the need for future research, which would have been a good segue to talk about the limitations of this study.

Does the story commit disease-mongering?

Satisfactory

No disease mongering here. However, it is worth noting that the story does make one confusing statement. In a sentence immediately following a paragraph about dementia, the story states that “In the United States, the condition is the sixth biggest cause of death among all adults.” That’s inaccurate. Alzheimer’s disease, specifically, is the sixth leading cause of death among all adults, according to the CDC. Dementia and Alzheimer’s are lumped together by the UK’s Office for National Statistics, which may have led to the confusion.

Does the story use independent sources and identify conflicts of interest?

Not Satisfactory

The story does not address conflicts of interest. The study abstract notes that several researchers have ties to The Brain Protection Company. It is not clear to what extent that company may potentially benefit from the findings, if at all. The company does have patents related to dementia treatment (such as this one).

Does the story compare the new approach with existing alternatives?

Satisfactory

The story explains that researchers are attempting to see if the test should be added as part of “routine screening” for risk factors. It would have been helpful to briefly explain what is currently included in routing screening.

Does the story establish the availability of the treatment/test/product/procedure?

Satisfactory

The story makes clear that more work needs to be done before this becomes anything approaching a standard of care.

Does the story establish the true novelty of the approach?

Not Satisfactory

The story doesn’t put this study in context of previous research. What is already known about FCW and dementia? Is the first study to find a pattern between the two?

Does the story appear to rely solely or largely on a news release?

Satisfactory

The story does not appear to be based on a news release.

Total Score: 4 of 10 Satisfactory

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