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Evaluating News on Medical Study Findings

Much like you learned in kindergarten, findings of medical studies get distorted as they go along the telephone chain. A journal article gets to a journalist who interprets it, highlighting eye-catching findings. Then an editor steps in and may jazz it up some more. By the time you hear the news, it’s distilled to soundbites.

This happens with nearly every study that’s reported to the public. Headache specialist Christina Peterson‘s comments on Migraines Linked With Brain Damage are a recent example of the need to take a close look at the news.

Evaluating medical studies is not as complicated as it may seem. Determining accuracy of the reporting is only one part. It’s also important to evaluate the study as a professional would. This includes asking whether the study has been replicated, how many participants were in the study and what was the time period for the study. See Cleveland Clinic’s Health Extra article for good tips on interpreting studies.

(According to the tips, journals usually offer press releases reviewed by a medical professional. Press releases published by the institution that the lead author works for — usually a university — can be helpful.)

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Reinterpreting Study on Migraine & Brain Damage

Headache specialist Dr. Christina Peterson‘s comment on Migraines Linked With Brain Damage points out that one study never reveals absolute truth. Nor are articles written for the general public usually preceeded by the analysis necessary to critically evaluate research findings. As Dr. Peterson writes, it is “distressing and somewhat irresponsible that every finding in the medical literature becomes a sound bite for the media.”

“For anyone who thinks the information presented here is condescending–please note that most of what Kerrie has put forward here has been written by journalists, and
not by medical experts
. It has been paraphrased from the original medical studies. I personally find it distressing and somewhat irresponsible that every finding in the medical literature becomes a sound bite for the media.

“It is the unfortunate fact that not every study can be taken as absolute gospel truth. This is why we call our ideas “hypotheses,” and we set up studies to test our hypotheses. Generally speaking, we consider them to be working hypotheses until newer ideas are discovered to expand our understanding of the concept. And even then, we are not
fully comfortable until new findings are confirmed by several studies.

“A good chunk of what we are taught in the early part of medical school is how to interpret studies in the medical literature–how to analyze the validity of study design, how to be certain the statistical analysis was done correctly, and how to tell if a given study actually measured anything that matters.

“There are a number of issues presented here. White matter lesions (those white spots on MRI scans that some migraineurs get) may or may not reflect anything to do with brain damage. We do not know yet. However, there was a paper presented this past week in Boston at the Academy of Neurology meeting that suggests not. But I would want to see
further confirmation before I would be certain about anything. White matter lesions, however, are unlikely to cause cognitive damage, as it is the gray matter that does the thinking.

In the study that suggests “older” migraine sufferers have no cognitive decline–this was determined by conducting a 10 minute test called the Mini-Mental Status Exam, which is not particularly rigorous testing. Genetic material was also collected for a test called APOE4, which has been associated with Alzheimer’s. However, very recent research conducted at Yale has demonstrated that the APOE4 genetic allele is associated with psychosis in Alzheimer’s, and not with cognitive decline or loss of function. (The migraine researchers could not have known that when they began their study some years ago.)

“In Boston, I saw microscopy pictures of blood vessels, brain cells, and receptors specially stained to show what happens during cortical spreading depression. This was research done at Harvard-MIT. It was fairly clear that there is oxygen loss in the cellular areas in between the capillaries during cortical spreading depression (CSD). Does this
cause cognitive loss? We don’t know.
The type of researcher who looks at cellular and subcellular structures is generally not the same type of researcher who studies cognitive responses in a whole person.

“Research can be excruciatingly slow. We have, for example, known about CSD since the 1930s, but it took time before it was proven to be associated with migraine, and even longer before we have been able to more clearly understand its significance. We are only now learning exactly what happens chemically during CSD.

“The take-home message is that not everyone with migraine is the same, and that, NO–it’s NOT JUST A HEADACHE!

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How the Media Dumb Down Medical Stories

As you all know, medical studies reported in news media always, always have to be taken with a grain (or pound) of salt. They go through a long chain of command and are ultimately reported by someone who doesn’t know much about the study being reported and whose job is to make readers pay attention. Don’t Dumb Me Down examines this issue using three categories of scientific reporting, wacky stories, scare stories and “breakthrough” stories.

The following quotes are from the scare stories section, but the entire article is fascinating. And is full of points that we, as the consumers of such news, should consider.

“[S]care stories are — of course — a stalwart of media science. Based on minimal evidence and expanded with poor understanding of its significance, they help perform the most crucial function for the media, which is selling you, the reader, to their advertisers.

“Once journalists get their teeth into what they think is a scare story, trivial increases in risk are presented, often out of context, but always using one single way of expressing risk, the ‘relative risk increase,’ that makes the danger appear disproportionately large. . . .”

(via Kevin, MD and Instapundit)