Dr David Tuller: Unconvincing Response to Letter on FND Prevalence Inflation

[Countrygirl]

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https://virology.ws/2024/02/12/tria...sponse-to-letter-on-fnd-prevalence-inflation/​

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Trial By Error: Unconvincing Response to Letter on FND Prevalence Inflation​

4 Comments / By David Tuller / 12 February 2024

By David Tuller, DrPH

As I wrote in a post the other day, the journal NeuroImage: Clinical has just published a letter from a group I organized about the misrepresentation of findings regarding the prevalence of functional neurological disorder (FND). They have also published a response from the authors of the article we criticized. The findings in question were from the Scottish Neurological Symptoms Study (SNSS), a major project that yielded multiple papers a dozen or so years ago.
Since then, more than 50 peer-reviewed articles have asserted, citing the SNSS, that FND prevalence at outpatient neurology clinics is 16% and/or that FND is the second-most-common diagnosis in those venues. In fact, as our letter explained, the only acceptable rate for FND to cite from the SNSS is 5.5%, which represented the patients diagnosed with conversion disorder symptoms–gait and motor disorders, non-epileptic seizures, and sensory deficits–and categorized in the study as “functional.” (Conversion disorder is the former name for FND.) The higher rate was for a group that included many participants who were labeled collectively as having “psychological” diagnoses, yielding a much larger combined “functional/psychological” category.

When we initially wrote to NeuroImage: Clinical about the inflated prevalence claim in one of those 50+ articles, a 2021 paper called “Neuroimaging in functional neurological disorder: state of the field and research agenda,” the journal and the authors quickly agreed to a correction. Our group felt that the proposed correction, as written, was an inadequate remedy. But we accepted it as the best that could be achieved.

After the correction had been agreed upon, I sent a letter to the lead and senior authors of the NeuroImage: Clinical paper. In the letter, I thanked them for agreeing to correct the citation and then urged them to correct the related misrepresentations of the SNSS in several other papers for which one or the other was either the lead or senior author. (This number did not cover the many other papers in which one or both served as a co-author but not the lead or senior author.)