Functional Neurological Disorder in people with Long-Covid: A Systematic Review 2023 Teodoro, Edwards et al

Background

Acute health events, including infections, can trigger the onset of functional neurological disorder (FND). We hypothesised that a proportion of people with long-COVID might be experiencing functional symptoms.

Methods
We performed a systematic review of studies containing original data on long-COVID. We reviewed the frequency and characteristics of neurological symptoms, looking for positive evidence suggesting an underlying functional disorder, and the hypothesised causes of long-COVID.

Results
We included 102 studies in our narrative synthesis. The most consistently reported neurological symptoms were cognitive difficulties, headaches, pain, dizziness, fatigue, sleep-related symptoms, and ageusia/anosmia.

Overall, we found no evidence that any authors had systematically looked for positive features of FND. An exception were three studies describing temporal inconsistency.

In general, the neurological symptoms were insufficiently characterised in order to support or refute a diagnosis of FND. Moreover, only 13 studies specifically focussed on long-COVID after mild infection, where the impact of confounders from the general effects of severe illness would be mitigated.

Only one study hypothesised that some people with long-COVID might have a functional disorder, and another 8 studies a chronic fatigue syndrome-like response.

Discussion
Neurological symptoms are prevalent in long-COVID, but poorly characterised. We are struck by the similarities between some manifestations of long-COVID and functional disorders triggered by acute illnesses. Unfortunately, the current literature is plagued by confounders, including the mixing of patients with initial mild infection with those with severe acute medical complications. The hypothesis that long-COVID might in part correspond to a functional disorder remains untested.

Paywall, https://onlinelibrary.wiley.com/doi/10.1111/ene.15721

 

The authors revealing their opinion on whether CFS is FND or not.

 

Response to this paper from Kachaner et al, https://onlinelibrary.wiley.com/doi/10.1111/ene.15911

Paywalled, so I'm unable to provide an abstract/preview.

 

Allow me. TLDR = "You guys said what we said, we're all awesome and totally understand this condition. You can tell this is true because we agree with each other." Key captures —

[... "internal inconsistency" ... fluctuation over time ... = SSD/FND]

Not sure what *a* chronic fatigue syndrome is supposed to mean, particularly when it's capitalised as a proper noun

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* Somatic symptom disorder in patients with post-COVID-19 neurological symptoms: a preliminary report from the somatic study (Somatic Symptom Disorder Triggered by COVID-19) (2022)

 

This paper appears to be open access now.

 

aren't we lucky!