Contemporary positive signs of functional limb weakness in post-acute sequelae of SARS-CoV-2: an exploratory analysis of their utility in diagnosis and follow-up.

Background: Sequelae of the acute phase of coronavirus disease-19, termed long COVID, are characterised by numerous indicators, including neurological symptoms. Functional neurological disorder (FND) can occur with or without various structural diseases. No previous study has examined the relationship between long COVID and FND, with positive signs for FND. This study confirmed positive signs of functional limb weakness (hereafter positive signs) in patients with long COVID.

Methods: This was an observational, retrospective, single-centre study at an outpatient clinic conducted from 1 June 2021 to 31 May 2024. We collected patients' clinical data, including positive signs. The primary outcome was the prevalence of positive signs. Patients with positive signs were followed up over 2 months, and subjective patient perceptions of symptomatic improvements and changes in positive signs were analysed.

Results: Overall, 502 were diagnosed with long COVID, and 100 assessed patients had positive signs. Female sex, time of infection after 2022, comorbidity of psychiatric diseases, fatigue, headache and muscle weakness were statistically significant in patients with positive signs compared with those in patients without positive signs. 89 patients (41 with positive signs and 48 without positive signs) were followed up, and 28 (68.3%) with positive signs and 33 (68.8%) without positive signs reported improvements. Positive signs disappeared in patients with symptomatic improvements but not in patients without symptomatic improvements (p=0.0001).

Conclusions: Positive signs were found in over one-third of patients (33.9%) who were investigated in this study. Some positive signs disappeared concurrently with their symptomatic improvement.