Impact of Parakinesia brachialis oscitans on limb functional recovery after stroke: a cohort study

Background Parakinesia brachialis oscitans (PBO), involuntary elevation of the paralyzed upper limb during yawning is a rare phenomenon after ischemic stroke, but its prognostic significance remains unclear due to limited systematic studies. Objective To compare 3-month motor recovery between ischemic stroke patients with PBO, without PBO, and with spontaneously resolved PBO using a propensity score-matched design. Methods This retrospective cohort study included 33 patients with PBO identified in the database as the PBO group, while the non-PBO group was selected from patients with acute ischemic stroke between March and June 2024. Two independent neurologists reviewed medical records according to standardized criteria to identify PBO (within 7 days of stroke onset) and collected baseline data from all patients within 24 h of stroke onset. PSM (1:2) was used to balance baseline characteristics (age, sex, vascular risk factors, stroke location, ASPECTS score, baseline Lovett score, and FMA score) between the PBO and non-PBO groups. The primary outcome was the FMA score at 3 months; the secondary outcome was the Lovett classification. All outcome assessors were blinded. Results After matching, 26 PBO patients were matched to 52 non-PBO patients with balanced baseline characteristics. At 3 months, the PBO group showed significantly higher FMA scores (mean difference 3.77, 95% CI: −0.54–6.97; p = 0.022) and Lovett grades ( p = 0.018) than the non-PBO group. Among PBO patients, the PBO disappearance group ( n = 19) within 1 month achieved higher FMA scores than the PBO persistence group ( n = 14) (mean difference 7.11, 95% CI: −13.10–-1.06; p = 0.021), whereas Lovett grades did not differ significantly ( p = 0.111). Conclusion In this propensity-score-matched cohort study, the presence of PBO was associated with better recovery of motor function at 3 months. Early spontaneous resolution of PBO was associated with better fine motor outcomes compared to persistent PBO. These findings, which support the hypothesis, suggest that PBO may serve as a potential prognostic indicator warranting further prospective research.