Rani Priyanka Vasireddy1, Ricardo Vivanco Menoscal2, Aishwarya Koppanatham3, Abhishek Lenka4
1Department of Neurology, UT Tyler School of Medicine, 2Department of Neurology, University of Kentucky, 3Andhra Medical College, 4Department of Neurology, University of Texas Southwestern Medical Center
Objective:
To summarize the demographic, radiologic, and etiologic features of Parakinesia Brachialis Oscitans (PBO) patients reported in the literature.
Background:
PBO is a rare neurological phenomenon characterized by the involuntary elevation of a paretic limb, typically triggered by yawning. Although its pathophysiology, prognosis, and treatment remain unclear, PBO is hypothesized to result from corticospinal/corticobulbar disruption, leading to disinhibited brainstem yawning with abnormal arm co-activation.
Design/Methods:
A systematic search was conducted across three electronic databases: PubMed, Embase, and Cochrane from inception to April 2025 for case reports and case series, including grey literature, using predefined keywords. Studies with at least one patient with PBO and imaging findings were included.
Results:
A total of 29 cases were identified. Most patients were men (86%) with a mean age of 55 years. All presented with hemiplegia, often accompanied by sensory loss, aphasia, or incoordination. Onset of PBO was reported as early as the day of presentation (31% of cases) and as late as 4 months following the initial insult. Ischemic stroke accounted for most cases (86%), though multiple sclerosis and intraparenchymal hemorrhage were also reported. The majority of the lesions were on the right side (62%), localized to the internal capsule (31%) and MCA territory (31%). PBO fully resolved in 21% of cases, partially improved in 10%, and persisted for up to 3 years in a few cases.
Conclusions:
PBO is a rare post-lesional movement disorder most commonly seen after ischemic stroke, though demyelinating and hemorrhagic lesions have also been implicated. Reported outcomes are variable and frequently underdocumented, underscoring the importance of systematic follow-up to clarify prognosis and clinical implications. Awareness of this phenomenon is clinically significant, particularly for trainees, as unfamiliarity with PBO may lead to unnecessary diagnostic testing or misattribution of symptoms. Recognizing this entity can help avoid redundant workups and improve patient counseling.
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