Alien Hand Syndrome as the Initial Presentation of Patent Foramen Ovale-Associated Stroke

Abstract

Alien Hand Syndrome (AHS) is a rare neurological condition characterized by involuntary, goal-directed movements of a limb without conscious control. It is most often associated with stroke in specific brain regions, including the medial frontal and parietal cortices. We report the case of a 33-year-old male with no previous medical history who presented with involuntary movements of the left upper limb, describing it as “moving on its own.” Neurological examination was unremarkable, but MRI revealed multiple cortical infarcts in the right frontal and parietal lobes, with both acute and subacute features. Extensive workup ruled out vascular stenosis, dissection, and hypercoagulable states. Transthoracic echocardiography showed normal left ventricular function and a hypermobile interatrial septum. Transesophageal echocardiography confirmed the presence of a tunnel-shaped patent foramen ovale (PFO; 0.4 mm × 0.3 mm) without thrombus. No deep vein thrombosis or other embolic sources were found. A diagnosis of cardioembolic stroke due to paradoxical embolism through a PFO was established. The patient underwent successful percutaneous closure and started dual antiplatelet therapy. At follow-up, AHS symptoms improved significantly. This case highlights an atypical initial presentation of ischemic stroke in a young adult and emphasizes the need for early neuroimaging and comprehensive cardiac evaluation in cryptogenic strokes.

Introduction

Alien Hand Syndrome (AHS) is a rare neurological condition characterized by involuntary, goal-directed movements of a limb-typically the hand-accompanied by the sensation that the limb is acting independently or feels foreign to the patient.^1,2 The phenomenon is typically associated with lesions of the corpus callosum, medial frontal cortex, or parietal lobes. ¹ AHS has been described in the context of neurodegenerative disorders, neoplasms, and, more rarely, cerebrovascular events. ³

In this report, we present the case of a young adult male whose chief complaint was “my hand feels strange.” A comprehensive diagnostic workup led to the diagnosis of a cardioembolic stroke caused by a patent foramen ovale (PFO). This case illustrates a rare initial presentation of ischemic stroke and underscores the importance of considering AHS in the differential diagnosis of isolated involuntary limb movements.

Objective

To present a case of AHS in a young male patient, emphasizing the atypical presentation of limb symptoms, the diagnostic workup revealing a cardioembolic stroke due to a PFO, and the successful management with an Amplatzer closure device. This case underscores the importance of recognizing AHS as a possible manifestation of embolic events and the need for comprehensive imaging and cardiac evaluation.

Case Presentation

A previously healthy 33-year-old male presented to the emergency department with a 2-hour history of acute symptoms affecting his left upper limb. He described a strange sensation, reporting that the arm felt as though it did not belong to him. He also experienced diminished strength and involuntary movements of the limb. Notably, 15 days before admission, he had experienced a self-limited episode of involuntary movements of the left upper limb, which resolved spontaneously. Concerned by this episode, the patient sought outpatient evaluation and underwent a brain MRI, which was performed 48 hours prior to his emergency department (ED) visit. He brought the MRI with him at the time of ED consultation; it revealed cortical infarcts in the right parietal and frontal lobes. The outpatient MRI had been ordered specifically to evaluate the transient neurological symptoms experienced during the earlier episode.

Although the patient reported diminished strength in the left hand during the episode, the neurological examination in the ED was unremarkable and did not show any motor deficits. Neurological assessment demonstrated preserved muscle strength, deep tendon reflexes, and normal sensation in all extremities. Pathological reflexes, including Tromner, Hoffman, and Babinski, were all negative. A detailed sensory examination was performed to assess for cortical sensory deficits, including 2-point discrimination and stereognosis, and yielded normal results. This discrepancy may reflect the transient nature of the initial symptoms, which had fully resolved by the time of evaluation, consistent with the diagnosis of a brief cortical ischemic event.

Given the MRI findings, an embolic etiology was suspected and further workup was initiated. Computed tomography (CT) angiography and carotid Doppler ultrasound showed no evidence of vascular stenosis or dissection. Routine laboratory tests including thyroid function, lipid profile, and glycated hemoglobin were within normal limits. Transthoracic echocardiography demonstrated a normal left ventricular ejection fraction (71%) and a hypermobile interatrial septum, prompting a transesophageal echocardiogram. This confirmed the presence of a tunnel-shaped patent foramen ovale (PFO) measuring 0.4 mm × 0.3 mm, with no thrombus observed. Figure 1 shows all the taken images.

Figure 1.

Composite panel illustrating key diagnostic findings in a young patient with ischemic stroke and Alien Hand Syndrome due to paradoxical embolism through a patent foramen ovale (PFO). (A) Brain MRI with FLAIR and DWI sequences showing multiple cortical infarcts in the right frontal and parietal lobes. Hyperintense areas are evident in both sequences, consistent with mixed acute and subacute ischemic changes. No hemorrhage or mass effect is observed. (B) CT angiography (left) and carotid Doppler ultrasound (right) showing normal caliber of extracranial and intracranial vessels. No evidence of vascular stenosis, dissection, or atherosclerotic plaques. (C) Transesophageal echocardiogram using color Doppler reveals right-to-left shunt through a tunnel-shaped PFO during Valsalva maneuver, with no visible thrombus. (D) Transthoracic echocardiogram showing normal left ventricular systolic function (ejection fraction of 71%) and a hypermobile interatrial septum (outlined in yellow), suggestive of increased risk of paradoxical embolism.

Based on these findings, a diagnosis of cardioembolic stroke due to paradoxical embolism through a PFO was made. To support this conclusion, an extensive diagnostic workup was performed to rule out alternative causes of ischemic stroke. Carotid Doppler ultrasound revealed no evidence of significant atherosclerosis or dissection. Continuous cardiac monitoring and a 7-day Holter showed no atrial fibrillation or other arrhythmias. Laboratory testing for thrombophilia—including antiphospholipid antibodies, protein C and S, antithrombin III, and factor V Leiden—yielded normal results. Given the absence of other etiologies and the presence of high-risk PFO characteristics, the patient underwent percutaneous closure of the defect with an Amplatzer device. He was discharged in stable condition, asymptomatic, and initiated on dual antiplatelet therapy along with high-dose statin for secondary stroke prevention.

The patient was followed up for 6 months after discharge. During this period, he reported complete resolution of involuntary hand movements and no recurrence of neurological symptoms. A neurological re-examination at 3 and 6 months revealed no signs of residual alien hand syndrome. Functional recovery was assessed based on both clinical examination and the patient’s report of full return to daily activities, including work and driving, without limitations.

Discussion

Alien Hand Syndrome (AHS) is an uncommon neurological condition characterized by involuntary, purposeful movements of a limb-usually the hand-that occur without conscious control. Patients often describe a sensation of estrangement, as if the limb does not belong to them or is acting independently.^1,2 The phenomenon is usually associated with lesions in specific brain regions, including the corpus callosum, medial frontal cortex, or parietal lobes.

The term “alien hand” was formally introduced in 1972 by Brion and Jedynak, who reported 3 patients with callosal tumors and involuntary hand movements with a sense of estrangement. ⁴ Earlier, Hugo Karl Liepmann, a student of Wernicke, had described “apraxia” as an inability to perform purposeful movements despite preserved motor function, and his work laid the foundation for recognizing disorders of volitional movement like AHS. ³ Later, Kurt Goldstein used the term “alien” to reflect the patient’s perception of the hand as foreign, further solidifying the clinical identity of the syndrome. ⁴

Hassan and Josephs ⁵ classified AHS into 3 primary subtypes based on lesion location and clinical features: frontal, callosal, and posterior. The frontal variant involves the dominant hand and is associated with impulsive groping or grasping behaviors due to lesions in the medial prefrontal cortex or supplementary motor area. The callosal variant typically affects the non-dominant hand and presents with intermanual conflict, often due to corpus callosum injury from infarction, demyelination, or surgery. ⁶ The posterior variant affects the non-dominant hand and is associated with lesions in the parietal or occipital lobes, accompanied by sensory deficits such as hemiasomatognosia or neglect. ⁵

Several clinical presentations of AHS have been described, including involuntary grasping, levitation, and intermanual conflict. Panikkath et al. ⁷ proposed subclassifications such as intermanual conflict, alien hand sign, anarchic hand movements, and the sensation of a supernumerary limb.

There are no standardized diagnostic criteria for AHS. Diagnosis is clinical and requires exclusion of other neurological or psychiatric conditions. Management is supportive, with options such as behavioral strategies, visuospatial coaching, occupational therapy, benzodiazepines, and botulinum toxin.^2,7,8 Prognosis varies with etiology, with stroke-related cases showing better outcomes than those due to neurodegenerative disease. ²

This case is unique in presenting AHS as the sole manifestation of an embolic stroke in a young adult without traditional stroke risk factors. While alien hand syndrome (AHS) has been described in association with ischemic strokes affecting the parietal lobe, corpus callosum, or medial frontal regions, most reported cases involve older individuals or occur alongside other neurological deficits. For example, Schaefer et al. ⁹ described posterior AHS following a left internal carotid artery infarct with additional neurological signs, McNabb et al. ¹⁰ reported AHS in a young adult with infarcts in both the parietal cortex and corpus callosum, though not as an isolated presentation, and Nahas et al. ¹¹ published a series of cases of AHS associated with acute parietal infarctions, highlighting both the rarity and the temporal association with ischemic stroke events. In contrast, our patient was a previously healthy 33-year-old whose only symptom was AHS, ultimately attributed to paradoxical embolism through a high-risk PFO. Closure of the PFO and initiation of secondary prevention led to marked clinical improvement. This case highlights the importance of considering rare stroke presentations in young adults and pursuing a thorough diagnostic evaluation to identify embolic sources.

The decision to proceed with PFO closure in this case was supported by high-risk anatomical features, including a long-tunnel PFO and a hypermobile interatrial septum, which have been associated with an elevated risk of recurrent stroke. These features align with patient selection criteria from major randomized trials such as RESPECT ¹² and CLOSE, ¹³ which demonstrated that PFO closure significantly reduces the risk of recurrence in young patients with cryptogenic stroke and high-risk PFO morphology. In addition, a comprehensive evaluation excluded alternative etiologies, including negative hypercoagulability studies, carotid Doppler imaging, and extended cardiac monitoring to rule out atrial fibrillation.

The patient’s PFO presented high-risk anatomical features, including a long tunnel and associated hypermobile interatrial septum, which are recognized predictors of recurrent embolism. Multiple trials have demonstrated the benefit of PFO closure in younger patients with cryptogenic stroke and high Risk of Paradoxical Embolism (ROPE) scores, particularly when other stroke etiologies have been excluded.^13,14 In this context, PFO closure was indicated to reduce the risk of recurrence.

Conclusions

This case highlights the importance of recognizing Alien Hand Syndrome as a rare but significant manifestation of stroke, especially in young patients without prior neurological history. Prompt neuroimaging and thorough cardiac evaluation-including screening for PFO-are essential in patients with cryptogenic stroke and unusual presentations. Early intervention can significantly reduce the risk of recurrence and improve outcomes.