Unraveling the mystery of alien hand syndrome: when your hand has a mind of its own.

Background: Alien Hand Syndrome (AHS) is a rare neurological disorder characterized by involuntary, complex movements of a limb, often with a sense of estrangement from the affected hand. Initially described in 1908, AHS has since been associated with various neurological conditions, including strokes, neurodegenerative diseases, tumors, and surgical interventions affecting the corpus callosum and frontal lobes.

Objective: This study aims to provide a comprehensive review of etiology, clinical manifestations, neuroanatomical basis, and differential diagnosis of AHS, synthesizing findings from published case reports and literature.

Methods: This scoping review followed PRISMA-ScR guidelines to systematically analyze AHS case reports from PubMed (2010-2025). Two independent reviewers screened studies using predefined criteria, extracting demographic, clinical, neuroimaging, and treatment data. Eligible case reports required a confirmed AHS diagnosis with complete clinical and neuroimaging documentation. Data synthesis combined descriptive statistics and qualitative analysis to map AHS characteristics across subtypes.

Results: A total of 72 cases were reviewed, with a mean patient age of 59.58 years (SD 18.24), ranging from 9 to 89 years. Males accounted for 48.6% (35 cases), while females represented 51.4% (37 cases). The most frequently implicated brain regions were the corpus callosum, supplementary motor area, and posterior parietal cortex. AHS was commonly associated with stroke, neurodegenerative diseases (e.g., corticobasal syndrome, Creutzfeldt-Jakob disease), and brain tumors. The disorder was categorized into three subtypes, each with distinct clinical presentations and underlying neuropathology. Differential diagnoses included psychiatric disorders, movement disorders, and body schema disturbances.

Conclusion: AHS remains a rare and complex neurological disorder with diverse etiologies and clinical manifestations. Accurate diagnosis requires thorough clinical evaluation and neuroimaging to differentiate AHS from psychiatric and other neurological conditions. Further research is needed to elucidate its pathophysiology and develop targeted therapeutic approaches.