Abstract
PURPOSE OF REVIEW: This article reviews alien hand, a neurological disorder that causes involuntary limb movements that appear to be purposeful. This review outlines the history that identified the three widely accepted forms of alien hand and their distinct clinical and neuroimaging findings. This material summarizes behavioral disturbances that can occur with alien hand but are seldom addressed in a single review article, including propensity for self-injury, pathological sexual behavior, alien hand activities during sleep, and communication disturbances of alien Quality. The article then presents other paroxysmal, involuntary disturbances that are not usually considered to be alien hand, despite their appearing to be purposeful. Finally, this article reviews all PubMed-listed articles from 2020 to mid-2025 that addressed either alien hand or limb, or anarchic hand, for trends in understanding and treating this illness. RECENT FINDINGS: Meritorious advances in recent years included proposed checklists for the component behaviors for diagnosing alien hand, structured interviews for querying the patients' experiences, and demonstrating white matter cerebral damage that extends far beyond the lesion boundaries that are identifiable on conventional structural brain MRI. This review summarizes the diversity of the presentations of alien hand. Many behaviors that are encompassed by alien hand are not so far explained by clinical or experimental brain MRI findings.