A neurological disorder in which one of the patient’s hands acts as if independently of his will. The patient may experience the sensation that his hand is performing movements that he has no control over and cannot stop them intentionally. These movements may be unconscious and often contrary to the patient’s wishes, for example, the hand may grasp objects or perform actions without conscious involvement. Alien hand syndrome usually occurs as a result of brain damage, such as in stroke, tumors, trauma, or neurodegenerative diseases (such as Alzheimer’s disease or Korsakoff’s syndrome).