First described by neurologists James Lance and Raymond Adams in 1963, Lance–Adams syndrome (LAS) is a chronic hyperkinetic involuntary movement disorder caused by anoxic brain injury, often secondary to cardiopulmonary arrest. Unlike acute post-anoxic myoclonus, which manifests acutely hours to days after cardiopulmonary arrest, LAS is a chronic sequela appearing days to weeks after the arrest, once the patient has regained consciousness, and often much of their baseline cognitive function. Though cardiac arrest is the most common inciting event, other causes of hypoxic brain injury have been reported to result in LAS such as surgical accidents, attempted suicides, drug overdoses, and asthma attacks.