Acute posthypoxic myoclonus portends a poor prognosis. Another form of posthypoxic myoclonus, Lance-Adams syndrome, is associated with a better outcome. Differentiating these two entities is important in prognostication and guiding further medical intervention. This can be difficult in the acute setting after hypoxic brain injury but the use of neurophysiologic studies may be helpful. In this article, we present a case of a patient who presented after pulseless electrical activity arrest, underwent targeted temperature management and subsequently developed Lance-Adams syndrome. The neurologic and electroencephalographic findings in Lance-Adams syndrome are discussed with an updated review.