According to the National Institute of Neurological Disorders and Stroke , LiS is defined by:
: Full alertness, cognitive function, and the ability to think and reason. Locked In
: The primary mode of communication is typically through vertical eye movements and blinking. Common Causes Locked In
: Quadriplegia (paralysis of all four limbs) and the inability to move the face or body. Anarthria : The complete loss of articulate speech. Locked In
While stroke is the leading cause (specifically basilar artery occlusion), other factors can trigger the syndrome: Case Report and Discussion of Decisional Capacity