Traumatic brain damage: Severe brain damage: Coma and disorders of consciousness

Progress in intensive care efforts has increased the number of patients who survive severe acute brain damage. Although the majority of these patients recover from coma within the first days after the insult, some permanently lose all brain function (i.e., brain death), while others evolve to a state of “vegetative” unresponsive wakefulness. Those who recover typically progress through different stages before fully or partially recovering consciousness (minimally conscious state; MCS). Functional neuroimaging and electrophysiology studies are changing our understanding of patients with coma and related states. Some severely brain-damaged patients may show residual cortical processing in the absence of behavioral signs of consciousness. When “vegetative”/unresponsive patients show minimal signs of consciousness but are unable to reliably communicate, the term “minimally responsive” or “minimally conscious state” (MCS) is used.