How Comas Work

How Do You Know if Someone is in a Coma?

A coma can look different depending on the situation. Some people will lie completely still and be unresponsive. Others will twitch or move involuntarily. If the breathing muscles are affected, the person may be unable to breathe on his or her own.

Doctors evaluate potentially comatose patients based on one of two scales: The Glasgow Coma Scale and the Rancho Los Amigos Scale. identifies the degree of mental impairment by assigning a score ranging from three to 15, with three being the deepest coma and 15 being normally awake and alert. The points are based on three main parameters:


The Rancho Los Amigos Scale, developed by doctors at Rancho Los Amigos Hospital in California, helps doctors follow the progression of a head injury survivor recovering from a coma. It is most useful during the first weeks or months after the injury.

Based on the results of these two scales, doctors put patients in one of four awareness states:

  • Comatose and unresponsive - The patient cannot move or respond to stimuli.
  • Comatose but responsive - The patient does respond to stimuli, with reactions such as movement or increased heart rate.
  • Conscious but unresponsive - The patient can see, hear, touch, and taste, but cannot respond.
  • Conscious and responsive - The patient is out of his or her coma and can respond to commands.

In the next section, we'll look at how doctors care for comatose patients.