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Severe Brain Injury and Coma

Severe Brain Injury and Coma

When a severe brain injury leads to a prolonged unconscious state that lasts days, weeks or months, it is called a coma. Read on or visit our Frequently Asked Coma Questions page to learn more.

Severe brain injury is categorized into subgroups with separate features. These subgroups are discussed below:


When persons experience a brain injury, they can become unconscious. When the unconscious state is prolonged, it is termed a “coma.” Coma is defined as a state of unconsciousness from which the individual cannot be awakened and in which the individual responds minimally or not at all to stimuli, and initiates no voluntary activities.

  • A coma is a continued unconscious state that can occur as part of the natural recovery for a person who has experienced a severe brain injury.
  • While in a coma, a person can continue to heal and progress through different states of consciousness.
  • Persons who sustain a severe brain injury and experience coma can make significant improvements, but are often left with permanent physical, cognitive or behavioral impairments.
  • A coma can last days, weeks, months or indefinitely. The length of a coma cannot be accurately predicted or known.
  • Physicians may not be able to state how long a person will be in a coma or what the person will be like when they come out of the coma. There is no treatment a physician can use to bring a person out of a coma. Likewise, there is no test to predict when a person will come out of a coma or what a person’s recovery will be like.
  • If the person with a brain injury remains in what seems like a comatose state, and there is no clear cut reason for this, it is imperative to get a good evaluation! The evaluation is to differentiate someone who is truly not responding at all to the environment, and someone who is responding in some manner.

Department of Defense and Veteran’s Head Injury Program & Brain Injury Association of America (1999). Brain Injury and You.


  • People in a coma may appear to be “asleep” because they cannot be awakened or alerted.
  • While in a deep coma, a person may not move at all, even to painful stimuli. The person may be unable to produce any voluntary actions or meaningful responses.
  • People in a coma can show various levels of non-purposeful movements. The person may respond minimally or not at all to stimuli.
  • A person in a coma will not be able to talk to you.

Talk to the person in your regular tone a voice with the assumption that the person can understand what you are saying and discussing while the person is nearby. Some people who have emerged from a coma report remembering the conversations of others.

Department of Defense and Veteran’s Head Injury Program & Brain Injury Association of America (1999). Brain Injury and You.

Vegetative State (VS)

Vegetative state (VS) describes a severe brain injury in which:

  • Arousal is present, but the ability to interact with the environment is not.
  • Eye opening can be spontaneous or in response to stimulation.
  • General responses to pain exist, such as increased heart rate, increased respiration, posturing or sweating.
  • Sleep-wake cycles, respiratory functions and digestive functions return.

There is no test to specifically diagnose vegetative state; the diagnosis is made only by repetitive neurobehavioral assessments.

Giacino, J. & Zasler, N. (1995). Outcome after severe traumatic brain injury: Coma, the vegetative state, and the minimally responsive state. Journal of Head Trauma Rehabilitation, 10, 40-56.

Persistent Vegetative State (PVS)

Persistent vegetative state (PVS) is a term used for a vegetative state that has lasted for more than a month.

  • The criteria are the same as those for vegetative state.
  • The use of this term is considered controversial because it implies a prognosis.

Giacino, J. & Zasler, N. (1995). Outcome after severe traumatic brain injury: Coma, the vegetative state, and the minimally responsive state. Journal of Head Trauma Rehabilitation, 10, 40-56.

Minimally Responsive State (MR)

Minimally responsive state (MR) is the term used for a severe traumatic brain injury in which a person is no longer in a coma or a vegetative state. Persons in a minimally responsive state demonstrate:

  • Primitive reflexes
  • Inconsistent ability to follow simple commands
  • An awareness of environmental stimulation

The frequency and the conditions in which a response was made are considered when assessing the meaningfulness or purposefulness of a behavior.

Giacino, J. & Zasler, N. (1995). Outcome after severe traumatic brain injury: Coma, the vegetative state, and the minimally responsive state. Journal of Head Trauma Rehabilitation, 10, 40-56.

Akinetic Mutism

Akinetic mutism is a neurobehavioral condition that results when the dopaminergic pathways in the brain are damaged. Damage to these pathways results in:

  • Minimal amount of body movement
  • Little or no spontaneous speech
  • Elicited speech only (For example: the person may answer a question when asked, but otherwise will not speak voluntarily.)
  • Eye opening and visual tracking
  • Infrequent and incomplete ability to follow commands
  • Vigilance and agitation for frontal akinetic mutism

Akinetic mutism is different from a minimally responsive state because the lack of movement and speech with akinetic mutism is not because of neuromuscular disturbance.

Giacino, J. & Zasler, N. (1995). Outcome after severe traumatic brain injury: Coma, the vegetative state, and the minimally responsive state. Journal of Head Trauma Rehabilitation, 10, 40-56.

Locked-in Syndrome

Locked-in syndrome is a rare neurological condition in which a person cannot physically move any part of the body except the eyes. The person is conscious and able to think.

  • Vertical eye movements and eye blinking can be used to communicate with others and operate environmental controls.

Brain Death

Brain death can result from a very severe injury to the brain. When brain death occurs, the brain shows no sign of functioning. The physician performs a specific formal brain death examination.

Treatment in the Intensive Care Unit (ICU)

After receiving emergency medical treatment, persons with severe brain injury and coma may be admitted to a hospital’s inpatient Intensive Care Unit. The goals in the ICU include achieving medical stability, medical management, and prevention of medical crisis.

  • Medications may be used to decrease brain swelling, treat infections, and prevent seizures. If a person’s intracranial pressure is very high or difficult to control, medication may be used to put the person into a medication induced coma to prevent more swelling.
  • Some preventive rehabilitation may be initiated in the ICU such as body positioning, splinting, and range of motion (a therapist moves the person’s body limbs).
  • Sometimes surgery may be necessary to remove blood clots and pressure.
  • To provide life sustaining medical care, the healthcare staff may have many tubes, wires and pieces of medical equipment attached to the person with a brain injury.

An explanation of the type of medical equipment frequently used in an ICU is provided below.

Possible medical equipment in the ICU

ventilator (Also called a respirator) is a machine that helps a person breathe.

  • A person who has sustained a brain injury may be unable to breathe on his or her own.
  • To use a ventilator, a tube is placed through the person’s mouth to the breathing passage, (trachea, or “windpipe”). This procedure is called intubation.
  • Intubation with the use of a ventilator allows a person to breathe and receive oxygen, which is necessary for life.

tracheotomy (trach) is a tube placed in a person’s windpipe to help them breathe. A trach may be used if a person has a lot of secretions in the lungs that need to be suctioned, or if they are on a ventilator for a long time.

Intravenous lines (IVs) are tubes placed in a person’s veins to deliver medications and fluids to the person’s body.

Arterial lines are tubes placed in a person’s arteries to measure blood pressure.

Foley catheter is used to collect and monitor a person’s urine output.

  • A person who has sustained a brain injury may be unable to control bladder functions.
  • A rubber tube is inserted into the person’s bladder. This allows urine to move from the bladder, through the tube, and to a container at the end of the tube.

A nasogastric tube (NG tube) is used to deliver medication and nutrients directly to a person’s stomach.

  • A person who has sustained a brain injury may be unable to swallow.
  • A tube is placed through a person’s nose or mouth and ran through the swallowing passage (the esophagus), to the stomach.

An EKG machine monitors a person’s heart.

  • Wires with sticky ends are placed on the body.

An intracranial pressure (ICP) monitor is a device that indicates the amount of pressure in the brain. The device is placed in or on top of the brain through a small hole in the skull.

  • As the brain swells, the skull does not also swell; therefore, the brain has limited room to expand in. Swollen brain tissues can compress, causing further injury or death.
  • Intracranial pressure is taken to assess a person’s condition and to provide information for treatment.
  • Intracranial pressure is taken by placing a monitor in or on a person’s brain through a small hole in the skull.

A ventricular drain (ventriculostomy) is a small tube placed in the brain that drains cerebral spinal fluid into a drainage bag. It is used as to measure pressure changes and drain fluid from the brain.

A pulse oximeter is a small clamp-like device placed on a person’s finger, toe, or earlobe. The Pulse oximeter measures the amount of oxygen in the blood stream.

Anti-embolism stockings (TED hose) are worn on the person’s legs to help prevent embolisms (blood clots) from forming and to assist in circulation of blood and fluids in the legs. The stockings are long (up to the thighs) and made of tight elastic material.

Sequential compression stockings (Kendalls) are worn on the person’s legs to help prevent blood pooling. These are plastic leg wraps operated by a machine to inflate and deflate around the person’s legs.

Possible Tests and Assessments

As each person is an individual, the tests and assessments selected by the healthcare professionals may differ from person to person. Possible tests and assessments that may be used are described below:

Arterial Blood Gas (ABG)

  • This lab tests measures levels of oxygen and carbon dioxide in the blood to determine breathing efficiency.
  • A blood sample from an artery is used for this test.


  • This lab test measures levels of electrolytes (sodium, potassium, chloride, bicarbonate, urea nitrogen, and creatine) in the blood to determine how efficiently the body is managing or producing amounts of electrolytes necessary for bodily functions.
  • A blood sample from a vein is used for this test.

EEG (Electroencephalogram)

  • An EEG detects electrical brain abnormalities, such as seizures.
  • Testing involves placing small metal discs, called electrodes, a person’s scalp.


  • X-rays are a type of picture taken to check the structural integrity of bones and the lungs.
  • X-rays are also used to evaluate the placement of tubes, such as feeding tubes, in the stomach.
  • To take a x-ray, a camera is focused on the body area to be examined and a picture is taken.


  • An angiogram is a type of picture showing the arteries and veins in the head and neck
  • To take an angiogram, x-ray pictures are taken after dye has been placed in the arteries

CT or CAT Scan (Computed Tomography Scan)

  • CT scans are used to view harm to brain structures, the skull, and facial bones.
  • CT scans are a good detector of bleeds, blood clots, swelling or compression in the brain.
  • CT scans take pictures of the brain in layers, so it produces images in the form of slices that make up the brain, like the slices that make up a loaf of bread.
  • Because some brain injuries may not show up on the first CT scan, a second CT scan may be taken within the first 24 hours. Not all types of brain injuries show up on CT scans.
  • To take a CT scan, a camera is focused on the body area to be examined and the pictures are taken.

MRI (Magnetic Resonance Imaging)

  • A MRI uses an imaging technique to provide a more detailed view of the brain structure than CT scans.
  • A MRI is advantageous for examination of the brain stem and cerebellum structure (deep brain structures), since these views can be limited on a CT scan.
  • To take a MRI, the MRI equipment is focused on the body part to be imaged.

PET Scan (Positron Emission Tomography)

  • A PET Scan is used to detect brain function and metabolism.
  • A PET Scan involves the injection of a radioactive solution, which is detected by imaging equipment to produce a cross-sectional picture of the brain.

SPECT Scan (Single Photon Emitting Computerized Tomography)

  • A SPECT Scan is a sensitive tool to measure brain function and metabolism.
  • Blood flow rates to the brain and cellular tissue are assessed.
  • A SPECT Scan involves the injection of a radioactive substance intravenously. Imaging equipment picks up the radioactive substance. This information creates a 3D image of the brain.

Neurological Exam

  • A neurological exam is performed through interaction and observation to assist in determining the person’s neurological functional ability
  • The healthcare professional may ask the person simple questions, such as “What year is it?” or give simple directions such as “Hold up one finger.”

Glasgow Coma Scale (GCS)

  • The Glasgow Coma Scale is used to determine the severity of a brain injury. It is often used at the emergency scene or emergency room.
  • Motor, verbal, and eye responses are solicited and rated.
  • A score of 15 is normal/near normal and a score of 3 indicates the worst possible neurological status.

Rancho Los Amigos Scale

  • The Rancho Los Amigos Scale is used to determine a level of cognitive functioning.
  • Cognitive abilities are categorized from Levels 1-10, with Level 1 being the lowest based on clinical observations and interactions. The original Rancho Los Amigos Scale, with levels from 1-8 may still be in use at some facilities.
  • This scale may be used repeatedly to monitor a person’s progress throughout recovery and rehabilitation.

Resources and Links

More information is offered on our website at:

Another resource with information about coma and severe brain injury: National Institute of Neurological Disorders and Stroke: Coma and severe brain injury information.

The Brain Injury Law Center is a supporter of the Brain Injury Association of America and encourages everyone to become a member of this outstanding organization.

Please contact the Brain Injury Law Center for a FREE case evaluation with a caring and knowledgeable personal injury lawyer who can help you understand your legal rights and options.