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Minimally Conscious State

By

Kenneth Maiese

, MD, National Heart, Lung, and Blood Institute

Last full review/revision Sep 2020| Content last modified Sep 2020
Click here for the Professional Version

A minimally conscious state is severe but not complete impairment of awareness. It results from widespread damage to the cerebrum (the part of the brain that controls thought and behavior).

  • A minimally conscious state may result from brain damage, or it may follow a vegetative state as people recover some function.

  • People in a minimally conscious state do some things that indicate some awareness of self and of their environment, such as making eye contact.

  • Doctors diagnose a minimally conscious state only after they observe people for a period of time and on more than one occasion and find some evidence of awareness in people whose consciousness is severely impaired.

  • People in a minimally conscious state require comprehensive care, including good nutrition and measures to prevent problems due to not being able to move (such as pressure sores).

A minimally conscious state may result directly from brain damage, or it may follow a vegetative state as people recover some function.

Symptoms

People in a minimally conscious state, unlike those in a vegetative state, do some things that indicate some awareness of self and of their environment. They may do the following:

  • Make eye contact

  • Follow objects with their eyes

  • Reach for objects

  • Respond to questions (although often with the same word whether it is appropriate or not)

  • React to all commands in a usual but usually inappropriate way (for example, by blinking)

Diagnosis

  • A doctor's evaluation

  • Imaging tests such as magnetic resonance imaging

Doctors suspect minimally conscious state based on symptoms. But before a minimally conscious state can be diagnosed, people should be observed for a period of time and on more than one occasion.

An imaging test, such as magnetic resonance imaging (MRI) or computed tomography (CT), is done to check for disorders that may be causing the problem, especially those that can be treated.

If the diagnosis is in doubt, doctors may do other imaging tests—positron emission tomography (PET) or single-photon emission computed tomography (SPECT). These tests can indicate how well the brain is functioning.

Electroencephalography (EEG) may be done to check for abnormalities in the brain's electrical activity that suggest seizures, which may impair consciousness.

Prognosis

Most people in a minimally conscious state tend to improve continuously, but improvement is limited. A few people regain the ability to communicate and understand, sometimes after many years. However, very few recover enough to live and function independently. The longer a minimally conscious state lasts, the less function people are likely to regain. However, with skilled nursing care, people can live for years. Recovery may be better when the cause is a head injury.

There have been reports of people awakening after spending years in what appears to be a coma. These reports often involve people who had been in a minimally conscious state after a head injury.

Treatment

  • Preventive measures for problems due to immobilization

  • Good nutrition

  • Possibly certain drugs

Long-term care

Like people in a coma, people in a minimally conscious state require comprehensive care.

Providing good nutrition (nutritional support) is important. People are fed through a tube inserted through the nose and into the stomach (called tube feeding). Sometimes they are fed through a tube inserted directly into the stomach or small intestine through an incision in the abdomen. Drugs may also be given through these tubes.

Many problems result from being unable to move, and measures to prevent them are essential. For example, the following can happen:

  • Pressures sores: Lying in one position can cut off the blood supply to some areas of the body, causing skin to break down and pressure sores to form.

  • Contractures: Lack of movement can also lead to permanent stiffening of muscles (contractures) causing joints to become permanently bent.

  • Blood clots: Lack of movement makes blood clots more likely to form in leg veins—called deep vein thrombosis.

  • Damage to muscles and nerves in the arms and legs: Lack of movement or lying in one position for a long time can put pressure on a nerve that runs close to the surface of the body near a prominent bone, such as a nerve in an elbow, a shoulder, a wrist, or a knee. Such pressure can injure the nerve. As a result, the muscles that the nerve controls function less well.

Pressure sores can be prevented by frequently repositioning the person and placing protective padding under parts of the body that are in contact with the bed, such as the heels, to protect them.

To prevent contractures, physical therapists gently move the person’s joints in all directions (passive range-of-motion exercises) or splint joints in certain positions.

Preventing blood clots includes use of drugs and compression or elevation of the person's legs. Moving the limbs, as occurs in passive-range-of-motion exercises, may also help prevent blood clots.

If people are incontinent, care should be taken to keep the skin clean and dry. If the bladder is not functioning and urine is being retained, a tube (catheter) may be placed in the bladder to drain urine. Catheters are carefully cleaned and regularly examined to prevent urinary tract infections from developing.

Other treatments

A very few people have improved after certain drugs were prescribed, but only for as long as the drug was continued. These drugs include zolpidem (a sleep aid), apomorphine (used to treat Parkinson disease), and amantadine (used to treat viral infections). However, no treatment has been proved effective.

Music therapy may have some slight beneficial effects by stimulating some response in people in a minimally conscious state. But the usefulness of this therapy is as yet unclear.

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