Coma & brain injury
Coma is generally the
result of damage or interference with particular structures of the
brain, and its length and depth provide a strong indication of the
severity of brain injury.
During a coma, a person is in a state of unconsciousness. They
do not show intentional response or movement, the eyes remain
closed, and they cannot be awakened or obey commands during this
The person may show some level of response to touch, pain, and
verbal commands, so it is more accurate to talk about depth of coma
rather than an all-or-nothing state. Family members often have
trouble accepting their loved one is in a coma when there are basic
A coma can be chemically induced to accelerate healing, protect
the brain from secondary damage, or to relieve severe chronic pain
during healing after a traumatic brain injury (TBI) or other kind
of brain disorder.
Some coma patients may progress to a wakeful but unconscious
state called post-coma unresponsiveness (previously called
persistent vegetative state) where the cerebral cortex is not
functioning. The person is unable to respond to stimuli in their
environment, but they maintain a normal sleep-wake cycle and
People can remain in this state for a long time, and it can be
difficult for family members to accept when there are seemingly
conscious behaviours e.g. a patient's eyes may follow them around
There are two scales commonly used to measure the depth and
duration of a coma. The most common is the Glasgow Coma Scale (GCS)
which scores actions and reactions in three specific areas
including eye, verbal and motor response. The scores in each area
are summed to give an overall score, ranging from 3 (deep coma) to
15 (fully awake). The Rancho Los Amigos Scale is another measure of
coma, it has a single scale and assesses global functioning.
Treatment during a coma
During a coma the medical team provides treatment to prevent any
further complications. A respirator may be used to assist
breathing, and surgery may be required to stop any bleeding or
swelling in the brain. There is constant monitoring of vital signs,
such as blood pressure and pulse and levels of any prescribed
Other therapies may be used to prevent problems upon awakening
from coma. There is a risk of the patient losing their range of
motion in their extremities, so the limbs will be moved regularly
to avoid spasticity (involuntary muscle tightness).
Changing the patient's position is necessary on a regular basis
to prevent pressure sores or skin ulcers, as the patient will not
have the reflex actions that prevent these sores from occurring as
in someone who is just asleep.
Can people be aware during a coma?
It is difficult to know if there is any degree of awareness
during a coma. As the patient emerges from coma, awareness of those
around them increases. There have been cases where patients
reported awareness of family members around them and could remember
some of what was said. For this reason families and medical staff
should be careful of what is said near the patient while in a
How long will a coma last?
There is no reliable way to accurately tell how long a coma will
last, and there are currently no medications, which will reliably
shorten the duration of a coma. A coma is usually said to last no
longer than four weeks, but post-coma unresponsiveness may last
from months to years.
Recently, programs that use sensory or physical stimulation to
accelerate the healing process and bring someone out of a coma have
been used in the United States and claim high levels of success.
Before any program is attempted, it should be discussed with the
treating medical team. It is also important to note that a coma may
accelerate healing, and attempts to rouse somebody from a coma
should not be attempted too soon after the accident.
Post-traumatic amnesia (PTA)
Unlike the popular concept of coma shown in many movies, an
individual coming out of a coma doesn't just wake up - individuals
will go through a gradual process of regaining consciousness. When
a patient responds with intentional movement or attempts to
communicate, they are generally considered to have emerged from
Following emergence from a coma, the patient enters another
level of consciousness known as post-traumatic amnesia ( PTA).
Individuals in PTA are partially or fully awake, but are confused
about the day and time, where they are, what is happening and
sometimes who they are.
The duration of PTA can be used along with that of the coma to
provide an indication of how severe the traumatic brain injury or
other type of brain disorder is, and what the long-term outcomes
are likely to be.
It is also possible for an injury or pressure to the frontal lobes
to mimic the effects of PTA, so diagnostic scans may be used during
PTA to ensure that the diagnosis is correct as well as to ensure
that healing is progressing normally.
References and further information
Leon-Carrion, J., del Rosario Dominguez-Morales, M., &
Dominguez-Roldan, L.M. (2006). Low-level responsive states. In J.
Leon-Carrion, K. R. H. von Wild and G. A. Zitney (Eds.), Brain
Injury Treatment: Theories and Practices. New York, NY: Taylor
Disability Online. (2004). Coma. Retrieved March 29, 2008, from
National Health and Research Council. (2003). Post-Coma
Unresponsiveness (Vegetative State): A Clinical Framework for
Diagnosis- An Information Paper. Retrieved March 29, 2008, from
Coma. (2008). Retrieved March 29, 2008 from http://en.wikipedia.org/wiki/Coma
Brain Foundation. (2003). Coma and Persistent Vegetative State.
Retrieved March 29, 2008, from http://www.brainaustralia.org.au/AZ_of_Brain_Disorders/coma
Centre For Neuro Skills. (2006). TBI Resource Guide: Coma and
Persistent Vegetative State. Retrieved March 29, 2008, from http://www.neuroskills.com/coma.shtml
Coma Recovery Association. (2006). Coma Recovery Program.
Retrieved March 29, 2008, from http://www.comarecovery.org/comarecoveryprogram.shtm
Stuart, J. (2007, March 27). Back from the dead: A cure for comas.
The Independent. Retrieved March 29, 2008 from