Coma - Fact Sheet

A person with a brain injury more often than not experiences some level of coma immediately or shortly after the onset of the injury.

What is a Coma?

In coma, a person is in a state of reduced consciousness or is unconscious. In this state, the person exhibits differing levels of responsiveness to touch, pain, and verbal commands. It is therefore proper to talk about depth or levels of coma rather than thinking of coma as an all or none type of experience. Family members often have trouble accepting their loved one is in a coma when there are basic responses evident.

A coma may also be chemically induced to accelerate healing or to relieve severe chronic pain during healing.

The person who is in a wakeful state but with profound non-responsiveness is referred to as Post-Coma Unresponsiveness (PCU). This state was previously referred to as a Persistent Vegetative State (PVS), and this term is still used internationally. In this state the Cerebral Cortex of the brain is not functioning, and the person is unable to respond to things in the environment. Many individuals can remain in this state for long periods of time. Once again this can be difficult for family members to accept. The patient’s eyes may follow them around the room. This is a very basic function of the brain, but it may appear as though the patient recognises people.

In the condition of locked-in syndrome, the patient appears unresponsive without the ability to move or verbally communicate, yet has full Cognitive abilities. Such individuals are able to use an eye blinking response to communicate.

Coma Scales

There are two scales commonly used to measure the severity, or degree, of a coma. The most common is the Glasgow Coma Scale (GCS) which scores actions and reactions in three specific areas (see scale at the end of this Fact Sheet), however the Rancho Los Amigos Scale, which has a single scale and assesses global functioning, may also be used. As it is not commonly used in Australia, details are not provided here.

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. The shortest coma may only last for a few seconds. The longest coma may last for the life of the patient.

Recently, programs which 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 consistent, high levels of success. The Coma Recovery Association, Inc. contains details on their website. Before any program is attempted, it should be discussed with the treating medical team.

Research is currently underway in several countries on zolpidem, commonly known in Australia by the trademark name Stilnox. In 1999, a man in a coma in a South African hospital was prescribed zolpidem to treat restlessness that seemed to indicate pain, and became conscious. This effect has been observed in numerous other individuals, with varying degrees of success, and only for as long as the drug is present in the bloodstream. As yet no information on the long-term effects of zolpidem is available, and it is important that any medication be thoroughly discussed with the treating medical team – coma can also result from an overdose of zolpidem. 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.

Does a Person in a Coma Dream?

We don’t know, but probably not. There is a great deal of difficulty in answering this question correctly: There have been reports of people in a coma displaying the Rapid Eye Movements (REM) that indicate dreaming sleep, but it is difficult to verify these reports. What we do know is that a low level of electrical activity does continue in the brain, but coma patients do not show a progression through sleep-wake cycles and it is extremely unlikely that anybody in a coma will ever progress into REM sleep.

Is a Person in a Coma Aware?

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 around the patient while in a coma.

Rehabilitation During a Coma

Even without attempting to accelerate the course of healing and bring someone out of a coma, there can be a limited amount of rehabilitation during a 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). Constant monitoring of vital signs and levels of any prescribed medications will always take place.

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 sorts from occurring in someone who is asleep.

Post Traumatic Amnesia

Unlike the popular concept of coma shown in many movies, an individual coming out of a coma doesn’t just wake up, but will go through a gradual process of regaining consciousness - see the coma scale described above. This stage of recovery is called Post Traumatic Amnesia (PTA) and may last for hours, days or weeks.

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. They may be afraid, physically and verbally aggressive, disinhibited, agitated and restless. If physically able, they may wander. In conjunction with the Glasgow Coma Scale, length of PTA is frequently used as a guide to the severity of brain injury.

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.

Further information

• Coma Recovery Association
• Glasgow Coma Scale
• Rancho Los Amigos Scale
• Zolpidem

The Glasgow Coma Scale

• A total score of 13 to 15 is classed as Mild Severity.
• A total score of 9 to 12 is classed as Moderate Severity.
• A total score of 3 to 8 is classed as Severe Severity.