Unconsciousness and coma
QUESTION: What is the difference between unconsciousness and coma?
P. Mohammed, Karnataka
ANSWER: Coma is a state of deep prolonged sleep. Origin of the word coma is from the Greek word `Koma' meaning deep sleep.
The word unconciousness can be used as an adjective and as a noun. When used as an adjective it means `not awake' or aware of and not responding to one's environment. When used as a noun then it is referred to as part of the mind which is inaccessible to the conscious mind but which affects behaviour and emotion, according to Dr. A. V. Srinivasan, an eminent neurophysician .
The unconsciousness state may be prolonged or brief. A brief period of unconsciousness may set in after a trauma such as seizures of fits. There may be a momentary one due to concussion. The prolonged period of unconsciousness is called coma.
Unconsciousness or impaired consciousness can be categorised as coma due to primary brain injury or disease (ex) head trauma, tumour, infection, seizures and strokes.
Or the coma may be due to systemic diseases affecting the brain subconsciously. These include physical conditions such as heat strokes, heat exhaustion, deficiency of thiamine (B12) or due to failure of organs such as the liver or kidney.
The levels of unconsciousness can be measured clinally on a scale called the Glasgow Coma Scale. This gives the depth of the coma. The total measure on the scale is 15 and the minimal scale is 3. Clinically coma can be quantified only on this scale. For example, the eye opening state has got 4 points, speech 5 points and motor movements 6 points on the scale. So a person in deep coma will score 3 points on the scale.
Further higher functions or the cognitive skills such as pain, touch, sound or sight are also lost in the coma state. Only if a person regains his cognitive skills alone we can say that he has totally recovered from coma. So we need to measure them too. But these cannot be measured with the Glasgow Coma Scale. For this the Rancho Los Amigos cognitive scale which has 8 levels is used.
Level 1 is no response to pain, touch, sound or sight.
Level 2 is a generalized reflex response to pain.
Level 3 indicates a localized response. The person blinks to strong light, turns towards or away from sound, responds to physical discomfort, inconsistent response to commands.
Level 4 is a confused state. The person is alert, very active, aggressive, performs motor activities but behaviour is non-purposeful and extremely short attention span.
Level 5 is a confused - non-agitated state. The person has gross attention to environment, highly distractible, requires continual redirection, has difficulty in learning new tasks and is agitated by too much stimulation.
Level 6 is a confused - appropriate state. The person has inconsistent orientation to time and place, retention space, recent memory impaired, and has goal-directed behaviour with assistance.
Level 7 is automatic - appropriate state. He performs his daily routine in familiar environment in a non-confused but automatic robot-like manner. Skills noticeably deteriorate in unfamiliar environment.
Level 8 is purposeful and appropriate.
To conclude, clinically the level of consciousness can vary from fully conscious state which is defined as a state in which there is awareness of the self to the comatose state of unarousable unresponsiveness. The altered states of consciousness include the confusional state where memory is faulty but the person is oriented to time and space. The delirium is characterized by disorientation, agitation and visual hallucination. Stupor implies a state of unresponsiveness but arousable with great difficulty. — The Hindu S & T Desk
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