Levels of consciousness in medicine


Level of Consciousness (LOC) is the medical term that refers to how awake, alert, and aware a person is of their surroundings. It also describes the extent to which a person can respond to routine attempts to get your attention.

Consistent medical terms that describe a person's level of consciousness aid in communication between healthcare providers, especially when the level of consciousness fluctuates over time.

There are many diseases and medications that affect a person's level of consciousness. Sometimes the decline in consciousness is reversible and sometimes it is not.

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Normal level of consciousness

According to medical definitions, a normal level of consciousness means that a person is awake or can be easily awakened from normal sleep. The terms include:

  • Consciousness determines the state in which the patient is awake, conscious, alert and receptive to stimuli.
  • Unconsciousness defines a state in which the patient lacks awareness and response to stimuli (touch, light, sound). However, a sleeping person cannot be considered unconscious if awakening leads to his normal consciousness.

Between these two extremes, there are various altered levels of consciousness, from confusion to coma, each with its own definition.

Altered level of consciousness (ALOC)

Altered or abnormal levels of consciousness describe states in which a person is cognitively impaired or cannot be easily awakened. Most medical conditions affect the brain and impair consciousness when they become serious or life-threatening, and an altered state of consciousness usually indicates a serious medical problem.

Often times, an altered level of consciousness can rapidly deteriorate from one stage to another, therefore requiring timely diagnosis and urgent treatment.


Confusion describes disorientation that makes it difficult to reason, provide a medical history, or participate in a medical examination. Causes include poor sleep, fever, medication, alcohol intoxication, recreational drug use, and post- natal status (recovery from an attack).


Delirium is a term used to describe an acute state of confusion. It is characterized by a decline in cognitive ability.

Specifically, attention, the disturbed sleep-wake cycle, hyperactivity (agitation) or hypoactivity (apathy), perceptual disturbances such as hallucinations (seeing things that do not exist) or delusions (false beliefs), and instability in heart rate and blood pressure can be seen in delirium.

Causes can include withdrawal symptoms, soft drugs, medications, illness, organ failure, and serious infections .

Lethargy and drowsiness

Lethargy and drowsiness describe extreme drowsiness, lethargy and lethargy, accompanied by decreased alertness. A slow patient often requires a light touch or verbal stimulation to elicit a response. Causes can include serious illness or infection, mild drugs, and organ failure.


Cloudiness It is a decrease in activity with a slow response to stimuli, requiring repeated stimulation to maintain attention, as well as prolonged periods of sleep and drowsiness between these periods. Causes can include poisoning, stroke, brain swelling (edema), sepsis (blood infection), and severe organ failure.


Stupor This is the level of impaired consciousness where a person responds only minimally to strong stimulation, such as pinching a toe or receiving light in the eyes. Causes can include stroke, drug overdose, lack of oxygen, cerebral edema, and myocardial infarction (heart attack).


Coma is a state of impermeability even to stimuli. A person in a coma may not have a gag reflex (gag reflex in response to a tongue depressor placed in the back of the throat) or pupillary response (the pupils generally contract in response to light).

It is caused by severe brain dysfunction, usually due to severe blood loss, organ failure, or brain damage.

The reasons for these altered states of consciousness may coincide. For example, the early stages of brain edema or organ failure can cause confusion, but can rapidly progress through stages of lethargy, dullness, stupor, and coma.

Coma classification

Coma and stupor states can also be subdivided into levels or classifications that further clarify a person's degree of immunity. Various systems have been developed to standardize these classifications, improving communication between healthcare providers and also aiding in research.

The most widely used classification systems are the Grady coma scale and the Glasgow coma scale:

  • The Grady Coma Scale assesses coma on a scale from I to V. Grades are determined based on a person's state of consciousness and their response to stimuli, such as responding to a person's call by name, mild and deep pain. Grade I indicates confusion, while V indicates lack of response to stimuli (coma).
  • The Glasgow Coma Scale uses a scale to measure the level of consciousness from 1 to 15, where 15 is the normal state of consciousness. This scale takes into account verbal, motor, and eye responses to stimuli to determine the overall score .

Get the word of drug information

There are also psychological terms that are used to describe consciousness (fully aware of your intentions) as opposed to subconscious (often describing deeper intentions) and preconscious (associated with memory).

There are also several other theories and definitions of consciousness that describe the stages of sleep, levels of self-consciousness, and the relationship between human beings and matter. While all of these definitions are certainly correct, they are not used to define medical states of consciousness.

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