How does traumatic brain injury affect consciousness?

Traumatic brain injury ( TBI) occurs when a sudden trauma causes damage to the brain. The damage can be focal - confined to one area of the brain - or diffuse - involving more than one area of the brain.

A person with a mild TBI may remain conscious or may experience a loss of consciousness for a few seconds or minutes. Other symptoms of mild TBI include headache, confusion, lightheadedness, dizziness, blurred vision or tired eyes, ringing in the ears, bad taste in the mouth, fatigue or lethargy, a change in sleep patterns, behavioral or mood changes, and trouble with memory, concentration, attention, or thinking.

A person with a moderate or severe TBI may show these same symptoms, but may also have a headache that gets worse or does not go away, repeated vomiting or nausea, convulsions or seizures, an inability to awaken from sleep, dilation of one or both pupils of the eyes, slurred speech, weakness or numbness in the extremities, loss of coordination, and increased confusion, restlessness, or agitation.
Pam Hays
Physical Medicine & Rehabilitation
Not all brain injuries result in a loss of consciousness. That is just one symptom of brain injury.  Even without LOC, a brain can be altered physically. It is important that anyone who has been injured in a way that could cause a brain injury, be checked out by a doctor.  Also important to note, is that someone might appear to be just fine after injury, but after time has elapsed, problems can occur.  "Better safe than sorry" is a good way to think when it comes to any possibility that a head has been injured in a way that could possibly cause a brain injury.
No matter how mild or severe, most traumatic brain injuries (TBIs) cause problems with arousal, consciousness, alertness, and reactions. Abnormal states of consciousness that may occur as a result of TBI include stupor, coma, persistent vegetative state, locked-in syndrome, and brain death. With stupor, the person is completely unresponsive but may be aroused by a powerful stimulus like intense pain. A person in a coma is unresponsive and cannot be aroused. While someone in a vegetative state is unconscious, they can have periods of alertness and may open their eyes, make grunting sounds, and have reflex responses. When someone has locked-in syndrome, a rare neurological syndrome, they are awake and alert but cannot move or communicate in any way except for muscles that control the eyes because of the complete body paralysis.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.