Traumatic Brain Injury

Traumatic brain injury is a disruption in the normal function of the brain that can be caused by a bump, blow, or jolt to the head, or penetrating head injury.

Everyone, from children to older adults, is at risk of traumatic brain injury. Mild traumatic brain injury may affect your brain cells temporarily. A traumatic brain injury can have wide-ranging physical and psychological effects. Some signs or symptoms may appear immediately after the traumatic event, while others may appear days or weeks later. Moderate to severe traumatic brain injury can result in prolonged or permanent changes in a person's state of consciousness, awareness, or  responsiveness.

Symptoms of a traumatic brain injury can be mild, moderate, or severe, depending on the extent of the damage to the brain. 

  • A person with a mild traumatic brain injury may remain conscious or may experience a loss of consciousness for a few seconds or minutes. Other symptoms of mild traumatic brain injury 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 traumatic brain injury 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. 

Moreover, some people with traumatic brain injury will develop seizures. The seizures may occur only in the early stages, or years after the injury. Recurrent seizures are called post-traumatic epilepsy.

The relationship between degenerative brain diseases and brain injuries is not entirely clear. Some research suggests that repeated or severe traumatic brain injuries might increase the risk of degenerative brain diseases. A degenerative brain disorder can cause gradual loss of brain functions, including:

  • Alzheimer's disease, which primarily causes the progressive loss of memory and other thinking skills;
  • Parkinson's disease, a progressive condition that causes movement problems, such as tremors, rigidity and slow movements; and 
  • Dementia pugilistica, most often associated with repetitive blows to the head in career boxing, which causes symptoms of dementia and movement problems.