What are the possible effects of traumatic brain injury (TBI)?

TBI can have a range of effects that depend on the type of injury, how severe the injury is, and what part of the brain is injured.¹ According to the Centers for Disease Control and Prevention, these health effects can sometimes remain for a long time or even be permanent.²

Immediate Problems

Sometimes, a person will have medical complications just after the injury. People with more severe TBI are more likely to have complications. Some complications of TBI include seizures, nerve damage, blood clots, narrowing of blood vessels, stroke, coma, and infections in the brain.¹

The likelihood of many of these problems decreases as more time passes and the person’s condition stabilizes. However, some problems, such as seizures, may continue even after a person’s condition is stable.

Longer-Term Effects

TBI may cause problems with various brain functions, and some of these problems do not appear until days or months after the injury. Some problems may be temporary, while others may persist throughout a person’s life after the injury. Possible longer-term effects of TBI include problems with:

• Cognition, such as difficulty learning, remembering, making decisions, and reasoning
• Senses, such as double vision, a bitter taste in the mouth or loss of the sense of taste, ringing in the ears, and tingling or pain
• Communication, such as trouble talking, reading, writing, and explaining feelings or thoughts
• Behavior, including difficulty with social situations, relationships, self-control, and aggression
• Emotions, including depression, anxiety, mood swings, and irritability^1,3

Degenerative Effects

Research suggests that having one or more TBIs may increase the likelihood of later having a disease that causes the breakdown of brain cells. Some evidence indicates that TBI is linked to:

• Alzheimer’s disease, which impairs memory, emotions, and thinking skills
• Parkinson’s disease, which causes problems with motor skills and controlling body movement
• Chronic traumatic encephalopathy, which causes problems with memory, thinking, and motor skills. It is more common in those who have repeated TBIs or head impacts, including athletes involved in boxing, football, and hockey.⁴