A traumatic brain injury (TBI) occurs when the brain is affected by a sudden impact, jolt or rapid movement of the head.

 

The brain floats in fluid inside the skull, and when the head moves quickly or is hit, the brain can shift or rotate. This can disturb how brain cells communicate with each other.

Importantly, a brain injury does not always involve a direct blow to the head, and medical scans such as MRI or CT often appear normal even when symptoms are present.

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Many different situations can lead to a traumatic brain injury.

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Falls

Falls are the most common cause of brain injuries, especially in older adults and young children. These may occur from:

• Falling out of bed

• Falling from a ladder

• Falling down stairs

• Slipping in the bathroom

• Tripping during daily activities

Even a seemingly minor fall can sometimes affect brain function.

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Traffic and vehicle accidents

Accidents involving cars, motorcycles, bicycles, scooters, or pedestrians are a major cause of traumatic brain injury.

In many cases, the injury occurs not only from impact but also from the sudden acceleration and deceleration of the head, which can cause the brain to move within the skull.

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Sports and recreational activities

Certain sports carry a higher risk of concussion or brain injury, especially those involving high speed, collisions, or repeated head impacts.

Examples include:

• Football or rugby

• Soccer (heading the ball)

• Boxing or martial arts

• Hockey

• Cycling or skateboarding

• Skiing and snowboarding

• Horse riding

Repeated minor head impacts over time may also affect brain function.

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Violence or physical assault

Brain injuries can occur as a result of domestic violence, physical assault, or child abuse.

In infants, a severe condition called shaken baby syndrome may occur when a baby is violently shaken. Because a baby’s brain and neck are still developing, this can lead to serious brain injury.

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Explosions and blast injuries

Among military personnel, explosive blasts are a common cause of traumatic brain injury. The pressure wave produced by an explosion can pass through the skull and affect the brain, even when there is no visible injury to the head.

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Sometimes the injury is subtle

Many people associate brain injuries only with severe accidents or loss of consciousness. However, this is not always the case.

A brain injury may occur even when:

• There was no loss of consciousness

• The person felt “dazed” or confused for a short time

• Symptoms appeared hours or days later

• Medical scans showed no abnormalities

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For some individuals, symptoms resolve quickly. For others, the brain may struggle to fully regain its normal balance and integration.

Understanding the possible causes of brain injury is an important first step in recognizing symptoms and supporting the brain’s natural ability to recover.