The human brain contains billions of nerve cells. These cells communicate with each other via axons which are long fibers and comprise the white matter in the brain. Traumatic events that happen in an accident can damage these axons resulting in diffuse axonal injury to the brain. Diffuse Axonal Brain Injury (“DAI”) is also known as acquired brain injury, axonal shearing, or a head injury.
How Axonal Injury Occurs
Examples of how DAI can occur include:
whiplash injury or acceleration/deceleration can result in traumatic twisting of the axons
An impact to the head can cut, stretch, twist, or otherwise injure the axon fibers
Often damage to the axons cannot be visualized on diagnostic imaging such as MRI or CT scans. However, a sheared axonal fiber can result in brain cell death.
The axon fiber can no longer serve as a pathway for communication between brain cells thereby cutting off flow to a brain cell which causes it to wither and die.
Diffuse Axonal Injury (DAI) is one of the most common traumatic brain injuries. It occurs in about fifty percent of head trauma accidents. Car Accidents especially whiplash type sudden acceleration / deceleration injury are the most common causes of DAI. Other types of accidents that cause DAI include falls, assaults, and shaken baby syndrome.
Diagnosis of DAI
A regular MRI may not show diffuse axonal injury due to the microscopic nature of the injury such as a tear in tiny axon fibers. However, newer technology including Diffusion Tensor Imaging (DTI) can show damage to the white matter indicative of axonal injury.
An example of DTI brain imaging:
DAI symptoms may not appear immediately after an accident. The injury to the axon fibers prevents brain cells from communicating with each other and over time the death of brain cells will manifest symptoms.
Symptoms of DAI
Common patient symptoms after a diffuse axonal injury include:
loss of consciousness during the accident or traumatic event