Diffuse axonal injury (DAI), is a common and important feature of traumatic brain injury, also known as TBI. Axons are the parts of nerve cells that send a signal from a nerve body to an adjacent nerve or nerves. In the case of severe head trauma, the brain can suffer damage that involves diffuse, or many, axons in the brain, states Merck.com. This occurs because the brain moves back and forth in the skull as a result of acceleration or deceleration. This can cause significant damage to certain parts of the brain.
Gray-White Matter Junction
Understanding the anatomy of the brain is important in understanding areas of the brain that are damaged in TBI. Diffuse axonal injury occurs throughout the brain; however, most cases occur at the gray-white matter junction. To view this gray-white matter junction, an MRI is usually performed in a patient with TBI. A radiologist will look at a sagittal image of the brain, which simply means a side view of the brain. In this view, the radiologist can assess the area between the cortex, or gray matter, which is located at the top of the brain, and the white matter, which is located just below the cortex. Grey matter is composed of nerve cells, and white matter is composed of axons. In traumatic injury, the connection between nerve cells and axons are damaged, which results in DAI.
Temporal Lobes
According to the Neurology Channel, the temporal lobes are particularly susceptible to DAI. The temporal lobes are located at the frontal sides of the brain and are involved in hearing. During a traumatic event that involves significant acceleration and deceleration forces, the temporal lobes can rub against bones in the skull. This movement of the brain against the skull can cause DAI. This can result in significant deficits in hearing and speech in a patient with a TBI.
Frontal Lobes
The frontal lobes are located in the front of the brain and may also be involved in diffuse axonal injury, states the Neurology Channel. The frontal lobes are involved in higher mental functions. For example, this part of the brain helps a patient make decisions that are socially acceptable, such as which actions are good or bad. During trauma, the brain moves around in the skull and the frontal lobes can come into contact with the bones in the front of the skull. This can result in significant psychological deficits in a patient.
