Unlike diffuse axonal brain injuries, focal brain injuries are concentrated in only one area of the brain. This makes the effects of the injury easier to predict, but it does not necessarily make it less serious.
It is also possible for a person to experience both focal and diffuse brain damage in a single injury.
Today you will learn the causes, types, and effects of focal brain lesions and how they differ from other brain injuries.
Causes of Focal Brain Injuries
Focal brain injuries are a result of collision forces acting on the skull, which compress the tissue underneath. They occur when these forces damage a single location in the brain.
Some of the most common causes of focal brain damage include:
- Blow to the head by a sharp object. Car accidents and violent assaults often lead to these injuries.
- A brain lesion that cuts off blood to a specific brain region.
- A blood clot that deprives oxygen from one area of the brain, such as an ischemic stroke.
Focal brain injuries occur at the site of impact, but can also occur on the brain tissue opposite the impact, due to the brain hitting the other side of the skull as well from the force. When focal injuries occur on both sides like this, they are called coup-contrecoup injuries.
Focal brain injuries sometimes lead to subdural hematomas, which are collections of blood on the brain. Hematomas can be deadly conditions, and they require immediate treatment.
Although doctors make a distinction between diffuse and focal brain injuries, both often arise after an injury. For example, if someone hits their head in a car accident, the initial blow may have only caused focal damage. But other, secondary injuries such as oxygen deprivation can lead to widespread damage in the brain.
In fact, a recent MRI study revealed that focal lesions and diffuse axonal damage occur in about 50% of TBI patients. This makes treatment more complex.
Types of Focal Brain Injuries
Doctors classify focal brain injuries into two main categories: open and closed injuries. For example, open injuries refer to injuries where the skull is fractured and the brain is exposed to the elements. Closed injuries, on the other hand, do not involve skull fractures.
There are also other categories that a focal injury can fall into, which refer to the type of hemorrhages they cause. These include:
- Intraventricular hemorrhage: bleeding which occurs in the brain’s ventricles
- Intracerebral hemorrhage: bleeding can also occur within the cerebrum, the brain’s main tissue
- Cerebral contusion: this refers to a bruise on the brain, which occurs when the brain hits the skull.
The best way to treat these types of focal injuries is through surgery.
Focal Head Injury Symptoms
The specific symptoms of a focal brain injury will depend on where the damage occurred. However, even though the injury only affected one area, the effects can vary widely. That is because a single brain region can control multiple functions.
For example, if you only damage your left frontal lobe, you can experience emotional problems and difficulty with memory. But you might also lose the ability to speak, because the left frontal lobe controls language skills as well.
While all symptoms of focal brain lesions require immediate medical attention, the following symptoms could signal a life-threatening hematoma and require intervention:
- Sudden, intense headache
- Drowsiness and difficulty staying awake
- Numbness, paralysis, or tingling on either side of the body
- Changes in mood or personality
- Sudden feelings of fear, paranoia, or depression
- Slurred speech
Once again, seek emergency treatment if you display any of these symptoms after a head injury. Prompt treatment could save your life.
‘Syndrome of the Trephined’
Focal brain injuries are often treated with a type of surgery known as a decompressive craniotomy. This involves the removal of a skull flap (a portion of the skull) to access the brain underneath for treatment, followed by replacement of the skull flap. Sometimes, a craniectomy is required instead – the difference between a craniotomy and a craniectomy is that the bone flap is not immediately replaced after a craniectomy to help relieve pressure on the brain. In these cases, the patient will be required to wear a helmet at all times to protect the brain.
One of the rare complications of removing a piece of the skull in a craniectomy is a condition called “Syndrome of the Trephined”. This syndrome is associated with sensorimotor deficits and neurological deterioration. Symptoms of “syndrome of the trephined” include several issues such as:
- Intolerance of vibration and noise
- Loss of motivation and concentration
However, the good news is that repairing the skull through early reconstructive surgery can often reverse these effects.
Treating Focal Brain Damage
Immediate treatment for focal brain injuries will involve monitoring to make sure you have not developed any life-threatening complications. For example, if you have any swelling in the brain, doctors will perform surgery to relieve the pressure.
If the injury only caused mild contusions, you will be sent home to rest. Then, after a few days, you can gradually return to your normal activities.
If the injury was more severe, however, treatment will follow the same course as most other types of brain injury. That is, you will likely require various types of therapy and will need to focus on activating your brain’s neuroplasticity, which will allow you to regain function.
Once again, focal brain injury symptoms are determined by where the damage occurred. Therefore, you should tailor your treatment to address your specific symptoms.
The following are a few of the best therapies to help you do this:
- Speech therapy. If your injury caused cognitive deficits and/or language deficits, begin speech therapy right away. A speech therapist can teach you how to retrain your brain to improve attention, memory, and other cognitive skills, as well as to improve language skills.
- Physical and occupational therapy. These therapies can help you recover muscle strength and coordination after a focal injury. They will work to help you improve your independence with mobility tasks and activities of daily living as well.
- Cognitive training. Usually part of speech therapy, this training can help improve memory, attention, problem-solving, and learning skills, which often occur after frontal lobe damage.
These are only a few of the therapies and treatments that can help you overcome the effects of focal brain injuries. Talk to your therapists for more recommendations.
Understanding Focal Brain Injury
Focal brain injuries affect only one particular region of the brain. But even though they only damage one area, they can still cause a wide range of problems.
Treatment for focal brain injuries will remain the same as every other type of brain injury. You may also require surgery to minimize the pressure on your brain.
Finally, by activating neuroplasticity through targeted therapies, patients can begin to reverse some of the worst effects of focal brain injuries and regain their abilities.
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