Global brain injuries are one of the most severe types of brain injury possible. While the road to recovery might be long, it is still possible with the right rehabilitation program.
This article will cover the causes, symptoms, and treatments for global brain injury. It will also explain which factors can impact a patient’s chances of recovery.
You can use the following links to jump ahead to relevant sections:
- What is Global Brain Injury?
- Causes of Global Brain Damage
- Effects of Anoxic Brain Injury
- Treating Global Brain Injury
- Factors that Affect Global Brain Injury Recovery
- Neuroplasticity’s Role in Anoxic Brain Injury Recovery
- Effective Therapies for Global Brain Injury
What is Global Brain Injury?
Global brain injury, also known as global ischemia or cerebral anoxia, occurs when the whole brain is deprived of oxygen, causing severe damage.
Anoxic injuries are often devastating because the brain uses oxygen to convert glucose into energy. Therefore, without oxygen, there is no longer any fuel to power brain cells. If this lack of power lasts for an extended amount of time, brain cells will eventually starve and die.
How long the brain can last without oxygen before suffering damage depends on the individual. For example, scuba divers can train their brains to more efficiently use oxygen. As a result, these people can last several minutes without oxygen before experiencing irreversible brain damage.
For the general population, however, serious brain damage can occur after about three minutes without oxygen.
The longer the oxygen supply is interrupted, the worse the damage can become. The following is a general timeline of what happens when the brain is deprived of oxygen:
- After five minutes, catastrophic brain damage can occur
- At ten minutes, if the brain is still functioning, the person will most likely fall into a coma.
- After fifteen minutes, survival is unlikely.
There are several different ways a person can experience loss of oxygen. We will discuss some of the most common in the section below.
Causes of Global Brain Damage
Any traumatic injury that results in oxygen loss can cause a global brain injury. The most common cause of global ischemia is cardiac arrest, but other causes can include:
- Significant blood loss
- Severe asthma attack
- Near drowning
- Drug overdose
- Carbon monoxide poisoning
Because anoxic brain damage causes the death of brain cells, secondary effects and outcomes are often more severe than other types of brain injuries.
Effects of Anoxic Brain Injury
The effects of global brain damage range from mild to severe, depending on how long the oxygen deprivation lasted.
When oxygen deprivation sets in, the body responds by increasing blood flow to the brain. This is meant to restore adequate oxygen and prevent damage.
Unfortunately, the body can only increase cerebral blood flow to twice its normal levels. If this is not enough, symptoms of global brain damage can develop.
The following are some of the most common effects of global brain injury:
1. Cognitive and emotional problems
However, if the damage was more severe, those skills will be more seriously affected. There can also be changes in personality, including:
- irritability and aggressive behavior
- impulsiveness and disinhibition
- apathy and lack of insight
Patients sometimes also have trouble with speech and language function, and struggle to find the right words or understand others. This is known as aphasia.
2. Blindness and other vision problems
When the occipital lobe is deprived of oxygen, loss of vision, also referred to as cortical blindness, can occur.
Global brain damage can also lead to a condition known as blindsight. This occurs when a person reacts to visual stimuli, such as an object in their way, without realizing it.
Conversely, damage to the occipital lobe sometimes causes Anton’s syndrome, in which a person with cortical blindness is not aware of their vision loss. Although they might walk into objects, the person believes they can see because the brain is creating a false image. This syndrome is serious but rare.
3. Abnormal movements
Damage to the cerebellum, basal ganglia, or primary motor cortex often leads to problems with movement, coordination, and balance.
Some of the most common movement disorders that occur after global brain injury include:
- involuntary writhing movements (athetosis)
- brief, jerky movements (chorea)
Global brain damage can also lead to muscle weakness and brain injury paralysis.
Treating Global Brain Injury
Treatment for global brain injury begins in the ICU where the person receives critical care to prevent as much brain damage as possible.
One new treatment for oxygen deprivation that some patients may undergo is therapeutic hypothermia. This is where cold packs are placed around the patient to lower their core body temperature.
Some evidence suggests that the cold has a protective effect on the brain and might decrease oxygen requirements. This could allow more time before neurons starve and may explain why some people survive after drowning in freezing water.
This is still a controversial treatment, however, and carries risks of its own.
Factors that Affect Global Brain Injury Recovery
Once emergency treatment has been given, the next step is to wait and see whether the person will emerge from their coma.
There are several factors that can help predict how well a person will recover from global brain injury. These include:
- Age. In general, the younger the person is, the better their chances are of a good recovery.
- Duration of oxygen deprivation. The more time the person was deprived of oxygen, the more severe their injury will be.
- Duration of coma. Similarly, the longer the person is in a coma, the lower the chances of a good recovery. This does not apply to medically induced comas, however.
- Pupil reaction. If their pupils do not constrict when bright light hits their eyes, the injury may have damaged the brain stem. This, again, will reduce the chances of a good recovery.
- Nerve responses. Doctors can electrically stimulate the nerves at the wrist and toes to see if the nerves are transmitting signals to the brain. If they are, that is a positive sign that could signal a good recovery.
While these signs can help doctors predict how severe an anoxic injury will be, they are not infallible. In other words, even if a patient does not show any nerve responses, for example, they may still survive. However, their likelihood of making a successful recovery will be lower than someone whose reflexes are intact.
Neuroplasticity’s Role in Anoxic Brain Injury Recovery
If the person regains consciousness after their global brain injury, recovery will start immediately.
Unfortunately, a global brain injury is harder to recover from than a TBI with a similar level of damage. That’s because most traumatic brain injuries damage the connections between neurons (called axons). Therefore, the brain can reorganize itself and create new connections to compensate. This process is known as neuroplasticity.
However, in a global brain injury, the neurons themselves are destroyed. This makes the brain damage much harder to overcome. That doesn’t mean it is impossible to recover from a global brain injury, of course. But it will take more time and effort.
In addition, you might consider trying hyperbaric oxygen therapy (HBOT) for brain injury. Oxygen therapy is a relatively new treatment option, so most insurances do not cover it, but several studies have shown that it can help activate neuroplasticity in global brain injury patients.
Effective Therapies for Global Brain Injury
Although anoxic brain injury is more severe than other brain injuries, the basic principle behind recovery is the same. You must activate neuroplasticity.
Neuroplasticity refers to the brain’s ability to repair itself after injury. You can engage it through repetitious exercise. While neuroplasticity may not be as effective for global brain injuries as it is for TBI, it still may help you recover your abilities.
Therefore, to encourage successful brain injury rehabilitation, you should participate in the following therapies:
The main goal of physical therapy during brain injury rehabilitation is to retrain the nervous system to control normal muscle movement.
After a global brain injury, the connection between the brain and muscles can become damaged or destroyed. Fortunately, engaging the brain’s neuroplasticity allows you to rebuild those neural connections.
There are a number of interventions a physical therapist might use to accomplish this, such as:
- Passive range-of-motion exercises
- Active exercises
- Electrical stimulation
- Task-specific exercises
The more you activate your muscles through physical therapy, the more skills you can hope to recover.
While physical therapy can teach you how to recover your physical strength, occupational therapy engages the skills you might need to regain independence after global brain injury.
Occupational therapists can teach you important activities that will directly improve your independence. Some areas of your life an occupational therapist might help you with include:
- Home management
- Social skills
- Cognitive functioning
To regain these skills, you must learn both restorative and compensatory strategies. Restorative techniques help you recover the ability to perform an activity like you did before your brain injury. Compensatory tactics, on the other hand, teach you how to adapt to your new limitations.
Of the two, restorative techniques are more permanent solutions. Therefore, occupational therapists prefer to focus on restorative techniques whenever possible, but typically a combination of restorative and compensatory strategies are used.
If your anoxic brain injury caused cognitive deficits, aphasia, or other communication disorders, begin speech therapy immediately. The sooner you can receive treatment, the more chance you can have to recover your abilities.
A speech therapist can walk you through the various brain injury speech therapy activities available. They can also show you precisely the steps you must take to improve your language skills.
Speech therapy can also help with more complex communication skills that you might struggle with after a global brain injury.
For example, you might struggle to match your voice pitch and volume with others. A therapist can also help you with cognitive-communication skills such as the ability to listen, pay attention, and respond appropriately.
Overcoming Global Brain Damage
Global brain injuries are serious medical conditions that require immediate treatment. Because every injury is unique, recovery is difficult to predict.
Generally, if oxygen can be restored quickly, the person can have an excellent chance of making a full recovery.
The most rapid recovery usually happens within the first six months. However, recovery is still possible several years after an injury, though progress will be slower.
Even if recovery is slow, it’s still possible to make some improvements. The key is to begin therapy as early as possible and to continue activating neuroplasticity.
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