Amnesia After Head Injury: Causes, Types, and Symptoms

Amnesia is one of the many effects of head injury that a person can experience.

While it is a normal part of TBI recovery, it can still be hard for friends and family to see a loved one go through it.

Today you will learn the causes and symptoms of amnesia after head injury plus how you can support your loved one during this time.

Causes of Amnesia After Head Injury  

Amnesia is the inability to form new memories or recall old ones. It is characterized by a state of confusion regarding place, time and person.

In other words, the person has no memory of where they are or how they got there, and they cannot retain new memories. When amnesia occurs after a concussion or brain injury, it is known as post-traumatic amnesia.

Post-traumatic amnesia most often appears after a person emerges from a coma. However, it can occur even if they never lose consciousness.

Several brain regions are involved in the processes of memory and new learning, and damage to any of these areas can cause amnesia. Some of the main areas of the brain that are in charge of memory include the:

• Cerebral cortex
• Hippocampus
• Parahippocampal gyri
• Thalamus

Even if these areas are not directly injured, research has shown that exposure to prolonged levels of stress has a direct effect on the hippocampus, causing it to shrink. This could explain why abuse victims and combat survivors sometimes experience amnesia.

Types of Amnesia  

There are a few types of amnesia that a person can develop after a head injury, including:

• Anterograde amnesia. With this type of amnesia, the person cannot remember new information. They cannot remember a conversation they just had, for example. They can, however, remember data and events that occurred before their injury.
• Retrograde amnesia. This type causes a person to forget events that occurred before their injury. However, they can still make new memories. Sometimes, after a severe head injury, both anterograde and retrograde amnesia can occur together. But this is rare.
• Dissociative amnesia. In rare cases, a person can not only forget their past but also their very identity. For example, they might not recognize their own reflection. This usually only occurs after extremely traumatic events, and most people will eventually remember who they are.

For traumatic brain injury patients, the most common type of amnesia is anterograde amnesia.

In fact, the presence and duration of anterograde amnesia is one of the best predictors of TBI outcome. In general, the shorter the amount of time a person has amnesia, the better their chances are of a full recovery.

Symptoms of Amnesia After Head Injury

The most prominent symptom of amnesia is memory loss and confusion, but there are other signs as well. These include:

• Agitation and distress
• Uncharacteristic aggressive behaviors, such as violence, shouting, and swearing
• Inability to recognize loved ones
• Childlike and clingy behavior

With post-traumatic amnesia, a person’s inhibitions are completely gone, and the brain is struggling to cope with its injury. Therefore, the patient will have almost no control over their actions and may seem very different.

This is no cause for alarm. As distressing as it might be to see your loved one in this state, try to remember that amnesia is almost always temporary. As their brain begins to heal, they should regain control of their behavior again.

How Long Does Post-Traumatic Amnesia Last?

Post-traumatic amnesia can last anywhere from a few hours to several months, depending on how severe the brain damage was.

There are several studies that suggest that the longer post-traumatic amnesia lasts, the more severe a person’s disability after injury will be. However, these findings are not definitive.

The following are predictions that doctors make based on the length of post-traumatic amnesia. Again, they are not definitive, but they may help you get an idea of what to expect during recovery:

• Under 1 hr. Injury is mild and patient will make a full recovery
• Between 1-24 hrs. Injury is moderate but patient will make a full recovery with some mild symptoms (headaches, dizziness)
• 1-7 days. Injury is severe and may take months to recover. Will most likely have mild cognitive deficits
• 1-2 weeks. Injury is very severe and will take several months to recover. Patient will have chronic cognitive problems but should be able to return to work
• 2-12 weeks. Injury is very severe and may take over a year to recover. Patient will most likely have permanent cognitive deficits in memory and attention.
• Over 3 months. Injury is very severe and will most likely result in significant disability.

In general, the length of time a person experiences post-traumatic amnesia correlates with the length of time they were in a coma. Meaning, the longer the person is unconscious, the longer they will have memory problems.

How to Help Someone With Amnesia After Head Injury

The following are some tips to help you interact safely with a person with amnesia after head injury:

• Identify yourself. Whenever you enter your loved one’s room, be sure to tell them who you are. This will help keep them from becoming too agitated. Even if you only left the room for a few seconds, make sure you remind them who you are when you return, since they probably won’t remember.
• Ask before touching. In the first few days after they wake up, the patient’s brain will be highly sensitive to stimulation. Therefore, the person with amnesia will probably not want to be touched. Always ask them if you can hold their hand before doing so and if they say no, respect their wishes.
• Stay calm. If your loved one sees other people acting distressed, that can add to their confusion and make the situation much worse.
• Be patient. Don’t try to make the person remember anything, and try not to correct any of their false beliefs. For example, if they think the year is 1987, don’t tell them they are wrong, as this will only cause them more distress.
• Allow time for yourself. It’s important to give yourself time to rest and not exhaust. While it’s normal to feel like you can’t leave your loved one’s side, taking a break allows you to have the energy to support them in their recovery.

Amnesia After Head Injury: Key Points

Amnesia is a stage of brain injury recovery that most patients will pass through, especially if they are emerging from a coma.

Symptoms of amnesia include loss of new memories, extreme confusion, and unpredictable behavior. Symptoms will usually resolve once the brain gets a chance to heal.

Finally, always remember that your loved one is not fully conscious right now. So try not to take any of their words or actions personally.

As time passes, your loved one will eventually regain control over their behavior and will start to remember you again.

When that happens, they will need you there to help them on their recovery journey ahead.

Featured Image: ©iStock/jacoblund