About Transient Global Amnesia

What Is Transient Global Amnesia?

Transient global amnesia (TGA) is a neurological syndrome that begins suddenly and temporarily affects the ability to form new memories. People experiencing TGA may be disoriented in regard to time and place, but they can remember who they are and recognize family members. TGA typically lasts for several hours, but can last up to 24 hours. It is more common in people aged 50 and older. TGA is not caused by another condition such as stroke or epilepsy. People experiencing transient global amnesia may keep repeating the same questions or be unable to answer questions about recent events. People recover slowly over the course of a few hours and typically begin to remember events. Most individuals have only one episode of TGA during their lifetime, and the underlying cause of TGA is unclear.

Causes and Risk Factors of Transient Global Amnesia

The exact cause of transient global amnesia is unknown, although several factors and events have been associated with episodes.

What Causes Transient Global Amnesia?

Experts are still uncertain about the specific causes of TGA.
Some research suggests a possible link between TGA and a history of migraine, but more studies are needed to confirm this connection.
Some theories suggest temporary changes in blood flow or pressure in the veins may play a role, but this has not been proven

Non-modifiable risk factors for transient global amnesia cannot be changed or controlled. They include:

Age: TGA is most common in adults older than 50
Gender: TGA is known to affect both men and women equally

Can Stress or Other Events Trigger Transient Global Amnesia?

Information about modifiable risk factors for is unknown. However, some people report that their episodes occurred after events such as:

Symptoms after head injuries should be evaluated urgently because they may indicate concussion or another injury rather than TGA
Intense physical activity
Sudden immersion in very cold or very hot water
Extreme stress
Sexual activity
Medical testing or procedures

It's important to note that these events are reported by individuals who have experienced TGA and may not be definitive causes. Further research is needed to better understand the modifiable risk factors of TGA.

Remember, if you or someone you know experiences symptoms of TGA, it's always a good idea to discuss the episode with a doctor and ask any questions you may have.

Symptoms of Transient Global Amnesia

The main symptom of transient global amnesia (TGA) is a sudden inability to form new memories. The person is awake, alert, and knows who they are, but may be confused about time, place, or what just happened. They may repeatedly ask the same questions because they cannot remember the answers.

Common features of TGA include:

Sudden memory loss, especially for recent events
Difficulty forming new memories during the episode
Repeatedly asking questions such as “Where am I?” or “What happened?”
Preserved personal identity and ability to recognize familiar people
Normal ability to speak, follow simple directions, and perform familiar tasks
Gradual improvement over several hours, with symptoms resolving within 24 hours

Some people may also have mild headache, dizziness, nausea, or anxiety during the episode. These symptoms can occur with TGA but are not required for the diagnosis.

TGA should not cause weakness, numbness, trouble speaking, vision loss, loss of consciousness, uncontrolled movements, seizure-like activity, or ongoing confusion after 24 hours. Sudden memory loss should be treated as urgent until a healthcare professional rules out more serious causes such as stroke, seizure, head injury, infection, or medication or substance effects.

How Is Transient Global Amnesia Diagnosed?

Transient global amnesia (TGA) is usually diagnosed based on the person’s symptoms, the findings of a neurological exam, and the fact that the episode fits the typical pattern of TGA. Because sudden memory loss can also be caused by more serious conditions, a healthcare professional must first rule out other causes such as stroke, seizure, head injury, infection, medication or substance effects, or metabolic problems.

A typical diagnosis of TGA includes:

Sudden memory loss that is witnessed by someone else
Trouble forming new memories during the episode, often with repeated questions
Being awake, alert, and able to recognize personal identity
No new weakness, numbness, speech problems, vision loss, loss of consciousness, or seizure-like activity
Symptoms that improve gradually and resolve within 24 hours

Tests are not always needed when the symptoms are classic, but they may be used to rule out other conditions or confirm the diagnosis. These may include blood tests, a CT scan or MRI of the brain, or an electroencephalogram (EEG) if seizure is a concern. In some people with TGA, a special MRI sequence called diffusion-weighted imaging may show small temporary changes in the hippocampus, a part of the brain involved in memory. These MRI findings may be easier to see after the first 24 hours, but they are not required for every person.

Anyone with sudden memory loss should receive urgent medical evaluation, especially if symptoms are new, the episode is unwitnessed, there are other neurological symptoms, there has been a recent head injury, or symptoms last longer than 24 hours.

How Is Transient Global Amnesia Treated?

There is no specific treatment for transient global amnesia itself. TGA usually improves on its own within several hours and resolves within 24 hours.

Care during an episode focuses on:

Getting urgent medical evaluation to rule out more serious causes of sudden memory loss, such as stroke or seizure
Keeping the person safe and staying with them until they are evaluated and symptoms improve
Providing reassurance, a calm environment, and help with orientation
Treating another condition only if one is found, such as a seizure disorder, stroke, infection, or medication-related problem

Therapy, hypnosis, or memory-retrieval techniques are not standard treatments for TGA. Medications are not used to treat TGA directly, although a healthcare professional may recommend treatment for another diagnosed condition, such as migraine, anxiety, depression, epilepsy, or cardiovascular risk factors, when appropriate.

After recovery, many people do not need ongoing treatment for TGA. Follow-up may be recommended if the episode was atypical, if symptoms recur, or if another diagnosis is suspected.

Progression or Complications of Transient Global Amnesia

Transient global amnesia usually has a good prognosis. Symptoms typically begin suddenly, improve gradually over several hours, and resolve within 24 hours. Many people recover fully, although they may never remember events that occurred during the episode.

TGA does not usually cause permanent brain damage, long-term memory loss, dementia, epilepsy, or stroke. However, sudden memory loss can look like these and other serious conditions, so urgent medical evaluation is important during a first episode or any atypical episode.

Some people have more than one episode of TGA, but recurrence is uncommon. Reported recurrence rates vary across studies. A healthcare professional may recommend additional evaluation if episodes are brief, repeated, occur with seizure-like symptoms, or include other neurological signs.

Potential concerns during or after an episode include:

Injury or safety risks if the person is confused and alone
Anxiety or distress about the episode
Misdiagnosis if stroke, seizure, head injury, infection, medication effects, or other causes are not considered
A persistent memory gap for the time during the episode

Seek emergency care if memory loss is sudden, lasts more than 24 hours, follows a head injury, recurs, or occurs with weakness, numbness, trouble speaking, vision changes, severe headache, loss of consciousness, fever, stiff neck, or seizure-like activity.