What Is Transient Global Amnesia?
Transient global amnesia (TGA) is a sudden occurrence of memory loss that lasts for a very short duration of time. Memory loss that occurs during this period is temporary. The individual who experiences this is otherwise alert but can not recall recent events because temporary global amnesia prevents a person from making new memories, which causes current memories to disappear.
This unexpected episode of memory loss is not caused by other neurological disorders like epilepsy or stroke. This is a rather dramatic event that usually resolves within 24 hours. An interesting fact about TGA is that a person with transient global amnesia finds themselves suddenly unable to remember recent events and will wonder where they are and how they got there. However, they can still recall their identities, the names of familiar things, and identify family members and other significant people.
What Are the Symptoms of Transient Global Amnesia?
The symptoms of TGA are discussed below:
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The individual, all of a sudden, forgets the time, day, and location they were at, prior to the TGA episode.
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The characteristic feature of TGA is that the person keeps on asking the same questions again and again despite continuously receiving the right answers.
This happens because TGA restricts them from storing the answers they are told. For example, the person will repetitively ask questions like "why am I here," "how did I come here" and "What is the date today" even after getting the answer.
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Another specific feature about TGA is that the person will not ask questions like "who am I" or "Who are you"?. Because the person is alert and able to recognize themselves and their family members during a TGA attack.
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The episode of TGA usually lasts for about six hours, and during this time, temporary memory loss is accompanied by confusion and altered behavior.
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TGA usually occurs in middle-aged and older adults.
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Once the TGA episode is over, most people return to their normal mental state, and the memory gradually returns. However, they do not remember what happened during the TGA episode.
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No signs of brain injury will be there, such as inability to move an arm and leg, inability to speak or understand words, or involuntary movements of limbs.
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During the period of TGA, seizures do not occur.
What Causes Transient Global Amnesia to Occur?
The exact cause of TGA is not clear, and no specific causative factor has been established yet for this condition. However, some triggering factors have been recognized, which are discussed below:
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Emotional stress, such as being deeply depressed due to any sad or negative news, heavy workload, or disagreement.
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Physical stress, such as vigorous exercises, activities, or exertion.
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TGA may occur as a result of sudden immersion in hot or cold water.
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It is assumed that migraine can trigger the episode of TGA. However, this association has not been proven in studies yet.
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Certain medical procedures like angiography or endoscopy can also result in TGA, as these procedures might induce stress.
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Sudden occurrence of pain (acute pain).
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A study conducted in 2015 showed that venous drainage obstruction (problem with blood flow) in the brain could trigger TGA.
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TGA can be triggered by conditions that cause decreased venous return and backward venous blood flow, as in sexual intercourse, stress, or the Valsalva maneuver. The Valsalva maneuver is a breathing technique that people intentionally use for purposes such as medical testing, heart-rate control, and other reasons. It is accomplished by closing the mouth, pinching the nose, and putting pressure as if having a bowel movement.
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It may occur in people with a history of head injuries or psychological disorders.
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Transient global amnesia is more common in adults over the age of 50 than in younger people.
What Are the Complications of Transient Global Amnesia?
- When a TGA event occurs, it may look scary to the witness. However, this event is rare, and it is unlikely to occur again. In some rare cases, it may occur twice, but not more than that.
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Temporary memory loss for a while that occurs in TGA can cause unpleasant experiences and may lead to emotional distress.
How Is Transient Global Amnesia Diagnosed?
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The diagnosis of TGA is made based on a thorough physical examination, symptoms as narrated by the witness, and neurological examination, which will check sensory function, reflexes, gait, balance, and coordination.
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Some tests will be conducted to check memory and the ability to recall.
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Some tests would be done to rule out if there are any abnormalities in the blood flow or electrical activities in the brain.
Brain Scans for Transient Global Amnesia:
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Computerized Tomography (CT)- Using specialized X-ray equipment, the images of the brain will be taken from various angles and combined together to create cross-sectional images of the brain and skull. CT scans can detect structural abnormalities in the brain, such as constricted, overstretched, or damaged blood vessels, as well as previous strokes.
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Magnetic Resonance Imaging (MRI)- This scan checks for abnormalities in the body's soft tissues. Here, a strong magnetic field and radio waves are used to create cross-sectional images of the brain. These images are combined together, and a 3-dimensional (3D) image is produced. If a CT scan is done at the time of the event and the CT reveals no signs of a brain disorder, an MRI may not be necessary.
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Electroencephalogram (EEG)- The electrical activity of the brain is captured by an EEG using electrodes placed on the scalp. This is an important test because, from this, alteration in the brain waves can be identified for epileptic patients even when they are not experiencing seizures. Usually, an individual has experienced more than one instance of transitory global amnesia, or if the operating doctor suspects seizures, this test will be prescribed.
How Is Transient Global Amnesia Treated?
Transient global amnesia resolves on its own after a few hours and does not require any treatment. However, if any underlying abnormality is detected on a CT scan or MRI of the brain, then that abnormality would be treated.
Conclusion:
Transient global amnesia is not very common; it occurs rarely. The best thing an individual can do during this episode is to be with their family members throughout the episode. TGA is usually considered harmless, but yes, it may be a unique experience for the person who experiences it.
