Introduction

Understanding transient global amnesia (TGA)

Imagine being unable to remember where you are or how you got there, yet still being able to recognise people and carry out routine tasks. This sudden, temporary loss of memory is known as transient global amnesia (TGA); it can be scary and last for a few hours. People with TGA often repeat the same questions during the episode. Unlike stroke or dementia, this condition does not cause permanent brain damage, but it can be distressing for both the person experiencing it and their loved ones.¹

Why identifying risk factors matters

While the cause of TGA is still unclear, researchers have identified several risk factors that may contribute to its occurrence. These include vascular health issues, age, and underlying neurological conditions. Understanding the triggers and early medical evaluations can help reassure individuals and prevent unnecessary anxiety over more serious health concerns.

Age as a risk factor

Who is most at risk?

• TGA is most common in people aged 50 and older
• It rarely affects people younger than 40²

How ageing affects the brain

• As people age, the brain may become less adaptable to stress, making older adults more vulnerable to temporary memory disruptions like TGA³
• Changes in blood flow regulation in the brain, particularly in the hippocampus (the area responsible for memory), may contribute to the risk of experiencing an episode. While the exact cause is not fully understood, these age-related changes may make the brain more susceptible to sudden memory lapses⁴

Vascular risk factors and their role in TGA

Link between migraines and TGA

• Studies have explored whether temporary disruptions in blood circulation could contribute to memory loss episodes⁴
• Unlike strokes, TGA does not cause permanent damage, and brain imaging studies do not consistently show major blood vessel blockages. However, some theories suggest that changes in blood circulation, such as those triggered by stress, physical exertion, or migraines, may be involved in some cases⁴
• People with a history of migraines have a higher risk of TGA⁴
• This may be due to temporary blood vessel spasms affecting memory-related areas of the brain

High blood pressure and poor circulation

• History of Migraines: People with migraines have a higher chance of experiencing TGA, possibly due to a shared underlying mechanism affecting brain circulation
• Sudden Changes in Blood Pressure: Some TGA episodes have been reported after intense physical activity or stress, which may temporarily affect blood vessel function
• Venous Insufficiency Theory: Some studies have proposed that problems with blood drainage from the brain (rather than blockages in arteries) could play a role, but this remains unproven⁵

Triggers that affect blood flow

• Physical exertion: Activities such as heavy lifting, intense exercise, or sexual activity have been linked to TGA episodes
• Emotional stress: Anxiety, panic, or strong emotions may act as a trigger, possibly affecting the brain circulation
• Sudden temperature changes: Immersion in cold water, such as diving into icy water, has been associated with the onset of TGA in some individuals. ⁵

Neurological conditions linked to TGA

Possible connection to seizures and epilepsy

• Distinguishing TGA from Epileptic Amnesia: Transient Global Amnesia (TGA) and Transient Epileptic Amnesia (TEA) both involve sudden memory loss. However, TGA is typically a single, benign episode, whereas TEA consists of recurrent brief amnesic episodes linked to temporal lobe seizures⁶
• Electroencephalographic Findings: Most EEG results in people who have TGA appear normal, indicating that there is no apparent link between TGA and epileptic activity. However, in certain cases, minor anomalies such as bilateral slowing have been observed. During the acute period, researchers have also seen temporary changes in brainwave activity, such as a drop in beta and theta activity. These findings demonstrate that while TGA does not normally include epileptic seizures, minor abnormalities in brain activity may occur during an episode⁷
• Clinical Implications: While both conditions cause temporary memory loss, TGA is a separate and self-limiting disorder that does not necessitate long-term neurological treatment. Unlike epilepsy, TGA does not include repeated seizures or necessitate anticonvulsant medication. Patients who have TGA episodes usually recover completely without any increased risk of future neurological diseases. However, as TGA can be frightening, an appropriate medical evaluation is required to rule out more dangerous disorders such as stroke or transient ischaemic attack (TIA)

The role of stress and emotional factors

• Stress as a Trigger: High-stress levels or emotional trauma may precipitate TGA episodes
• Hippocampal Vulnerability: Stress may trigger transient lesions in the hippocampal CA1 region, which are thought to be the structural and functional correlate of TGA
• Psychological Aftermath: The sudden nature of TGA can cause significant anxiety and distress for patients and their families during the acute episode⁸

Recurrent episodes of TGA

• Frequency of Recurrence: Most individuals experience only one TGA episode in their lifetime; however, recurrence is possible, though rare
• Implications of Recurrence: While recurrent TGA can cause anxiety, it does not lead to long-term neurological complications⁹

FAQs

How long does it take to recover from transient global amnesia?

There is no treatment for temporary global amnesia. Within 24 hours, the problem resolves itself, and your memory function returns to normal.

Does TGA lead to dementia?

In the majority of cases, transient global amnesia doesn’t cause long-term memory problems like those seen in dementia. 

What triggers a TGA?

Theories have pointed to strenuous activity, high stress, hypertension, migraine, vascular congestion, depression, exhaustion and anxiety as potential triggers for an episode.

What’s the difference between TIA and TGA?

TGA is an isolated memory disorder with no other neurological symptoms. A TIA is often coupled with other neurological symptoms such as motor or sensory dysfunction.

What are the causes of TGA?

• Sudden immersion in cold or hot water
• Strenuous physical activity
• Medical procedures, such as angiography or endoscopy
• Mild head trauma
• Being emotionally upset by bad news, conflict or overwork

Summary

Transient Global Amnesia (TGA) is a sudden and temporary loss of memory that can be distressing but is generally harmless. While the exact cause remains uncertain, research suggests age-related changes and neurological conditions may contribute to its occurrence. Potential triggers include factors like temporary disruptions in blood flow, stress, and physical exertion.

Although TGA is usually a one-time event, some individuals may experience recurrence. However, it does not appear to increase the risk of stroke, epilepsy, or long-term cognitive decline. Understanding risk factors, such as ageing, vascular health, and emotional stress, can help individuals recognise potential triggers and seek proper medical attention if necessary.

Early recognition and reassurance are key to managing TGA effectively. By staying informed and maintaining excellent vascular and neurological health, individuals can reduce their risk of recurrence and address concerns with healthcare providers when needed.