Overview: Repeated episodes of Transient Global Amnesia can become frustrating

The world is temporarily forgotten. Then it comes back. Living in this way can be disorienting. In episodes where you forget things which are accessible to others can be concerning for both yourself and your loved ones. Of course, the range of problems can be more totalising. Transient Global Amnesia (TGA) is a neurological condition characterised by a temporary but almost total loss of short-term memory.¹ An episode of TGA lasts no more than twenty-four hours before a person returns to normal and can form new memories. No other neurological functions are compromised.

Only 5.8% of people who have experienced TGA report recurrent episodes.² Different values may be given depending on the study and frame of time. However, given that recurrent episodes are an extremely rare phenomenon, it is important to study this clinical entity and ensure people are aware of its existence. This is because it can become very frightening and frustrating to repeatedly lose access to one’s abilities to produce memories, as it can lead to a whole range of problems impacting quality of life. The purpose of this article is to make you aware of the frequency of recurrence and identify key risk factors of repeated TGA episodes.

Key points

• Transient Global Amnesia (TGA) is a neurological condition related to a dysfunction of the hippocampus, a part of our brain which plays a major role in learning and memory development.
• Whilst TGA usually goes away by itself, recurrent episodes of TGA can become a significant issue since each episode affects one’s ability to form new memories and causes disorientation concerning people and places.
• Risk factors for repeated episodes of TGA include sexual intercourse, emotional stress, and mild physical trauma to the head.

• Since a TGA episode resolves itself, there are currently no treatments in place to prevent it. Self-soothing strategies and reassurance foster a sense of security, which plays a big role in maintaining well-being in the long-term.
• Interdisciplinary medical support, which includes primary care physicians and neurologists, can help provide you with comprehensive care for repeated episodes of TGA.

Understanding transient global amnesia

Whilst the cause of TGA is unknown, the condition is linked to congestion of the veins, migraines, or ischemic events.³ The term ‘ischemic’ here refers to issues related to a limited supply of blood flow, such as the brain. The condition is correlated to a temporary dysfunction of the hippocampus. The hippocampus is a complex structure of the brain and is known for its role in learning and memory formation. In addition to this, the hippocampus consolidates information in our spatial memory, which is what enables navigation. This is the reason why TGA can cause general disorientation. 

The clinical presentation of TGA is marked by a sudden onset of anterograde amnesia alongside the preservation of personal identity and other cognitive functions.³ It’s like the mind becomes a sieve and memories keep passing through. Anterograde is a term which refers to something that is directed forward in time. So in this case, it refers to a form of amnesia where one is unable to remember information encountered after the onset of an episode. Other symptoms of TGA include nausea, dizziness, chills or hot flushes, cold extremities, paresthesias, trembling, chest pain, limb weakness, ataxia, and other sensory disturbances.⁴ It is common for people to ask repetitive questions during an episode. 

Based on this clinical presentation, and since the underlying cause of TGA remains obscure, a healthcare practitioner needs to exclude other causes or comorbidities such as seizures and stroke.

Frequency of recurrence of TGA

Whilst figures can vary depending on different populations and study methodologies being used, TGA has an estimated recurrence rate of 6-20%.^2,4 Recurrence, though rare, may occur within months or years, but the average time interval used in current studies is often a year. Patterns of recurrence differ for patients due to possible seasonal and situational patterns which promote multiple episodes. Current research is limited but points towards dysfunction in the neurological circuits of what is known as the cornu ammonis (CA1) field of the hippocampus. This is because CA1 is involved in the transference of memories to the neocortex network and is very sensitive to cell stress.⁴

Risk factors for repeated episodes of TGA

TGA is more prevalent in people over the age of 50, with 96% of reported individuals being between the ages of 51 and years.⁴ Several small-scale studies also show that TGA is slightly more prevalent in females.

Pre-existing medical and neurological conditions also affect the likelihood of repeated occurrences of TGA. In particular, a history of migraines is strongly correlated with TGA, along with cardiovascular problems such as high blood pressure or atherosclerosis (buildup of plaque on the walls of our arteries, reducing blood flow). TGA can also be caused due to psychological stress and physical exertion (including sex) prior to the onset of an episode.⁵ There may also be a family history of TGA, along with related neurological and psychological conditions. Due to its obscure nature, an analysis of environmental and predispositional factors is needed to understand if a patient is at risk for multiple episodes of TGA.

Long-term outcomes

At present, once a diagnosis has been made, it is understood that all a person needs is reassurance.⁵ This is because TGA is a benign conditionmeaning that in itself, the condition is not harmful. This is because during an episode of TGA, other cognitive functions remain intact, and there is typically no long-term cognitive impairment. However, it is understandable that losing one’s ability to form memories on a repeated basis can be distressing. It is important to discuss the impact TGA recurrences have on your quality of life with a healthcare practitioner who is capable of initiating the process of setting up a multi-approach plan to help you.

Whilst living with TGA may seem alarming, management strategies can be implemented to reduce the risk of recurrence. Since it has been observed that TGA is often precipitated by physical and emotional stress,^4,5 it is recommended that patients address situational factors. Examples of this would be dealing with intense depression through cognitive-behavioural or dialectical-behavioural approaches, or taking care of your cardiovascular health by engaging in non-intense exercise. 

Whilst TGA is shown to have minimal impact on overall quality of life, using self-management strategies alongside consulting with a healthcare practitioner can reduce fears related to recurrence.

Current research and future directions

Whilst there are currently limitations on what we know about the nature of TGA, future research aims to identify clear biomarkers that can help practitioners predict if someone is at risk of experiencing repeated episodes. There is also research being done which aims enhance our understanding of the role of hippocampal dysfunction in recurrence.⁴ This may lead to exploring preventative strategies for high-risk individuals who feel that living with the condition is distressing.

Summary

Recurrent episodes of TGA can be deeply unsettling. Whilst the condition poses no harm and does not result in long-term cognitive impairment, the sudden and repeated inability to form new memories can disrupt daily life and create distress. Understanding the risk factors, such as emotional stress, physical exertion, and a history of migraines, can help individuals take proactive steps in managing their condition. Though there is no current treatment to prevent recurrence, self-management techniques remain essential in maintaining well-being.

Future research will play a crucial role in uncovering clearer biological markers and potential preventive measures. As our understanding of hippocampal dysfunction advances, medical professionals may be better equipped to assess individual risk and provide tailored recommendations. In the meantime, those affected by repeated episodes of TGA should seek medical support, engage in lifestyle adjustments, and foster a sense of security through self-soothing strategies. With the right approach, it is possible to navigate repeated episodes of the condition with confidence and resilience!

• Transient Global Amnesia (TGA) is a temporary neurological condition that causes sudden memory loss and disorientation. It does not impact other cognitive functions, and episodes resolve within 24 hours
• Recurrent episodes of TGA are rare, with recurrence rates estimated between 6-20%. These figures vary based on study methodologies and the population of a study
• Risk factors for repeated episodes include emotional stress, physical exertion (including sex), migraines, and cardiovascular conditions
• While TGA is considered to be a benign condition, repeated episodes can be distressing. Self-management strategies, reassurance, and lifestyle adjustments may help reduce recurrence risk
• Future research aims at understanding hippocampal dysfunction patterns to better predict and manage recurrence, potentially leading to preventative strategies