Transient global amnesia: symptoms and causes

Although we usually talk about memory as if it were a whole, the truth is that there are several types of memory, each with its own internal logic. Furthermore, each of these memories stores a different kind of information. For example, the emotional memory stores information related to the emotional state, while the declarative works with information that can be verbalized.

Just as there are different forms of memory, amnesia, which is a harmful alteration in the functioning of this cognitive process, does not always manifest itself in the same way.

In this article we will see the characteristics of transient global amnesia, one of the strangest memory disorders.

• Related article: "The different types of amnesia (and their characteristics)"

What is transient global amnesia?

We know as transient global amnesia a disorder in which the person is not able to remember the events they have experienced for the last few minutes or hours and some minor information about what happened to you ago time, although it preserves memories related to its own identity and is capable of forming new ones memories.

Thus, the symptoms of this type of amnesia focus on the past, and not on the ability to transform present events into memories. It is therefore about a retrograde character amnesia, because it affects only the recovery of already stored memories.

Thus, a person with transient global amnesia may wonder "how did I get here?" and not knowing what happened during their journey to the place he occupies in the present, although he does remember his name and, probably, his characteristics and personality traits, family ties and friends, place of work, etc

• You may be interested in: "Types of memory: how does the human brain store memories?"

Symptoms

The main symptoms of transient global amnesia are the following:

• Confusion
• Anxiety not remembering the most recent events
• It is frequent anger and the feeling that "someone has played a joke on me"

On the other hand, it should also be noted that during the crises produced by this type of amnesia, a person He does not lose consciousness at any time, as any witness can assure in case he did. had.

In addition, the symptoms of transient global amnesia dthey should disappear before 24 hours have passed from its onset (usually lasting no more than 8 hours), and other cognitive functions must not be impaired. In addition, during this attack of amnesia, symptoms associated with epilepsy should not appear either.

If these last criteria are not met, it is considered that another type of amnesia has been suffered.

Course of this disorder

Transient global amnesia comes on abruptly and, as we have seen, without loss of consciousness. As time passes, usually after two hours from the start, Memories that had been "locked" are accessible again, gradually (the first to be "recovered" are usually the oldest).

Causes

The causes that produce transient global amnesia are not clear, and there is probably not just one, but several.

For example, it has been hypothesized that in some cases their symptoms may be due to a poor blood supply to small parts of the brain, so that there are no detectable sequelae.

Small ischemic strokes could make the cognitive abilities that take place in the brain appear blocked or even prevented for a while, until this set of organs can recover from this problem.

On the other hand, it is also possible that certain traumatic events come to affect memory. However, this explanation has a flaw, as we will see.

Differences with other memory disorders

It must be taken into account that transient global amnesia It is relatively benign, since its effects wear off in a few hours and by definition does not leave sequelae. However, it can be confused with other types of amnesia. A similar effect could occur with great efforts or sudden changes in temperature.

In global amnesia, for example, many things are forgotten about what happened in the past, but this information will not be recovered. On the other hand, in drug-induced amnesia, a specific cause that produces the symptoms is known.

As for traumatic events, it is known that these are capable of making us not store information about what is happening in the present for a while, due to the secretion of corticosteroids on an area of ​​the brain known as hippocampus. However, this is not what happens in transient global amnesia, since in the latter the problem is in accessing already stored memories, not in storing new memories. For this reason, its character is purely retroactive, while the stress of traumatic moments has effects in the form of anterograde amnesia, as far as is known.