What is anterograde amnesia and what are its symptoms?

When we talk about a person with amnesia, we automatically think of a person who does not remember their past. There is another type, anterograde amnesia, which is the inability to form new memories..

This memory problem usually goes hand in hand with retrograde amnesia, that of past episodes, but it is not always related. It is therefore an independent form of amnesia with its own modified causes and mechanisms.

Causes of anterograde amnesia

The causes of brain damage can be very diverse: Traumatic brain injury, hypoxia, herpetic encephalitis or vascular problems. The lesion that causes purer anterograde amnesia is damage to the anterior thalamus, usually of vascular origin.

Additionally, it is possible to lose pyramidal cells in the bilateral hippocampus due to lack of oxygen or sometimes in the skull, causing amnesia which can either be pure or occur in conjunction with other types of disease. ‘amnesia.

What is the problem with this type of amnesia?

Basically, patients with anterograde amnesia cannot learn new information. They are unable to keep a name, a new face, or learn some kind of game they previously ignored in the long run.

They have no perception problem and have a good working memory. These patients can remember new information and work with it for a short time, however. they are unable to hold her back and remember her after a few hours. It is as if new information, once it is no longer present, disappears.

We know that in order to save information in memory, it takes a process of encoding and storage. Science, curious by nature, wonders at what point exactly in this process individuals with anterograde amnesia fail. Here are the most commonly used assumptions.

1. Coding issues

Some hypotheses claim that this is a coding problem. The brain, although it receives sensory stimuli, has difficulty making sense of them and extracting the most important characteristics from them.

For example, patients with Korsakoff syndrome have difficulty learning apple-cheese-like word pairs. Normally, this learning is made easier because the two things share a characteristic, but the Korsakoffs fail to establish that relationship. However, this explanation is weak and does not seem the most fundamental.

2. Consolidation issues

Another hypothesis is that the biological processes responsible for transporting and storing the encoded information are damaged.. Thus, although the subject can process the information and work with it at that time, he is unable to save it for later.

For example, he was taken to a group of footballers who, 30 seconds after suffering a bruise, were asked what had happened. Players were able to explain the order of events well, but over time they were able to remember fewer events, showing that the memory had not been consolidated.

This theory, however, does not answer the reasons why the loss of these memories due to non-union is progressive.

3. Problems with contextual information

From this hypothesis people with anterograde amnesia are said to lose the function of storing contextual information. Although they can remember specific words, they are not able to relate them to anything. Therefore, when asked to repeat the words they have heard before, not relating these words to any previous situation, they are unable to recover them.

This hypothesis is problematic because context coding deficit is closely related to temporal lobe damage, and uninjured patients may have anterograde amnesia without specific context deficit.

4. Accelerated forgetfulness

The fourth possibility says that the processing and storage of memories is intact, the problem is that new information is forgotten very quickly. However, this is a hypothesis that has conflicting scientific support that has not been replicated.

5. Recovery issues

This way of understanding anterograde amnesia can be subdivided into two hypotheses. The hypothesis of “pure” recovery dysfunction indicates that there will be difficulties in accessing information learned regardless of how it was learned. The other hypothesis postulates that since the search for information is highly dependent on how it was learned, the amnesiac has difficulty accessing the recording due to an initial coding problem.

In short, the different theories point to a problem of acquiring and consolidating information, with a more subtle impact on the recovery process. The exact explanation of why this acquisition problem occurs is pending. One possible explanation may be that the brain of the amnesiac patient is unable to relate different types of information, such as contextual.

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