Memory disturbances

Memory is, without a doubt, one of the most precious resources available to human beings. Thanks to it, our intelligence is capable of advancing and evolving. Memory disorders are, unfortunately, more common than we imagine. Next we will see throughout this text what types of memory disorders exist, and we will see some examples for a better understanding.

We fix memories through the various memories that exist at the brain level, and when one of them fails our world is dislocated . Memory disturbances can be classified into recall and fixation disturbances. From a temporal point of view, these alterations can be anterograde or retrograde.

It is clear that memory represents one of the most important psychic activities in our lives . This mental function is of vital importance for the formation of learning, and to be able to develop ourselves in any area of ​​our daily life. We have, so to speak, a great dependence on this function, which helps us to understand the world around us and to develop all our abilities and potentials.

What happens when there is any alteration associated with memory? This ability, as it is linked to previous aspects and experiences, and to the settlement of all the experiences we go through, when there is an alteration in this regard, our world changes radically, limiting us in many basic aspects.

What are the causes of memory impairment? The causes can be very diverse, since they can be organic or produced by an accident, where a structure of the brain associated with a type of memory has been affected.

To better understand how an alteration affects memory, how it occurs and what implications it has, let’s take a more in-depth look at what memory represents and how it works.

Main functions of memory

As we have indicated previously, memory has a fundamental role in our daily activities, and in the day-to-day life of the person we are. Some of the main most basic functions of memory are as follows:

Fixation

Through the senses we perceive all kinds of information which is present in our environment. This information that reaches us we are able to capture, elaborate and fix it thanks to our memory . This activity gives rise to experience and therefore to learning. This is how we can save, retain and process the information we receive from our environment.

Conservation

This function of our memory allows us to keep the information that we have previously captured . Its main characteristic is that it helps us retain what we have perceived and captured, so that it can later serve us in some way.

Evocation

The ability to fix and preserve must have some end, that end is that of evocation. Since it is the function of memory that allows us to have access to our memories, to be able to reproduce, update and assimilate them , so that having them stored is of some use to us. Many years can pass and those memories are still there, and we realize when there is a stimulus that makes us evoke them. One of the stimuli that produces a greater evocation are emotions and feelings.

Main types of memory disorders

Memory impairment related to executive functions

This type of memory alteration does not affect what the content represents, but rather the use we make of memory, the strategy. Research has linked frontal brain damage to specific memory deficits:

• Source amnesia.
• Difficulties in prospective memory.
• Impaired working memory.
• Metamemory problems.

Source amnesia

This is one of the alterations that have a greater relationship with the functioning of the prefrontal cortex. In clinical cases, it is observed how patients are able to remember specific information or something that has already happened. However, they cannot remember when or how the acquisition of that knowledge happened . The context of what they remember has no structure. These patients do not know when they learned what they remember.

What is altered is the explicit declarative memory . Which indicates that there is a differentiation of memory on the one hand for the context and memory for the facts on the other hand. both found within explicit memory. Episodic memory is in charge of collecting the specific context of the experiences we go through. While semantic memory is what gives us information about the world, about what we know, reflecting our knowledge in general. Thanks to the study of these patients, who were diagnosed with source amnesia, the idea that semantic memory and episodic memory are separate and are part of different brain structures was supported.

Alterations in prospective memory

As we well know, memory does not consist only of remembering events from the past, it is much more than that. It also allows us to store plans, generate ideas and express future intentions. In this regard, prospective memory has the function of remembering what can be done at a specific time in the future, and the execution of a plan that has been previously considered. This type of memory is part of episodic memory, divided into both prospective (towards the future) and retrospective (towards the past). This type of memory makes us learn from our past to carry out future plans . Arguably, it is the memory associated with our self-awareness.

It is very useful and important, since it also allows us to incorporate new actions , as a result of previous intentions. Thanks to the fact that it provides us with control and planning to give way to new experiences.

Alterations in working memory

This type of memory is of great importance to retain digits, names, words and other series of items for short periods of time. This memory is also known as short-term memory, however, it is much more complex. We could define it as the ability to perform tasks that involve a simultaneity between the storage and manipulation of information .

We would have a clear example in something as everyday as reading and understanding what we read.

Metamemory alterations

With metamemory refers to the ability we have to have knowledge about our own memory. It involves complex aspects such as understanding how we learn, and the strategies we use to memorize what interests us. It is the own conscience about what we know and what not, also about the own beliefs that we have about our memory. It is, above all, the knowledge we have about how our memory works, the strategies we use and their self-efficacy.

A clear example of this alteration can be seen in Korsakoff Syndrome .

Memory alterations in relation to chronology

After a brain injury, two types of alterations can occur that are related to chronology. These are aspects that cannot be remembered, whether they are part of the past or the future. These are the two types of memory disturbances related to these basic aspects:

Anterograde amnesia

This type of memory impairment is quite unique. It consists in that new memories are not stored by long-term memory. So everything that is experienced is forgotten. Long-term memories are not stored, which results in a great limitation to face life, losing all autonomy. A clear example of anterograde amnesia is reflected in the film Memento , in which the protagonist suffers from this memory alteration, and the difficulties he has to go through to survive with this alteration are clearly seen.

It is a neurological disorder produced by certain lesions in the brain , more specifically in the hippocampus. These injuries may have been caused by a head injury, but also by some medications such as benzodiazepines or by excessive alcohol consumption. A period of temporary amnesia can occur in these cases.

Retrograde amnesia

Retrograde amnesia is the opposite of antegrade amnesia. It is characterized by a loss of memory to the previous events of the trauma. Many of the things that have already been learned are forgotten. In severe cases it happens that everything previously learned has been forgotten , and all past experiences as well. Although everything that is forgotten can be mainly from the most recent years (recent memory) to trauma, since the oldest memories (remote memory) are usually better preserved in these circumstances.

In these cases, some patients have managed to recover some of their memory, of their previous experiences, remembering people or places with specific circumstances, and even following routines that they used to carry.

Memory alterations due to a specific physical pathology

Age-related memory impairment (AMAE)

This memory impairment is associated with the passage of time . Memory is affected with aging. Difficulties appear to remember specific data and recall fragments of one’s own experience. Although the distant memory is the one that is best preserved.

In general, the affected person is usually aware of this difficulty that he has with his memory, and for that reason he shows some concern.

This memory impairment is mild, and can only be diagnosed when the person is over 50 years of age , and presents subjective complaints of frequent memory loss in their daily life. One of the capabilities that is most affected by this alteration is to fix new information, making the task of associating names with faces more difficult.

Dementia

Dementia is one of the main causes of memory disorders. It is different from AMAE, dementia is usually caused by neurodegenerative diseases such as Parkinson’s or Alzheimer’s . There are cognitive difficulties that affect language, object recognition and even certain motor skills.

This type of alteration is irreversible. Once it appears, it becomes chronic and progressively increases. Memory failures are becoming more serious.

Korsakoff syndrome

This amnesia is caused by a deficiency of thiamine (vitamin b1). Being the result of a large intake of alcohol. The main symptoms of this syndrome are:

• Retrograde amnesia, with a loss of memory more specifically of the episodes close to the trauma.

• Severe anterograde amnesia.

• Little content of conversation.

• Anosognosia (lack of awareness of its alteration and problems).

• Conspiracies

Transient global amnesia

This type of amnesia is characterized by being suffered for a few specific hours, from 3 hours to 24 hours. With an average of 6 hours. It is mainly presented by people who are between 50 and 70 years of age, being more likely to suffer from it men than women. Through this alteration, a predominantly verbal type of anterograde amnesia appears.

The most distant memory is somewhat affected and knowledge in general is preserved. This type of alteration appears suddenly and its recovery is gradual . Its causes are not well known, although researchers give an explanation for alterations in vascular tone in the arteries of the vertebro-basilar territory, in the posterior cerebral artery.

These that we have reviewed are some of the most frequent types of memory disorders. Thanks to memory we are able to have a meaningful life, full of experiences and good feelings. Both emotions, feelings and perceptions, all form a framework where memory is essential. As Aristotle said: “Thanks to memory, what is called experience occurs in men.”