Types Of Amnesia
The types of amnesia or amnesic syndromes are various, as well as their classifications. It is a disorder that is characterized by the partial or complete loss of memory on the part of the person. According to diagnostic books, it is estimated that dissociative amnesia – a specific form – is present in up to 2.6% of some populations.
Amnesia can be classified into several types encompassed in two main ones. The first refers to the chronology of memory loss, that is, what type of information the patient is not able to remember. The second group brings them together according to the etiology or, what is the same, the underlying cause of the disease.
In general, the origins of amnesia can be organic or functional. Some of the most common triggering events are brain trauma and the use of certain drugs, for example.
Types of amnesia according to their chronology
According to the chronology, two types of amnesia can be distinguished: retrograde and anterograde. It should be noted that a patient can present both at the same time, so they are two complementary disorders.
On the other hand, this categorization does not refer to the causes, but to its symptoms. The Memory Health Check portal provides us with the definitions of these terms.
Anterograde amnesia
In this case, the new events are not transferred to the patient’s long-term memory. This means that the individual only remembers what happened before.
This type of amnesia supposes a serious loss of autonomy on a day-to-day basis, since not being able to make new memories and experiences causes various disorders from an emotional point of view. This also carries health risks in the form of accidents, for example, you can forget that you have started a fire soon after.
Retrograde amnesia
Here we are facing the other side of the coin, because in retrograde amnesia the patient does not remember anything about what happened before the onset of the disease. According to the International University of Valencia, all the information that was collected throughout life prior to the brain injury or triggering event can be forgotten.
Types of amnesia according to its etiology
On the other hand, the Cleveland Clinic indicates that the types of amnesia can also be categorized according to their etiology, that is, based on the causal agent that triggers the disease. Let’s see each of them in detail.
Post-traumatic amnesia
According to neurological studies, traumatic brain injury (TBI) is one of the most common causes of disability and mortality in the world. The data show that there are more than 2.5 million hospital admissions for this type of injury in the United States, which corresponds to 16% of hospitalizations due to falls and blows.
Post-traumatic amnesia is caused by injuries that damage the brain, but do not penetrate the skull. This type of disorder is often accompanied by a loss of consciousness and even coma. Fortunately, memory loss is temporary in most cases.
Transient global amnesia (TGA)
According to the Mayo Clinic, transient global amnesia is a temporary memory loss that cannot be attributed to the most common neurological disorders, such as epilepsy or stroke. The incidence of this disease – that is, the number of new cases in a given place – is about 2.9 to 10 cases per 100,000 people.
Therefore, it is considered a very rare disorder. Although the trigger for the disease is not known, it is suspected that it may be correlated with the presence of migraines or diseases of vascular origin.
Medial diencephalic amnesia
As its name suggests, it is a type of amnesia characterized by injuries to the medial diencephalon. The main functions of this structure are to connect the nervous and endocrine systems, as well as to control the secretion of certain glands.
An example of this type of disorder is Korsakoff syndrome. In this specific case, the loss of memory and faculties is determined by a deficiency in vitamin absorption —generally vitamin B1— due to gastric damage caused by excessive alcohol consumption.
Childish
Childhood amnesia is common in all human beings, as it refers to the inability of adults to remember the first 3 to 4 years of their childhood. Research indicates that the limit of this memory loss is variable and that it is influenced by both individual and cultural factors.
Alzheimer’s-induced amnesia
Although all the causes of Alzheimer’s are not yet known – although metabolic disorders are suspected – societies such as Elalzheimer.com point out that amnesia is one of the first symptoms of this disease. This clinical picture causes the patient to lose both short-term memory and the memory of immediate events.
Drug-induced amnesia
According to the San Diego Hospital, some drugs such as flunitrazepam produce anterograde amnesia, which, as we have said previously, makes the patient unable to remember everything that happened while under the influence of the drug.
Unfortunately, flunitrazepam is known as the rape drug . This is because it is usually the substance that is placed in pill form in women’s drinks so that they do not remember what happened and do not know how to put a face to the abuser in question.
Dissociative amnesia
In this case, we are facing a type of amnesia that is an unconscious self-protection mechanism. The patient who suffers in this way blocks personal information that refers to a traumatic event.
According to the MSDmanuals portal, these memory gaps can span from a few minutes to entire decades of life. Hypnosis and drug-facilitated interviews can help patients remember the characteristics of the traumatic event.
Qualitative amnesias or paramnesias
According to the Medical Dictionary portal, paramnesia is a memory disorder characterized by the distortion of memories. These fictitious events replace real situations, which cannot be remembered.
This type of amnesia appears frequently in cases of chronic alcoholism and organic brain syndromes. They understand the terms deja vú and jamais vú. The first expression refers to a situation in which a new experience is felt as already lived before. On the other hand, the second describes when a person does not explicitly remember having seen something before.
When to consult the doctor?
After a severe contusion that causes loss of consciousness, even for a few seconds, an emergency doctor visit is mandatory. Some brain injuries don’t show up right away, so a prompt checkup is always the best idea.
On the other hand, it is necessary to emphasize that short-term memory loss is common in the general population. We live at a hectic pace, and anxiety disorders sometimes cause us to feel dissociated and confused. Therefore, it is not necessary to be alarmed in the first instance if we do not remember something perfectly.
The types of amnesia are many and varied
As can be seen, amnesia is a disorder of simple definition, but it hides many different types depending on the chronology and the causative agent. In general, this condition usually arises after a head injury and memory loss is transitory.
As much as being forgetful is common in a society full of stimuli, when a person forgets integral things of their day to day, feels confused within their own home or is not able to identify their location in a physical space , it is necessary to see a doctor urgently.
