Retrograde and Anterograde Amnesia – Causes and Types

Retrograde and anterograde amnesia can occur with the inability to recall events prior to or subsequent to the onset of the amnesic deficit.

The word “amnesia” refers to a memory disorder. Although many do not know it, it is a condition that can have antegrade and retrograde components. In this case, we will see what retrograde amnesia consists of, what its causes are and what to do about it.

According to information published in the Encyclopedia of Clinical Neuropsychology, in this form of amnesia the loss of memories can be partial or total. And although it has been observed after direct brain damage, it also appears to be the result of psychiatric illness.

Retrograde and anterograde amnesia

In general, the person suffering from an amnesic state has a time (they do not know what day it is, the time, etc.) and space disorientation (they do not know where they are). As we have mentioned, amnesia is a disorder that can be anterograde or retrograde.

People with anterograde amnesia have trouble creating new memories after the onset of the disorder. On the other hand, if it is retrograde or evocative, there is a difficulty in accessing the events prior to the start of it. That’s why we’ll talk about both retrograde and anterograde amnesia, but we’ll focus more on the retrograde and its types.

Types of retrograde amnesia

Retrograde amnesia has various forms of presentation. Based on its clinical manifestations, it has been classified into various types. We detail them below.

  • Pure retrograde amnesia: in these cases, there is no alteration in anterograde memory.
  • Psychogenic or dissociative retrograde amnesia: it is the inability to remember important personal information. Remembering that information is often traumatic or stressful.
  • Retrograde amnesia with time gradient: Not all memories of the past are affected in retrograde amnesia. Often the memories that are lost first are the most recent. In this way, the person can recall older events. In any case, the impact can vary from person to person.

Causes of retrograde amnesia

There are multiple factors that influence the appearance of retrograde amnesia. In most cases, the two types of amnesia mentioned are present. Also, overlap is common. Let’s see in detail its possible causes.

Traumatic brain injury

Traumatic brain injury refers to any contact trauma, such as a fall or blow to the head, but also a type of injury that occurs by acceleration and deceleration (without a direct hit), such as what occurs in car accidents.

In the case of trauma, amnesia can occur immediately, or it can appear minutes later. Also, the patient may present with headache, dizziness, nausea, vomiting and other secondary neurological signs.

In these cases, amnesia implies the loss of memory of the traumatic event (fall, blow, accident, etc.), but there is also a tendency to forget the events just before and after the head injury.

Transient global amnesia

Transient global amnesia is a clinical syndrome with characteristics of acute onset of anterograde amnesia (the inability to form new memories) and, in turn, retrograde amnesia, for the duration of the episode. It often occurs in old age, although it resolves after 24 to 48 hours.

People who suffer from it often regain their ability to name events and dates in the past. However, they are unable to recall the events that occurred during the amnesic attack. It is estimated that in 20% of patients the episode repeats at some point.

Chronic alcoholism

Alcoholism is a chronic disease that is associated with malnutrition and a wide variety of central nervous system disorders. Among the nutritional deficiencies that it causes we find that of a vitamin called thiamine or B1.

This deficit, in particular, can cause an encephalopathy (neurological disorder) called Wernicke Korsakoff’s. The same is observed both in alcoholism and in cases of severe malnutrition. The amnesia it causes is global.

Electroconvulsive therapy

Electroconvulsive therapy uses a small electrical current to produce a generalized cerebral seizure under general anesthesia. It is a treatment for severe depression, but it is also indicated for patients with other psychiatric conditions. It is related to the appearance of global amnesia, although it will not always be complete.

Traumatic events

Certain stressful situations can trigger retrograde amnesia. In particular, it occurs after events that are a person witnesses, such as witnessing a murder or an accident.

Infections

Patients with brain infections or other types of systemic infections are at high risk for neurological impairments, including retrograde amnesia.

Dementias

Dementias are common among the elderly. What characterizes them is causing a progressive deterioration of brain functions, which compromises memory. Estimations are that 50% of cases correspond to Alzheimer’s disease.

Transient epileptic amnesia

Transient epileptic amnesia is a subtype of epilepsy that affects an area of ​​the brain related to memory. Those who suffer from it often develop global amnesia. However, they usually have a good response to antiepileptic treatment.

When to visit the doctor?

Whenever there is suspicion of difficulties to remember events, either permanently or sporadically, visit the family doctor. The professional will determine if it is necessary to also go to the neurologist.

In certain cases, the person experiencing warning symptoms denies their condition or feels confused. Therefore, it is essential to have family support and close people, who are also key to achieving the diagnosis.

Diagnosis of retrograde amnesia

The way to assess the retrograde component of amnesia is through questions about the past, such as important dates or historical events. Then you get a suggestion to do a complete clinical examination, including neurological evaluation and standardized cognitive tests.

As we have commented, family opinion is decisive, as it will be the ones who confirm the questions and data that are requested from the patient. Based on this, and after the suspicion of amnesia and associated diseases, the practice of imaging studies and laboratory tests is suggested.

The goal is to determine if there are infections, brain injury, or nutritional deficits that may explain the problem. Then, if necessary, the neurologist will carry out a more thorough review.

Treatments for retrograde amnesia

There are no specific medications for the treatment of memory problems such as retrograde amnesia. However, based on the underlying cause, you will get recommendations for therapeutic options. In turn, this will determine the forecast.

Thus, some cases of amnesia will have a full recovery, while others will have an incomplete evolution or a progression of the picture will be observed. In any case, once you get the diagnosis, it is possible to put into practice strategies for memory stimulation and psychological support.

What to do if you suspect the onset of a memory disorder?

Mild memory loss is a normal part of aging; But when there are episodes that lead to suspicion of a major disorder, it is worth consulting a doctor or specialist. According to the diagnosis, it is useful to implement personal and family strategies to prevent the progression of the problem or promote its recovery.

On the other hand, it is convenient to ensure a healthy and varied diet, which ensures all the essential nutrients. Likewise, excessive consumption of alcoholic beverages and substances that are toxic to the brain should be avoided. Habits like exercise and relaxation techniques also have preventive effects.

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