Anterograde Amnesia: Causes, Symptoms & Treatment

Anterograde amnesia is characterized by a complete cessation, or at least a very severe reduction, in the ability to store or remember new events from the time of the disease or brain injury. Anterograde amnesia is caused either by lesions to specific brain regions or by degenerative processes of neurons in specific brain regions.

What is anterograde amnesia?

In the strictest sense, anterograde amnesia is a memory impairment for new memory-worthy events from the time of the causative disease or injury. This means that events occurring after the onset of anterograde amnesia cannot be remembered retrogradely, i.e. in the past. The best-known diseases that gradually or progressively lead to anterograde amnesia are all forms of dementia, such as Alzheimer’s disease. As a rule, new memory-worthy events can only be stored retrievably for a few seconds to a few minutes. Amnesia primarily affects episodic memory, in which all available sensory impressions of an event are stored together. Motor memory, in which the skills for complex movements such as walking upright can be stored and recalled unconsciously, are often not initially affected by amnesia.

Causes

Three different complexes of causes can trigger anterograde or retrograde amnesia. The first cause complex involves neurodegenerative disease processes, in the course of which degradation processes result in damage to specific nerve areas in the brain, always associated with functional impairment or even total loss of function. The functional limitations are expressed not only by anterograde amnesia, but also always by dementia symptoms. One of the best known neurodegenerative diseases is Alzheimer’s disease. Meningitis and inflammation of the neurons in the brain (encephalitis) can also be the cause of amnesia. The second complex of causes involves lesions that affect specific brain regions in head injuries or strokes and can lead to irreversible total loss of episodic memory. Anterograde amnesia is usually associated with a lesion of the two hippocampi. These are brain structures located in the two temporal lobes. However, some nuclei in the diencephalon are also important for storing and retrieving memories. If they are functionally impaired due to a stroke, for example, anterograde amnesia may develop although the memory storage site is not affected. A third complex of causes for amnesia are strong psychological experiences, which can lead to temporary or persistent amnesia. A special role is played by nerve poisons (neurotoxins), which can cause a wide range of reversible or irreversible damage to the cranial nerves, depending on the type and dose. In some cases, neurotoxins are even used medicinally.

Symptoms, complaints, and signs

This disease is associated with serious symptoms. Affected individuals are usually unable to remember new events, suffering from a significantly reduced ability to remember and store new information. Due to the damage to the brain, the disease can often no longer be treated, so that the patient is dependent on the help of other people in his life and there are significant restrictions in the quality of life of the patient. Even simple information and cannot be stored, which can make everyday life more difficult. The disease is often also associated with epilepsy, although it can also be caused by a tumor or hemorrhage. Frequently, the affected person also suffers from psychological complaints or depression, and it is not uncommon for this to affect parents, relatives or children. Often, the disease also severely reduces the patient’s ability to speak. As a result, the affected person can no longer easily participate in conversations or remember simple words. Information about the patient’s own family can also no longer be fully recalled. Furthermore, the loss of information can also put patients in dangerous situations.

Diagnosis and course

Suspicion of the presence of anterograde amnesia is usually manifested by the failure to recall newly occurring events or certain frequently used words and terms. Important for an initial assessment is a detailed discussion with the physician (anamnesis), in which a relative should also participate if necessary. Simple standardized memory tests are available to quantify any anterograde amnesia that may be present. In a positive case, it should be clarified during the anamnesis, if possible, whether the anterograde memory loss occurred suddenly after a specific event or whether it is a gradual process. A well-founded anamnesis leads to initial suspicions of a possible cause of the amnesia. Blood tests may then follow, indicating possible causative agents of encephalitis or meningitis, or possible intoxications. Single-photon emission computed tomography (SPECT) can provide insights to clarify the blood flow situation in the brain. Together with the measurement of brain waves (EEG), indications of epilepsy or Alzheimer’s disease may emerge. Other imaging techniques, such as computed tomography (CT) or magnetic resonance imaging (MRI), allow conclusions to be drawn about the presence of hemorrhages, tumors, or other injuries.

Complications

Anterograde amnesia can severely limit a patient’s daily life, reducing quality of life in the process. Typically, the affected person has very poor or no recollection of events that occurred after a particular accident. As a result, life is severely restricted. The affected person is dependent on the help of other people. The ability to speak is also limited, as the patient can no longer remember various words. This includes names or other data of acquaintances or family. Often it is also not possible for the patient to remember their own address, which is why they are dependent on outside help. If the amnesia is caused by a tumor disease, some complications can arise from it. A complete cure is not possible in every case. In the case of meningitis, the pathogens are fought by medication, so that the amnesia is greatly reduced and there are usually no further complications. If it is already advanced, its course can at least be stopped. Most often, stress reduction and relaxation treatments are also undertaken to activate the damaged areas in the brain and promote function.

When should you see a doctor?

In most cases, this disease is already diagnosed directly by a doctor when the injury to the brain has occurred. In this case, the affected person can no longer speak properly and suffers from word-finding disorders. Also complaints with the memory or difficulties with simple thinking tasks can point to the illness, whereby a visit of the physician is necessary in any case. Especially in the case of complete memory loss, the patient should see a doctor to prevent further consequential damage. This is also the case if the affected person suffers from epilepsy or has had an epileptic seizure. Disturbances in concentration or coordination can also indicate a serious injury in the brain, which must be treated by a doctor. In most cases, the symptoms cannot be limited, so that the affected person is dependent on the help of other people in his daily life. It is also impossible to predict whether this will result in a positive course of the disease. However, some symptoms can be limited by various therapies. The earlier the treatment of this disease begins, the higher the chances of a cure.

Treatment and therapy

Treatment of anterograde amnesia is primarily aimed at curing or ameliorating the underlying disease causing the condition. For example, in the case of meningitis or encephalitis, the causative agents, usually viruses, must be combated. In a positive case, anterograde amnesia can then improve again or the progressive course can at least be stopped. If cerebral hemorrhages are present or if tumors are recognizable, the first therapeutic goal is to reduce the mechanical pressure on the surrounding nervous tissue by eliminating the hemorrhage and by eliminating the tumor.Here, too, physical relief of the nervous tissue can stop anterograde amnesia in its progressive course and possibly even improve it again. In the case of neurodegenerative diseases such as Alzheimer’s disease, drug therapies are usually used to slow down the progressive course of the disease. In the presence of lesions in the brain due to an accident or the loss of certain nerve areas due to a stroke, recovery of function is usually not possible. Since these cases are singular events, the functional impairment that has occurred usually shows a static course. Any therapies aim to compensate for the functional impairment by activating and training other brain areas, if possible, so that there is an overall improvement. In many cases, relaxation training, stress reduction, autogenic training, and muscle relaxation exercises also have a positive effect on anterograde amnesias.

Outlook and prognosis

Anterograde amnesia can be overcome in some patients with targeted short-term memory training. Reactivation of specific memories is helpful in this regard. The procedure depends on the underlying disease and the cooperation of the patient. In the case of traumatic experiences or slight hemorrhages, after some time of therapy there is a possibility that the usual skills will return and new memories will be acquired. The chances of recovery from anterograde amnesia due to severe lesions in the brain are less optimistic at this time. Medical advances often allow for relief of symptoms. The damage to the brain is considered irreparable and cannot be cured. Despite various testing procedures and different therapeutic methods, it has not been possible to date to repair damaged brain tissue or to replace it successfully as well as functionally. Depending on the cause of the brain damage, the symptoms may increase. The functional capacity of further cortical areas can be limited. In the worst case, the entire memory, the activity of short-term memory as well as the working memory is lost. In some patients of anterograde amnesia, it has been demonstrated that new memories were established for a period longer than a few minutes despite the disease. However, the contents of consciousness are minimal and can still be forgotten in a few days.

Prevention

The most important preventive measures to avoid anterograde amnesia consist of a healthy lifestyle in which periods of stress can alternate with periods of relaxation so that there is a balance between the degree of activation of the sympathetic and parasympathetic nervous systems.

Aftercare

In this disease, there are usually no or very few aftercare measures or options available to the affected person. First and foremost, the disease must be properly diagnosed and treated by a physician in order to prevent further complications or discomfort. The earlier the diagnosis is made, the better the further course of the disease usually is. However, since a complete cure is not possible, only a purely symptomatic treatment can take place. In order not to aggravate the symptoms of this disease unnecessarily, the affected person should refrain from the consumption of alcohol and tobacco. The treatment itself can be carried out by taking medication. Those affected are dependent on the correct dosage and also on taking the medication regularly so that the symptoms are permanently alleviated. However, many damages to the brain are irreparable, so that there is not always an improvement. In severe cases, those affected are dependent on the help and support of their own family or friends. In most cases, this disease also reduces the life expectancy of the affected person.

What you can do yourself

Provided that the anterograde amnesia is due to an infectious disease such as meningitis or encephalitis, the patient can help to treat the underlying disease. In these cases, it is particularly helpful to strengthen the body’s own defenses. First and foremost, a healthy lifestyle contributes to this. It is important to get enough sleep, eat a vitamin-rich, predominantly plant-based diet, and get regular exercise in the fresh air.In naturopathy, the active ingredients of the red coneflower (Echinacea purpurea) are also used. The intake of ascorbic acid (vitamin C) is also recommended. If the anterograde amnesia is due to other causes, the patient usually cannot help treat the underlying disease himself. In neurodegenerative disorders, attempts can be made to compensate for the reduction in brain function by activating and training other, unaffected, brain areas. Relaxation exercises, especially autogenic training, can also positively influence anterograde amnesias. To better cope with memory loss in everyday life, affected individuals should get into the habit of recording everything of importance in a timely manner. Easier and more practical than notepads are tape recordings, and almost all modern cell phones have a dictation function. In addition, there are inexpensive and qualitatively sufficient dictation devices in the size of memory sticks that can be taken anywhere. However, conversations with third parties should not be recorded without their knowledge for legal reasons.