Anterograde Amnesia

Of Greek origin, the word amnesia literally means “without memory . ” Amnesia is a neuropsychological pathology that produces partial or total loss of memory. This pathology occurs when complex neurobiological processes are altered, in the processing and storage of information in the short and long terms. When it is an amnesia that affects the “new memory” and the person is unable to learn new things but remembers his past life well, we speak of an anterograde amnesia . Thus, the person cannot fix the new events that have just happened and forgets them as they occur.

Causes of anterograde amnesia

Anterograde amnesia appears when certain areas of the prefrontal cortex of the brain, or of the occipital or parietal area, alter the normal functioning of the neural networks involved in learning and working memory. This disorder can be caused by various causes, such as a stroke, a head injury, inflammatory diseases, a tumor, lack of oxygen, Alzheimer’s disease or excessive alcohol consumption . In most cases, the brain is permanently damaged.

On the other hand, anterograde amnesia can be caused by medications (many benzodiazepines are known to have powerful amnesic effects) or by a surgical procedure in which there is damage to the hippocampus or the middle temporal lobe of the brain.

Also, oxygen deprivation or a seizure of epilepsy can be the cause of anterograde amnesia. Finally, rarely, a shock or an emotional disturbance can be the origin of this form of amnesia.

Consequences

The person with anterograde amnesia has difficulties in storing new information and thus is unable to remember new aspects and presents many learning difficulties.

Thus, anterograde amnesia prevents, for example, the memorization of a name, a number, a procedure that has just been read, seen or heard by the person suffering from this pathology. This is how this form of amnesia slows down or makes it impossible to learn and appropriate new knowledge . In the most severe cases, the patient discovers a totally new world every 10 to 20 minutes. It is said that the person cannot make plans for the future or in any case, forgets them.

Symptoms

• It is not possible to retain the information that the environment provides , which causes great concern.
• The same questions are constantly being asked, progressively forgetting the answers.
• The patient is disoriented in time since he does not identify the days or the hours. However, it can be oriented in space.
• New information is processed normally but is almost immediately forgotten, since it never reaches the brain regions in which long-term memories are stored.
• In general , there is a loss of declarative memory (memory of facts or events) but non-declarative or procedural memory (learning of skills and habits) is preserved.
• He is able to carry on a conversation since working memory works normally, although minutes later, the patient is not able to remember the episode.

Diagnosis

In general , when diagnosing a memory disorder, factors such as head injuries, accidents, surgery, traumatic emotional events, among others, that could cause memory loss are considered.

On the other hand, it is elementary to carry out psychometric tests or cognitive tests . In addition, a detailed physical evaluation is necessary to pinpoint the cause of the amnesia, including, for example, a brain scan, cerebral angiography, or blood tests.

To determine whether it is a particular anterograde amnesia, it is necessary to assess whether the memory loss is short-term or long-term .

Treatment of anterograde amnesia

The treatment of anterograde amnesia is generally based on memory training and strategies capable of helping people with this disorder to live better in their daily lives . It involves establishing very strict rituals and repeating the same information to the patient every day. In general, an agenda is used in which the information that allows the patient to locate himself in time and space is found.

Examples

• An example of anterograde amnesia is the case of Henry Molaison , a patient who became amnesic in 1953 after a surgical operation. During the intervention, he lost a large part of his hippocampus, which disabled him to form new long-term memories. His short-term memory continued its function and he was able to perfectly remember the events that happened to him before the operation but he always forgot what happened a few minutes before.
• A patient who plays piano every day and improves his technique to do so over time since although he cannot create new memories, he can learn new procedural or implicit skills. This patient does not explicitly remember having played the piano, each day is like the first for him.
• The movie 50 first dates starring Drew Barrymore and Adam Sandler shows an example of anterograde amnesia. Lucy (Drew Barrymore) is unable to store the new information in her long-term memory due to a car accident. In order for her to know what is happening in her life, Lucy must read or watch a video in which she is told what disorder she has and the things that happened that she cannot remember. Henry (Adam Sandler) is a marine biologist who intends to make her fall in love day after day since she does not remember him and considers him a stranger every day. Hence, the title of the movie 50 first dates.