What is Anterograde Amnesia: Causes, Symptoms, Treatment, Risk Factors

Everyone is familiar with the term amnesia, but there is often quite a few misunderstanding associated with this condition. Though it may seem to be straight out of a Hollywood movie plot, the fact is that amnesia is a genuine condition that causes a person to suffer from memory loss. Unlike what they show in movies, though, the reality of amnesia is quite different. There are two types of amnesia – anterograde and retrograde. Anterograde amnesia is a very complex subset of amnesia that can either be permanent or temporary. Anterograde amnesia refers to the loss of short-term memory. It usually happens after a certain event has taken place, and from there on, a person is unable to store information in their short-term memory. Let us take a closer look at understanding anterograde amnesia.

Anterograde amnesia refers to the loss of short-term memory. In people with anterograde amnesia, the brain has a decreased ability to retain new information, which tends to affect their day to day activities. Anterograde amnesia also disrupts your work, social events, and your relationships since you have difficulties in creating new memories.⁽¹⁾

A subset of amnesia, anterograde amnesia, is a complex form of amnesia that can either be temporary or permanent. It typically happens after an event or accident occurs.⁽²⁾ From the point when the event occurs, a person loses the ability to store information in their short term memory. It is possible for them to remember some specific moments from a year or two ago, but they tend to forget something that happens just a day before.

Anterograde amnesia happens due to damage caused to the memory-making parts of the brain. Depending on the incident that causes the anterograde amnesia episode, there are some forms of therapies available that help people cope with this type of amnesia and also help boost a person’s memory. However, it is not always necessary that the memory will be reversed or that the memory will return to normal.

Anterograde amnesia can also be drug-induced. Alcohol intoxication and many benzodiazepines are known to have potent amnesic effects.⁽³⁾

An acute event such as a heart attack, a concussion, oxygen deprivation, or even an epileptic attack can lead to anterograde amnesia. Though rare, sometimes an emotional disorder or shock can also lead to anterograde amnesia.

There are two types of amnesia – retrograde amnesia and anterograde amnesia.⁽⁴⁾ People with anterograde amnesia have difficulty making new memories, and people with retrograde amnesia suffer from an inability to remember events and people from the past. Retrograde amnesia can also cause a person to forget well-established daily information, for example, the usual time at which they go to work.⁽⁵⁾

Anterograde amnesia is also known as proactive amnesia.

Many people tend to confuse amnesia with dementia. While dementia is a neurodegenerative disease that affects your memory and leads to confusion and general memory loss, anterograde amnesia deals specifically with the inability to remember new information.

Dementia can also lead to brain damage that causes more severe cognitive difficulties. Such cognitive challenges can affect your everyday activities, including your work, studies, or even sports.

The symptoms of anterograde amnesia typically affect the brain’s short term memory processing abilities. This causes confusion and leads to frustration. For example, it is possible for someone with anterograde amnesia to forget:

• What they had to eat in the morning or the day before
• Someone they have recently met
• A new phone number
• The names of famous people
• Any recent changes made to their routine, such as changes in their work timings

Symptoms such as these are different from the symptoms of retrograde amnesia, which generally focuses on forgetting information a person already knew before the event that caused the amnesia. For example, you might forget that you knew a person you are meeting again and believe that you are meeting them for the first time.

Remember that the symptoms of anterograde amnesia occur after you have already started experiencing the memory loss, since the event that triggered the amnesia has already happened.

In 2010, the University of Edinburgh in the United Kingdom published a study in Neuropsychology journal that found that seven out of ten patients having anterograde amnesia were capable of retaining new information for a short time.⁽⁶⁾ However, these patients experience a phenomenon known as retroactive interference, which causes interference between the new information and the previously memorized information. For example, a person might remember a number temporarily, but if they learn a new number shortly afterward, then the original information will get canceled out.

Any type of amnesia is caused by some form of damage to your brain. This damage affects the memory-making parts of the brain, such as the thalamus.

Research has also shown that anterograde amnesia is caused by a failure of memory encoding and storage.⁽⁷⁾

So in people affected by anterograde amnesia, new information gets processed normally, but it is forgotten almost immediately. The new information does not make it into the parts of the brain where the long-term memories get stored.

Anterograde amnesia results from damage caused to the hypothalamus and the thalamus, as well as the surrounding cortical structures, due to which the new memories do not get stored since the connection between the hippocampus and cortex are disrupted.

A CT scan or an MRI test helps your doctor diagnose the physical causes behind anterograde amnesia. These imaging tests also help your doctor look for damages or changes to the brain that led to anterograde amnesia.

There are currently no treatments that can cure amnesia, but the treatments focus on managing the symptoms of amnesia. The treatment of anterograde amnesia focuses on therapies that help improve the overall quality of life. Some of the treatment options include:

• Memory training
• Occupational therapy
• Taking vitamin B1 supplements (only in case of deficiency)
• Technology assistance in the form of reminder apps on mobile
• Currently, there are no medications approved by the US Food and Drug Administration (FDA) for the treatment of any type of amnesia.

Anterograde amnesia is primarily caused by damage to the brain. You may be at an increased risk of developing any form of amnesia if you have had any of the following:

• Brain injury
• Brain tumors
• Brain surgery
• Stroke
• Seizures
• Car accident
• Dementia
• Vitamin B1 deficiency
• Sports-related injury, especially to the head
• History of alcohol abuse
• Electroconvulsive Therapy (ECT)

Sometimes, mild brain injuries may also lead to short-term memory loss, but the symptoms may improve as the wound heals. Severe injuries to the brain, though, is likely to lead to permanent amnesia.

There is a high chance that amnesia may be permanent. This means that over time, the symptoms of anterograde amnesia will only become worse. However, there is a chance that the symptoms may also improve or just remain the same, even after a traumatic brain injury. In maximum cases, though, it has been observed that anterograde amnesia is usually permanent.

Always seek immediate help if you experience any type of unexplained memory loss or if you suffer any kind of head injury. Your doctor will be able to detect any damages or changes to the brain and come up with the most appropriate treatment plan.

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