Understanding Anterograde vs Retrograde Amnesia

Have you ever watched movies or shows in which a character loses their memories, sometimes for a short time and sometimes their memories are completely gone! This makes one wonder, what exactly happens when you’re talking about “Memory Loss”?

Amnesia, in simple terms, is the loss of memory, but there are different types of amnesia. In this article, we will discuss two of the most common kinds: anterograde amnesia, which involves being unable to form new memories, and retrograde amnesia, which involves losing memories from the past. We will discuss both forms, understand their differences, and examine their diagnosis and treatment.

Memory is a major component of who we are as individuals, and it guides us in our day-to-day lives. It is basically our essence, but losing our memories can have a profound impact on how we function and connect with those around us.

There are a number of different reasons why we can experience amnesia, including a brain injury, disease, infection, or psychological trauma.

Our memory allows us to store, retain, and retrieve information; however, disorders like amnesia impair that ability.

There are different types of memory, each performing unique functions.

• Sensory memory contains brief sensory impressions, such as sights and sounds, for a few seconds.

• Short-term memory (STM) or working memory holds and processes information temporarily required for an immediate task, like recalling a phone number or figuring out a problem.

• Long-term memory (LTM) retains information for an extended period and encompasses both explicit memory, which involves recalling events and facts, and implicit memory, such as habits and skills.

In amnesia, you lose this memory function, which can have a significant impact on your daily life. Amnesia can be a result of several factors, such as head or psychological trauma, certain illnesses, and even some medications.

Anterograde amnesia is a disorder that is characterised by the inability to form new memories after the onset of the amnesia. Memory from the time before the amnesia is typically unaffected.

Causes of Anterograde Amnesia:

There are many reasons for the onset of anterograde amnesia, from trauma to side effects. Listed below are some common reasons why one may get anterograde amnesia:

• Damage to parts of the brain, such as the hippocampus, due to injury, surgery, stroke, infection, or excess alcohol consumption.

• Some medications, like benzodiazepines or general anaesthetics, can also cause anterograde amnesia.

• Conditions like encephalitis or Wernicke–Korsakoff syndrome.

Symptoms May Include:

Understanding the symptoms will help you quickly identify whether you have anterograde amnesia and get quick intervention. Some common symptoms are:

• Forgetting conversations or events soon after they occur.

• Repeating questions.

• Difficulty remembering faces or learning new information.

Retrograde Amnesia can be defined as the inability to remember events, experiences, or information from before the onset of amnesia. It usually has a greater impact on more recent memories than older core memories, following a curve described as Ribot's law.

Common causes of retrograde amnesia:

Depending on the reason, retrograde amnesia can be classified into temporary, permanent, or progressive. There can be several reasons for it, some of which are:

• Traumatic brain injury, stroke, or conditions like Alzheimer's

• Emotional or psychological trauma involving dissociative amnesia.

Symptoms may include:

To identify the onset of retrograde amnesia, you should know the symptoms. Some of the common ways in which retrograde amnesia presents itself are:

• Loss of memory from a few days, months, or years before the amnesia.

• The ability to create new memories remains intact, especially when assessing retrograde amnesia in isolation.

The diagnosis of each type of amnesia follows the same steps:

• Neurological examination: An evaluation of brain function.

• Memory testing: Formal tests that evaluate recall response and learning new information.

• Imaging (MRI, CT): An imaging technique for assessing any structural damage to the brain.

• Blood tests and lumbar puncture: Tests that determine if there is an infection or nutrient deficiency.

• Psychological evaluation: Required only for dissociative or psychogenic amnesia.

Although there is usually no cure, treatment includes addressing the underlying cause and developing coping strategies.

Methods include:

• Intervention or treating the underlying cause (e.g., infection or vitamin deficiency).
• Cognitive rehabilitation uses procedural learning and memory aids, which may include notes, diaries, etc., to cope with amnesia.
• Counselling and therapy are helpful with trauma-related amnesia patients who need to be handled gently.
• The family, reminder apps, behavioural techniques and a solid support system are very important when it comes to managing amnesia.

Anterograde amnesia can be temporary(e.g. following anaesthesia) or permanent, depending on the amount of damage caused to the hippocampus. On the contrary, retrograde amnesia may improve over time, especially with older memories, but its permanence is variable.

Anterograde and retrograde amnesia are different, but are the two sides of the same coin, as one prevents you from forming new memories, whereas the other takes away pre-existing memories.

With accurate diagnosis and good supportive care, many people can adjust well and go back to enjoying all that life has to offer them.

Awareness and understanding in this situation can help individuals and families maintain dignity and perseverance when dealing with amnesia.

Q. What is anterograde amnesia, and how does it occur?

A. It occurs when a person is unable to form new memories after a brain injury or illness that has affected the hippocampus.

Q. How is retrograde amnesia different from anterograde amnesia?

A. Retrograde amnesia refers to the loss of memories before the onset of the condition, and anterograde amnesia occurs when a new memory cannot be formed after the onset of the condition.

Q. What causes each type of amnesia?

A. Anterograde amnesia can happen because of a brain injury, infection, drugs, alcohol, etc. Retrograde amnesia can occur from trauma, stroke, dementia, emotional shock, etc.

Q. Can people recover from anterograde or retrograde amnesia?

A. Recovery is possible if the underlying cause of the amnesia is treatable. People can also use memory aids, and therapy can help create ways to cope with memory loss.

Q. How are these memory conditions diagnosed and treated?

A. Doctors diagnose these memory conditions by using clinical tests and assessments, as well as imaging. Treatment involves identifying the underlying cause, rehabilitation, therapy for support, and establishing strong support systems.