Amnesia facts for kids

Amnesia is a condition where a person has trouble remembering things. It's like a puzzle where some pieces of memory are missing. This can happen because of things that affect the brain, like an injury or certain illnesses. Sometimes, memory loss can be total, meaning a lot is forgotten, or it can be partial, where only some things are hard to remember.

The word "Amnesia" comes from ancient Greek words that mean "without memory" or "forgetfulness."

Types

Scientists often talk about two main types of amnesia:

• Retrograde Amnesia': This is when a person can't remember things that happened before a specific date, like before an accident or when an illness started. Imagine a timeline of your life; with retrograde amnesia, the part of the timeline before a certain point becomes blurry or completely blank. Sometimes, people might forget things that happened decades ago, while others might only forget the last few months or years.

• Anterograde Amnesia: This is when a person has trouble forming new memories after a certain event or injury. It's like their brain's ability to save new information into long-term storage is broken. People with this type of amnesia might forget what happened just a few minutes ago, even though they can still remember things from before the amnesia started.

It's possible for someone to have both retrograde and anterograde amnesia at the same time.

How Memory Works

Our brains are amazing! Different parts of the brain work together to help us remember things. A key area involved in memory is called the hippocampus, which is located deep inside the brain. Other areas, like the medial temporal lobe and parts of the diencephalon, are also important. When these areas are damaged, it can lead to amnesia.

Even with amnesia, people often still have some memory abilities. For example, they might still be able to remember things for a very short time (like a phone number someone just told them, but only for a few seconds). They might also be able to learn new skills, like how to play a simple game or solve a puzzle, even if they don't remember when or where they learned it. This shows that different types of memory are handled by different parts of the brain.

Signs and Symptoms

The main sign of amnesia is, of course, memory loss. But it can look different for different people.

• Difficulty Recalling Information: This is the most obvious symptom. It could be trouble remembering past events (retrograde) or trouble remembering recent events and new information (anterograde).
• Confusion: People with amnesia might feel confused about where they are or what's happening.
• Difficulty Recognizing People or Places: In some cases, amnesia can make it hard to remember familiar faces or locations.

Interestingly, people who recover from temporary amnesia often don't remember the time when they had amnesia.

Different Kinds of Memory

Scientists divide memory into different types:

• Declarative Memory: This is memory for facts and events that you can consciously recall and talk about.
• Semantic Memory: This is memory for general knowledge and facts, like knowing that Paris is the capital of France or what a dog is.
• Episodic Memory: This is memory for specific events and experiences in your life, like what you had for breakfast this morning or your last birthday party.
• Non-Declarative Memory: This is memory for skills and habits that you do without consciously thinking about them.
• Procedural Memory: This is memory for how to do things, like riding a bike, tying your shoes, or playing a musical instrument.

People with amnesia often have more trouble with declarative memory (facts and events) than with non-declarative memory (skills). Someone might not remember learning to play the piano (episodic memory loss), but they can still sit down and play a song (procedural memory intact).

Causes

Amnesia can be caused by different things that affect the brain. Some common causes include:

• Head Trauma: This is when the brain is injured, like from a fall, a sports injury, or a car accident. The severity of the injury can affect how much memory is lost and for how long.
• Brain Illnesses or Conditions: Certain medical conditions can damage the brain and cause memory problems. Examples include strokes (when blood flow to the brain is interrupted), infections that affect the brain (like encephalitis), or conditions that cause brain cells to break down over time, like Alzheimer's disease.
• Lack of Oxygen to the Brain: If the brain doesn't get enough oxygen for a period, it can cause damage that leads to amnesia.
• Certain Medical Procedures: Sometimes, doctors use special medications during medical procedures to help patients relax and forget the experience afterward. This is a temporary, intentional type of amnesia.
• Severe Stress or Traumatic Events: In rare cases, very upsetting or traumatic experiences can cause a type of amnesia called dissociative amnesia. This is a psychological response where the mind blocks out the memory of the event. It's different from amnesia caused by physical brain damage. A very rare form called dissociative fugue can cause someone to forget their identity and sometimes travel away from home.

Diagnosing Amnesia

Doctors figure out if someone has amnesia by doing different tests. They will ask questions about the person's memory, their health history, and what might have caused the memory problems. They might also do memory tests to see what kinds of things the person can and cannot remember. Brain scans, like MRI, can help doctors see if there is any physical damage to the brain.

Treatment and Coping

Sometimes, amnesia gets better on its own, especially if it was caused by a temporary event like a mild head injury or transient global amnesia. However, if the amnesia is caused by more severe brain damage or a progressive illness, it might be permanent.

Even if amnesia is permanent, there are ways to help people cope and manage their daily lives:

• Therapy: Occupational therapists or cognitive therapists can help people develop strategies to improve their memory skills or find ways to work around their memory problems. This might involve learning techniques to organize information or using reminders.
• Memory Aids: Using tools like notebooks, calendars, smartphone apps, or even taking lots of pictures can help people remember appointments, tasks, and important people.

Treating Underlying Causes: If the amnesia is caused by a treatable medical condition (like a vitamin deficiency or a thyroid problem), treating that condition can sometimes help improve memory.

• Support: Emotional support from family and friends is very important for people with amnesia.

Currently, there are no specific medications that can cure amnesia itself, but medications might be used to treat the condition that caused the amnesia.

Famous Case Studies

Scientists have learned a lot about memory by studying individuals with amnesia. Here are a few famous examples:

• Henry Molaison (H.M.): Born in 1926, Henry had severe epilepsy. In 1953, when he was 27, doctors performed surgery to try and stop his seizures. The surgery involved removing parts of his brain, including the hippocampus. The surgery helped his epilepsy, but it caused severe anterograde amnesia. Henry could remember things from before the surgery, but he couldn't form new long-term memories. He would forget people he met just minutes before and couldn't remember events that happened after his surgery. However, he could still learn new skills, like a mirror-drawing task, even though he didn't remember ever doing it before. Henry's case, studied extensively until his death in 2008, showed scientists that the hippocampus is crucial for forming new long-term memories and that different types of memory exist.
• Clive Wearing: Clive was a musician and conductor who developed severe amnesia in 1985 due to a brain infection that damaged his hippocampus. Like H.M., he had severe anterograde amnesia and also significant retrograde amnesia. He felt like he was waking up for the first time every few moments. He kept a diary where he would constantly write entries like "I am awake" and then cross them out later, writing "I am awake" again, because he couldn't remember writing it before. However, he could still play the piano and conduct music beautifully, showing his procedural memory was intact. His case further highlighted the separation between different memory systems in the brain.
• Patient R.B.: This patient developed anterograde amnesia after a specific type of brain injury (ischemia) during heart surgery in the 1980s. After his death, examination of his brain showed damage limited mainly to a specific part of the hippocampus called the CA1 region. This case helped scientists understand the specific role of this area in forming new memories.

These case studies have been incredibly important in helping us understand how memory works in the brain.

See also

In Spanish: Amnesia para niños