How Does Dementia Affect Long-Term Memory?

Effects of Alzheimer's Disease on Long-Term Memory

Vietnam Vets' Nightmares May Unlock Hidden Link to Dementia. Credit: Bloomberg / Contributor / Getty Images

When you or someone you love is diagnosed with dementia or Alzheimer's disease, it can be very scary. It might also bring up questions about what memories are lost: does it mostly affect short-term memory or does dementia cause long-term memory to fade as well? This article explains the difference between different types of long-term memory and how it's affected by dementia.

What Is Long-Term Memory?

Long-term memory is a function of your brain where you remember something longer than a day or two, and often for many decades.

These long-term memories, unlike short-term memories, are relatively permanent.

Most people's earliest memories often go back to the age of four or five, if they were significant in some way.

Different Kinds of Long-term Memory

There are several different types of long-term memories stored in your brain. These include:

  • Semantic Memory
    Semantic memories are part of the declarative memory (memories that can be explained and declared), and refer specifically to knowing the meaning of words and actions. An example of a semantic memory is understanding what the word "memory" means.
  • Episodic Memory
    Episodic memories are also part of your declarative memory, and encompass specific events and the information related to that experience. The memory of your best friend's wedding, including the people who were there and the dress you wore, is an example of an episodic memory.
  • Procedural Memory
    Procedural memories consist of how to do something, including the specific steps required to accomplish a task. Procedural memories are often more difficult to explain in words, and are known as non-declarative memories. For example, you may "just know how" to ride a bike, but find it challenging to describe every step or explain how your body balances and how your brain makes your legs work to push the pedals.

    Strategies to Improve Long-Term Memory 

    There are several ways you can improve your long-term memory. When trying to store new information in your long-term memory, it helps to repeat it several times and pay full attention. It also helps to attach meaning. For example, try to link new information with something you already know and understand.

    Teaching information to others is another very effective way to get knowledge into your memory and remain there, since it requires you to understand it and then express it well to someone else.

    How Does Alzheimer’s Affect Long-Term Memory?

    In its early stages, Alzheimer’s disease affects short-term memory. However, as the disease progresses, people gradually experience more long-term memory loss, also called amnesia.

    Alzheimer’s and other dementias can affect long-term memory in two different ways. A person can have difficulty storing the information in the long-term memory, and also have challenges with retrieving it. Different kinds of dementia can result in either or both of these disruptions to long-term memory.

    As Alzheimer's progresses, semantic, episodic and procedural memories all gradually erode. People with Alzheimer's may have difficulty finding words; memories of significant events, such as weddings, may fade; and anything that requires multiple steps might become lost.

    For example, family members often appear familiar to those with advancing dementia, but they might not be able to identify the specific relationship.

    In the late stages of Alzheimer's, your loved one might not be able to demonstrate an awareness of your presence.

    Other Causes of Long-Term Memory Loss

    Dementia is the most common cause of long-term memory loss, but not the only one. A few other causes include:

    Responding to Long-Term Memory Loss in Dementia

    Here are a few helpful things you can do:

    • Display pictures of family and friends.
    • If you have DVDs or other recordings of family events or meaningful people, play that recording from time to time for the person.
    • Always introduce yourself by name.
    • Remember that the loss of a special memory, or even who you are, is not an indicator that you aren't meaningful or special to that person. It's a result of the disease, not a choice that he is making.
    • Don't constantly remind the person of her memory loss. Love her unconditionally and be with her.

    Sources:

    A.D.A.M. Memory Loss. Accessed February 22, 2012. http://adam.about.net/encyclopedia/Memory-loss.htm

    Online Education Database. Hacking Knowledge: 77 Ways to Learn Faster, Deeper, and Better. Accessed February 23, 2012. http://oedb.org/library/college-basics/hacking-knowledge

    Purdue University. Long-Term Memory. Accessed February 22, 2012. 

    DementiaGuide. Memory. Accessed February 21, 2012. http://www.dementiaguide.com/aboutdementia/alzheimers/memory/

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