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4 Types of Memory: Sensory, Short-Term, Working & Long-Term

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Updated May 24, 2013

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People have several different kinds of memory. What are they, and how does Alzheimer's disease impact them?

Sensory Memory

Sensory Memory is a very brief recall of a sensory experience, such as what we just saw or heard.

Short-Term Memory

Short-term memory is that brief period of time where you can recall information you were just exposed to. Short-Term often encompasses anywhere from 30 seconds to a few days, depending on who is using the term.

Working Memory

Some researchers use the term working memory and distinguish it from short-term memory, though the two overlap. Working memory can be defined as the ability of our brains to keep a limited amount of information available long enough to use it. Working memory helps process thoughts and plans, as well as carries out ideas. You can think of the working memory as the short-term memory combining strategies and knowledge from the long-term memory bank to assist in making a decision or calculation.

Long-Term Memory

Long-term memory encompasses memories that range from a few days to decades. In order for successful learning to take place, information has to move from the sensory or the short-term memory to the long-term memory.

How Does Alzheimer’s Affect Memory?

In Alzheimer’s disease, one of the earlier symptoms is short-term memory loss. When discussing Alzheimer’s, clinicians often use the term “short-term memory loss” to refer to a time period encompassing both extremely short times, such as 30 seconds, as well as the intermediate time period that may last up to several days.

Individuals with early signs of Alzheimer’s may repeat questions frequently over the course of several hours, or tell the same story that they told five minutes ago. This type of short-term memory loss is often one of the first visible signs that an individual’s cognitive functioning is declining. In contrast, the long-term memories of an individual with early Alzheimer’s typically remain intact.

Coping with early-stage Alzheimer’s can be challenging. Individuals may know in their long-term memory that they’ve been diagnosed with Alzheimer’s and also may be aware of, and distressed by, their short-term memory deficit. Using these 6 tips to help store information in memory can be helpful in this stage.

As Alzheimer's progresses to the middle and late stages, the long-term memory is impacted as well. It becomes difficult for individuals to recognize people they've known for many years, such as close friends or family members. This can be hard for loved ones to handle, but reminding yourself that this is an effect of Alzheimer's disease, rather than something the individual is choosing, may help you cope and respond positively to your loved one.

Sources:

Cowan, Nelson. National Institutes of Health. What are the differences between long-term, short-term, and working memory? Accessed December 18, 2011. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2657600/

Kesnera, Raymond P. & Hunsaker, Michael R. The temporal attributes of episodic memory. Behavioural Brain Research. Volume 215, Issue 2, 31 December 2010, Pages 299-309. http://www.sciencedirect.com.libproxy.library.wmich.edu/science/article/pii/S0166432809007554

Myers, Catherine E. Memory. The Newsletter of the Memory Disorders Projects at Rutgers University. Accessed December 18, 2011. http://www.memorylossonline.com/glossary/memory.html

Univeristy of Louisana. Memory. Accessed December 17, 2011. http://www.ucs.louisiana.edu/~rmm2440/Memory.pdf

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