How Short-Term Memory Is Affected by Alzheimer's

Short-term memory (STM) includes immediate and recent recall. One of the earliest symptoms of Alzheimer's disease is a decline in short-term memory. There are other conditions that also affect short-term memory. Some tests, such as the mini-mental status examination (MMSE) and the Montreal Cognitive Assessment (MoCA) can be used to help determine whether there is a decline in other aspects of executive function (thinking skills), which can help identify the cause of short term memory loss.

Capacity of Short-Term Memory

It has long been established that short-term memory holds between five to nine items of information, with the average being seven.

This capacity can be extended by using memory strategies, such as chunking information or attaching meaning to it. You can also hold information indefinitely in your short-term by rehearsing it (repeating it over and over), which may result in it eventually being transferred over to your long-term memory.

Clinicians' Definition

Short-term memory is considered the memory of events from approximately a few minutes to a day or two.

Some experts measure short-term memory in hours, days, or weeks. For example, if it’s late afternoon and you can’t recall what you ate for breakfast or you forgot that you went to the doctor four days ago, your physician may call that "short-term memory impairment."

Immediate memory is the ability to remember information immediately after being exposed to it. For example, after hearing a phone number and repeating it a couple of times, you may be able to remember it long enough to dial it accurately. Five minutes later, however, it’s entirely likely you won't be able to recall that phone number.

How Is Short-Term Memory Affected by Alzheimer's Disease?

Short-term memory impairment is one of the earlier symptoms of Alzheimer's disease. It can cause people to forget things like the question they just asked or where they set their glasses down.

Repeating questions is one of the signs of short-term memory impairment in dementia.

Other Causes of Short-Term Memory Impairment

There's a wide variety of reasons you might experience short-term memory impairment, many of which are temporary or easily treatable. Some of the causes of short-term memory loss are medical problems, but often, emotional issues or mood disorders can be the cause. And many of the causes can be treated with various therapies.

Mood disorders and adjustment issues that can interfere with short term memory:

• Acute grief
• Chronic depression
• Stress/feeling overwhelmed
• Anxiety
• Fatigue/lack of sleep

Medical problems that can interfere with short term memory:

• Normal-pressure hydrocephalus
• Vitamin B12 deficiency
• Mild cognitive impairment
• Other kinds of dementia
• Delirium from an infection or illness
• Head injuries
• Conditions in the brain (tumor, infection, blood clots)
• Certain diseases of the thyroid, kidney, or liver
• Medications, among them the antidepressant Paxil (paroxetine) and the heartburn drug Tagamet (cimetidine)
• Chronic or acute alcohol or drug use

Assessment

If you notice a persistent problem with your short-term memory or someone else has identified this as a concern, you should seek an evaluation to determine the cause and appropriate treatment. If it's related to a reversible condition, you'll be able to get treatment to improve the symptoms. If it's caused by dementia, like Alzheimer's, early treatment can help you cope with that new diagnosis.