Memory Loss

The most common causes of memory loss are

• Age-related changes in memory (most common)

• Mild cognitive impairment

• Dementia

• Depression

Age-related changes in memory (called age-associated memory impairment) refer to the normal slight decline in brain function that occurs as people age. Most older adults have some memory problems. Retrieving memories of new things, such as what is a new neighbor's name or how to use a new computer program, takes longer. Older adults also have to rehearse new memories more often for the memories to be stored. People with this type of memory loss occasionally forget things, such as where they left their car keys. But for them, unlike people with dementia, the ability to do daily activities or to think is not impaired. Given enough time, these people usually remember, although sometimes later than is convenient. This type of memory loss is not a sign of dementia or early Alzheimer disease.

Mild cognitive impairment is an imprecise term used to describe impairments in mental function that are not severe enough to affect daily functioning. Memory loss is often the most obvious symptom. Memories are actually lost, not merely slow to retrieve, as occurs in people with age-related changes in memory. People with mild cognitive impairment have trouble remembering recent conversations and may forget important appointments or social events, but they typically remember past events. Attention and the ability to do daily activities are not affected. However, up to half of people with mild cognitive impairment develop dementia within 3 years.

Dementia is a much more serious decline in mental function. Memory loss, particularly for recently acquired information, is often the first symptom, and it becomes worse with time. People who have dementia may forget entire events, not just the details. They may do the following:

• Have difficulty remembering how to do things they have done many times before and how to get to places they have often been to

• No longer do things that require many steps, such as following a recipe

• Forget to pay bills or keep appointments

• Forget to turn off a stove, lock the house when they leave, or take care of a child left in their care

In the early stages of dementia, people may be aware of their memory loss. But as dementia progresses, they, unlike people with age-related changes in memory, become unaware of their memory loss and often deny that they have such loss.

Finding the right word, naming objects, understanding language, and doing, planning, and organizing daily activities become more and more difficult. People with dementia eventually become disoriented, not knowing what time or even what year it is or where they are. Their personality may change. They may become more irritable, anxious, paranoid, inflexible, or disruptive.

There are many forms of dementia. Alzheimer disease is the most common. Most forms of dementia progressively worsen until the person's death.

Some conditions that increase the risk of heart and blood vessel disorders (such as high blood pressure, high levels of cholesterol, and diabetes) seem to increase the risk of dementia.

Depression can cause a type of memory loss (called pseudodementia) that resembles memory loss due to dementia. Also, dementia commonly causes depression. Thus, determining whether dementia or depression is the cause of memory loss can be difficult. However, people with memory loss due to depression, unlike those with dementia, are aware of their memory loss and complain about it. Also, they rarely forget important current events or personal matters and usually have other symptoms, such as intense sadness, sleeping problems (too little or too much), sluggishness, or loss of appetite.

Stress can interfere with forming a memory and with recalling a memory, partly by preoccupying people and thus preventing them from paying attention to other things. However, in certain circumstances, particularly when stress is mild to moderate and does not last long, it can enhance memory.

Many disorders can cause a deterioration of mental function that resembles dementia.

Some of these disorders may be reversed with treatment. They include the following:

• Hypothyroidism (an underactive thyroid gland)

• Normal-pressure hydrocephalus (due to excess fluid around the brain)

• Subdural hematomas (pockets of blood under the outer layer of the membranes covering the brain)

• Vitamin B12 deficiency

Other disorders are only partially reversible. How much they can be reversed depends on how much tissue has been damaged. They include

• Disorders that interfere with the supply of blood or nutrients to the brain, such as a cardiac arrest and certain types of stroke

• Unusually long seizure

• Head injuries

• Brain infections

• HIV (human immunodeficiency virus) infection

• Brain tumors

• Overuse of certain medications or substances (including alcohol)

In people with these disorders, treatment can sometimes improve memory and mental function. If damage is more extensive, treatment may not improve mental function but can often prevent further deterioration.

In delirium, memory is affected, but memory loss is not the most noticeable symptom. Rather, people with delirium are very confused, disoriented, and incoherent. Severe alcohol withdrawal (delirium tremens), a severe bloodstream infection (sepsis), lack of oxygen (as may result from pneumonia), and many other disorders can cause delirium, as can use of illicit drugs.

In people with memory loss, certain symptoms are cause for concern:

• Difficulty doing usual daily activities

• Difficulty paying attention and fluctuations in level of consciousness—symptoms that suggest delirium

• Symptoms of depression (such as loss of appetite, suicidal thoughts, difficulty sleeping, and slowing of speech and general activity)

People with warning signs should see a doctor. They should see a doctor immediately if they

• Cannot pay attention and seem very confused, unfocused, and disoriented—symptoms that suggest delirium

• Feel depressed and are thinking of hurting themselves

• Have other symptoms that suggest a problem with the nervous system, such as headaches, difficulty using or understanding language, sluggishness, vision problems, or dizziness

People who do not have warning signs but are concerned about their memory or have difficulty doing basic daily activities should call their doctor. The doctor can determine how quickly they need to be seen based on other symptoms they have and the severity of the symptoms.

Doctors ask about the person’s symptoms and medical history. Doctors then do a physical examination. Having a family member present is helpful because people with memory difficulties may not be able to describe their symptoms accurately. What doctors find during the history and physical examination often suggests a cause and the tests that may need to be done (see table Some Causes and Features of Memory Loss).

Doctors often talk to the person and the person’s family members separately because family members may not feel free to describe the symptoms candidly with the person listening.

Doctors ask specific questions about the memory loss:

• What types of things the person forgets (for example, whether the person forgets words or names or gets lost)

• When the memory problems started

• Whether memory loss is getting worse

• How the memory loss is affecting the person’s ability to function at work and at home

Doctors also ask whether the person has other symptoms, such as difficulty using or understanding language and changes in their eating and sleeping habits or mood. They ask about all disorders the person has had and all the medications, illicit drugs, over-the counter medications, and nutritional supplements the person is taking to check for possible causes. Doctors also ask the person about any unusual dietary habits. Information about the person’s education, jobs, and social activities can help doctors better assess the person's previous mental function and gauge the severity of the problem. Doctors ask whether any family members have had dementia or early mild cognitive impairment.

During the physical examination, doctors evaluate all body systems but focus on the nervous system (neurologic examination), including evaluation of mental function (mental status testing).

In mental status testing, doctors ask people to answer questions or do specific tasks to evaluate various aspects of mental function, such as

• Orientation to time, place, and person: State the current date and place and who they are.

• Attention: Repeat a short list of words.

• Concentration: Spell "world" backwards or repeat their phone number forward, then backward.

• Short-term memory: Recall the short list of words after several minutes.

• Long-term memory: Answer questions about the distant past.

• Use of language: Name common objects and body parts, and read, write, and repeat certain phrases.

• Ability to understand spatial relationships: Copy simple and complex structures (for example, using building blocks) and draw an object such as clock, cube, or house.

This testing also assesses abstract thinking, comprehension, the ability to follow commands and solve math problems, awareness of the illness, and mood.

Doctors can usually determine whether the cause is age-related changes, mild cognitive impairment, or early dementia based on the type of memory loss and the symptoms that accompany it.

However, when the diagnosis is unclear, neuropsychologic testing can provide more information. This testing is similar to mental status testing except it is much more detailed. Complete testing may take hours. These tests must be given by a trained, licensed psychologist or psychiatrist with expertise in memory loss. These tests may not be as useful in people over 65.

If doctors suspect dementia or find any abnormalities during the neurologic examination, they usually do magnetic resonance imaging (MRI) or, if MRI is unavailable, computed tomography (CT) to check for abnormalities such as a brain tumor, normal-pressure hydrocephalus, damage due to a head injury, and stroke.

Doctors may also do blood tests to measure levels of vitamin B12 and thyroid hormones to determine whether vitamin B12 deficiency or a thyroid disorder could be causing memory loss. These disorders are reversible causes of memory loss.

If a brain infection is suspected, doctors usually do a spinal tap (lumbar puncture) to obtain samples of the fluid around the brain (cerebrospinal fluid) for analysis.

Some generally healthful measures are often recommended for people who are worried about memory loss:

• Exercising regularly

• Eating a healthy diet with lots of fruits and vegetables

• Getting enough sleep

• Not smoking

• Minimizing use of alcohol or other substances (such as marijuana)

• Participating in social and intellectually stimulating activities

• Getting regular check-ups

• Avoiding high levels of stress

• Protecting the head from injury

These measures, along with controlling blood pressure, cholesterol levels, and blood sugar levels, also tend to reduce the risk of heart and blood vessel disorders. Some evidence suggests that they may reduce the risk of dementia, but this effect has not been proved.

Some experts recommend the following:

• Learning new things (such as a new language or a new musical instrument)

• Doing mental exercises (such as memorizing lists, doing word puzzles, or playing chess, bridge, or other games that use strategy)

• Reading

• Working on the computer

• Doing crafts (such as knitting and quilting)

• Using cues to help with remembering and organizing things

These activities may help maintain or improve mental function, possibly because they strengthen connections between nerves. Having stronger nerve connections helps people postpone the decline in mental function that results from changes in the brain and then helps them compensate for that decline.

For dementia, medications called cholinesterase inhibitorsAlzheimer disease or dementia with Lewy bodies

Mild cognitive impairment

No treatment can restore mental function or completely stop the progression of dementia. Thus, treatment of dementia focuses on keeping the person safe and providing support as the person declines.

If memory loss is relatively severe or family members are concerned about the person's safety, the person's home can be evaluated by occupational or physical therapists. They can recommend ways to prevent falls and other accidents and may suggest protective measures, such as hiding knives, unplugging the stove, and taking the car keys away.

A supportive environment has the following characteristics:

• Orientation is frequently reinforced (for example, by large calendars and clocks).

• The atmosphere is bright and cheerful.

• A regular routine is followed.

• Some stimulation (for example, from a television or radio) and enjoyable activities are available.

Eventually, the person may need a housekeeper or home health aide or may need to move to a one-story home, an assisted-living facility, or a skilled nursing facility.

Strategies that can help people cope with a declining memory include

• Making lists

• Keeping a detailed calendar

• Establishing routines

• Making associations or relating new information to information already known, such as associating a new person’s name with the name of a movie star

• Repeating information, such as repeating a new person’s name several times

• Focusing on (paying attention to) one thing at a time

• Improving organizational skills, such as keeping frequently used items such as car keys in the same place

Making sure that they can hear and see well can help people stay engaged with others and participate in social activities. Such participation helps people maintain confidence in themselves and often improves mental function.