Memory Impairment: Prevention and Improving Functioning

Welcome to the educational program Memory Impairment: Prevention and Improving Functioning. This program will provide a brief overview of how memory works and some strategies for preventing memory impairment and promoting a healthy brain.

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This is Lesson 30 of The Alzheimer’s Caregiver. You may view the topics in order as presented, or click on any topic listed in the main menu to be taken to that section.

We hope that you enjoy this program and find it useful in helping both yourself and those you care for. There are no easy answers when it comes to the care of another, as every situation and person is different. In addition, every caregiver comes with different experiences, skills, and attitudes about caregiving. Our hope is to offer you useful information and guidelines for caring for someone with dementia, but these guidelines will need to be adjusted to suit your own individual needs. Remember that your life experiences, your compassion and your inventiveness will go a long way toward enabling you to provide quality care.

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How Memory Works

Let’s take a look at what happens in the brain to make memory possible. Several specialized areas in the brain, such as the hippocampus, are responsible for processing, storing, and retrieving memories. Although there is a lot of research on how memory works, much is still unknown. The important things to remember about memory is that it is subjective, and people only store information that they are paying attention to.

The brain is made up of trillions of nerve cells, called neurons. Each of these nerve cells has antenna-like structures called axons and dendrites that reach out to other axons and dendrites. This reaching out establishes the pathways of information that allow communication between nerve cells in different parts of the brain and the body.

Millions of nerve cells make up what is called the gray matter of the brain, which forms the outer portion of the brain. Gray matter contains the processing centers for the brain’s functions. In Alzheimer’s disease, it is primarily the gray matter that is lost in various parts of the brain.

The deeper white matter of the brain is made up of the fibrous axons that reach out to other nerve cells. These axons are covered with a myelin sheath, which is a whitish fatty coating that insulates them, allowing signals to travel more efficiently along the nerve fiber. Millions of these myelinated nerve fibers form a structure called the corpus callosum, which connect the left and right sides of the brain to allow efficient communication between them. In some forms of dementia, such as vascular dementia, areas of the myelin sheath usually suffer damage and break down, causing the brain to lose its ability to transmit information.

How Memory Works (Part 2)

When babies are born, they do not have fully developed brains. The nerve fibers do not have fully developed insulation called myelin sheaths. Because of this, thoughts and memories are erratic. As the myelin sheath develops, the nerve cells, also called neurons, are able to send signals more efficiently and form connections with other nerve cells.

Forming connections and networks of nerve cells is a tricky process because the axon of one nerve cell is not physically connected to other nerve cells, but rather, there is a minuscule space between them called a synapse. When a signal in a nerve cell travels from the dendrite to the cell body and onto the end of an axon, chemicals called neurotransmitters are released. Neurotransmitters leave the axon and cross the synapse to get picked up by a dendrite of the next neuron. When enough neurotransmitters are picked up by the receiving nerve cell, it triggers a signal that travels down this new nerve cell to cause the release of new neurotransmitters from its axon. This cascade of nerve cell firing and neurotransmitter release is how one nerve cells sends a signal to the next nerve cell and so on.

The signal that travels from the dendrite to the cell body and axon is called an action potential. A complex pattern of action potentials through networks of nerve cells and pathways is how information is stored and transmitted in the brain.

In Alzheimer’s disease, the brain produces less neurotransmitters, affecting the ability to transmit information and make new connections between nerve cells. Over time, nerve cell networks and pathways are damaged and lost, resulting in loss of the abilities to understand, learn new information, and retrieve old information.

How Memory Works (Part 3)

Memory is the ability to retain and recall information. Memory and learning are closely related and involve complex processes of information association and storage. For example, a child can learn a new word by pairing a visual image with auditory sound information, which causes two pathways of brain cells in the brain to fire at the same time. For example, if the child sees a bird and hears someone say “dove,” an association between the visual and auditory pathways is made, and learning occurs. The more this information is rehearsed, the better the memory for this association.

In order to become a memory, all information must go through three steps: Encoding, which is the process of registering the information; Storage, which creates a permanent record of the encoded information; and Retrieval, which is calling back the stored information.

Information is first acquired, then passed into short-term memory. Short term memory allows recall for a period of several seconds to a minute without rehearsal. The rehearsal or repeated exposure to information can lead to memory consolidation, which is the process by which recent or short-term memories are transformed into long-term memories.

Memory consolidation occurs through repeated firing of pathways in the brain that strengthens connections between a network of nerve cells and their pattern of firing, giving meaning to information and storing it.

With continued rehearsal, or repeated firings between a network of nerve cells, the connections become stronger, allowing the information to remain in storage forever in some cases.

Working Memory

Working memory is a system for temporarily storing and managing information. Working memory is where information is processed and manipulated so that learning, reasoning, and understanding can occur. It acts as the bridge between encoding, storing, and retrieving information.

Working memory is used to bring information in and out to manipulate it in order to develop a plan or make a decision. In some theories, short-term memory is a type of working memory. An example of working memory is briefly showing someone a list of four words and then taking away the list and asking the person to recall the words in alphabetical order. The person would need to use working memory to recall the words and then organize them alphabetically.

Working memory has limited capacity. For example, one test of working memory is memory span, the number of items that a person can hold onto and recall. In a typical test of memory span, an examiner reads a list of random words aloud and then asks the person to recall the items in order. The average adult can remember 7 items. Another example of working memory capacity is asking someone to quickly name the last five presidents. Most people would be able to do so fairly quickly, but if asked to cite the last five presidents in alphabetical order, they would take more time to manipulate the information.

Many older people lose working memory capacity. As people age, their ability to hold onto information in the working memory declines so that concentration and attention suffer. It is also harder for older people to refocus when they are interrupted or distracted.

One of the main areas in working memory that is affected by age is the comprehension of speech. To understand language, a person must analyze the sounds, intonations, pauses, timing and grammatical factors in the working memory. This ability diminishes with age. So the more rapid the speech and more complex the sentences, the more difficult it is for older people to understand what is being said. With the addition of hearing difficulties to declining working memory, it is easy to understand why older people often tune out what is being said or do not understand or remember what they were told.

Memory Retrieval

After information is encoded and stored, information must be retrievable in order to remember it. Retrieval is a process of accessing stored memories. There are four types of memory retrieval.

Recall involves being able to access the information without being provided with any part of the memory. For example, answering fill-in-the-blank questions on a test require recall of information.

Recollection involves reconstructing a memory of a fact or event using pieces of memories, and oftentimes, clues, logical structure, and narrative. An example that involves recollecting information is answering an essay question. Recognition is identifying information as a memory after experiencing it again. For instance, answering multiple choice or matching questions require recognition of learned information.

Relearning involves relearning information that has been previously learned, which often strengthens the memory and makes it easier to remember and retrieve the information in the future.

Retrieved information is often not a faithful reproduction of the original information. During retrieval, people use a variety of strategies to generate a consistent and coherent memory, including comparison, inferences, shrewd guesses, and suppositions. Research shows that people tend to reorder, reconstruct and condense information to fit their own perceptions. It is not a conscious process, as when someone lies, but it is an unconscious process influenced by the rules that people acquire through their experiences, education, culture and beliefs. These rules automatically transform information as it is perceived as well. As individuals grow and develop, family values, culture, and education allow them to specialize their brains to process and use information in terms of their own unique values, knowledge, and behaviors.

Preventing Memory Loss

Although memory is imperfect at all ages, there are many environmental, physical and mental factors that can affect memory. Knowing what these factors are can help people to improve and optimize their memory. The best approach to preventing memory loss is to minimize the modifiable risk factors for memory impairment. By making some adjustments in lifestyle, it is possible to prevent or delay memory changes associated with aging as well as some diseases.

Memory loss greater than what is expected from normal aging can be caused by either reversible or non-reversible conditions.

Though many of the reversible conditions that cause memory impairment can occur at any age, they are much more common among older individuals. Thus, elderly people have increased vulnerability to memory difficulties. The key to preventing memory loss from reversible conditions is to diagnose and treat the condition before the memory impairment worsens or becomes permanent. The memory loss from reversible causes can usually be completely or nearly completely resolved by treating the underlying cause. In general, the best outcomes happen when treatment is started early and the treatment plan is properly followed as directed by healthcare professionals.

Preventing memory loss from irreversible forms of dementia, such as Alzheimer’s disease, requires a different approach, because there are no known cures for these conditions. So once the disease has been diagnosed, the goals of treatment are to slow the progression of the disease and to preserve function for as long as possible. Medical treatments for Alzheimer’s disease help to delay the onset of the more severe symptoms, so that affected individuals and their family can have better lives.

Non-drug approaches to managing Alzheimer’s disease and slowing memory loss include providing an environment that is safe and familiar with clear cues and minimal distractions, and to encourage and support the use of remaining capacities.

Slowing Memory Loss

As researchers continue to discover more about memory and how the brain functions, they learn more about how to optimize memory and slow down its loss, whether due to aging or dementia.

There are two basic approaches for optimizing memory: one is to reduce the modifiable risk factors for memory impairment, and the other is to use strategies for improving memory and overall brain health.

In the first approach, it is important to know what the major risk factors for memory impairment are. Some of the major risk factors for memory problems either associated with or without Alzheimer’s disease, include family history, older age, female gender, lower education level, history of severe head trauma, illness, medications, including alcohol or illicit drugs, vision or hearing loss, and chronic medical conditions such as heart disease, stroke, high blood pressure, high cholesterol, obesity, diabetes, hormonal imbalances, and depression. Some of these risk factors, such as family history, age, and gender, cannot be changed. But for those risk factors that can be modified, addressing them can significantly reduce or delay the onset of memory issues or Alzheimer’s disease. Therefore people should diligently treat medical conditions such as depression, heart disease, high blood pressure, high cholesterol, diabetes, thyroid disease, menopause and other hormonal imbalances.

It is important to take precautions to prevent head injuries and to reduce hearing and vision loss. Preventing strokes by lowering one’s risk factors for them is also very important.

When possible, it is best to avoid medications and psychoactive drugs that cause mental impairment.

Lastly, pursuing higher education can help delay memory loss by increasing brain reserve. Reducing these risk factors for memory impairment and Alzheimer’s disease can be quite effective in delaying memory loss and preserving functional abilities.

Click here to learn more about the risk factors for memory impairment. [memory impairment risk factors]

Strategies for Optimized Memory

Physical Exercise

Now let’s discuss some strategies for optimizing memory and brain health. Many studies have shown that physical exercise is very effective at preventing or delaying age-related memory loss. This may be because exercise improves blood circulation to the brain, delivering more oxygen and nutrients and taking away more toxins and waste products.

Exercise also increases blood flow to other important organs and muscles. It promotes muscle tone and flexibility, improves digestion and prevents constipation, all of which provides a sense of well-being. Exercise also promotes the production of natural mood elevating substances in the body, such as epinephrine and serotonin. This increased alertness, improved mood, and sense of well-being increase one’s attention and concentration.

Exercise comes in many forms and should be adjusted to the abilities of each individual. Dancing, walking, using a stationary bicycle, and water aerobics are all great examples of fun exercises. For those with limited mobility, less strenuous activities such as chair or bed exercises or tossing a ball can be taught and encouraged. Keep in mind that exercise can also offer opportunities for social interactions, which can help improve moods, increase self-esteem, and reduce isolation.

A healthy diet is essential for maintaining good mental function. As previously noted, one way to reduce the risk of memory decline and Alzheimer’s disease is to avoid high cholesterol levels, high blood pressure, obesity, diabetes, heart disease, and stroke risks. A healthy diet can help prevent these risk factors for memory loss.

A diet rich in carbohydrates and fat can increase the risk for diabetes, heart disease, and strokes, whereas a healthy diet, exercise, and weight loss can reduce this risk. Junk foods and sweetened drinks should be avoided as they have little or no nutritional value but are filling, reducing the appetite for nourishing foods at meal time.

A nutritious diet consisting of whole grains, fruit, vegetables, lean meat and fish, and low fat content can help maintain a healthy brain.

Some studies suggest that a diet rich in omega-3 fatty acids or a Mediterranean diet high in olive oil, fish, and plants, can protect against age-related mental decline.

Foods and beverages high in anti-oxidants, such as vitamins C, E, and flavonoids, may be particularly protective. Beverages and foods with high anti-oxidant effects include cocoa, blueberries, strawberries, tomatoes, spinach, broccoli, walnuts, almonds, soybeans, and other fruits, vegetables and nuts. Supplemental vitamins may be given in moderate doses, but very high doses (over 1000 mg of Vitamin C and over 400 mg of vitamin E) have not been found to be significantly beneficial and may have harmful side effects.

The B vitamins, vitamins B12, B6 and folic acid, help maintain healthy brain cells. Foods high in these vitamins include beef, liver, banana, avocado, brewers yeast, spinach, cabbage and shellfish. Vitamin supplements may be given in moderate doses to augment a person’s diet when consumption of these foods is declining.

Dietary supplementation with the phospholipids, phosphatidylserine and glycerophosphocholin, and the energy nutrient, acetyl-L-carnitine, can also help optimize brain function.

Lastly, consumption of water and other liquids is very important, especially for the elderly. Dehydration can result in acute confusion as well as dizziness, constipation and kidney and heart problems. Older people often are reluctant to drink because of frequent toileting or incontinence, so it is important to encourage them to drink adequately.

There is ongoing research to find drugs that will optimize memory and protect against mental decline. We will briefly present a few of these unapproved drugs for slowing memory decline.

Some studies suggest that high doses of Vitamin E (2000 units daily) may delay functional decline in people with Alzheimer’s disease.

Other studies suggest that non-steroidal anti-inflammatory drugs (NSAIDs), postmenopausal estrogen in women, and cholesterol-lowering statin drugs may be protective against memory decline.

Reducing stress is another important way to reduce memory problems and improve brain health.

High levels of stress hormones impair memory and other brain functions. Additionally, chronic or excessive stress can contribute to serious medical issues and lead to depression and anxiety disorders, which can all impair memory and mental functioning.

Unhealthy approaches to dealing with stress include alcohol abuse, drug abuse, and the use of tobacco products. These substances can directly and indirectly kill brain cells and contribute to mental decline. Smokers have double the risk of developing Alzheimer’s compared to nonsmokers. It is best to avoid abusing any of these substances.

Mental exercise is another key way to optimize memory and mental functioning. As previously mentioned, the risk of developing Alzheimer’s disease is lower in people who have obtained higher levels of education. The key to maintaining optimal mental function is to stay intellectually active. People who spend time reading, learning new things, working at mentally stimulating jobs, and have strong educational experiences maintain their memories better as they age. Studies show that mental stimulation is healthy for the brain, improves memory performance, and can prevent or delay future memory loss.

Therefore it is important to engage in mental exercises appropriate to one’s level of ability.

It is never too late to start new and creative activities. Challenge yourself by learning something new, such as a foreign language, reading new books and newspapers, solving puzzles and brain teasers, learning new songs, playing video and board games, writing letters, and talking to people about interesting topics.

There are three general principles for mental exercises to improve your memory. First, find something that will hold your interest. Second, make sure that you give your full attention to the exercise, and third, gradually increase the difficulty of the exercises.

Though there are many ways to exercise your brain, you need to choose a mental activity that interests you. Finding an activity or a topic that piques your curiosity will promote the release of neurotransmitters, chemical messengers that travel between nerve cells. This will help improve and restore the memory function.

Another principle in memory strengthening is the importance of focusing enough mental resources on the memory task. This has been referred to as mindful attention. It requires attention and concentration. When people are learning something new, they are in a focused, engaged mode in which the brain is ready to acquire and process new information. If people are bored, disengaged, inattentive or paying attention to something else, the brain is switched off and learning will not occur. It is important to consciously make the effort to attend to the activity.

For best results, new tasks should be difficult to do at first, but still be doable, with only minor frustrations on the initial trial. With practice and success, people will find it easier to complete the tasks. This will increase confidence and self-esteem as well as improve mental functioning. As people age, they need to make an effort to maintain memory, so mental activities should increase in difficulty to challenge the brain.

When tasks are too easy or too routine, the brain becomes lazy, and the motivation and attention pathways in the brain are not stimulated. Sitting back and letting others do the work is not productive, because the brain is not being challenged or practicing any skills.

For those with dementia, performing tasks involving multiple factors can be a good exercise in manipulating many items in their working memory. Because aging and dementia can slow performance and make it harder to keep many things in the working memory, it may be necessary to allow sufficient time, use memory aids and coach when needed to improve performance.

Puzzles and games such as crosswords and trivia games can be fun and will also increase brain activity. Learning about current events by reading newspaper or magazine articles can also be a useful mental exercise. Try to include positive events and items of personal interest to the person.

Strategies for Mental Exercises

Repetition or rehearsal of the mental exercise or information is essential for consolidation of the memory. Each rehearsal strengthens the brain’s memory for that particular skill.

You can help the brain to learn and remember by rehearsing in an organized way. One approach is from simple to complex. For example, you learn mathematics by starting with basic arithmetic before advancing to algebra and geometry. The brain also naturally learns from the general to the more particular. For example, we learn the category – flower, and then learn about daisies, tulips and roses. Another way the brain learns is by chunking related data, such as learning a telephone number or memorizing a grocery list by categories of fruits, vegetables, dairy, and meats.

Elaboration is another memory exercise that involves giving meaning to the information that needs to be remembered. The more meaning your are able to give to the thing to be remembered, the more successful you will be in recalling it later. For example, if someone was reading an article on cancer research, any personal knowledge about a family member who died of cancer would help to encode the information in the article.

Another memory exercise is the use of imagery. Mental imagery is the mental invention or recreation of an experience or event that in some ways resembles the perception of the actual experience or an event. For example, when trying to perfect a dance step or yoga pose, you can conjure up in a mental image of yourself in that perfect pose. The image you visualize is the standard you are striving for, and your actions will gravitate toward that image.

Another technique for encoding memory is the distinctiveness rule, which involves making the information distinct from the rest. Attributing a distinct characteristic to the item to be remembered will make it more memorable. For example, if you are trying to remember the names of ten goldfish in a fish tank, it may be easier to remember the name of each fish if you associate a distinctive feature about each fish with the name. Pointing out distinct and unique aspects of information will help in storing that information.

For an older person or someone with dementia to master a memory task, it is essential that the environment be optimal. This involves optimal sensory stimulation, task volume, task interruption and time.

It is important to minimize loud or irritating noises, glaring lights, and human or animal traffic in a room, because these things can overload a person’s senses. Some stimulation, of course, is desirable but not be so much as to be distracting.

The volume of the activity should be adjusted to match the person’s capacities and level of comfort.

Because people with dementia have difficulty refocusing on a task when they are interrupted, it is best not to interrupt or interfere with a memory task if possible.

It is also important to allow adequate time to perform a task because they will need more time to mentally and physically get through a task.

In summary, one approach to preventing memory decline is to reduce one’s risk factors, including managing medical conditions such as heart disease, stroke, high blood pressure, high cholesterol, obesity, diabetes, hormonal imbalances, depression, and reducing stroke risk. It is important to minimize head injuries, hearing loss, and vision loss. When possible, it is best to avoid psychoactive medications, alcohol, tobacco, and illicit drugs.

Some strategies for maintaining a healthy brain and delaying memory impairment include physical exercise, eating nutritional meals high in fruits, vegetables, and some nuts. Vitamins C, E, B12, and folate supplements can also be beneficial. Lastly, getting a high level of education and maintaining mental stimulation are important for delaying memory loss. A combination of mental and physical stimulation is the most effective approach to improving mental function and preventing memory impairment.

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Written by: Catherine M. Harris, PhD, RNCS (University of New Mexico College of Nursing)

Edited by: Mindy J. Kim-Miller, MD, PhD (University of Chicago School of Medicine)

 

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