Helping People with Progressive Memory Disorders »

Chapter 2: Major Forms of Mental Decline or Dementia


Many conditions or diseases keep the brain from working normally. "Mental decline" or decline of a person's memory, knowledge, or thinking ability is called dementia.

People who suffer from dementia may have difficulty keeping up with activities at work or daily chores, such as cooking. They may not be able to remember names. They may even forget the name of their spouse of 50 years. Events that happened a short while ago may be hard for them to recall. Mental decline may lead to a person's inability to care for himself or herself.

There are more than 50 diseases that can be associated with dementia. However, the behavioral disorders associated with dementia can be grouped into four major categories:

  1. Amnesic Disorders
  2. Cognitive Disorders
  3. Attention Disorders
  4. Motivation (Conative) Disorders

Some people with dementia have only one type of behavioral disorder, while other people may have more than one type.

The first part of this chapter discusses briefly each of these four major categories of mental decline. The remainder of the chapter briefly discusses some of the specific dementing diseases that can cause each of these four types of behavioral disorders.

Amnesic Disorders

Amnesia (amnesic disorders) is the medical word for memory loss (forgetting or not remembering). Not all people with dementia have memory loss or amnesia. However, memory loss is the most common problem. People with amnesia may have the most difficulty learning or recalling new or recent information, such as events that happen during the day. They are less likely to have problems with previously learned skills, such as dressing or using the telephone. Old memories seem to be remembered better than new ones. There is some change in efficiency of memory associated with normal aging.

Severe memory loss usually results from changes in brain cells primarily in the temporal lobe or from a loss of brain cells in the basal forebrain that produce the neurotransmitter acetylcholine. A serious blow to the head may result in temporary or permanent memory loss. A problem with memory is often the first sign of Alzheimer's disease. Difficulty with memory is associated with many other dementias, such as vascular dementia, Huntington's disease, Creutzfeldt-Jakob disease, and normal aging. These conditions will be discussed later in the chapter.

There are two types of amnesia - retrograde and antegrade. Retrograde amnesia occurs when people are not able to remember their old memories. Events that happened before the start of their disease may not be recalled. Examples include a family reunion or buying a new home.

Antegrade amnesia occurs when people are not able to form new memories. They are not able to store information about what just happened. They may have forgotten that two hours ago they visited the dentist.

Cognitive Disorders

Patients with cognitive disorders have a loss of different types of knowledge. Cognitive disorders are usually associated with damage to the temporal and parietal lobes in either the left or right hemisphere. Damage to these lobes may result in:

Cognitive disorders can occur after almost any type of brain injury, such as that sustained in a car accident or after a stroke. The cognitive disorders associated with brain damage can also come on slowly and be progressive such as in Alzheimer's disease.

Attention Disorders (Delirium and Confusion States)

People with attention disorders may be easily sidetracked or distracted. They may not be able to do an activity long enough to complete the task, such as reading an article in the newspaper. They may miss seeing or hearing important information because their attention wanders off. They miss information because they are easily distracted by a noise, by other people, or by something they see.

Their speech may be slow. They may not use small connecting words such as "to" or "the" as in "I want to go to the store." Instead they may say "I ... want ... store." Their sentences may be hard to understand. Their speech may get off the subject and not make sense. Sometimes people with attention disorders are too active or, the opposite, too indifferent or drowsy.

An attention disorder may come on suddenly when a person has an illness, such as an infection or the flu. Uncontrolled diabetes, a poor diet, or drug reactions may also result in an attention disorder. Typically this kind of problem can be treated.

Many times, if a person takes too many drugs to calm their nerves or takes many different drugs for different health problems, the medicines build up and can cause delirium. Attentional disorders such as delirium and states of confusion are generally treatable and reversible. Prompt treatment, which may involve stopping some drug, adjusting the amount taken, or treating an infection may prevent permanent problems. Attention disorders and delirium can also result from brain compression (pressure on the brain) caused by tumors or blood clots. These conditions need immediate treatment. Strokes may also be associated with confusion.

Motivation Disorders (Intention and Conative Disorders)

Motivation means wanting or being willing to put effort into doing an activity. Patients with Motivation Disorders may not have the desire to achieve goals.

They may seem unwilling to do any kind of work, play, or other activity. They also may lose interest in their jobs, families, or hobbies. Often they leave projects unfinished. They may have to be encouraged to do any sort of activity, even personal activities, such as eating a complete meal.

Sometimes they may not keep themselves clean, groom, or change clothes. It may even be too much for them to go to the toilet unless the caregiver reminds them or guides them.

Many people with motivation disorders lose their ability to react with feelings and to show emotions. They may stop expressing feelings on their faces and with words. Their voice may sound flat or dull.

These behaviors may be due to brain damage in the frontal lobes or damage to areas such as the basal ganglia or thalamus that connect to the frontal lobes. Damage in these areas can also affect memory. These changes may result from head injury, decreased blood circulation to the brain, and degenerative diseases where there is slow brain cell loss, such as in Picks disease or in the later stages of Alzheimer's disease.

Sometimes motivation disorders can be associated with depression. Prompt medical attention is important because depression is a treatable condition. Other treatable conditions that cause changes in patient behavior are hydrocephalus, infections, tumors, and other diseases.


The four general categories of dementia are: 1) amnesic disorders, 2) cognitive disorders, 3) attention disorders, and 4) motivation disorders. In amnesic disorders, probably the most common problem includes memory loss of two types, antegrade amnesia (unable to form new memories) or retrograde amnesia (unable to recall past memories). Cognitive disorders are the loss of special types of knowledge, such as language, math, visual spatial skills (such as finding the right way to a place), drawing, building something, or using tools. Attention disorders include being easily distracted by a noise or the sight of an object and not being able to stay on a task for more than a few minutes. Motivation disorders are the decreased ability to exert enough effort to do an activity or a general loss of interest.

These four types of behavioral disorders may be seen in many types of dementing diseases. The next section discusses briefly some of these specific diseases.


Almost any disease that affects the brain can cause dementia. In this section we briefly describe some of the more common diseases that may be associated with dementia. Sometimes changes in the frontal lobes result in signs of depression.


Depression is the most common psychiatric disorder in older people. Depression may be associated with memory loss and/or lack of motivation.

Not all people with depression feel sad, down in the dumps, or "blue." Other signs of depression include a change in appetite with weight loss or gain, trouble falling asleep, early morning awakening, such as at 4:00 am, or trouble getting out of bed in the morning. People who do not enjoy or look forward to any activities may be depressed.

Often there is no apparent cause for depression. However, depression sometimes occurs in older people who suffer from an illness or take many different medicines for a number of medical conditions. For example, a person taking medicine for high blood pressure and a heart condition may become depressed. Often when the physician adjusts the medicines, the person will feel better have more energy and be in better spirits.

Sometimes people who have had a stroke suffer from depression afterwards. This depression can be treated. Depression may be associated with many other neurological disorders such as Parkinson's disease, Huntington's disease, and brain tumors, or it may present as one of the first signs of dementia. Often in the late stages of the diseases, depression may go away.

During the medical evaluation, the doctor may uncover a severe memory loss that is progressive. Sometimes people with progressive dementia, such as Alzheimer's disease, will be very aware of their decline and, as a result, will be depressed. Although the progressive dementia is not completely treatable at this time (1998), a physician almost always can treat the depression. When the depression is treated, the person with severe memory loss can function better.

Suicide Risks

All people who are depressed must be asked about suicidal thoughts and plans. If there are such plans, a physician must be contacted immediately and the depressed person closely observed. All depression should be treated. It can be successfully treated with medicines, psychotherapy, or both. It is important to keep up with appointments to the doctor when being treated for depression. The treatment goes on only for as long as the medical evaluation shows that treatment is still needed.

Multiple Sclerosis

Multiple sclerosis usually causes movement and sensory problems. However it can also cause memory loss, decreased motivation, and even cognitive disorders. There are now several effective therapies to help manage multiple sclerosis. More information on multiple sclerosis is available (see the Appendix Directory).

Parkinson's Disease

Parkinson's disease is a progressive disorder that affects more than one million Americans. People with Parkinson's disease have decreased dopamine, a chemical in the brain responsible for controlling movement. Symptoms of Parkinson's disease include tremors when the muscles are at rest, stiffness in the limbs and neck, speech and walking difficulties, slow movement, difficulty starting any movement, difficulty switching to a different kind of movement, and a lack of facial expression.

Most patients with Parkinson's disease do not have memory problems. However, late in the course of the illness, about one-third to one-half of people with Parkinson's disease seem to develop amnesia (memory loss) and some cognitive problems, such as difficulty understanding a conversation or speaking. Others may show signs of an intentional or conative dementia. They may think slowly and have difficulty putting forth the effort to do any task or activity.

People with Parkinson's disease or Parkinson's-like symptoms must deal with muscle cramps, involuntary arm or leg (limb) movement (the limb seems to move on its own), constipation, and problems emptying the bladder.

More information about Parkinson's disease is available from different national organizations (see Appendix Directory).

Metabolic / Toxic / Deficiency

There are several forms of dementia caused by a build up or lack of specific chemicals in the body. Long-term alcohol use has been shown to cause dementia. However prolonged abstinence may improve this form of dementia.

If left untreated, deficiencies in vitamins such as thiamine (vitamin B1), niacin, and vitamin B12 can cause dementia. B1 deficiency is usually caused by alcohol use. Some people do not keep a good, healthy diet and, thus, do not receive enough folic acid (folate). Others eat well but their bodies cannot absorb essential nutrients, such as vitamin B12.

Foods rich in thiamine include whole grain cereals and bread. Folate is present in leafy vegetables, liver, fruits, and yeast. Vitamin B12 sources are eggs, meat, and dairy products.

When the thyroid gland is not working correctly, dementia may also result. In liver or kidney failure, chemicals normally found in the body may build-up to the point where they act as poisons and interfere with brain cells working properly. Many medicines can also cause metabolic defects in the brain and therefore cause dementia. Whenever possible, all such medicines should be either changed or eliminated. Metabolic disorders usually cause delirium or motivational disorders, but they can also cause memory loss. When metabolic, toxic, and deficiency conditions are treated, the person's health will improve.

Normal Pressure Hydrocephalus

Normal pressure hydrocephalus is a disorder resulting from a build up of the fluid in and around the brain. The build up of fluid usually puts pressure on the brain. People with a build up of pressure often have problems with incontinence of urine and unsteady walking. They also have problems with memory, motivation, and thinking. Treatment depends on the general health of the person and involves a small operation to place a tube (shunt) in the brain to drain the fluid from the brain.


When tumors grow in or into certain parts of the brain they may cause dementia. Some tumors can be removed by surgeons. Others may be treated with radiation therapy and medicines.


Dementia can result from infections of the brain cells or the tissue that covers the brain. Most of these infections are treatable; some result in severe progressive change. In order to determine that an infection is present, the physician may have to do a spinal tap (lumbar puncture) in which a small amount of fluid is removed from the spinal canal.

Syphilis - Untreated syphilis can cause a dementia, primarily destroying parts of the frontal lobes and damaging nerves throughout the body. A blood test for syphilis is a routine part of the doctor's evaluation for severe memory problems. Intense antibiotic treatment can help stop the progress of third stage syphilis with some improvement in health and ability to carry out the daily routine.

Zyme Disease - Carried by ticks, this infection can involve the brain and is treated with antibiotics.

Herpes Simplex - The virus, Herpes simplex, the same virus responsible for "cold sores," may affect the brain and cause a rapid loss of memory with emotional and personality changes. This virus must be diagnosed and treated immediately.

Cryptococcus Infection - A yeast, such as that causing the cryptococcus infection, may lead to dementia. The dementia is usually characterized by amnesia as well as motivation and attention disorders. Infections should be treated as soon as possible.

AIDS - Related Dementia or Acquired Immune Deficiency Syndrome (AIDS)—These conditions appear to cause dementia in young or middleaged adults. The disease seems to affect first the frontal areas of the brain with changes in attention and motivation. This disease may also affect memory, and then later, general cognitive functions. Some individuals are able to respond better than others to the medicines available for treatment. Patients with AIDS may become infected with other viruses, fungi, and parasites that may also cause dementia. For further information on AIDS Dementia, see the Appendix Directory.

Creutzfeldt-Jakob Disease - Creutzfeldt-Jakob, disease is a rare, progressive dementia that is caused by an infectious agent. It usually results in loss of memory, motivational-intentional disorders or cognitive disorders. Other typical behaviors include jerking muscle movements, leg or arm spasms, extra sensitive reactions to sudden loud noises, and a lack of coordination. This disease progresses rapidly over a period of several months or a few years.

Vascular Dementias

A major cause of dementia and somewhat treatable progressive dementias are the vascular dementias. Vascular dementias result from changes of the blood vessels in the brain. These dementias are usually associated with a long history of high blood pressure, diabetes, or high levels of cholesterol. Impaired blood flow to the brain may cause brain cells to weaken or die out. Diagnosing and treating the underlying condition, such as high blood pressure, may help keep further strokes from occurring. Thus the dementia may not progress. Sometimes good health care can slow down the strokes and slow down the progression of dementia. Aspirin and similar medicines, diet, exercise, and reduced stress are some ways to prevent or slow down the incidence of future strokes. Medicines that dilate or widen the vessels in the brain may also be useful.

The signs and symptoms of the dementia depend on the blood vessel involved. There may be only one category of symptoms involved. For example, maybe sudden amnesia (memory loss) is the only problem. Or maybe there are several categories of symptoms because blood vessels to the front, center, and rear of the brain are involved. Such a person may have amnesia (memory loss), cognitive disorders (problems writing and doing math), motivation problems (seems uninterested in doing self care, being with friends or going outdoors), or have difficulty with vision.

Two types of vascular dementias are multi-infarct dementia and Binswanger's disease.

Alzheimer’s Disease

Dementia of the Alzheimer's type or Alzheimer's disease is the most common progressive dementia. It affects more than four million Americans. This dementia may be associated with damage to different parts of the brain. Amnesia and cognitive problems, especially language difficulties, occur in early stages. Motivation and attention difficulties often occur in later stages.

Symptoms of Alzheimer's disease include a progressive memory loss, decline in ability to perform daily routine activities, not knowing the time (such as the current month or year), and confusion about location (not knowing the correct place, i.e., building, city, or state).

Memory loss and decline in language skills often show up first. For example, a person may be unable to find the right word for expressing a thought (inability to recall a word is called anomia). The person may struggle to understand long complicated sentences. Other symptoms include difficulty making decisions, starting and not finishing a task, change in personality, and a change in personal care or habits.

Although there is currently no known cure for Alzheimer's disease, there are now several medicines that offer limited relief and other medicines that may slow the progress of the disease. Behaviors, such as poor sleeping or uncontrolled pacing, can improve with treatment. Day care, respite programs, and support groups provide excellent assistance to families managing long-term care.

More information about Alzheimer's disease is available from the Alzheimer's Association (see Appendix Directory).

Huntington's Disease

Huntington's disease affects about 25,000 Americans. Typically, it is an inherited disease that can be easily diagnosed. It usually begins in middle age. It results in emotional changes, such as depression, early in the disease. Later in the course of the disease, there is spontaneous twisting muscle activity. Also later in the disease there is progressive dementia with problems of amnesia and motivation.

The parts of the brain first affected by Huntington's disease are the basal ganglia and the frontal lobe systems. Medicine can ease the movement disorder and help some of the psychiatric symptoms, such as depression. More information on Huntington's disease is available through the Huntington's Disease Society of America (see Appendix Directory).

Pick's Disease

Pick's disease is a progressive dementia that involves the frontal and temporal lobes. The first signs of this condition may show up as difficulties with motivation. In others there may be speech problems and amnesia. Early in the disease, people with this condition may have personality changes and more spontaneous behavior, impulsive behaviors, or speech abnormalities. Medicine may be used to help manage some of the problems with behavior.

Lewy Body Disease

Lewy body disease may start with hallucinations (seeing things that are not there). Persons with this condition often have early symptoms of Parkinson's disease and symptoms of Alzheimer's disease.

The condition gets its name from the small, round Lewy bodies found in the cell body of brain cells in the brain stem, the cerebrum, and the basal ganglia. Some of the medicines used to treat Alzheimer's disease may be successfully used to treat Lewy body disease. It is important to keep people on a routine, active schedule. The person may need some help with walking and related activities. Patients with Lewy body disease are often sensitive to the side effects of strong tranquilizers (neuroleptic or antipsychotic) medicines.

Progressive Supranuclear Palsy

Another uncommon progressive dementia is progressive supranuclear palsy WSP). Typically the first difficulty is with balance while walking. There may be stumbling, an awkward walk, or a stiffness of the legs. Early on, there also may be a change in personality, such as becoming more irritable or disinterested and unmotivated. People with this condition have difficulty moving eye muscles, for example, moving the eyes up or down. Memory difficulties usually begin much later, maybe after several years of struggling with balance. There are some medicines that may offer slight improvement to some individuals. More information is available from the Society for Progressive Supranuclear Palsy (see Appendix Directory).

Corticobasal Degeneration (Rebeiz Syndrome)

Corticobasal degeneration gets its name from the changes in the brain cells of the cortex (the cerebrum) and the basal ganglia. It is one of the uncommon forms of progressive dementia

Early on, there may be a decline in skilled hand movements (apraxia). For example, the person may struggle to use a knife and fork. The person may have trouble walking or may stumble or tip off balance while walking. While sitting on a bench or chair without back support, the person may fall backwards (retropulse).

There may be some unusual wave-like hand movements or one hand may get in the way of the other hand. The body or limbs may jerk rapidly. After the changes in muscle movement, there may be changes in thinking. Changes in frontal lobes may show up as personality changes, decreased ability to make decisions, or difficulty performing tasks from start to finish. Memory may also decline.

Suggestions to Help
Suggestions to help patients with Lewy body disease, corticobasal degeneration, progressive supranuclear palsy, and Parkinson's disease include:


Dementia is a mental decline. It is a decline in memory, knowledge, and thinking functions. Dementia diseases fall into four general categories:

1) amnesic disorders, 2) cognitive disorders, 3) attention disorders, and 4) motivation disorders.

Some dementias are treatable while others are less treatable and progressive. Dementias resulting from depression, chemical imbalance, and certain infections often respond to treatment. Whereas all patients with depression need help, patients with suicidal thoughts need immediate attention.

Vascular dementias, such as multi-infarct dementia, Binswanger's disease, Alzheimer's disease, and Lewy body disease, are somewhat treatable. Many programs are available to help families manage the long-term care of relatives diagnosed with dementias.

All people who suspect they have dementia need a medical, neurological psychiatric evaluation. The first reason is to find any conditions that are treatable. Second, in those cases where there is no specific treatment, a routine lifestyle, adapting to changing ability, behavioral strategies, and sometimes medicine may help the patient and family with long-term care. Routine respite (taking a break or time out from regular care duties) is essential for the caregiver to be able to manage well over the course of a progressive, untreatable dementia.


To provide care for a long time, respite for the caregiver is critical. Respite means taking a break or time out on a regular basis. It means relaxing or doing an activity for a few hours (at least once a week) to refresh oneself. Respite is essential for the caregiver to maintain personal health. Respite enables a caregiver to manage the care of someone with untreatable progressive dementia that may last many years.

The Next Chapter
In the next chapter we discuss the importance of visiting a physician for a medical evaluation when there are problems with memory and other thinking functions. Then there are suggestions to guide the person and family in planning for long-term care.

Go back to the index.

Material taken from

"Helping People with Progressive Memory Disorders: A Guide For You And Your Family, 2nd ed." (University of Florida Health Science Center). Used with permission from the authors: K. M. Heilman, MD, L. Doty, PhD, J. T. Stewart, MD, D Bowers, PhD, & L. Gonzalez-Rothi, PhD. (1999).


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College of Public Health and Health Professions, University of Florida