Dementia is not a disease but a result of certain diseases. It is a group of symptoms marked by the gradual loss of mental function. These functions involve thinking, recall, memory loss, reasoning, and planning.
What is going on in the body?
The ability of the brain to work correctly depends on a complex communication system among billions of neurons, or brain cells. Certain parts of the brain are responsible for creating a memory. Others catalogue this memory. Still others retrieve it. This is similar to the workings of a computer.
If an area of the brain in charge of these special functions is damaged, dementia may occur. Damage may be caused by infection, loss of blood supply, chemicals, or a genetic tendency for losing neurons. People normally lose a certain number of brain cells as they age. However, major losses cause progressive and widespread loss of normal brain function.
In normal ageing, memory loss is usually slow. It may involve forgetting names, phone numbers, or the location of a recently placed item. Intelligence and problem-solving skills are not affected. True dementia involves loss of intelligence and problem-solving skills. True dementia cannot be reversed and will become worse over time.
What are the signs and symptoms of the condition?
Symptoms of dementia often go unrecognised. People sometimes assume that dementia is a normal part of ageing. Family members also may not want to face the seriousness of the decline of a loved one. Doctors may misdiagnose the condition. Symptoms can be subtle at first. However, as more brain cells die, more brain functions are lost, and symptoms become more severe. Symptoms of dementia include the following:
What are the causes and risks of the condition?
- memory loss that affects the person's skills. Short-term memory, or memory of recent events, is particularly affected in individuals with dementia.
- difficulty doing familiar activities
- misplacing belongings
- poor or decreased judgment
- language deterioration, with slurred speech and difficulty finding the right words
- disorientation to time and place
- changes in mood, including depression and anxiety
- hallucinations, which include hearing, seeing, feeling, and smelling things that do not exist
- delusions, or believing things that are not true
- personality changes, including agitation, irritability, paranoia, and hostility
- impaired ability to orient the body to the surrounding space
- a loss of interest in activities that were previously pleasurable
- loss of bowel and bladder control
Dementia is always caused by an underlying disease or condition. Brain tissue is damaged, and functioning is diminished. The most common cause of dementia is Alzheimer's disease, a progressive brain disorder causing deterioration in memory and thought processes. Other causes are as follows:
Certain abnormalities of a person's metabolism or hormones may also be responsible for the development of dementia, including the following: In some of these cases, dementia can be reversed by removing the toxic agent or bringing vitamin levels back to normal.
- Huntington disease, a progressive degenerative disease that causes dance-like movements and mental deterioration
- arteriosclerosis, or hardening of the arteries
- multiple sclerosis, a disorder of the sheath that lines the brain and spinal cord
- HIV, the immunodeficiency disorder that leads to AIDS
- Parkinson's disease, a degenerative disorder of part of the nervous system
- Creutzfeld-Jakob disease, a rapidly progressing degenerative disorder of the nervous system causing problems with walking, talking, and the senses
- Pick's disease, a disorder of the brain that causes slowly progressing dementia
- viral or bacterial encephalitis, an inflammation of the brain
- Lewy body disease, a degenerative disease of the nervous system
- normal pressure hydrocephalus, or increased cerebrospinal fluid in the brain
- chronic subdural haematoma, or bleeding between the brain lining and brain tissue
- brain tumour
- Wilson disease, a rare disease causing an accumulation of copper in the liver, brain, kidneys, and corneas
- neurosyphilis, an infection of the nervous system by the syphilis bacteria, which causes weakness and mental deterioration
- progressive supranuclear palsy, also known as Steele-Richardson syndrome, a rare disorder of late middle age that causes widespread neurological problems
What can be done to prevent the condition?
Most cases of dementia are caused by Alzheimer's disease. Although there are no proven methods to prevent Alzheimer's disease, recent research findings provide some options that may slow the onset of the disease or the progression of symptoms. These findings, which need further study, include the following:
Strokes are another major cause of dementia. Preventing or treating high blood pressure, obesity, diabetes, high cholesterol, and alcohol abuse can lower the risk of stroke.
- low doses of aspirin and nonsteroidal anti-inflammatory drugs, or NSAIDs, which may work by making blood cells and vessels less sticky and by improving blood flow
- actively engaging in cognitive activities such as reading, which may increase the nerve connections in the brain and delay the onset of the disease
- taking antioxidants such as vitamin E
- hormone replacement therapy for menopausal women, which may delay the onset of symptoms of Alzheimer's disease. The relationship between the hormone oestrogen and Alzheimer's disease needs further investigation.
- avoiding head injuries. A person should wear a seat belt at all times when riding in a motor vehicle. Sports safety guidelines for children, adolescents, and adults can be helpful in avoiding other head injuries.
How is the condition diagnosed?
Dementia can be diagnosed only if a doctor is made aware of the problem. The family should be able to tell the doctor the range of the person's symptoms over time. The doctor will be interested in how the symptoms progressed and whether they have improved or become worse. Also, the family should report how suddenly or gradually symptoms appeared.
A complete list of all medications the individual is taking will be needed. This includes over-the-counter products, herbal remedies, and prescription medications. Combinations of drugs may impair thinking at times.
To determine if other medical conditions are contributing to the symptoms, tests may be done. Tests may include the following:
Since there is no definitive test for dementia, it is important to rule out other conditions or diseases that may cause the symptoms.
- blood tests, such as a full blood count, or FBC, thyroid function tests, tests for infectious diseases, and tests to determine vitamin levels in the blood
- memory testing
- electroencephalogram, or EEG, which measures brain waves
- electrocardiogram, or ECG, which measures the electrical activity of the heart
- cranial MRI or cranial CT scans, which can be used to view the structures of the brain
- spinal tap, a procedure in which a small amount of fluid is withdrawn from the spinal column to check for infection or bleeding
What are the long-term effects of the condition?
Long-term progressive dementia results in the continued loss of mental abilities. Ultimately, this makes independent living impossible. A person suffering from the condition often requires nursing home care. Falls, trauma, infections, and depression may also result in a need for extensive medical care.
What are the risks to others?
Dementia is not contagious and poses no risk to others. If the dementia is caused by an infection such as AIDS, the infection may be contagious.
What are the treatments for the condition?
The 2 medications currently available for treatment of Alzheimer's disease are donepezil and rivastigmine. These medications are designed to improve memory by increasing the amount of acetylcholine in the body.
Other medications, such as risperidone may also be used to help behavioural problems such as hallucinations, delusions, or agitation. Some individuals with dementia may also need medications for depression, anxiety, or insomnia.
Other treatments include support and education for those caring for people with dementia. Individual and family counselling can be beneficial. Support groups have also been found to assist caregivers. As the disease progresses, many families are unable to provide home care for the person with dementia and placement in a special facility is needed.
What are the side effects of the treatments?
Medications used to treat dementia can damage the liver, so periodic liver function tests are needed. Other side effects may include nausea, diarrhoea, insomnia, vomiting, fatigue, or muscle cramps.
What happens after treatment for the condition?
In most cases, dementia is a degenerative disease without a cure. Treatment is lifelong. Because the course of dementia is unpredictable, individuals with the condition should make plans for end-of-life care while they are still able to participate in the decision-making.
Following are some of the difficult issues that family members may face:
How is the condition monitored?
- promoting independence while making sure the individual is safe
- removing driving privileges
- finding supportive care among family, in an assisted living facility, or in a nursing home
- making business decisions
- determining executors of written wills and making sure that advanced directives are in the individual's patient file at his or her doctor's office
Individuals with dementia will have periodic visits to the doctor for evaluation and treatment. Periodic liver function tests may be ordered if the person is taking one of the medications that can cause liver damage. Any new or worsening symptoms should be reported to the doctor.
Author: Ann Reyes, Ph.D.
Reviewer: HealthAnswers Australia Medical Review Panel
Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia
Last Updated: 1/10/2001
Potential conflict of interest information for reviewers available on request