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About Alzheimer's Disease
Alzheimer's disease: Alzheimer’s disease is a neurodegenerative disease that progressively attacks the brain's nerve cells, or neurons, resulting in loss of memory, thinking and language skills and behavioral changes.
Fact: It is estimated that 2.4 million to 4.5 million people in the United States currently have Alzheimer’s disease.
Alzheimer’s Disease & Dementia
Alzheimer's disease is the most common cause of dementia, or loss of intellectual function, among people aged 65 and older. It represents about 60 percent of all cases of dementia. It is not a normal part of aging.
While some forms of dementia are reversible, Alzheimer's disease is one of the types of dementia that is irreversible.
Alzheimer’s disease is a progressive disease that attacks the brain’s nerve cells, which produce the brain chemical, or neurotransmitter, acetylcholine. The cells break connections with other nerve cells and ultimately die. For example, short-term memory fails when Alzheimer's disease first destroys nerve cells in the hippocampus, and language skills and judgment decline when neurons die in the cerebral cortex.
Two types of abnormal lesions clog the brains of individuals with Alzheimer's disease: Beta-amyloid plaques—sticky clumps of protein fragments and cellular material that form outside and around neurons; and neurofibrillary tangles—insoluble twisted fibers composed largely of the protein tau that build up inside nerve cells. Although these structures are hallmarks of the disease, scientists are unclear whether they cause it or a byproduct of it.
Origin of the term Alzheimer's disease dates back to 1906 when Dr. Alois Alzheimer, a German physician, presented a case history before a medical meeting of a 51-year-old woman who suffered from a rare brain disorder. A brain autopsy identified the plaques and tangles that today characterize Alzheimer's disease.
There are two types of the disease: sporadic Alzheimer's disease, or late-onset, and familial Alzheimer's disease (FAD), or young-onset. Unlike sporadic Alzheimer's disease, FAD follows an obvious inheritance pattern. This rare form of Alzheimer's disease usually occurs between the ages of 30 and 60.
Causes of Alzheimer’s Disease
The causes of Alzheimer's disease are still unknown.
Current research indicates a number of risk factors that may cause Alzheimer's disease, including age, genetics, oxidative damage to neurons from the overproduction of toxic free radicals, serious head injuries, brain inflammation, diabetes and other illnesses, and environmental factors.
Age is the most important known risk factor for Alzheimer's disease.
Warning Signs of Alzheimer’s Disease
Although every case of Alzheimer's disease is different, experts have identified common warning signs of the brain disease. Remember, Alzheimer's disease is not a normal part of aging, and it is important to look for signs that might indicate Alzheimer's disease versus basic forgetfulness.
With Alzheimer's disease, the symptoms gradually increase and become more persistent.
If someone is exhibiting symptoms, the person should check out his or her concerns with a healthcare professional. Awareness of these warning signs is not a substitute for a structured screening or consultation with a primary care provider.
Typical warning signs include:
- Memory loss, especially of recent events, names, placement of objects, and other new information
- Confusion about time and place
- Struggling to complete familiar actions such as brushing teeth or getting dressed
- Trouble finding the appropriate words, completing sentences and following directions and conversations
- Poor judgment when making decisions
- Changes in mood and personality such as increased suspicion, rapid and persistent mood swings, withdrawal, and disinterest in usual activities
- Difficulty with complex mental assignments such as balancing a checkbook or other tasks involving numbers
Diagnosis of Alzheimer’s Disease
Proper diagnosis of Alzheimer's disease is critical since there are dozens of other causes of dementia that could exhibit the same symptoms.
Clinicians can now diagnose Alzheimer's disease with up to 90 percent accuracy. But it can only be confirmed by an autopsy, during which pathologists look for the disease's characteristic plaques and tangles in brain tissue.
Clinicians use the following tools to diagnose "probable" Alzheimer's disease:
- A complete medical history
- Lab tests
- Physical exam
- Brain scans
- Neuropsychological tests, including memory screening tools, that gauge memory, attention, language skills and problem-solving abilities
The sooner an accurate diagnosis of "probable" Alzheimer's disease is made, the easier it is to manage symptoms and plan for the future.
Symptoms of Alzheimer’s Disease
Cognitive Symptoms of Alzheimer’s Disease
Symptoms of Alzheimer’s disease vary from person to person. They are divided into these categories: cognitive, or intellectual, symptoms, psychiatric symptoms and functional symptoms.
Differentiating between cognitive and psychiatric symptoms is important so that behavioral problems that are caused by loss of cognitive functioning are not treated with antipsychotic or antianxiety medications.
Cognitive, or intellectual, symptoms (the 4 A’s of Alzheimer’s disease) are:
- Amnesia—loss of memory or the inability to remember facts or events. We have two types of memories: short-term (recent, new) and long-term (remote, old) memories. Short-term memory is programmed in a part of the brain called the temporal lobe, while long-term memory is stored throughout extensive nerve cell networks in the temporal and parietal lobes. In Alzheimer's disease, short-term memory storage is damaged first.
- Aphasia—the inability to communicate effectively. The loss of ability to speak and write is called expressive aphasia. An individual may forget words and have increasing difficulty with communication. With receptive aphasia, an individual may be unable to understand spoken or written words or may read and not understand a word of what is read. Sometimes an individual pretends to understand and even nods in agreement; this is to cover up aphasia. Although individuals may not understand words and grammar, they may still understand non-verbal behavior, such as smiling.
- Apraxia—the inability to do pre-programmed motor tasks or to perform activities of daily living such as brushing teeth and dressing. An individual may forget all motor skills learned during development. Sophisticated motor skills that require extensive learning, such as job-related skills, are the first functions that become impaired. More instinctive functions like chewing, swallowing and walking are lost in the last stages of the disease.
- Agnosia—the inability to correctly interpret signals from a person’s five senses. Individuals with Alzheimer's disease may not recognize familiar people and objects. A common yet often unrecognized agnosia is the inability to appropriately perceive internal information such as a full bladder or chest pain.
Psychiatric Symptoms of Alzheimer’s Disease
In addition to cognitive symptoms that develop in individuals with Alzheimer’s disease, psychiatric symptoms are common.
Differentiating them is important so that behavioral problems that are caused by loss of cognitive functioning are not treated with anti-psychotic or anti-anxiety medications.
Major psychiatric symptoms of Alzheimer’s disease may include:
- Personality changes—personality changes can become evident in the early stages of Alzheimer's disease. Signs include irritability, apathy, withdrawal and isolation.
- Depression—individuals may show symptoms of depression at any stage of Alzheimer’s disease. Depression is treatable, even in the latter stages of Alzheimer's disease.
- Psychotic symptoms—psychotic symptoms include hallucinations and delusions, which usually occur in the middle stage of Alzheimer’s disease. Hallucinations typically are auditory and/or visual, and sensory impairments, such as hearing loss or poor eyesight, tend to increase hallucinations in the elderly. Hallucinations and delusions can be very upsetting to the person with the disease. Common reactions are feelings of fear, anxiety and paranoia, as well as agitation, aggression and verbal outbursts.
Individuals with psychiatric symptoms tend to exhibit more behavioral problems than those without these symptoms.
Treatment may include carefully-supervised use of medications and behavioral interventions. Use of antipsychotic drugs for dementia has been controversial, and the U.S. Food and Drug Administration in recent years has required drug labels to carry so-called “black box” warnings regarding them. Current research shows that antipsychotic drugs are associated with increased mortality rates in individuals with dementia.
Functional Symptoms of Alzheimer’s Disease
Functional impairments include inability to perform common activities of daily living (ADLs)—the basic tasks involved in every day life.
Activities of daily living include:
- Bathing
- Dressing
- Toileting
- Eating
- Personal hygiene (grooming, oral care)
- Transferring
Treatment of Alzheimer’s Disease
Currently, there is no cure for Alzheimer's disease.
The U.S. Food and Drug Administration (FDA) has approved various medications that may help slow the progression of symptoms.
One class of medications is known as cholinesterase inhibitors, which inhibit the enzyme that breaks down the brain chemical known as acetylcholine. These are:
- Donepezil hydrochloride (brand name: Aricept), approved for all stages of Alzheimer's disease;
- Rivastigmine (brand name: Exelon), approved in pill and patch form for mild to moderate Alzheimer's disease;
- Galantamine hydrobromide (brand name: Razadyne), approved for mild to moderate Alzheimer's disease
The second class of medications is memantine HCI (brand name: Namenda), approved for the treatment of moderate to severe Alzheimer's disease. Unlike the other medications approved for Alzheimer’s disease, this drug targets a brain chemical known as glutamate.
Clinicians may prescribe one or a combination of these drugs.
Most researchers agree that most available medications are best given earlier in the disease when the individual has mild symptoms.
Researchers are continually testing the effectiveness of various drug therapies that will control symptoms; slow, reduce and/or reverse mental and behavioral symptoms; and prevent or halt the disease. Private and government-sponsored clinical trials are occurring throughout the world.
Currently, research supports behavioral management interventions for many individuals with dementia, as well as education and counseling for caregivers of older adults.
Life Expectancy with Alzheimer’s Disease
Alzheimer's disease stretches from two to 20 years, and individuals live on average for eight to 10 years from diagnosis.
Individuals with Alzheimer's disease are likely to develop co-existing illnesses and most commonly die from pneumonia.
Alzheimer's disease is the sixth leading cause of death in the United States.