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What is Alzheimer's Disease? Questions and Answers

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Download the 2021 Alzheimer’s Association Facts and Figures Report (PDF)

Download the 2021 Alzheimer's Association Texas Fact Sheet (PDF)

1. What is Alzheimer's disease?
Alzheimer’s disease is an irreversible brain disease that slowly destroys memory skills, thinking skills and, eventually, the ability to carry out daily activities, leading to the need for full-time care. Dementia is the general term for a group of brain disorders that cause problems with thinking, memory and behavior. Alzheimer’s disease is the most common type. Symptoms vary from person to person, but all people with Alzheimer's disease have problems with memory loss, disorientation and thinking ability. People with Alzheimer's disease may have trouble finding the right words to use, recognizing objects (such as a pencil), recognizing family and friends, and may become frustrated, irritable, and agitated. As the disease gets worse over time, physical problems may include loss of strength and balance, and diminishing bladder and bowel control. As more and more of the brain is affected, areas that control basic life functions, like swallowing and breathing, become irreversibly damaged, resulting eventually in death.

2. What is dementia?
Dementia is a group of symptoms that cause a decline in thinking and memory skills severe enough to interfere with a person's normal daily activities and social relationships. Alzheimer's disease is the most common cause of dementia in older people. The second most common cause of dementia is multi-infarct dementia, which is caused by a series of strokes. Some of the other diseases that cause dementia are: Creutzfeldt-Jakob disease, normal pressure hydrocephalus, Pick's disease, Parkinson's disease, Lewy body disease, and Huntington's disease. Symptoms of dementia may also result from depression, drug interaction, metabolic disorders (such as thyroid problems), head injury, vision or hearing problems, tumors, and infection. It is important to identify the actual cause, as many of these conditions are reversible. Early diagnosis increases the chances of treating these conditions successfully.

3. What is senile dementia?
Senile dementia is an outdated term once used to refer to any form of dementia that occurred in older people.

4. What is Mild Cognitive Impairment?
Mild cognitive impairment (MCI) is a borderline condition between normal, age-related memory loss and early Alzheimer's disease. A person with MCI is characterized as having memory problems beyond that expected for a person's age, yet without other clinical signs of dementia. Individuals with MCI have a higher than normal chance of developing Alzheimer's disease.

5. How many people have Alzheimer's disease?
The Alzheimer's Association estimates that 6.2 million people of all ages have Alzheimer's disease in the United States. In Texas, 400,000 people age 65 and older have Alzheimer's disease.

6. What is the age of most people with Alzheimer's disease? An estimated 6.2 million Americans of all ages are living with Alzheimer’s disease in 2021.

  • More than 1 in 9 people (11.3%) age 65 and older has Alzheimer’s disease.
  • The percentage of people with Alzheimer's dementia increases with age: 5.3% of people age 65 to 74, 13.8% of people age 75 to 84, and 34.6% of people age 85 and older have Alzheimer's dementia.

7. Does Alzheimer's disease occur in younger adults?
Yes - the disease can occur in people in their 30s, 40s, and 50s; however, most people diagnosed with Alzheimer's are older than age 65. 

8. What causes Alzheimer's disease? Researchers believe there is not a single cause of Alzheimer's disease. The disease likely develops from multiple factors, such as genetics, lifestyle and environment. Scientists have identified factors that increase the risk of Alzheimer’s. While some risk factors — age, family history and heredity — can't be changed, emerging evidence suggests there may be other factors we can influence.

9. If a member of my family has Alzheimer's disease, am I at increased risk for developing it?
Two types of Alzheimer's disease exist: familial Alzheimer's disease (FAD), which is an early-onset form of the disease that appears to be inherited, and sporadic Alzheimer's disease, where no obvious inheritance pattern is seen. Approximately 5% of Alzheimer's disease is familial and approximately 95% is sporadic. In familial Alzheimer's disease, several members of the same generation in a family are often affected. Sporadic Alzheimer's disease develops as a result of a variety of factors, which scientists are still attempting to determine. Age is the most important known risk factor for sporadic Alzheimer's disease.

10. Do men or women have a higher risk of developing Alzheimer's disease?
Although Alzheimer's disease strikes both sexes, it is a disease that particularly affects women. More women than men die from the disease - possibly because women generally live longer than men.

11. What is the relationship between aluminum and the development of Alzheimer's disease?
One of the most publicized and controversial hypotheses in the area of Alzheimer's disease research concerns aluminum, which became a suspect in Alzheimer's disease when researchers found traces of this metal in the brains of people with Alzheimer's disease. Many studies since then have failed to provide consistent or conclusive evidence of a role for aluminum in Alzheimer's disease.

12. What are the symptoms of Alzheimer's disease? Alzheimer's is a progressive disease, which means the symptoms get worse over time. When symptoms appear and how they change over time will vary from person to person. Symptoms can change at different rates and in different patterns. The most common first sign of Alzheimer’s disease is gradual loss of short-term memory. Other symptoms may include:

  • Anxiety, suspiciousness, and agitation;
  • Confusion;
  • Difficulties with activities of daily living, such as feeding and bathing;
  • Difficulty recognizing family and friends;
  • Forgetting how to use simple, ordinary things, such as a pencil;
  • Inability to recognize objects;
  • Loss of appetite; weight loss;
  • Loss of bladder and bowel control;
  • Problems finding or speaking the right word;
  • Loss of speech;
  • Repetitive speaking or action;
  • Sleep disturbances;
  • Total dependence on caregiver; and
  • Wandering and pacing.

13. How is Alzheimer's disease diagnosed?
There is no single clinical test that can be used to identify Alzheimer's disease. A comprehensive patient evaluation includes a complete health history, physical examination, neurological and mental status assessments, and other tests, including analysis of blood and urine, electrocardiogram, and an imaging exam, such as CT or MRI. While this type of evaluation may provide a diagnosis of possible or probable Alzheimer's disease with up to 90 percent accuracy, absolute confirmation requires examination of brain tissue at autopsy. For information on diagnosing Alzheimer’s disease, visit the Alzheimer’s Association: Diagnosis Information

(En Español: Diagnostico)

14. How important is a diagnosis of Alzheimer's disease?
Early and careful evaluation and diagnosis is important because many conditions can cause dementia-like symptoms, some of which are treatable or reversible. Potentially reversible conditions include depression, adverse drug reactions, metabolic changes, and nutritional deficiencies. The earlier an accurate diagnosis of Alzheimer's disease is made, the greater the gain in managing symptoms and allowing the person to take part in planning for their future.

15. How long do people with Alzheimer's disease live after developing the disease?
Every case is different, and progression of the disease varies from person to person. On average, from onset of symptoms, people with Alzheimer's disease can live from 8 years (the average) up to 20 years.  

16. How is Alzheimer's disease treated?
No treatment is yet available that can stop Alzheimer's disease. However, the drugs donepezil (Aricept), rivastigmine (Exelon), or galantamine (Reminyl) may help delay the progression of symptoms associated with Alzheimer's disease. Some behavioral symptoms such as sleeplessness, agitation, wandering, anxiety and depression can be reduced by helping people with Alzheimer's disease and their family caregivers learn ways to identify triggers for these behaviors and methods to help manage them. Some medicines may help with behavioral symptoms if clinically necessary. For information on the treatment of Alzheimer’s disease, visit the Alzheimer’s Association: Treatment Information

(En Español: Tratamientos)

Sources of information:

  • Agency for Healthcare Research and Quality, Clinical Practice Guidelines, Number 19
  • Alzheimer's Association
  • Mayo Clinic Alzheimer's Disease Research Center
  • National Institute on Aging/National Library of Medicine
Last updated April 13, 2021