Alzheimer's and Dementia Overview

Alzheimer's disease (AD) is a progressive, fatal brain disease. According to the 2011 Alzheimer's Disease Facts and Figures report from the Alzheimer's Association, 5.4 million people in the U.S. have Alzheimer's disease. With the aging of the population, and without successful treatment, there will be 16 million Americans and 106 million people worldwide with AD by 2050.

Increasing age is the primary risk factor for developing AD, but severe memory loss is not a normal part of aging. AD is the most common form of dementia among older people.

What are the symptoms of Alzheimer's disease?

Alzheimer's disease affects the areas of the brain that are essential for thinking, memory and behavior. Symptoms of the disease include:

• Memory loss

• Tendency to misplace things

• Trouble performing familiar tasks

• Changes in personality and behavior

• Poor judgment

• Problems with language

• Impaired visuospatial skills (trouble understanding spatial relationships of objects)

What causes Alzheimer's disease?

Alzheimer's disease is caused by the abnormal build-up of proteins in the brain. The build-up of the proteins - amyloid protein and tau protein - leads to cell death.

What are some risk factors for Alzheimer's disease?

Risk factors for AD include:

• Age

• Family history

• Certain genes

• High blood pressure

• High cholesterol

Protective factors include:

• Mental activity

• Education

• Physical activity

• The Mediterranean diet or another healthy diet that includes antioxidants

How common is Alzheimer's disease?

One in 10 people older than 65 and nearly half of people older than 85 have Alzheimer's disease. AD can affect people in their 40s. The percentage of people who have AD rises every decade beyond the age of 60.

While AD is the most common cause of dementia (accounting for 62 percent to 70 percent of cases), there are other causes. These include:

• Frontotemporal dementia

• Parkinson's or Huntington's disease

• Dementia with Lewy bodies

• Vascular dementia

• Kidney or liver disease

• Vitamin B12 deficiency

• Thyroid problems

• Bad reaction to medication

• Drug or alcohol abuse

• Psychiatric disorders

How is Alzheimer's disease diagnosed?

These tests are used to diagnose AD or to rule out other medical conditions:

• Mental status testing - measures how great a decline in mental functioning (orientation, memory, language skills) exists

• Neuropsychological testing - assesses mood, thinking and personality

• Magnetic resonance (MR) scan of the brain

• Blood tests - blood counts, vitamin levels, liver and kidney function, mineral balance and thyroid gland function tests

• Positron emission tomography (PET) metabolic or amyloid scanning in some patients

Brain imaging helps to diagnose and understand Alzheimer's disease. For instance:

• Magnetic resonance imaging (MRI) can show brain shrinkage (atrophy).

• FDG PET scans can show lower brain metabolism. (FDG is the tracer molecule used to show how well your tissues and organs are working.)

• Amyloid PET scans show higher levels of amyloid protein in the brain.

How does Alzheimer's disease progress (get worse)?

The progression of Alzheimer's disease can be broken down into stages:

• No symptoms with Alzheimer's present in the brain

• Mild symptoms, with Alzheimer's changes in the brain. This is called prodromal AD and is the phase before Alzheimer's dementia.

• Alzheimer's dementia

• Alzheimer's dementia (mild), in which daily function is beginning to be impaired

• Alzheimer's dementia (moderate), in which thinking and memory skills are getting worse. Changes in behavior are common in this stage.

• Alzheimer's dementia (severe) is linked to very serious impairment. People in this stage often have trouble walking and experience incontinence.

How do changes in the brain happen because of Alzheimer's disease?

Key changes in the brain in AD include:

• Brain shrinkage. This is called atrophy.

• The loss of nerve cells

• The presence of neuritic amyloid plaques (protein deposits that collect between nerve cells, or neurons)

• The presence of neurofibrillary tangles (twisted fibers in the nerve cells, thought to contribute to cell breakdown)

• Brain inflammation (swelling)

Which medicines are used to treat Alzheimer's disease?

The medicines used to treat AD include the cholinesterase inhibitors (donepezil, rivastigmine and galantamine), and the NMDA antagonist memantine.

Cholinesterase Inhibitors

These drugs work by slowing the breakdown of acetylcholine, the chemical that helps nerves communicate. The medications do not cure AD or stop the progression of the disease. They do help relieve some memory problems and reduce some behavioral symptoms. The most common side effects of these drugs are nausea, vomiting and diarrhea. Some people may have loss of appetite, insomnia or bad dreams.

Memantine

Memantine blocks a brain receptor that is thought to add to the cellular harm associated with AD. Side effects include drowsiness, headache and dizziness.

Patients can help develop new and better treatments for AD by participating in clinical trials. Cleveland Clinic Lou Ruvo Center for Brain Health is conducting several trials of promising drugs.

What is the outlook for people with Alzheimer's disease?

Alzheimer's disease gets worse over time and is ultimately fatal. The course of the disease varies from person to person.

What research is being done on Alzheimer's disease?

Researchers continue to study medications to treat AD. Carefully designed and conducted studies are needed to give a clear picture of safety and effectiveness before any approval might be considered.

Alzheimer's Disease Treatment

Is there a cure for Alzheimer's disease?

At this time, there is no cure for Alzheimer's disease and no proven way of slowing its progression. However, there are a number of medicines available that can help improve the intellectual functioning of people with Alzheimer's or delay progression. These medicines may enable people to carry out their daily activities for a longer period of time and might prolong the time that patients can be managed at home.

There are also medicines available to help manage some of the most troubling symptoms of Alzheimer's disease, including depression, behavioral problems, and sleeplessness.

In addition to medications, exercise, good nutrition, activities, and social interaction are important. A calm, structured environment also might help the person with Alzheimer's disease to continue functioning as long as possible.

How is Alzheimer's disease treated?

Your doctor will determine the best treatment for you based on various factors, including:

• Your age, overall health, and medical history

• Your tolerance for specific medicines, procedures, and therapies

• Expectations for the course of the disease

• Your opinion or preference

What are the medicines used to treat Alzheimer's disease?

• Aricept® - Aricept is the most widely used drug for Alzheimer's disease. Aricept works by slowing down the breakdown of acetylcholine, a chemical that helps nerve cells in the brain communicate with each other. Aricept doesn't cure Alzheimer's or keep it from getting worse, but it can help relieve some of the cognitive difficulties. Side effects are usually mild and include diarrhea, vomiting, nausea, fatigue, insomnia, and weight loss.

• Exelon® and Razadyne® - These drugs also work by inhibiting the breakdown of acetylcholine. They have side effects similar to Aricept. Exelon is available as a patch that may be a convenient way to administer the medication.

• Namenda® - Namenda is prescribed to treat moderate-to-severe Alzheimer's. Namenda works by a different mechanism than the other drugs. It is thought to play a protective role in the brain by regulating a chemical messenger called glutamate. Namenda might have increased benefit when used with Aricept, Exelon, or Razadyne. Side effects of Namenda include tiredness, dizziness, confusion, and headache.

Exelon and Razadyne seem to help only those with mild or moderate symptoms of Alzheimer's disease. Namenda is prescribed for patients who have moderate-to-severe Alzheimer’s. Aricept is approved for mild, moderate, and severe Alzheimer’s disease.

It is important to know that new research findings are giving reason for hope, and several drugs and vaccines are being studied in clinical trials to determine if they can slow the progression of the disease, or improve memory or other symptoms for a period of time. Patients and caregivers can help find better treatments for Alzheimer’s disease by participating in clinical trials.

References

Cleveland Clinic Lou Ruvo Center for Brain Health.
http://my.clevelandclinic.org

American Health Assistance Foundation. Alzheimer's Disease Research. Accessed 4/21/2011.
http://www.ahaf.org/alzheimers/about/understanding/facts.html

Alzheimer's Association. Accessed 4/21/2011.
http://www.alz.org/index.asp

National Institute on Aging. Alzheimer's Disease Education and Referral Center. Accessed 4/21/2011.
http://www.nia.nih.gov/Alzheimers/

Alzheimer’s Association. Treatment: Medications for Memory Loss. Accessed 9/30/2014.

National Institute on Aging. Alzheimer’s Disease Education and Referral Center. Alzheimer’s Information: Treatment. Accessed 9/30/2014.