Dementia is a loss of brain function that occurs with certain diseases. Alzheimer’s disease (AD), is one form of dementia that gradually gets worse over time. It affects memory, thinking, and behavior. Memory impairment, as well as problems with language, decision-making ability, judgment, and personality, are necessary features for the diagnosis.
Alzheimer’s Disease Cause, Incidence, and Risk Factors
Age and family history are risk factors for AD.
- As you get older, your risk of developing AD goes up. However, developing Alzheimer’s disease is not a part of normal aging.
- Having a close blood relative, such as a brother, sister, or parent who developed AD increases your risk.
- Having a certain combination of genes for proteins that appear to be abnormal in Alzheimer’s disease also increases your risk.
Other risk factors that are not as well proven include:
- Long standing high blood pressure
- History of head trauma
- Female gender
There are two types of AD — early onset and late onset.
- In early onset AD, symptoms first appear before age 60. Early onset AD is much less common than late onset. However, it tends to progress rapidly. Early onset disease can run in families. Several genes have been identified.
- Late onset AD, the most common form of the disease, develops in people aged 60 and older. Late onset AD may run in some families, but the role of genes is less clear.
The cause of AD is not entirely known, but is thought to include both genetic and environmental factors. A diagnosis of AD is made when certain symptoms are present, and by making sure other causes of dementia are not present.
The only way to know for certain that someone has AD is to examine a sample of their brain tissue after death.
The following changes are more common in the brain tissue of people with AD:
- “Neurofibrillary tangles” (twisted fragments of protein within nerve cells that clog up the cell)
- “Neuritic plaques” (abnormal clusters of dead and dying nerve cells, other brain cells, and protein)
- “Senile plaques” (areas where products of dying nerve cells have accumulated around protein).
When nerve cells (neurons) are destroyed, there is a decrease in the chemicals that help nerve cells send messages to one another (called neurotransmitters). As a result, areas of the brain that normally work together become disconnected.
The buildup of aluminum, lead, mercury, and other substances in the brain is no longer believed to be a cause of AD.
Alzheimer’s Disease Symptoms
The symptoms progress with Alzheimer’s Disease stages. Dementia symptoms include difficulty with many areas of mental function, including:
- Emotional behavior or personality
- Cognitive skills (such as calculation, abstract thinking, or judgment)
Dementia usually first appears as forgetfulness.
Mild cognitive impairment (MCI) is the stage between normal forgetfulness due to aging, and the development of AD. People with MCI have mild problems with thinking and memory that do not interfere with everyday activities. They are often aware of the forgetfulness.
Not everyone with MCI develops AD.
Symptoms of MCI include:
- Forgetting recent events or conversations
- Difficulty performing more than one task at a time
- Difficulty solving problems
- Taking longer to perform more difficult activities
The early symptoms of AD can include:
- Language problems, such as trouble finding the name of familiar objects
- Misplacing items
- Getting lost on familiar routes
- Personality changes and loss of social skills
- Losing interest in things previously enjoyed, flat mood
- Difficulty performing tasks that take some thought, but used to come easily, such as balancing a checkbook, playing complex games (such as bridge), and learning new information or routines
As the AD becomes worse, symptoms are more obvious and interfere with your ability to take care of yourself.
Symptoms can include:
- Forgetting details about current events
- Forgetting events in your own life history, losing awareness of who you are
- Change in sleep patterns, often waking up at night
- Difficulty reading or writing
- Poor judgment and loss of ability to recognize danger
- Using the wrong word, mispronouncing words, speaking in confusing sentences
- Withdrawing from social contact
- Having hallucinations, arguments, striking out, and violent behavior
- Having delusions, depression, agitation
- Difficulty doing basic tasks, such as preparing meals, choosing proper clothing, and driving
People with severe AD can no longer:
- Understand language
- Recognize family members
- Perform basic activities of daily living, such as eating, dressing, and bathing
Other symptoms that may occur with AD: