UNDERSTANDING ALZHEIMER DISEASE
Understand What Memory Changes May Mean—and What Comes Next
Understanding the difference between memory changes, mild cognitive impairment, Alzheimer’s disease, and dementia can help clarify what is happening and what options may be available.
When Should Memory or Cognitive Changes Be Evaluated?
Occasional forgetfulness can be a normal part of aging. More persistent changes in memory or thinking—especially changes that worsen over time or begin to affect everyday life—deserve medical evaluation. Because people may not always recognize changes in themselves; observations from a spouse, family member, or someone else who knows them well can be important.
Changes worth discussing with a physician may include:
These Changes Do Not Necessarily Mean Alzheimer’s Disease
What Is Mild Cognitive Impairment?
Mild cognitive impairment, often called MCI, means that a person has changes in memory or other thinking abilities that are greater than expected with normal aging, but not severe enough to substantially interfere with independence in everyday life.
A person with MCI may have more difficulty remembering recent information, finding words, staying organized, or managing complex tasks. These changes can be noticeable to the person or to family members, yet the person can generally continue to handle most daily activities independently.
MCI is not the same as dementia
A person can therefore have Alzheimer’s disease without yet having dementia.
What is Dementia?
Dementia is a general term for cognitive decline that becomes severe enough to interfere with independence and everyday activities. It can affect memory, language, judgment, problem-solving, attention, or other aspects of thinking.
Alzheimer’s disease is the most common cause of dementia, but it is not the only type of dementia
What Is Alzheimer’s Disease?
Alzheimer’s disease is a progressive brain disease that affects memory, thinking, and, over time, the ability to function independently. It is the most common cause of dementia.
The most common early symptom is difficulty remembering recent information and events. A person may forget a recent conversation, repeat the same question or story, or have trouble remembering information they learned only a short time earlier. Memories from many years ago may remain much clearer at first. As the disease progresses, other abilities can also be affected, including finding words, planning and organizing, solving problems, making decisions, and finding the way in familiar places.
Alzheimer’s disease is associated with characteristic changes in the brain, including the buildup of amyloid plaques between nerve cells and abnormal tau within nerve cells. These biological changes can begin many years before noticeable symptoms appear.
Alzheimer’s can begin while a person is still largely independent, a stage often called mild cognitive impairment due to Alzheimer’s disease. As the disease advances and cognitive changes begin to interfere with independent daily life, it is described as dementia due to Alzheimer’s disease.
How These Terms Fit Together
The terms mild cognitive impairment (MCI), dementia, and Alzheimer’s disease describe different things—but they can also overlap.
Mild cognitive impairment and dementia describe the degree to which thinking/memory changes affect a person’s daily life. With mild cognitive impairment, changes in memory or thinking are noticeable, but the person can still manage everyday activities independently. With dementia, those changes begin to interfere with independent daily life.
Alzheimer’s disease describes an underlying brain disease that can cause either mild cognitive impairment or dementia. A person may therefore have mild cognitive impairment due to Alzheimer’s disease before the condition progresses to dementia due to Alzheimer’s disease.
This is why the terms should not be used interchangeably. Mild cognitive impairment does not always mean Alzheimer’s disease, and dementia can have causes other than Alzheimer’s disease.
In other words, when Alzheimer’s disease is the cause, cognitive impairment may progress through these stages:
Mild cognitive impairment → Mild dementia → Moderate dementia → Severe dementia
Understanding both the cause of cognitive changes and the stage of impairment helps determine the most appropriate next steps, including whether anti-amyloid treatment may be an option.
What Comes Next?
If you or someone close to you has noticed persistent changes in memory or thinking, the next step is a careful evaluation to determine what may be causing them.