Already have an account?
Get back to the

Alzheimer’s Looks Different in Everyone — Understand the Stages So You Know What To Look Out For

Knowledge is power.


Sometimes it starts with innocuous questions that seem quite normal. “Have you seen my car keys?” “What was that movie we saw last week?” Over time, however, the signs get worse: driving through stop signs; neglecting personal hygiene; losing weight unintentionally; having hallucinations; forgetting how to unlock the front door. Alzheimer’s is a progressive disease that doctors and researchers often categorize using three broad classifications: mild, moderate, and severe. Some clinicians use a more expansive system, but the generic terms still apply. Despite how one might score it, when the doctor finally utters a diagnosis of Alzheimer’s, the pronouncement can blindside patients and loved ones. Understanding the stages of Alzheimer’s is a good place to start.

Although AD affects each patient differently, doctors can make several generalizations. While pulling apart the disease and placing it into neat little categories is somewhat arbitrary, it is a necessary exercise that can help patients and caregivers know what to expect and when.


Alzheimer’s takes root before anyone suspects anything, a stage called pre-clinical Alzheimer’s disease. There are no changes in behavior. Symptoms are nonexistent. Preclinical Alzheimer’s can last for years, or even decades, as the brain undergoes serious yet indistinguishable changes. While the person is outwardly healthy, amyloid plaque, the tiny fragments of protein at the heart of the disease, are already present.

Moreover, the brain’s so-called default mode network (DMN) begins to weaken. The network connects different regions of the brain, allowing them to work as a team, especially when a person is awake and not involved in any strenuous mental activity. Scientists say that the connection hubs in the DMN — areas in the cortex that reach out and touch other regions to coordinate how the brain functions — are especially vulnerable to amyloid plaque.

In recent years, researchers have developed new imaging technologies that allow doctors to peer into the brain during the preclinical stage. Also, doctors have identified several Alzheimer’s biomarkers — biological indicators that are obvious signs that a person has an increased likelihood of getting the disease. In fact, researchers are trying to pinpoint AD biomarkers in various groups, including those with Down syndrome, whose brains start to change in their 30s, often leading to AD and other forms of dementia when they get older.

“Hopefully, one day, we will also use these biomarkers to determine the effectiveness of promising treatments,” says Laurie Ryan, chief of the Dementias of Aging Branch in the National Institute on Aging’s division of neuroscience.

Mild Cognitive Impairment

Also known as MCI, mild cognitive impairment is the first sign that something might be amiss. Doctors use the term when the first symptoms become noticeable but do not interfere with a person’s ability to function. Those with MCI will start to notice slight changes in how they think and how they behave. They’ll start to forget things, such as conversations they just had. Even if they were to go to the doctor for an evaluation, they would not meet the criteria for AD; instead, they most likely would be monitored for any further decline in cognitive ability.

That’s because diagnosing AD at this stage is extremely dicey. For one thing, as we age, our brains, organs, and entire bodies go through normal changes. We’re not meant to live forever, and the older we get, the more likely our cognitive abilities will start to slide. We have slower reaction times and some trouble with short-term memory. We’ll easily forget important dates or appointments, and our ability to comprehend what another person is telling us worsens, especially if our hearing starts to wane.

Distinguishing what is normal cognitive behavior and what is pathological is extremely difficult. But while a definitive diagnosis of AD can be hard to make, new techniques and tools are giving doctors ammunition to better assess the health of a patient. Not everyone with MCI has Alzheimer’s, nor will everyone with MCI become afflicted with the disease. In fact, doctors use the same techniques to figure out whether MCI is related to Alzheimer’s or something else, such as age-associated memory impairment.

Mild Dementia Due to Alzheimer’s

Mild dementia is the next stage in the progression and the point at which doctors can make a diagnosis with some degree of certainty. Keep in mind, there is no one test that definitely tells the doctor if a patient has AD. Doctors must use a variety of cognitive and laboratory tests to make a “differential diagnosis,” which rules out other maladies. The only way to get a definitive diagnosis is to autopsy the brain after death.

People with mild dementia have a hard time remembering information that they have just learned. They’ll repeatedly ask the same questions, and their judgment and problem-solving capabilities decline. Simple tasks, such as balancing a checkbook or dialing a phone number, prove problematic. Familiar places are suddenly unrecognizable. Patients will forget the names of people and objects or the right word in a sentence. They might be less motivated to socialize or pursue their formerly favorite hobbies.

Moderate Dementia Due to Alzheimer’s

By this stage, the problems become more acute. Confusion grips the mind. Patients will show signs of poor judgment. They’ll lose track of what day of the week it is or the season. They won’t remember where they are. A person might mistake one family member for another. People transitioning into this stage will often wander, trying to find a familiar place.

Those with moderate Alzheimer’s often need help with daily activities, such as choosing appropriate clothing and going to the bathroom. A patient’s personality will also show further and more severe signs of change. Patients may become suspicious, believing a family member, friend, or caregiver is stealing from them. Others may see or hear things that aren’t really there.

One tool at the doctor’s disposal during this stage is the Functional Activities Questionnaire. This is a short series of questions that focus on a variety of tasks, such as writing checks and paying bills, shopping alone for clothes or groceries, and preparing a balanced meal.

Severe Dementia Due to Alzheimer’s Disease

The final stage of AD is the most difficult for patients and those in their inner circle. People who reach this stage of Alzheimer’s will generally lose their ability to communicate coherently. In addition, patients will not be able to take care of their personal needs on their own. They will probably have trouble walking. As the brain degenerates, it makes the body more vulnerable to infections. Patients can lose control of their body’s functions. For example, swallowing ultimately becomes difficult, putting a person at risk of inhaling bits of food that can cause pulmonary aspiration and pneumonia. A person with AD can easily become dehydrated or malnourished, causing another set of ailments. Although AD shortens a person’s life, it is not the direct cause of death. Instead, people die from complications caused by the disease.

In general, it will take five to 10 years from when the first symptoms of AD appear to the time a person dies, although some people have lived much longer. Women, studies have shown, seem to live longer than men. Survival time also depends on how early the diagnosis is made and the rate of cognitive decline. Studies show that those who decline quickly will die eight times faster than those who fail at a slower rate.

Alzheimer’s Myths and Facts

It can often be hard to keep track of what is legitimate medical advice and facts, and just plain nonsense. Because an Alzheimer’s diagnosis is so jarring, it’s difficult for someone to take a minute to assess if the information they’re being told or reading about is actually true. Allow us to debunk some common myths and misconceptions.

Myth #1

False: Occasional memory loss is a sign of Alzheimer’s.

True: As people age, it is normal to have occasional memory loss. What distinguishes Alzheimer’s is significant memory loss.

Myth #2

False: Alzheimer’s disease is not fatal.

True: No one survives Alzheimer’s.

Myth #3

False: Only elderly people get Alzheimer’s.

True: AD can affect people younger than 65.

Myth #4

False: Drinking out of aluminum cans or cooking in aluminum pots and pans can cause Alzheimer’s.

True: Studies have failed to confirm suspicions about aluminum, which first gained traction more than 40 years ago.

Myth #5

False: Using the artificial sweetener aspartame can lead to memory loss.

True: The Food and Drug Administration, which regulates artificial sweeteners that contain aspartame, has found no scientific evidence that memory loss is a side effect of the ingredient.

A version of this article appeared in our partner magazine Alzheimer’s: New Hope for a Cure in 2020.

Use left and right arrow keys to navigate between menu items. Use right arrow key to move into submenus. Use escape to exit the menu. Use up and down arrow keys to explore. Use left arrow key to move back to the parent list.