Stages of Alzheimer’s Disease

Find an Alzheimer’s Specialist Near You

Houston Methodist’s team of neurologists understands the unique needs and challenges patients and their families face at every stage of Alzheimer’s disease, from prediagnosis through late stage.

Alzheimer’s disease requires extensive and accurate medical attention. Our distinguished doctors have specialized training in memory loss and geriatrics to help determine the cause, develop a comprehensive treatment plan and connect you with an ongoing support system.

Researchers at the Nantz National Alzheimer Center continue to make key scientific discoveries aimed at finding new and more effective ways to slow the progression of the disease or even stop it in its tracks. Currently there is no cure for Alzheimer’s disease — but there is hope. Our team of neurologists is here to help you understand what to expect and to guide you through the various stages of dementia as the disease progresses.

Causes of Alzheimer's Disease

The exact cause of Alzheimer's disease is still unknown. Researchers believe Alzheimer’s disease may result from a combination of genetics, environment and lifestyle leading to damage to the cells of the brain. 


Risk factors include:


  • Age – Alzheimer's typically occurs in people over the age of 65, though it can occur at an earlier age. More research is needed to study the effects of aging on cognitive decline in the brain and its relationship to Alzheimer’s disease.
  • Genetics – Researchers have identified several genes that may play a role in the development of Alzheimer’s disease. One is identified as apolipoprotein E (APOE4), although genetic testing for APOE4 will not predict whether a person will develop Alzheimer’s disease.
  • Variants – Everyone has the normal (also called wild type) APOE4 gene, but some people inherit one of many variants (also called alleles or mutations) of APOE4. Having an unusual form of APOE4 does not mean you will get Alzheimer’s disease and having normal APOE does not guarantee that you will not.
  • Vascular and metabolic disorders – Current research shows a link between cognitive decline and disorders such as heart disease, hypertension, stroke, diabetes and obesity. More research is needed to better understand these relationships and to determine whether changing these risk factors can affect the development or progression of Alzheimer’s disease. 

Signs and Symptoms Before Diagnosis

Subtle behavior changes, such as forgetfulness or mood swings, may occur in a person with Alzheimer's disease, even before a diagnosis. If you are concerned you or a loved one may be showing signs of dementia, the earlier you seek medical attention, the better.


If an Alzheimer’s diagnosis is confirmed, our physicians can begin treatment that might slow the progression of the disease and provide the caregiver with much-needed help and support. Swift care is needed to maximize the ability to function and respond to treatment. 

Symptoms of Mild Cognitive Impairment (MCI)

This is the stage between the normal cognitive decline of aging and serious decline of dementia. During this stage, issues relating to memory, language and judgment are more severe than normal age-related changes. However, they are not severe enough to restrict regular work or activities of daily living.


There is still no diagnosis of early stage or mild Alzheimer’s disease. But there is an increased risk of developing Alzheimer’s disease or other types of dementia. 

Stages of Alzheimer’s Disease

Early Alzheimer’s Disease

In the early or mild stage of Alzheimer's disease, patients experience problems with memory and thinking.  


Additional cognitive issues may develop, such as: 


  • Getting lost
  • Misplacing important items in unusual places
  • Having trouble handling money — balancing a checkbook or making change
  • Repeating questions without realizing it
  • Being unable to follow a recipe
  • Needing more time to complete normal daily tasks


People with mild Alzheimer’s disease sometimes stop doing things that they have always enjoyed, such as playing cards, volunteering or leaving the house alone. They might know something is wrong and not want others to see it. Or, Alzheimer's-related brain changes may alter their mood and personality.

Moderate Alzheimer's Disease

Patients with middle-stage or moderate Alzheimer's disease typically exhibit changes in behavior and increased memory problems. They often need continuous attention. Environmental factors or disease progression can cause these changes.


In this stage, damage may spread to areas of the brain that control language, reasoning, sensory processing and conscious thought. Patients often struggle to recognize family and friends, or to remember their address, phone number, what day it is or where they are. They may wander, possibly looking for a place that seems like home. 


Performing daily activities, such as getting dressed, becomes increasingly difficult. Changes in behavior late in the day (known as sundowning) can cause patients to become more suspicious, restless or agitated, especially in the evening hours.


Most common Alzheimer’s-related behaviors at this stage:


  • Arguing about bathing or taking medications
  • Changing sleep patterns
  • Making up stories to fill in gaps of memory
  • Telling the same story over and over
  • Using words or saying things that do not make sense


These changes can be confusing and frustrating to the person struggling with Alzheimer’s disease and to the caregiver. It will be important that you seek help and support for yourself as well as for your loved one.

Severe Alzheimer’s Disease

Patients in the later stages of Alzheimer’s disease require 24/7 care.


Patients with severe Alzheimer’s may not recognize loved ones and may lose memories of their own life events. These situations can cause fear and anxiety. Muscles can lose muscle tone due to decreased activity.


Common symptoms at this stage include: 

  • Inability to speak coherently
  • Inability to get out of bed, bathe, dress or use the bathroom without help
  • Impaired swallowing
  • Loss of bladder control

Learn More About Alzheimer’s Disease

patient researching on laptop and taking notes

Patient education and community resources for Alzheimer’s disease treatment and improving quality of life.
Alzheimer’s disease education >

Patient Success 

Watch stories of patients living with Alzheimer’s disease.
Alzheimer’s disease patient stories >

Find Alzheimer’s Clinical Trials

Learn about Alzheimer’s clinical trials
Houston Methodist is leading the way in Alzheimer’s research to find innovative treatment options.

Choose a Doctor at One of Our Locations

    Clear All Filters
    No results were found that matched your search criteria. Please try removing filters or zooming out on the map.