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What Are the Signs of Alzheimer's Disease?

The symptoms of Alzheimer’s can vary from one person to another. Memory problems are typically one of the first signs of the disease. Decline in non-memory aspects of cognition, such as finding the right word, trouble understanding visual images and spatial relationships, and impaired reasoning or judgment, may also signal the early stages of Alzheimer’s. As the disease progresses, symptoms become more severe and include increased confusion and behavior changes.

graphic of a woman sitting at a desk with a laptop looking confused.

For most people with Alzheimer’s — those who have the late-onset variety — symptoms first appear in their mid-60s or later. When the disease develops before age 65, it’s considered early-onset Alzheimer’s, which can begin as early as a person’s 30s, although this is rare.

Alzheimer’s typically progresses clinically in several stages: preclinical, mild (sometimes called early-stage), moderate, and severe (sometimes called late-stage).

Preclinical Alzheimer’s disease

Research suggests that the complex brain changes associated with Alzheimer’s, such as the formation of amyloid plaques or tau tangles, start a decade or more before memory and thinking problems appear. This stage, in which changes in the brain appear before the onset of dementia, is called preclinical Alzheimer’s. However, it’s important to note that not everyone with these brain changes develops dementia.

Signs of Mild Alzheimer’s disease

In mild Alzheimer’s, a person may seem healthy but has more and more trouble making sense of the world around them. The realization that something is wrong often comes gradually to the person and their family. Problems can include:

Alzheimer’s is often diagnosed at this stage.

Signs of moderate Alzheimer’s disease

In this stage, more intensive supervision and care become necessary. These changes and increasing needs can be difficult for many spouses and families. Symptoms may include:

  • Age-related forgetfulness or signs of dementia infographic. Click to open webpage.
    Read and share this infographic to learn about how to tell the difference between age-related forgetfulness and dementia.
    Increased confusion and memory loss, such as forgetting events or personal history
  • Withdrawal from social activities
  • Inability to learn new things
  • Difficulty with language and problems with reading, writing, and working with numbers
  • Difficulty organizing thoughts and thinking logically
  • Shortened attention span
  • Problems coping with new situations
  • Changes in sleeping patterns, such as sleeping more during the day and being restless at night
  • Difficulty carrying out familiar, multistep tasks, such as getting dressed
  • Occasional problems recognizing family and friends
  • Hallucinations, delusions, and paranoia
  • Impulsive behavior, such as undressing at inappropriate times or places, or using vulgar language
  • Inappropriate emotional outbursts  
  • Restlessness, agitation, anxiety, tearfulness, wandering — especially in the late afternoon or evening
  • Repetitive statements or movement, occasional muscle twitches

Signs of severe Alzheimer's disease

People with severe Alzheimer’s cannot communicate and are completely dependent on others for their care. Near the end of life, the person may be in bed most or all of the time as their body shuts down. Symptoms often include:

  • Inability to communicate
  • No awareness of recent experiences or surroundings
  • Weight loss with little interest in eating
  • Seizures
  • General physical decline, including dental, skin, and foot problems 
  • Difficulty swallowing
  • Groaning, moaning, or grunting
  • Increased sleeping
  • Loss of bowel and bladder control

A common cause of death for people with Alzheimer’s is aspiration pneumonia. This type of pneumonia develops when a person cannot swallow properly and takes food or liquids into the lungs instead of air.

While there is currently no cure for Alzheimer’s, there are medicines approved by the U.S. Food and Drug Administration that may help treat the disease. There are also changes that can be made to the home environment and daily activities to help a person manage their changes in thinking.

  • Symptoms of mild cognitive impairment

    Some people have a condition called mild cognitive impairment (MCI), which can be an early sign of Alzheimer’s. However, not everyone with MCI will develop Alzheimer’s. People with MCI can still take care of themselves and perform their normal activities. MCI memory problems may include:

    • Losing things often
    • Forgetting to go to events or appointments
    • Problems communicating because of difficulty finding words

When to visit the doctor for memory loss

If you, a family member, or friend has problems remembering recent events or thinking clearly, talk with a doctor. A doctor may ask questions and conduct various tests and procedures to see what might be causing the symptoms. A doctor may also refer you to a specialist, such as a neurologist, for further assessment. Learn more in How Is Alzheimer’s Disease Diagnosed? If you or someone you know has recently been diagnosed with Alzheimer’s, visit Next Steps After an Alzheimer’s Diagnosis.

You also may be interested in participating in research on cognitive health, aging, and dementia. Learn more about volunteering for research to advance Alzheimer’s treatments.

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For More Information About the Signs of Alzheimer's Disease

NIA Alzheimer’s and related Dementias Education and Referral (ADEAR) Center
The NIA ADEAR Center offers information and free print publications about Alzheimer’s and related dementias for families, caregivers, and health professionals. ADEAR Center staff answer telephone, email, and written requests and make referrals to local and national resources.
Explore the website for information and resources on Alzheimer’s and related dementias from across the federal government.

National Library of Medicine

This content is provided by the NIH National Institute on Aging (NIA). NIA scientists and other experts review this content to ensure it is accurate and up to date.

An official website of the National Institutes of Health