Alzheimer’s Disease Stages and How They Progress

Alzheimer’s is a progressive disease that damages neurons (nerve cells) in the brain, affecting the ability to remember, reason, judge, use language, and otherwise meet the demands of daily life.

Although there are treatments that can help sharpen the mind for a short while and make behavioral symptoms more manageable, there is currently no cure.

Every person with Alzheimer’s will experience the disease in a different way. Some retain their cognitive abilities longer than expected, while others move through the various stages quicker.

Among the factors that influence the speed of progression are age, overall health, emotional resilience, medication regimen, and network of support.

Outlining the stages of Alzheimer’s is helpful for understanding the overall arc of the disease and planning for changes to come. “Knowing how long [a person with Alzheimer’s has] before having to move in with loved ones or needing the kind of care that a nursing home offers can be helpful,” says Dylan Wint, MD, an Alzheimer’s expert and the director of the Cleveland Clinic Lou Ruvo Center for Brain Health in Las Vegas, Nevada.

The earlier someone is diagnosed, the more helpful it will be to know the stage, says Dr. Wint. “Tying the stage to available treatments when someone is in the preclinical or mild cognitive impairment stage has benefits,” he says. If someone is diagnosed in the early stages, lifestyle interventions such as diet, exercise, and socialization can have the most benefits and lead to a better quality of life, he adds.

• Some symptoms can appear earlier or later than usual, in a different order, or not at all.
• Some stages can overlap.
• Some symptoms, such as irritability, may appear and then disappear, while others, such as memory loss, continually worsen.

The onset of Alzheimer’s can begin 25 to 30 years before symptoms arise. During this period, there is an accumulation of amyloid-beta peptides, which play a role in the formation of amyloid plaques, a hallmark of Alzheimer’s disease.

Currently, there are clinical trials under way that involve testing people for amyloid buildup and then treating them with the latest anti-amyloid medication, says Gregory Day, MD, vice chair of research in the department of neurology at Mayo Clinic in Jacksonville, Florida. Because the disease is asymptomatic at this stage, researchers are looking at people over 55 who may have a family history of dementia.

Toward the end of this stage and before the next stage, there is a less defined transitional phase when mild symptoms start to manifest, even if cognitive testing shows no change, says Wint.

Mild cognitive impairment (MCI) involves lapses in memory, language, thinking, and judgment that are noticeable to the person and their family and close friends, yet not serious enough to interfere with everyday life.

There are very specific criteria for MCI, according to Dr. Day. “It’s a clear change in memory and thinking that is different from before. It’s outside of the realm of normal for aging, yet importantly does not impair activities of daily living,” he says. People in this stage often continue to maintain day-to-day function. But someone exhibiting symptoms might have problems with complex tasks, such as finances or taxes.

“Learning new technology may be hard. They may have trouble going to the grocery store and getting everything on the list. But they are not going to need reminders to bathe or shave,” Day says.

Emotionally, a person with these early signs of dementia may also show irritability or signs of depression. Some of that may come from frustration due to the effects of the symptoms.

After this phase, the disease normally progresses through three main stages: mild (early stage), moderate (middle stage), and severe (late stage).

The accumulation of amyloid plaques triggers the formation and spread of neurofibrillary (tau) tangles inside the neurons. These tangles block the neurons’ synapses, and this breakdown in communication causes substantial cognitive impairment.

A person experiencing the earliest symptoms of Alzheimer’s disease may still be able to drive, take part in social activities, work, and otherwise live independently. “The list of things they can do is longer than the list of things they can’t do,” says Day.

But problems with memory or concentration may begin. They may have trouble retaining new information — the name of someone they’ve just met, for instance, or material they’ve just read.

Unfortunately, this symptom is often dismissed as a normal part of aging or the result of stress, delaying diagnosis and treatment.

Other symptoms, says Day, include requiring help with activities of daily living, such as keeping track of schedules and appointments, managing medications, preparing meals, and tracking household finances. The risk of driving accidents increases, too.

Emotionally, there may be more anxiety, apathy, and withdrawal.

Other common symptoms of mild Alzheimer’s include:

• Difficulty completing familiar home, leisure, or work tasks
• Increasingly poor judgment, leading to bad decisions
• Language problems, such as having trouble coming up with the right words
• Losing the sense of time
• Misplacing items
• Mood and personality changes, such as becoming anxious, confused, depressed, or irritable
  
• Trouble organizing, planning, or solving problems
• Vision-related problems, such as with depth perception and color contrast
  
• Withdrawal from social or work engagements
  

In most cases of moderate Alzheimer’s dementia, the disease has spread to areas of the brain that control conscious thought, language, reasoning, and sensory processing, causing previous symptoms to become more pronounced. But they may still remember important details about their personal history.

Increased supervision for the safety of the individual is necessary at this point, says Day. While the motor system remains very functional, there is a higher risk of self-endangering behaviors, such as leaving the stove on or wandering outside the home, he says. “They are unable to care for themselves nutritionally and will need increased help with personal care. Driving is out of the question,” Day says.

Emotions are harder to assess in people with moderate Alzheimer’s, because they often live in the moment. “Apathy is a bigger problem — motivating people to be engaged,” Day says.

Symptoms of this period may include:

• Agitation, anxiety, restlessness, tearfulness, and an increased risk of wandering, especially in the late afternoon or evening (called sundowning)

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• Behavioral problems, such as inappropriate anger outbursts or moodiness
  
• Delusions, hallucinations, and paranoia
• Difficulty reading, writing, or working with numbers
• An inability to learn new things or cope with new situations
• Incontinence
• Increased confusion and memory loss, including forgetting names or personally significant events
• Loss of impulse control, such as undressing at inappropriate times or using vulgar language
• Repetitive statements or movements, such as hand-wringing or shredding tissues
• Trouble carrying out activities that require multiple steps, such as getting dressed
• Trouble recognizing family and friends

People with severe Alzheimer’s dementia are completely dependent on others for around-the-clock care.

They become increasingly unable to communicate, respond to their environment, and perform basic daily activities, such as bathing, dressing, or eating. They become bedridden or chairbound. Eventually, they become unable to control movement.

This stage may last several weeks to several years.

Other symptoms of advanced Alzheimer’s may include:

• Difficulty swallowing
• Failure to recognize family and friends
• Groaning, grunting, and moaning
• Increased risk of infections, including pneumonia and skin infections
• Increased sleeping
• Loss of bladder and bowel control
• Seizures
• Weight loss

Even at this advanced stage, people with severe Alzheimer’s may experience flashes of lucidity (being aware of their situation), and some of their abilities may come back for a short while.

They may be capable of feeling happy or safe in the presence of loved ones, even when they don’t seem to recognize them.

Wint believes more people are coming to get diagnosed in the earlier stages now. His hope is that the blood tests that screen for Alzheimer’s in the early stages will become more accurate and common (and eventually be offered by your primary care physician) to help diagnose and monitor people with the disease.

• Alzheimer’s can be asymptomatic and go undetected for decades as amyloid plaques and neuron tangles develop in the brain.
• The stages of Alzheimer’s are preclinical, mild cognitive impairment, mild, moderate, and severe.
• Knowing the stages of Alzheimer’s disease can help optimize treatment and interventions and help you prepare for what’s next.