The Stages of Alzheimer's Disease
Though the time from diagnosis to death differs among people with Alzheimer's disease, the disease generally progresses through the same stages.
Dr. Ron Petersen was the first to define a condition called mild cognitive impairment (MCI) to describe early changes in memory. Dr. Petersen defined MCI as a condition in which a person has memory problems greater than expected for a person that age, but who does not have the other cognitive or personality changes that typically accompany AD. People with MCI are an important group for researchers to understand because about 80 percent of people with MCI characterized by memory loss go on to develop AD within seven years. (In contrast, only from 1 to 3 percent of people older than sixty-five with healthy cognitive abilities will develop AD in any given year.)
The definition and description of MCI has been a big advance because it provides a framework in which experienced clinicians, using sophisticated neuroimaging techniques and sensitive memory and cognitive tests, can monitor a person's cognitive changes over time. Being able to characterize and track cognitive changes is critical to determining whether a person has AD and when treatment may be most effective.
Over time, as the plaques and tangles continue to proliferate, an individual with MCI may progress to a clinical diagnosis of Alzheimer's disease. This stage is called mild, or early, Alzheimer's disease. More of the cerebral cortex will be affected so memory loss will increase, and other cognitive abilities will diminish. An individual with mild AD may get lost in familiar places or fail to recognize his surroundings. He may take longer to accomplish the daily tasks of living like washing, dressing, and eating. He may have trouble handling money or paying bills or exercise poor judgment. Mood and personality changes can also occur; he may lose spontaneity or drive, or show increased anxiety or aggression. Although a person with mild AD may still seem healthy, it will be harder for him to make sense of his world. Although the individual and his family members and friends may have been aware of troubling changes for some time, AD is often diagnosed during this phase. The diagnosis often helps families make sense of their loved one's behaviors.
As Alzheimer's disease progresses and the damage spreads further in the brain, the person enters a stage referred to as moderate Alzheimer's disease. The brain continues to shrink and symptoms become more pronounced as the disease reaches the areas of the cerebral cortex that control language, reasoning, sensory processing, and conscious thought. A person with moderate AD may wander or become confused, anxious or agitated, engaging in angry outbursts, tearfulness, irritability or restlessness. His attention span may shorten. He may have problems recognizing family and friends, and difficulty with language, reading, writing, and arithmetic, and with the logical organization of thoughts. He may be unable to learn new things and consequently be unable to cope with new situations. At this stage, a person with AD might also experience hallucinations and paranoid delusions, and lose impulse control, leading to things like inappropriate undressing or the use of vulgar language. It is helpful for caregivers to understand the disease and to be more prepared for these sorts of behaviors before they happen, and to know that it is the disease that is causing them.
A person with moderate AD may be unable to carry out activities that require him to follow a sequence, like getting dressed or setting the table. Anger may mask anxiety and confusion. According to the National Institute on Aging, a person at the moderate stage of AD "may angrily refuse to take a bath or get dressed because he does not understand what his caregiver has asked him to do. If he does understand, he may not remember how to do it."
At the last stage of this illness, severe Alzheimer's disease, plaques and tangles are found throughout the brain. Most areas have shrunken further, leaving only a thin ribbon of gray matter and even larger fluid-filled ventricles. An individual at this final stage cannot communicate in any way except moaning and grunting. He doesn't recognize loved ones and is completely dependent on others for care. He may experience weight loss and difficulty swallowing, seizures, skin infections, lack of bladder and bowel control, and increased sleeping. If bedridden, he is likely to die from pneumonia as a result of having inhaled food or drink because of difficulty swallowing.
Next: Defining Early Changes
Excerpted from THE ALZHEIMER'S PROJECT: MOMENTUM IN SCIENCE, published by Public Affairs, www.publicaffairsbooks.com.
In This Section
Momentum in Science: The Supplementary Series
- Understanding and Attacking Alzheimer's 12 min
- How Far We Have Come in Alzheimer's Research 15 min
- Identifying Mild Cognitive Impairment 20 min
- The Role of Genetics in Alzheimer's 12 min
- Advances in Brain Imaging 11 min
- Looking Into the Future of Alzheimer's 6 min
- The Connection Between Insulin and Alzheimer's 21 min
- Inflammation, the Immune System, and Alzheimer's 29 min
- The Benefit of Diet and Exercise in Alzheimer's 16 min
- Cognitive Reserve: What the Religious Orders Study is Revealing about Alzheimer's 20 min
- Searching for an Alzheimer's Cure: The Story of Flurizan 30 min
- The Pulse of Drug Development 15 min
- The DeMoe Family: Early-Onset Alzheimer's Genetics 25 min
- The Nanney/Felts Family: Late-Onset Alzheimer's Genetics 20 min
- The Quest for Biomarkers 17 min
Video: Inside the Brain: Unraveling the Mystery of Alzheimer's Disease
This 4-minute captioned video shows the progression of Alzheimer's disease in the brain.
Inside the Brain: An Interactive Tour
The Brain Tour explains how the brain works and how Alzheimer's affects it.
Alzheimer's Disease: Unraveling the Mystery
This book explains what AD is, describes the main areas in which researchers are working, and highlights new approaches for helping families and friends care for people with AD.
- About The Scientists
Connect with Alzheimer's Research
Find out how you can participate in clinical trials or studies, find a research center, or get up-to-date information at 1-800-438-4380.
The Alzheimer's Association 24/7 Helpline provides reliable information and support to all those who need assistance. Call us toll-free anytime day or night at 1-800-272-3900.
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The Alzheimer's Association message boards and chat rooms are your online communication forum. Share your thoughts and experiences, query your colleagues, and make new friends.
- Rapid advances in our knowledge about AD have led to the development of promising new drugs and treatment strategies. However, before these new strategies can be used in clinical practice, they must be shown to work in people. Advances in prevention and treatment are only possible thanks to volunteers who participate in clinical trials.
- Among those touched by Alzheimer's (excluding self), nearly one-third provide support as a friend or relative, another 3% provide support as a healthcare professional, and the remaining two-thirds provide no support to the person suffering from Alzheimer's. When support is provided, it most often entails emotional support, followed by care-giving support. While small in comparison, more than one person in ten is providing financial support. Read more.