Alzheimer’s disease (AD) is a type of dementia where brain cells die. The condition affects memory, thinking, and behavior. According to the Alzheimer’s Association, this disease accounts for 60 to 80 percent of dementia cases. Alzheimer’s disease is more common in people over the age of 65, but some people have early onset AD and show symptoms as early as their 40s or 50s.
This is a progressive disease that worsens over time. It’s the sixth leading cause of death in the United States. After a diagnosis, people with the condition can live an average of four to 20 years.
Recognizing early symptoms of AD and intervening early helps prolong and improve your quality of life.
Early symptoms of AD can be mild and subtle — so subtle that you may not notice a change in your thinking or behavior. In the early stage of the disease, you’ll likely have trouble remembering new information. This is because the disease often begins to impact areas of the brain responsible for learning new information. You may repeat questions over and over, forget conversations or important appointments, or misplace objects such as your car keys.
Occasional memory loss can be a normal part of aging, so forgetfulness isn’t necessarily a sign of AD. However, you should speak with your doctor if the problem worsens.
The top 10 warning signs include:
- misplacing objects and being unable to retrace steps
- memory loss that affects everyday life (unable to budget, drive to a location)
- difficulty planning or problem solving
- taking longer to accomplish normal daily tasks
- losing track of time
- having trouble determining distance and distinguishing colors
- difficulty following a conversation
- poor judgment leading to bad decisions
- withdrawal from social activities
- mood and personality changes and increased anxiety
Eventually, AD spreads to more regions of the brain. Family and friends may recognize changes in your thinking and behavior before you do. Sometimes, it’s hard to identify memory problems in ourselves. But as the disease progresses, you may recognize telltale symptoms in yourself, such as confusion and a shorter attention span. As more of your brain cells die, you’ll begin to show signs of moderate AD, which include:
- problems recognizing friends and family members
- difficulty with language and problems with reading, writing, or working with numbers
- difficulty organizing thoughts and thinking logically
- inability to learn new tasks or to cope with new or unexpected situations
- inappropriate outbursts of anger
- perceptual-motor problems, such as trouble getting out of a chair or setting the table
- repetitive statements or movement, and occasional muscle twitches
- hallucinations, delusions, suspiciousness or paranoia, and irritability
- loss of impulse control, such as undressing at inappropriate times or places or using vulgar language
- exacerbation of behavioral symptoms, such as restlessness, agitation, anxiety, tearfulness, and wandering — especially in the late afternoon or evening — called, “sundowning”
At this point in the disease, brain plaques (clusters of protein that destroy brain cells) and tangles (dying nerve cells that twist around one another), may appear on imaging tests of the brain. Both are hallmarks of AD. This is the final stage of AD. People at this stage lose control of physical functions and depend on others for care. They sleep more often and are unable to communicate or recognize loved ones.
Other symptoms of severe AD include:
- lack of bladder and bowel control
- weight loss
- skin infections
- groaning, moaning, or grunting
- difficulty swallowing
Due to the loss of physical function, people with late-stage AD may deal with complications. Difficulty swallowing can result in inhaling liquids into the lungs, which increases the risk of pneumonia. They may also suffer from malnutrition and dehydration. Limited mobility also increases the risk of bedsores.
Conditions with similar symptoms
There are other causes of dementia with symptoms similar to AD. A doctor conducts physical and neurological examinations and uses brain imaging technology to diagnose or rule out AD. The following list of neurodegenerative diseases can mimic AD:
- Parkinson’s disease with dementia leads to shaking and difficulty with walking, movement, and coordination.
- Vascular dementia occurs from impaired blood flow to the brain and leads to problems with reasoning, planning, judgment, and memory.
- Frontotemporal lobar degeneration affects the frontal and temporal lobes of the brain, which are associated with personality, behavior, and language.
- Frontotemporal dementia affects the temporal and frontal lobes that influence decision-making, behavioral control, emotion, and language.
- Pick’s disease is a rare and permanent form of dementia similar to AD except it often affects only certain brain areas.
- Supranuclear palsy is a rare brain disorder that causes serious and progressive problems with control of gait and balance, complex eye movement, and thinking problems.
- Corticobasal degeneration occurs when areas of your brain shrink and nerve cells die over time. The result is growing difficulty moving on one or both sides of your body.
Other possible causes of dementia include:
- medication side effects
- vitamin B-12 deficiency
- chronic alcoholism
- certain tumors or infections of the brain
- blood clots in or on the brain
- metabolic imbalances, including thyroid, kidney, and liver disorders
Talk to a doctor if you or a loved one is experiencing symptoms of AD. Because symptoms worsen over time, it’s important to recognize the possibility of AD. Your doctor can make a diagnosis and assess whether symptoms are mild, moderate, or severe.