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Common Symptoms & Signs of Dementia & Alzheimer’s Disease

Written by 
Jennifer Co

Article at a glance

  • Dementia is a term used to describe a group of diseases that can cause a person to lose cognitive function.

  • Among the many types of dementia, Alzheimer’s disease is by far the most common, making up 60–80% of all cases.

  • Dementia symptoms can vary greatly between people, but they generally involve problems with memory, attention, communication, reasoning, judgment, problem-solving, and visual perception.

  • The main risk factor for developing dementia is advanced age, with most cases occurring in those age 65 and over.

  • Dementia is divided into seven distinct stages, starting from the no to little presentation and ending with the most severe.

Every 3 seconds, someone in the world develops dementia. In 2020, more than 55 million people around the world were living with the disease, and this number is predicted to double every 20 years, reaching 139 million in 2050. Dementia can be difficult to live with, both for the person affected and those around them. Fortunately, understanding the disease, recognizing its early signs, and knowing what to expect can help make managing dementia easier and maximize the quality of life, whether it affects you or a loved one.

What is dementia?

Dementia is the loss of cognitive capacity, which simply means the ability to think, remember, and reason. This can interfere with daily life and activities, and may even change someone’s personality or lessen their ability to control their emotions. Even though dementia is mostly seen in older adults, it’s not a normal part of aging. Memory changes that may be normal as you get older include occasionally misplacing your car keys or forgetting the name of an acquaintance — but your old memories, knowledge, and experiences should stay intact.

A number of factors can lead to the development of dementia, but most of the time, the exact cause is unknown. In general, it’s thought to be due to damage to the brain cells. This interferes with their ability to communicate with one another to facilitate proper thinking, behavior, and processing feelings. Changes in the brain that lead to dementia are often permanent and worsen over time, but there are select causes of dementia that are reversible, especially if properly addressed or treated. These include:

  • depression

  • thyroid problems

  • vitamin deficiencies

  • medication side effects

  • excessive alcohol use

What are the signs and symptoms of dementia?

Signs and symptoms of dementia can vary from person to person. They generally revolve around problems with memory, attention, communication, reasoning, judgment, problem-solving, and visual perception. These may include:

  • confusion, memory loss, poor judgment, and impulsivity

  • hallucinations, delusions, or paranoia

  • problems with speaking, understanding, and expressing thoughts

  • difficulty reading and writing

  • repeating questions

  • using unusual words to refer to objects

  • getting lost or wandering around a familiar area

  • trouble with paying bills

  • being slower than normal in completing daily tasks

  • losing interest in activities and not caring about people’s feelings

  • problems with balance and movement

What is the difference between dementia and Alzheimer’s?

Dementia itself is not a particular disease; rather, it’s an umbrella term used to describe several conditions that cause cognitive decline. Alzheimer’s disease is the most common type of dementia. It accounts for 60–80% of dementia cases, and is the sixth leading cause of death in the US. There are two types of Alzheimer’s disease: early-onset, which affects those between the ages of 30 and 60, and late-onset, which occurs in those over 60 years old. It can be difficult to determine whether a person truly has Alzheimer’s disease since its symptoms are very close to the general symptoms of dementia. While it used to be that the only way to know for sure was for a pathologist to examine a person’s brain through an autopsy after death, now most diagnoses are made through tests, brain scans and by excluding other conditions. A cure has yet to be developed. However, several treatments are available to slow down or manage symptoms, which can help improve quality of life.

Other types of dementia

Parkinson’s disease

Parkinson’s disease is a long-term and progressive disorder that primarily affects movement. Around 50–80% of people with Parkinson’s will eventually develop mild dementia, while up to 20% will develop a more severe form. Symptoms often develop gradually, and years may pass before a person starts to notice any changes. The most noticeable symptoms of Parkinson’s include tremors, slow movements, and changes in writing. Similar to Alzheimer’s, there currently isn’t a cure for Parkinson’s, but there are many treatment options available that can help manage symptoms. 

Huntington’s disease

Huntington’s disease is a progressive illness most commonly caused by an abnormal gene that parents pass down to their children. Symptoms typically manifest between 30–50 years old, and may include changes in behavior, abnormal muscle movements, and problems with speech, memory, and judgment. There’s no cure for Huntington’s at this time, but symptoms can be managed with medications, psychotherapy, and occupational therapy.

Vascular dementia

Vascular dementia occurs when blood flow to the brain is reduced or blocked. It’s the second most common cause of dementia and is frequently associated with stroke, poor heart health, and diabetes. Although it’s irreversible, it’s possible to prevent vascular dementia by following a heart-healthy diet, exercising, and managing blood pressure, cholesterol, and sugar levels.

Lewy body dementia

Lewy body dementia is like a combination of Alzheimer’s disease and Parkinson’s disease. It causes an irreversible decline in cognitive functions as well as movement problems, either of which can come first. 

Frontotemporal dementia

Frontotemporal dementia specifically involves the degeneration of the brain’s frontal lobe, which can sometimes extend into the temporal lobe. Most notable symptoms include an obvious difference in behavior, a gradual decline in speech, and a loss of comprehension.

Creutzfeldt-Jakob disease

Creutzfeldt-Jakob disease (CJD) is sometimes thought of as the human form of bovine spongiform encephalopathy (Mad Cow disease) due to their similar presentations, but these two illnesses are not related. CJD is caused by the presence of incorrectly folded proteins in the brain, which leads to rapidly progressive dementia, involuntary muscle spasms, seizures, and ultimately, death. No cure has been found for CJD, and there’s currently no known method to prevent further loss of brain function.

Normal pressure hydrocephalus

Normal pressure hydrocephalus (NPH) occurs when there’s buildup of cerebrospinal fluid (CSF) in the brain. The fluid compresses and damages the surrounding brain tissue leading to the signs and symptoms of dementia. NPH presents similarly to Alzheimer’s disease, but unlike it, NPH can be treated and reversed to a certain point. This involves inserting a tube to drain the excess fluid that’s causing the damage.

Wernicke-Korsakoff syndrome

Wernicke-Korsakoff syndrome is related to excessive alcohol consumption. Too much alcohol can lead to a deficiency in thiamine, a vitamin that helps the brain process and produce energy from sugar. Without energy, brain damage may occur, which can lead to the development of dementia. This damage is permanent, but abstaining from alcohol and maintaining a healthy diet can help slow its progression.

Mixed dementia

As the name implies, mixed dementia can be seen in people who have symptoms of more than one type of dementia at the same time. It’s more commonly seen in adults over 80 years old, and the most common combination is Alzheimer’s disease with vascular dementia. Not much is known about this type of dementia, and it’s difficult to establish a diagnosis because of the overlapping symptoms.

Who is at risk of developing dementia?

There are many risk factors — modifiable and nonmodifiable — that increase a person’s likelihood of developing dementia.


  • Age: It’s the strongest risk factor for developing dementia. Most cases are seen in those age 65 and older.

  • Family history: You’re more likely to develop dementia if you have parents or siblings with it.

  • Race/​ethnicity: African Americans and Hispanics are 2 times and 1.5 times more likely, respectively to develop dementia compared to Whites.


  • Poor heart health: High blood pressure, high cholesterol levels, and smoking can lead to dementia.

  • Alcohol use: Excessive drinking can increase your risk of dementia.

  • Diabetes: This chronic condition increases the risk of heart disease and stoke, which in turn increases your chances of getting dementia.

  • Traumatic brain injuries: This is especially true if injuries are severe and happen repeatedly.

What are the stages of dementia?

Loss of cognitive ability in dementia happens gradually, making it possible to divide the disease into seven distinct stages.

Stage 1: No cognitive decline

This is known as the normal functioning stage when dementia is still undetectable.

Stage 2: Age-associated memory impairment

Those having occasional lapses in memory that can be attributed to normal age-related memory changes fall under this stage. Examples include forgetting where they left their keys, or forgetting the names of people they used to know. 

Stage 3: Mild cognitive impairment (MCI)

At this stage, cognitive problems can be clearly seen. These may manifest as getting lost easily, forgetting names of close friends or family members, and problems with concentrating or retaining information. These symptoms may start interfering with daily life which can cause anxiety, and in this stage, it’s encouraged to consult with a doctor to establish a diagnosis. 

Stage 4: Mild dementia

Symptoms of mild dementia include changes in personality and mood, and social withdrawal. Denying the presence of symptoms is common, so much so that people in this stage often avoid social situations in order to hide their symptoms and prevent stress. Other symptoms may include decreased knowledge of current or recent events, disorientation, difficulty recognizing faces, difficulty remembering details about their personal history, and difficulty handling finances or making plans. 

Stage 5: Moderate dementia

The main symptom of moderate dementia is not being able to recall major details like a home address, phone number or a close family member’s name. It’s also possible to become confused about the time of day and place and have difficulty in making decisions. People in this stage need some minor forms of assistance to carry out certain tasks, but they’re still able to independently perform basic functions like eating and using the bathroom. 

Stage 6: Moderately severe dementia

People who have moderately severe dementia need full-time care. They’re unaware of their surroundings, unable to remember recent events, and have altered memories of their past. They may experience delusions, hallucinations, difficulty sleeping, and anxiety, and exhibit obsessive behavior, anxiety, aggression, agitation, and loss of willpower. 

Stage 7: Severe dementia

Those who reach the last stage of dementia often have lost the ability to speak, move, and do anything on their own. At this point, although they are still alive, it’s said that the brain has lost its connection to the body.

Although knowing that dementia is permanent and mostly incurable can be daunting, it’s more than possible to manage and even slow down the symptoms. That’s why it’s important to recognize the disease early on so that you can take the necessary steps for you or your loved one. 

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