Dementia describes various symptoms of cognitive decline, such as forgetfulness. It is a symptom of several underlying conditions and brain disorders.

Dementia is a general term for symptoms affecting memory, communication, and thinking. Although the likelihood of having dementia increases with age, it is not a normal part of aging.

Types and causes of dementia include:

Experts may refer to these as Alzheimer’s disease and Alzheimer’s disease-related dementias.

This article discusses the potential causes of dementia, the various types, and any available treatment options.

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Symptoms of dementia depend on the type a person has, but they typically include:

  • memory problems
  • asking the same question repeatedly
  • difficulty finding or understanding words
  • feeling confused in an unfamiliar environment
  • problems dealing with money and numbers
  • anxiety and withdrawal
  • difficulty planning and carrying out tasks
  • mood changes
  • personality and behavioral changes
  • sleep disturbances
  • changes in social awareness, such as making inappropriate jokes
  • obsessive tendencies

The symptoms tend to become more severe over time. The person may notice some symptoms themselves, but their family members or caregivers may notice others.

Learn more about the symptoms of dementia in older adults here.

The World Health Organization (WHO) divides dementia into roughly three stages: early, middle, and late. The sections below will look at each of these in more detail.

Early stage

At this stage, it may not seem that a person has dementia. They may:

  • become more forgetful
  • lose track of time
  • feel lost in familiar locations

Middle stage

At this stage, the symptoms become more noticeable and include:

  • forgetting names and recent events
  • feeling lost when at home
  • difficulty communicating
  • behavioral changes
  • repeatedly asking questions
  • needing help with personal care

Late stage

At this stage, a person needs full-time assistance, as the impact of the symptoms typically becomes more severe. The person may:

  • be unaware of where they are
  • be unaware of time
  • have difficulty recognizing loved ones
  • find it hard to walk
  • experience behavioral changes, which may include aggression

Learn more about the stages of dementia here.

There are several types of dementia. They include but are not limited to the following.

Alzheimer’s disease

Alzheimer’s disease is the most common cause of dementia, accounting for 70–80% of cases. In Alzheimer’s disease, “plaques” and “tangles” develop in and between the brain cells. Both are due to changes in proteins.

A person may have short-term memory problems, difficulty finding words and making decisions, and difficulty seeing things in three dimensions.

Lewy body dementia

Lewy body dementia occurs when unusual structures known as Lewy bodies develop in the brain. These brain changes involve a protein called alpha-synuclein.

In the early stages, there may be fluctuations in alertness, hallucinations, and difficulty judging distance. The impact on short-term memory may be less severe than it is with Alzheimer’s disease.

People with Parkinson’s disease may also have Lewy bodies. Although doctors often consider Parkinson’s disease a disorder of movement, symptoms of dementia can also appear.

Frontotemporal dementia

This condition involves damage to the front and sides of the brain. It happens when brain cells die due to clumps of protein developing inside them.

Depending on the part of the brain the condition affects, the person may have difficulty with behavior, speech and communication, or both.

Huntington’s disease

Huntington’s disease is an inherited genetic condition. The main symptoms are uncontrolled movements, but dementia can also occur.

Early symptoms may include difficulty focusing, irritability, and impulsivity. Depression may also be present. The person may have difficulty with organizing, multitasking, and planning. These symptoms may appear before movement changes develop.

Mixed dementia

When this happens, a person has a diagnosis of two or three types together. For instance, a person may have both Alzheimer’s disease and vascular dementia at the same time.

Learn more about the types and causes of dementia here.

Early symptoms of dementia vary between types but typically include:

  • forgetfulness
  • mood changes
  • anxiety, anger, or depression
  • difficulty finding the right words
  • apathy
  • confusion
  • repeating speech or actions
  • difficulty following a storyline or recounting a story
  • difficulty completing everyday tasks
  • a reduced sense of direction
  • difficulty adapting to changes
  • leaving everyday items in unusual places

Learn more about the early symptoms of dementia here.

Some types of dementia, such as Alzheimer’s disease, result from the progressive death of brain cells and neurons. It develops and worsens over time.

However, dementia can also result from head injuries, stroke, brain tumors, and other causes. A stroke, for example, can stop blood and oxygen from reaching brain cells, resulting in damage and cell death. Receiving a blow to the head can damage brain cells directly.

Some types of traumatic brain injury — particularly if repetitive, which can happen in some sports — may increase the risk of certain types of dementia later in life.

Some other factors and conditions with similar symptoms include:

  • the use of some drugs
  • some infections, such as HIV or neurosyphilis
  • depression
  • vitamin B12 or E deficiency
  • thyroid problems

Is there a link between dementia and memory loss? Find out here.

Assessment usually involves a number of questions and tasks. The following sections will explore these in more detail.

Cognitive dementia tests

Experts established the dementia tests that doctors currently use in the 1970s. A doctor may ask questions such as:

  • What is your age?
  • What is the time, to the nearest hour?
  • What is your address?
  • What is the year?
  • What is your date of birth?

The doctor may also take into account observations by family members and caregivers.

If the results suggest memory loss, the doctor may carry out blood tests and a CT brain scan to investigate further and rule out other possible causes.

Another test, called the mini-mental state examination — which has also been in use since the 1970s — measures:

  • orientation to time and place
  • word recall
  • language abilities
  • attention and calculation
  • visuospatial skills

It can help diagnose dementia due to Alzheimer’s disease. It can also rate its severity and assess whether or not drug treatment is appropriate.

Mini-Cog test

The doctor may also carry out a test known as the Mini-Cog test. This involves the following steps:

  1. The doctor will take three words from a specific set, “banana, sunrise, chair,” and ask the person to repeat them. The person can have three attempts at this.
  2. If the person cannot do this, the doctor will ask them to draw a clock face, fill in the numbers, and set the hands to a specific time. The person should do this within 3 minutes.
  3. If the individual cannot complete the clock task in time, the doctor will ask them to recall and repeat the three words from the first task.

There will be a maximum of 10 points. If the person scores fewer than 3–4 points, the doctor will consider dementia as a possible diagnosis.

There is currently no cure for most types of dementia, as it is not yet possible to reverse brain cell death. However, treatment may help manage symptoms.

Some medications may help reduce the symptoms of Alzheimer’s disease. Three drugs, known as cholinesterase inhibitors, have approval for use in the United States. They are:

  • donepezil (Aricept)
  • galantamine (Reminyl)
  • rivastigmine (Exelon)

Cholinesterase inhibitors can also help manage behavioral symptoms of Parkinson’s disease.

A person may also use memantine (Namenda), which is an NMDA receptor antagonist, either alone or with a cholinesterase inhibitor.

If the symptoms result from an injury, medication use, or a vitamin deficiency, it may be possible to prevent further damage.

Other forms of care

Some lifestyle strategies that may help manage dementia include making sure the person:

  • follows a healthy diet
  • gets regular exercise
  • attends all medical appointments
  • takes their medication as prescribed
  • has regular sleep habits
  • has a safe living space
  • has support from family members and caregivers, as needed

Does Medicare cover dementia care? Find out here.

In most cases, it is not possible to prevent dementia. However, the WHO suggests that the following habits may lower the risk:

  • exercising regularly
  • avoiding smoking
  • limiting alcohol consumption
  • maintaining a moderate weight
  • eating a healthy diet
  • seeking treatment for conditions such as high blood pressure, high cholesterol levels, and high blood sugar levels

Wearing protective headgear during contact sports may also lower the risk of sustaining repeated head injuries, which could be a risk factor for dementia.

Dementia is a term that describes symptoms affecting remembering, thinking, and behavior. It is a part of Alzheimer’s disease and can occur with some movement disorders, such as Huntington’s disease and Parkinson’s disease.

The symptoms usually worsen over time, and there is currently no cure. Some drugs may help manage the symptoms, but the person may eventually need full-time help.