Semantic Dementia: What to Know

Medically Reviewed By Shilpa Amin, M.D., CAQ, FAAFP

Semantic dementia is a rare dementia type that causes problems with language and understanding. Symptoms include difficulty selecting the correct words or understanding their meaning. Dementia is a set of symptoms affecting memory, thinking, language, and behavior. Many conditions can cause dementia.

Semantic dementia is a form of frontotemporal dementia (FTD). FTD is an uncommon dementia type resulting from damage to the lobes in the front and sides of the brain. This leads to language and behavorial symptoms that worsen over time.

Learn more about semantic dementia, including its symptoms, causes, and outlook.

Symptoms

Two older adults work side by side in a home kitchen.
Photography by Cavan Images/Paula Berezo/Getty Images

“Semantic” refers to logic and the meaning of words. Semantic memory is a type of long-term memory that stores ideas, facts, and concepts.

Semantic dementia causes symptoms affecting speech, general memory, and understanding of words and speech. Dementia is progressive, meaning symptoms worsen.

Semantic dementia symptoms include:

  • semantic jargon, using words that do not make sense together or in the context of the sentence
  • difficulty naming an object or using an incorrect word to replace another, such as saying “apple” to refer to an orange
  • asking the meaning of previously familiar words
  • difficulty naming items correctly
  • excessive talking, beyond what is usual
  • difficulty with:
    • using or understanding body language and facial expressions
    • taking turns in conversation
    • being concise or clear, or staying on topic
    • remembering what the listeners already know
    • understanding others Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source or following instructions
    • interpreting implied meaning, such as understanding that someone stating “it’s cold” could mean that they would like the heat turned up

Other symptoms of semantic dementia include:

  • impaired long-term memory, leading to difficulty remembering past events, known facts, or experiences
  • difficulty recognizing people
  • difficulty understanding how items such as machinery work
  • difficulty calculating risks
  • behavior or personality changes, such as:
    • apathy or depression
    • compulsive or addictive behavior

Semantic dementia vs. other dementia subtypes

People with semantic dementia may not have as many problems with:

  • orientation
  • short-term memory
  • performing daily tasks

FTD and semantic dementia usually develop at younger ages than other types of dementia. According to the National Institutes of Health (NIH), about 60% Trusted Source National Institute on Aging Governmental authority Go to source of people with FTD are between 45 and 64 years. However, it is possible to develop FTD at any age.

It is possible to have FTD and another type of dementia at once.

Causes

FTD develops when the brain’s frontal and temporal lobes become damaged. This damage occurs when high levels of proteins build up in the brain, impairing the function of the cells.

More research is needed to understand the cause of the protein buildup and why some people develop semantic dementia and others do not.

Researchers also suggest Trusted Source National Institute on Aging Governmental authority Go to source that hereditary genetic mutations may play a role in FTD. People with a family history of FTD may be more likely to develop it.

Read more about FTD, including its possible causes.

Risk factors

More research and studies of semantic dementia are needed to identify specific risk factors and development.

General risk factors for dementia may include:

Low cognitive reserve may also be a dementia risk factor. Cognitive reserve is the brain’s ability to problem solve and cope with challenges. Causes of low cognitive reserve include:

  • leaving education early
  • infrequent use of mental skills such as problem-solving, organization, memory, and communication
  • social isolation

Diagnosis

Doctors will ask about your symptoms and medical history. You may have trouble explaining or remembering your symptoms. In this case, a symptom diary or bringing a trusted friend to your appointment can help.

FTD and semantic dementia are rare Trusted Source National Institute on Aging Governmental authority Go to source , and there is no single test for them. Therefore, they can be challenging to diagnose.

However, the following may help identify FTD and rule out other conditions:

  • genetic testing
  • cognitive tests to check memory, language, and thinking skills
  • imaging scans of the brain, such as an MRI
  • blood tests
  • spinal tap, removing a sample of cerebrospinal fluid with a needle to look for signs of protein buildup

Treatment and support

Currently, there is no treatment to cure, slow, or prevent FTD and semantic dementia. Experts typically do not recommend medications used for other dementia types for people with FTD. These medications may worsen FTD symptoms.

Treatment options to alleviate symptoms and improve quality of life include:

  • speech and language therapy
  • antidepressants, selective serotonin reuptake inhibitors (SSRIs)
  • antipsychotics for severe behavior symptoms
  • occupational therapy to help with daily life and access to care
  • relaxation therapies, such as music therapy
  • self-care and social support approaches, such as:
    • staying socially active with friends or family
    • asking your doctor about local services, such as local support groups

The Alzheimer’s Association provides a directory of resources and a 24/7 helpline at 800-272-3900. The U.S. government and NIH also offer a list of resources, including government-funded support.

Prevention

Dementia cannot be prevented, even for people with a low level of risk. However, actions that may reduce the risk of developing dementia include:

  • following your doctor’s treatment recommendations for underlying conditions, such as high blood pressure
  • getting regular physical activity
  • quitting smoking
  • limiting alcohol
  • staying socially active
  • maintaining a moderate body mass
  • reducing the risk of traumatic brain injury, such as wearing a helmet when playing sports

Learn more about preventing traumatic brain injury.

Outlook

The outlook for people with semantic dementia can vary per person.

FTD usually develops slowly, gradually worsening over several years. Eventually, symptoms may result in social withdrawal, communication difficulties, and a need for full-time care.

Generally, survival with FTD is about 8–10 years after symptoms begin. However, the NHS says this time varies, and some people may live longer.

Treatment and support can also improve the quality of life for the person with FTD and their caregivers.

Talk with a doctor for personalized advice about outlook and treatment.

Summary

Semantic dementia, a form of FTD, causes difficulty with language. Symptoms include reduced vocabulary, difficulty keeping up with conversations, and memory difficulties.

Protein buildup in the brain may cause FTD.

There is currently no cure for semantic dementia. However, antidepressants, occupational therapy, and speech and language therapy may improve quality of life.

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Medical Reviewer: Shilpa Amin, M.D., CAQ, FAAFP
Last Review Date: 2024 Jan 30
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