Frontotemporal dementia

Overview

Frontotemporal dementia (FTD) is an umbrella term for a group of brain diseases that mainly affect the frontal and temporal lobes of the brain. These areas of the brain are associated with personality, behavior and language.

In frontotemporal dementia, parts of these lobes shrink, known as atrophy. Symptoms depend on which part of the brain is affected. Some people with frontotemporal dementia have changes in their personalities. They become socially inappropriate and may be impulsive or emotionally indifferent. Others lose the ability to properly use language.

Frontotemporal dementia can be misdiagnosed as a mental health condition or as Alzheimer's disease. But FTD tends to occur at a younger age than does Alzheimer's disease. It often begins between the ages of 40 and 65, although it can occur later in life as well. FTD is the cause of dementia about 10% to 20% of the time.

Symptoms

Symptoms of frontotemporal dementia differ from one person to the next. Symptoms get worse over time, usually over years.

People with frontotemporal dementia tend to have clusters of symptom types that occur together. They also may have more than one cluster of symptom types.

Behavioral changes

The most common symptoms of frontotemporal dementia involve extreme changes in behavior and personality. These include:

• Increasingly inappropriate social behavior.
• Loss of empathy and other interpersonal skills. For example, not being sensitive to another person's feelings.
• Lack of judgment.
• Loss of inhibition.
• Lack of interest, also known as apathy. Apathy can be mistaken for depression.
• Compulsive behaviors such as tapping, clapping, or smacking lips over and over.
• A decline in personal hygiene.
• Changes in eating habits. People with FTD typically overeat or prefer to eat sweets and carbohydrates.
• Eating objects.
• Compulsively wanting to put things in the mouth.

Speech and language symptoms

Some subtypes of frontotemporal dementia lead to changes in language ability or loss of speech. Subtypes include primary progressive aphasia, semantic dementia and progressive agrammatic aphasia, also known as progressive nonfluent aphasia.

These conditions can cause:

• Increasing trouble using and understanding written and spoken language. People with FTD may not be able to find the right word to use in speech.
• Trouble naming things. People with FTD may replace a specific word with a more general word, such as using "it" for pen.
• No longer knowing word meanings.
• Having hesitant speech that may sound telegraphic by using simple, two-word sentences.
• Making mistakes in sentence building.

Movement conditions

Rare subtypes of frontotemporal dementia cause movements similar to those seen in Parkinson's disease or amyotrophic lateral sclerosis (ALS).

Movement symptoms may include:

• Tremor.
• Rigidity.
• Muscle spasms or twitches.
• Poor coordination.
• Trouble swallowing.
• Muscle weakness.
• Inappropriate laughing or crying.
• Falls or trouble walking.

Causes

In frontotemporal dementia, the frontal and temporal lobes of the brain shrink and certain substances build up in the brain. What causes these changes is usually not known.

Some genetic changes have been linked to frontotemporal dementia. But more than half of the people with FTD have no family history of dementia.

Researchers have confirmed that some frontotemporal dementia gene changes also are seen in amyotrophic lateral sclerosis (ALS). More research is being done to understand the connection between the conditions.

Risk factors

Your risk of getting frontotemporal dementia is higher if you have a family history of dementia. There are no other known risk factors.