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Frontotemporal Dementia

by Juebin Huang, MD, PhD

Frontotemporal dementia, which refers to a group of dementias, results from hereditary or spontaneous (occurring for unknown reasons) disorders that cause the frontal and sometimes the temporal lobe of the brain to degenerate.

  • Personality, behavior, and language function are affected more and memory less than in Alzheimer disease.

  • Doctors base the diagnosis on symptoms and results of a neurologic examination and use imaging tests to assess the brain damage.

  • Treatment aims to manage symptoms.

About 1 of 10 dementias is a frontotemporal dementia. Typically, the dementia develops in people younger than 65. Men and women are affected about equally. These dementias tend to run in families. Brain cells contain abnormal amounts or types of a protein called tau.

In these dementias, the frontal and temporal lobes (see Cerebrum) shrink (atrophy), and nerve cells are lost. These areas of the brain are generally associated with personality and behavior. There are several types of frontotemporal dementia, including Pick disease.

Pick disease

In this rare disorder, Pick bodies develop in nerve cells. Pick bodies contain abnormal amounts or types of tau. Pick disease differs from Alzheimer disease in that the first symptoms of Pick disease are usually personality changes rather than the memory loss typical of early Alzheimer disease. Pick disease affects the frontal lobes of the brain more than other lobes and progresses more rapidly. Symptoms usually start during a person's 40s or 50s. They include inappropriate behavior, apathy, memory loss, carelessness, and poor personal hygiene. Death usually occurs in 2 to 10 years.

Symptoms

Frontotemporal dementias are progressive, but how quickly they progress to general dementia varies.

Generally, these dementias affect personality, behavior, and language function more and affect memory less than Alzheimer disease does. People with a frontotemporal dementia also have difficulty thinking abstractly, paying attention, and recalling what they have been told. They have difficulty putting ideas or doing actions for a task in the right order (sequencing). They are easily distracted. However, they usually remain aware of time, date, and place and are able to do their daily tasks.

In some people, muscles are affected. They may become weak and waste away (atrophy). Muscles of the head and neck are affected, making swallowing, chewing, and talking difficult. They may inhale (aspirate) food, sometimes resulting in aspiration pneumonia.

Different types of symptoms develop, depending on which part of the frontal lobe is affected. People may have more than one type of symptom, particularly as the dementia progresses.

Changes in personality and behavior

Some people become uninhibited, resulting in increasingly inappropriate behavior. They may speak rudely. Their interest in sex may increase abnormally.

Behavior may become impulsive and compulsive. They may repeat the same action over and over. They may walk to the same location every day. They may compulsively pick up and manipulate random objects and put objects in their mouth. They may suck or smack their lips. They may overeat or eat only one type of food.

People neglect personal hygiene.


Problems with language

Most people have difficulty finding words. They have increasing difficulty using and understanding language (aphasia). For some, physically producing speech (dysarthria) is difficult. Paying attention is very difficult. For some people, language problems are the only symptom for 10 or more years. For other people, other symptoms appear within a few years.

Some people cannot understand language, but they speak fluently, although what they say does not make any sense. Others have difficulty naming objects (anomia) and recognizing faces (prosopagnosia).

As dementia progresses, people speak less and less or repeat what they or others say. Eventually, they stop speaking.


Diagnosis

The diagnosis is based on symptoms, including how they developed. Family members may have to provide this information because affected people may be unaware of their symptoms. A neurologic examination and mental status tests are usually done.

Computed tomography (CT) and magnetic resonance imaging (MRI) are done to determine which parts and how much of the brain is affected and to exclude other possible causes (such as brain tumors, abscesses, or a stroke). However, CT or MRI may not detect the characteristic changes of frontotemporal dementia until late in the disorder. Positron emission tomography (PET—see see Other Tests for Heart and Blood Vessel Disorders : Positron Emission Tomography) may help differentiate frontotemporal dementia from Alzheimer disease, but PET is used mainly in research.

Treatment

There is no specific treatment. Generally, treatment focuses on managing symptoms and providing support ( Dementia : Treatment). For example, if compulsive behavior is a problem, antipsychotic drugs may be used. Speech therapy may help people with language problems.