Frontotemporal dementia (frontotemporal lobar degeneration) is an umbrella term for a diverse group of uncommon disorders that primarily affect the frontal and temporal lobes of the brain — the areas generally associated with personality, behavior and language. In frontotemporal dementia, portions of these lobes atrophy, or shrink. Signs and symptoms vary, depending upon the portion of the brain affected. Some people with frontotemporal dementia undergo dramatic changes in their personality and become socially inappropriate, impulsive or emotionally blunted, while others lose the ability to use and understand language. Frontotemporal dementia is often misdiagnosed as a psychiatric problem or as Alzheimer's disease. But frontotemporal dementia tends to occur at a younger age than does Alzheimer's disease, typically between the ages of 40 and 70.
Identifying precisely which diseases fall into the category of frontotemporal dementia presents a particular challenge to scientists. The signs and symptoms may vary greatly from one individual to the next. Researchers have identified several clusters of symptoms that tend to occur together and are dominant in subgroups of people with the disorder. More than one symptom cluster may be apparent in the same person. The signs and symptoms of frontotemporal dementia progressively worsen with time, almost always over years, eventually requiring 24-hour care.
The most common signs and symptoms of frontotemporal dementia involve extreme changes in behavior and personality. These include:
- Increasingly inappropriate actions
- Loss of empathy and other interpersonal skills
- Lack of judgment and inhibition
- Repetitive compulsive behavior
- A decline in personal hygiene
- Changes in eating habits, predominantly overeating
- Lack of awareness of thinking or behavioral changes
Speech and language probleme
Some subtypes of frontotemporal dementia are marked by the impairment or loss of speech and language difficulties.
Primary progressive aphasia, one subtype, is characterized by an increasing difficulty in using and understanding written and spoken language. For example, people may have trouble finding the right word to use in speech or naming objects.
People with another subtype, semantic dementia, utter grammatically correct speech that has no relevance to the conversation at hand. They may have difficulty understanding written or spoken language, or they may have difficulty recalling the words for common objects.
People with logopenic phonological aphasia talk slowly and have difficulty finding the right word to use or naming objects. They may have memory difficulties as well.
Rarer subtypes of frontotemporal dementia are characterized by problems with movement, similar to those associated with Parkinson's disease or amyotrophic lateral sclerosis.
Movement-related signs and symptoms may include:
- Muscle spasms
- Poor coordination
- Difficulty swallowing
- Muscle weakness
In frontotemporal dementia, the frontal and temporal lobes of the brain shrink.
A variety of mutations on several different genes have been linked to specific subtypes of frontotemporal dementia. However, more than half the people who develop frontotemporal dementia have no family history of dementia.
Frontotemporal lobar degeneration is divided into two subtypes, one involving the accumulation in the brain of a protein called tau and one involving the protein TDP-43.
In some cases, the affected parts of the brain contain microscopic abnormal tau protein-filled structures that develop within brain cells (Pick bodies).
Frontotemporal dementia was once known as Pick's disease, but now that terminology is reserved for the subtype that actually features these abnormal structures.
No single test can identify frontotemporal dementia, so doctors attempt to identify certain characteristic features while excluding other possible causes.
To see if your symptoms are being caused by a different condition, such as liver or kidney disease, your doctor may order blood work.
Sometimes doctors undertake a more extensive assessment of reasoning and memory skills. This type of testing, which can take several hours to complete, is especially helpful in trying to differentiate between the different types of dementia at an early stage.
By looking at images of the brain, doctors may be able to pinpoint any visible abnormalities — such as clots, bleeding or tumors — that may be causing signs and symptoms.
- Magnetic resonance imaging (MRI). An MRI machine uses radio waves and a strong magnetic field to produce detailed images of your brain. You lie on a narrow table that slides into the tube-shaped MRI machine, which makes loud banging noises during scans. The entire procedure can take an hour or more. MRIs are painless, but some people feel claustrophobic in the machine.
- Computerized tomography (CT). For a brain CT scan, you lie on a narrow table that slides into a small chamber. X-rays pass through your head from various angles, and a computer uses this information to create cross-sectional images, or slices, of your brain. The test is painless and takes about 20 minutes.
- Positron emission tomography (PET). PET scans use a small amount of low-dose radioactive material that's injected into a vein to help visualize brain metabolism, which can help identify abnormalities.
Symptoms of frontotemporal dementia progress at a rapid, steady rate. Patients suffering from the disease can survive between 2–15 years. Eventually patients will need 24-hour care for daily function.
CSF Leaks are a known cause of reversible frontotemporal dementia.
Frontotemporal dementia can't be cured. There is no effective way to slow its progression. Treatment involves managing the symptoms.
Antidepressants. Some types of antidepressants, such as trazodone (Oleptro), may reduce the behavioral problems associated with frontotemporal dementia.
Selective serotonin reuptake inhibitors (SSRIs) — such as sertraline (Zoloft), paroxetine (Paxil) or fluvoxamine (Luvox) — also have been effective in some people, although study results have been mixed.
Antipsychotics. Antipsychotic medications, such as olanzapine (Zyprexa) or quetiapine (Seroquel), are sometimes used to combat the behavioral problems of frontotemporal dementia. However, side effects include an increased risk of mortality in older people.
People experiencing language difficulties may benefit from speech therapy to learn alternate strategies for communication.