About frontotemporal dementia
The nerve cell damage caused by frontotemporal dementia leads to loss of function in these brain regions, which variably cause deterioration in behavior and personality, language disturbances, or alterations in muscle or motor functions.
There are a number of different diseases, that cause frontotemporal degenerations. The two most prominent are 1) a group of brain disorders involving the protein tau and 2) a group of brain disorders involving the protein called TDP43. For reasons that are not yet known, these two groups have a preference for the frontal and temporal lobes that cause dementia.
FTD used to be called Pick's disease after Arnold Pick, a physician who in 1892 first described a patient with distinct symptoms affecting language. Some doctors still use the term "Pick's disease." Other terms you may see used to describe FTD include frontotemporal disorders, frontotemporal degenerations and frontal lobe disorders.
Symptoms of FTD (Pick’s Disease)
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, usually 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 problems
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
Behavior variant frontotemporal dementia (bvFTD)
This condition is characterized by prominent changes in personality, interpersonal relationships and conduct that often occur in people in their 50s and 60s, but can develop as early as their 20s or as late as their 80s. In bvFTD, the nerve cell loss is most prominent in areas that control conduct, judgment, empathy and foresight, among other abilities.
Primary progressive aphasia (PPA)
This is the second major form of frontotemporal degeneration that affects language skills, speaking, writing and comprehension. PPA normally comes on in midlife, before age 65, but can occur in late life also. The two most distinctive forms of PPA have somewhat different symptoms:
* In semantic variant of PPA, individuals lose the ability to understand or formulate words in a spoken sentence.
* In nonfluent/agrammatic variant of PPA, a person’s speaking is very hesitant, labored or ungrammatical.
Disturbances of motor (movement or muscle) function
There are three disorders, which are a part of the frontotemporal degeneration spectrum that produce changes in muscle or motor functions with or without behavior (bvFTD) or language (PPA) problems.
* Amyotrophic lateral sclerosis (ALS), which causes muscle weakness or wasting. ALS is a motor neuron disease also known as Lou Gehrig’s disease.
* Corticobasal syndrome, which causes arms and legs to become uncoordinated or stiff.
* Progressive supranuclear palsy (PSP), which causes muscle stiffness, difficulty walking and changes in posture. It also affects eye movements.
Both bvFTD and PPA are far less common than Alzheimer’s disease in those over age 65 years. However, in the 45 to 65 age range, bvFTD and PPA are nearly as common as younger-onset Alzheimer’s. Only rough estimates are available, but there may be 50,000 to 60,000 people with bvFTD and PPA in the United States, the majority of whom are between 45 and 65 years of age.
How is FTD Different from Alzheimer's Disease?
Although FTD and AD present with different symptoms, both are likely to affect reason and other forms of cognition. Many substantial differences exist between these disorders, however. Not surprisingly, these changes in cognition and behavior are brought about by pathological changes in the brain that are also quite different from those of AD. Whereas AD involves the deposit of plaques and tangles and the eventual loss of the much of the cerebral cortex, FTD seems to be caused by more focal changes in specific brain regions, as a result of alternate protein changes. Instead of plaques and tangles, FTD brains show the deposit of Pick bodies and balloon neurons. These inclusions occur mostly in the frontal and temporal (side) parts of the brain, and some patients will experience very focal changes in these regions. For example, patients experience focal losses on the left side of the brain, where the regions that control language abilities are found. Other patients experience more frontal changes, resulting in social behavior symptoms such as unusual speaking to or touching strangers.
* Age at diagnosis may be an important clue. Most people with FTD are diagnosed in their 40s and early 60s. Alzheimer's, on the other hand, grows more common with increasing age.
* Memory loss tends to be a more prominent symptom in early Alzheimer's than in early FTD, although advanced FTD often causes memory loss in addition to its more characteristic effects on behavior and language.
* Behavior changes are often the first noticeable symptoms in bvFTD, the most common form of FTD. Behavior changes are also common as Alzheimer's progresses, but they tend to occur later in the disease.
* Problems with spatial orientation — for example, getting lost in familiar places — are more common in Alzheimer's than in FTD.
* Problems with speech. Although people with Alzheimer's may have trouble thinking of the right word or remembering names, they tend to have less difficulty making sense when they speak, understanding the speech of others, or reading than those with FTD.
* Hallucinations and delusions are relatively common as Alzheimer's progresses, but relatively uncommon in FTD.
Not surprisingly, these changes in cognition and behavior are brought about by pathological changes in the brain that are also quite different from those of AD. Whereas AD involves the deposit of plaques and tangles and the eventual loss of the much of the cerebral cortex, FTD seems to be caused by more focal changes in specific brain regions, as a result of alternate protein changes. Instead of plaques and tangles, FTD brains show the deposit of Pick bodies and balloon neurons. These inclusions occur mostly in the frontal and temporal (side) parts of the brain, and some patients will experience very focal changes in these regions. For example, patients experience focal losses on the left side of the brain, where the regions that control language abilities are found. Other patients experience more frontal changes, resulting in social behavior symptoms such as unusual speaking to or touching strangers.
Causes and risks
Frontotemporal degenerations are inherited in about a third of all cases. Genetic counseling and testing is available now in individuals with family histories of frontotemporal degenerations. There are no known risk factors for any frontotemporal degenerations except for a family history or a similar disorder.
Treatment and outcomes
There are no specific treatments for any of the frontotemporal subtypes. There are medications that can reduce agitation, irritability and/or depression. These treatments should be used to help improve quality of life.
FTD inevitably gets worse over time and the speed of decline differs from person to person. For many years, individuals with FTD show muscle weakness and coordination problems, leaving them wheelchair- or bedbound. These muscle issues can cause problems swallowing, chewing, moving and controlling bladder and/or bowels. Eventually people with frontotemporal degenerations die because of the physical changes that can cause skin, urinary tract and/or lung infections.
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.
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