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.
Behavioral changes
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
* Apathy
* 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.
Movement disorders
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:
* Tremor
* Rigidity
* Muscle spasms
* Poor coordination
* Difficulty swallowing
* Muscle weakness
Types
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.
Medications
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.
Therapy
People experiencing language difficulties may benefit
from speech therapy to learn alternate strategies for communication.
Sources and
Additional Information:
http://www.mayoclinic.org/diseases-conditions/frontotemporal-dementia/basics/definition/con-20023876
