The symptoms of frontotemporal dementia (FTD) and other frontotemporal disorders gradually rob people of basic abilities — thinking, talking, walking, and socializing — that most of us take for granted. FTD and other frontotemporal disorders are a common cause of early-onset dementia. They often strike people in the prime of life when they are working and raising families. Families suffer, too, as they struggle to cope with the person’s daily needs as well as changes in relationships and responsibilities.

There is currently no cure for FTD or related disorders, and no treatments to slow or stop the progression of the disease, but there are ways to help manage the symptoms. Research is improving our awareness and understanding of these challenging conditions. This progress is opening doors to better diagnosis, improved care, and eventually, new treatments.

Frontotemporal disorders result from damage to neurons primarily in the frontal and temporal lobes of the brain. As neurons die in these regions, the frontal and temporal lobes atrophy, or shrink. Gradually, this damage causes difficulties in thinking and behaviors normally controlled by these parts of the brain. Many possible symptoms can result in unusual behaviors, emotional problems, trouble communicating, difficulty with work, or difficulty with movement and walking. FTD and related disorders are rare and tend to occur at a younger age than other forms of dementia. Roughly 60% of people with FTD are 45 to 64 years old.

Frontotemporal disorders are progressive, meaning symptoms get worse over time. In the early stages, people may have just one type of symptom. As the disease progresses, other symptoms will appear as more parts of the brain are affected. It is difficult to predict how long someone with FTD will live. Some people live more than 10 years after diagnosis, while others live less than two years after they are diagnosed.

How frontotemporal disorders affect the brain

Frontotemporal disorders affect the frontal and temporal lobes of the brain. They can begin in the frontal lobe, the temporal lobe, or both. Initially, frontotemporal disorders leave other brain regions unaffected, including those that control short-term memory.

The frontal lobes, situated above the eyes and behind the forehead, direct executive functioning. This includes planning and sequencing (thinking through which steps come first, second, third, and so on), prioritizing (doing more important activities first and less important activities last), multitasking (shifting from one activity to another as needed), and monitoring and correcting errors.

When functioning well, the frontal lobes also help manage emotional responses. They help people avoid inappropriate social behaviors, such as shouting loudly in a library or at a funeral. They aid in making decisions that make sense for a given situation. When the frontal lobes are damaged, people may focus on insignificant details and ignore important aspects of a situation.

The frontal lobes are also involved in language, particularly linking words to form sentences, and in motor functions, such as moving the arms, legs, and mouth. The temporal lobes, located below and to the side of each frontal lobe on the right and left sides of the brain, contain essential areas for memory and play a major role in language and emotions. They help people understand words, speak, read, write, and connect words with their meanings. They allow people to recognize objects and to relate appropriate emotions to objects and events. When the temporal lobes aren’t working properly, people may have difficulty recognizing and responding appropriately to emotions.

Which lobe — and which part of the lobe — is affected first determines which symptoms appear initially. For example, if the disease starts in the part of the frontal lobe responsible for decision-making, then the first symptom might be trouble managing finances. If it begins in the part of the temporal lobe that connects emotions to objects, then the first symptom might be an inability to recognize potentially dangerous objects — a person might reach for a snake or plunge a hand into boiling water, for example. 

In rare cases, frontotemporal disorders can begin in a different part of the brain. For example, when a person has early movement problems, such as falls, swallowing difficulties, or muscle stiffness, the disease may be beginning in the movement parts of the brain, such as the basal ganglia or brainstem.

What are the types and symptoms of frontotemporal disorders?

Frontotemporal disorders can be grouped into three types, defined by the earliest symptoms. In the early stages, it can be hard to know which type of frontotemporal disorder a person has because symptoms and the order in which they appear can vary from one person to another. Also, the same symptoms can appear across different disorders and vary from one stage of the disease to the next as different parts of the brain are affected.

In general, changes in the frontal lobe are associated with behavioral symptoms, while changes in the temporal lobe affect language and emotions. Because it is rare and not well understood, FTD is sometimes misdiagnosed as Alzheimer’s disease or other types of dementia.

Symptoms of FTD and related disorders are often misunderstood. Family members and friends may think that a person is misbehaving, leading to anger and conflict. It is important to understand that people with these disorders cannot control their behaviors and other symptoms and (before they are diagnosed) lack any awareness of their illness.

Behavioral variant frontotemporal dementia

The most common FTD, behavioral variant frontotemporal dementia (bvFTD), involves changes in personality, behavior, and judgment. People with bvFTD can act strangely around other people, resulting in embarrassing social situations. Often, they don’t know or care that their behavior is unusual and don’t show any consideration for the feelings of others. People with this disorder may or may not have problems with cognition or memory.

Symptoms can include:

• Problems planning and sequencing
• Difficulty prioritizing tasks or activities
• Repeating the same activity or saying the same word over and over
• Acting impulsively or saying or doing inappropriate things without considering how others perceive the behavior
• Becoming uninterested in family or activities they used to care about
• Displaying flat, exaggerated, or improper emotions that seem disconnected from the situation
• Difficulty reading social signals, seeming to lack empathy
• Compulsive eating or taking food from others’ plates

Over time, language and/or movement problems may occur, and the person living with bvFTD will need more care and supervision.

Primary progressive aphasia

Primary progressive aphasia (PPA) involves changes in the ability to communicate — to use language to speak, read, write, and understand what others are saying. This includes difficulty using or understanding words (aphasia) and difficulty speaking properly (e.g., slurred speech). People with PPA may have one or both of these symptoms. They may eventually become unable to speak.

Many people with PPA develop symptoms of dementia. Problems with memory, reasoning, and judgment are not apparent at first but can develop over time. Some people with PPA may experience significant behavioral changes, similar to those seen in bvFTD, as the disease progresses.

There are three types of PPA, categorized by the language problems that appear first.

• Semantic PPA: A person slowly loses the ability to understand single words and sometimes to recognize the faces of familiar people and common objects.
• Agrammatic PPA: A person has more and more trouble speaking and may omit words that link nouns and verbs (such as to, from, and the). Eventually, the person may no longer be able to speak at all. The person may later develop movement symptoms similar to those seen in corticobasal syndrome (see below).
• Logopenic PPA: A person has trouble finding the right words during a conversation but can understand words and sentences. The person does not have problems with grammar. Logopenic PPA is usually accompanied by the hallmark brain changes seen in Alzheimer’s.

Researchers do not fully understand the biological basis of the different types of PPA. But they hope one day to link specific language problems with the changes in the brain that cause them.

Movement disorders

Two rare neurological movement disorders associated with FTD, corticobasal syndrome and progressive supranuclear palsy, occur when the parts of the brain that control movement are damaged. The disorders may affect thinking and language abilities, too.

• Corticobasal syndrome (CBS) can be caused by corticobasal degeneration — a gradual atrophy (shrinking) and loss of nerve cells in specific parts of the brain. This causes progressive loss of the ability to control movement, typically beginning around age 60. The most prominent symptom may be apraxia, the inability to use the hands or arms to perform a movement despite normal muscle strength. Apraxia leads to problems such as difficulty fastening buttons or operating small appliances. Other symptoms can include muscle rigidity and difficulty swallowing. Symptoms may appear first on one side of the body, but eventually both sides are affected. Occasionally, a person with corticobasal syndrome first has language problems or trouble orienting objects in space and later develops movement symptoms. Not everyone who has corticobasal syndrome has problems with memory, cognition, language, and behavior in addition to the loss of their ability to control their movements.
• Progressive supranuclear palsy (PSP) typically causes problems with balance and walking. People with the disorder often move slowly, experience unexplained falls, lose facial expression, and have body stiffness, especially in the neck and upper body. These symptoms are similar to those of Parkinson’s disease. A hallmark sign of this disorder is trouble with eye movements, particularly looking down. These symptoms may give the face a fixed stare. Problems with behavior, language, problem solving, and judgment can also develop.

Other movement-related types of FTD include frontotemporal dementia with parkinsonism and frontotemporal dementia with amyotrophic lateral sclerosis (FTD-ALS).

• Frontotemporal dementia with parkinsonism is usually caused by CBS or PSP, and in rare cases can be an inherited disease. Symptoms are similar to those of Parkinson’s and include slowed movement, stiffness, balance problems, and changes in behavior or language.
• FTD-ALS, also called FTD with motor neuron disease, is a combination of bvFTD and amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig’s disease. In addition to the behavioral and/or language changes seen in bvFTD, people with FTD-ALS experience the progressive muscle weakness, fine jerks, and wiggling in muscles (fasciculation) seen with ALS. Symptoms of either disease may appear first, with other symptoms developing over time.

What causes frontotemporal disorders?

Scientists are beginning to understand the biological and genetic basis for the changes observed in brain cells that lead to FTD.

Scientists describe FTD using the patterns of change in the brain seen in an autopsy after death. These changes include loss of neurons and abnormal amounts or forms of proteins called tau and TDP-43. These proteins occur naturally in the body and help cells function properly. When the proteins don’t work right, for reasons not yet fully understood, neurons in specific brain regions are damaged.

People can have changes in their brain associated with multiple forms of dementia. For example, people with corticobasal syndrome or logopenic PPA may also have beta-amyloid plaques in their brain, which are associated with Alzheimer’s.

In most cases, the cause of FTD is unknown. Individuals with a family history of the disease are more likely to develop FTD.

FTD that runs in a family is often related to variants (permanent changes) in certain genes. Genes are basic units of heredity that tell cells how to make the proteins the body needs to function. Even small changes in a gene may produce an abnormal protein, which can lead to changes in the brain and, eventually, disease. An estimated one-third of FTD cases are inherited, meaning the genetic variant is passed from parent to child. These genetic variants can often be identified through genetic testing.

Scientists have discovered several different genes that, when changed or mutated, can lead to FTD. These include:

• MAPT gene — A change in this gene causes abnormalities in the tau protein, which can then form tangles inside neurons and ultimately lead to the destruction of brain cells. Inheriting a variant in this gene means a person will almost surely develop a frontotemporal disorder, usually bvFTD, but the exact age of onset and symptoms cannot be predicted.
• GRN gene — A change in this gene can lead to lower production of the protein progranulin, which in turn causes another protein, TDP-43, to go awry in brain cells. This can lead to frontotemporal disorders, with bvFTD being the most common. A change in the GRN gene can cause different symptoms in different family members, and the disease can begin at different ages.
• C90rf72 gene — An unusual variant in this gene appears to be the most common genetic abnormality in familial frontotemporal disorders and familial ALS. This variant can cause a frontotemporal disorder, ALS, or both conditions.

In recent years, researchers have discovered several other genetic changes that lead to rare familial types of frontotemporal disorders. These other variants account for less than 5% of all cases of FTD.

Scientists are continuing to study these genes and to search for other genes and proteins, as well as nongenetic risk factors, that may play a role in FTD. They are trying to understand, for example, how variants in a single gene can lead to different types of FTD in members of the same family. Environmental factors that may influence risk for developing the disorders are also being examined.

How are frontotemporal disorders diagnosed?

FTD can be hard to diagnose because the symptoms resemble those of other conditions. For example, bvFTD is sometimes misdiagnosed as a mood disorder, such as depression. To make matters more confusing, a person can have both FTD and another type of dementia, such as Alzheimer’s. Also, because these disorders are rare, physicians may be unfamiliar with the signs and symptoms.

To help diagnose FTD, a doctor may:

• Perform an exam and ask about symptoms
• Review personal and family medical history
• Use laboratory tests to help rule out other conditions, including Alzheimer’s
• Order genetic testing
• Conduct evaluations to assess behavior, memory, thinking, language skills, and physical function
• Order imaging of the brain

A psychiatric evaluation can help determine if depression or another mental health condition is causing or contributing to the condition. A diagnosis of FTD can only be confirmed by genetic tests (in familial cases) or a brain autopsy after death.

Getting the wrong diagnosis can be frustrating. Without an accurate diagnosis, people with FTD and related disorders may not get appropriate treatment to manage their symptoms. Families may not get the help they need. Learn about medical centers that can help people with FTD get diagnosis and treatment.

Read more about how FTD is treated and managed.

Researchers are studying ways to diagnose FTD earlier and more accurately, and to distinguish these conditions from other types of dementia. One area of research involves biomarkers, such as proteins or other substances in the blood or cerebrospinal fluid, which can be used to help diagnose FTD and measure disease progression. Results from biomarker tests also can help rule out other causes of dementia. For example, a blood test for Alzheimer’s could help establish whether the cause of dementia is likely to be Alzheimer’s or something else. Researchers are also exploring ways to improve brain imaging and neuropsychological testing.

To learn more, please visit https://www.nia.nih.gov/health/frontotemporal-disorders/what-are-frontotemporal-disorders-causes-symptoms-an