Frontotemporal dementia (FTD) is a disorder marked by progressive degeneration of the frontal and or temporal lobes of the brain. It is the most common form of dementia in people under 60, and it is sometimes referred to as Pick’s disease.
There is no one distinctive way the disorder presents itself. The frontal and temporal lobes of the brain are involved in many functions, any of which can be affected, and the initial symptoms of the disorder can vary significantly from person to person. The frontal lobe of the brain is essential for judgment and decision-making, voluntary movement, expressive language, working memory, planning and organizing, and self-monitoring and self-control. The temporal lobes, one on either side of the skull, house such functions as processing sensory information, processing and retrieving memories, emotion management, and language understanding.
A persistent problem in any of those functions can be the first sign of FTD. FTD is not considered a psychiatric disorder. However, the disease alters people’s personality and behavior as well as language capability and movement, and it may first manifest in behavioral irregularities resembling those seen in schizophrenia and bipolar disorder and be given a psychiatric diagnosis. Disinhibition, apathy, loss of empathy, and compulsions are common features.
Because of its variable presentation, FTD is frequently misdiagnosed. In 2022, the family of actor Bruce Willis disclosed that he was suffering from aphasia, a disorder affecting his ability to communicate. In 2023 the family announced that his condition had progressed, and the actor had more recently received a diagnosis of FTD.
FTD is marked by changes in language, behavior, and movement, and symptoms may first emerge in any of these domains, compromising the ability to function. One variation of the disorder affects movement primarily, leading to frequent misdiagnosis as Parkinson’s disease.
As the disease progresses, which may take anywhere from two to 20 years, executive functions such as planning and organizing are affected. Over time, symptoms can increasingly resemble those of Alzheimer’s disease.
In one variant of FTD, the so-called behavioral variant, the earliest and most prominent symptoms are changes in personality and behavior. The nerve-cell loss occurs most prominently in nodes of the brain that control conduct, judgment, empathy, and planning. Self-control fails. Memory typically remains intact. This is the most common form of FTD.
In another variant, primary progressive aphasia, the most prominent symptoms center on language. People may lose the ability to understand or generate words, they may lose the ability to write, or they may lose fluidity of speech and speak only with great hesitation and great effort, if at all. People with this form of the disorder often develop problems with memory and reasoning over time.
Another variant of FTD affects muscle mass or movement without necessarily affecting speech or behavior. Patients may develop amyotrophic lateral sclerosis (also called Lou Gehrig’s disease), lose coordination of arms and legs, or develop muscular rigidity causing difficulty in walking and changes in posture (supranuclear palsy).
Because FTD is so frequently misdiagnosed, there is no source of accurate information on the frequency of its occurrence in the population. It is known, however, that frontotemporal dementia is the most common form of dementia in people under age 60. It is thought to be as common as early-onset Alzheimer’s disease. But among people over 65, it is far less common than Alzheimer’s disease.
There is no definitive test for FTD, and because symptoms can resemble those of other disorders, or they fully unfold only as the disorder progresses, accurate diagnosis can be delayed. In the case of Bruce Willis, for example, difficulties with words and speech were the earliest symptoms and led to a diagnosis of aphasia. Soon, however, other symptoms emerged.
The most important tools in FTD diagnosis are detailed personal and family history, genetic tests, and brain scans. Diagnosis usually begins with observation of and a detailed history of a person’s symptoms. A personal and family medical history is also important. A family history of related disorders may prompt the need for genetic tests and laboratory tests to rule out other possible causes. Psychiatric tests may be ordered to rule out such conditions as depression and other psychiatric disorders. Neurological tests are conducted to assess memory, cognitive skills, language skills, and motor function. And finally, brain scans may be used to detect patterns of regional brain atrophy as a way to confirm a diagnosis.
The cause of FTD is unclear, but a mix of biological and experiential factors appears to put people at risk. Researchers report that there is a familial basis of the disorder in up to 40 percent of cases, with close relatives experiencing some form of dementia, a major psychiatric condition, or a progressive movement disorder. In up to half of the familial cases, a distinctive genetic variation is implicated, and genetic testing, while not definitive by itself, may, along with a detailed family history, help clinicians render a diagnosis.
It is not clear what causes FTD, and in most cases, the cause remains unknown. There is evidence that an array of aberrant proteins accumulate in affected neurons, including tau, a protein normally found in brain cells but whose malfunction is implicated in various forms of neural degeneration, including Alzheimer’s disease. In some cases of FTD, genetic mutations of the tau protein are implicated, some of which may be inherited and some spontaneous.
Estimates vary, but genes are thought to play some kind of role in 10 to 30 percent of cases of FTD. Researchers report that inherited or spontaneous mutations of the tau gene cause dysfunction of the protein serious enough to lead to dementia in approximately 5 percent of cases of FTD. The specific nature of the tau dysfunction seen in FTD resembles that seen in cases of chronic traumatic encephalopathy.
Another protein in brain cells, called TDP-43, can also misbehave in brain cells. Its dysfunction is attributed to a mutation in the so-called GRN gene. Mutations in the GRN gene are linked to many symptoms of FTD, but especially to the behavioral variant.
As matters now stand, FTD is a progressive disease for which no disease-modifying treatment exists. It typically strikes people between the ages of 45 and 65, men and women in roughly equal numbers.
As degeneration of the frontal and or temporal lobes of the brain progresses, more functions are affected. In addition to language, behavior, and movement problems, people with FTD develop problems with memory and cognition that somewhat resemble those of Alzheimer’s disease. They also develop physical complications such as pneumonia, infection, and injuries from falls. Among people with FTD, the most common cause of death is pneumonia. Researchers found that the average life expectancy from the start of symptoms is seven to 13 years.
There is as yet no known way to stop the progression of FTD, slow it, or prevent it. There are, however, ways to manage symptoms. For example, certain psychiatric medications may be used to modify behavioral symptoms. Antidepressants such as SSRIs are commonly prescribed to treat the social disinhibition and impulsive behaviors that occur in patients with FTD. Antipsychotic medications may be given in small doses to help curb aggressive behavior or delusions.
For patients whose FTD involves language problems, several strategies may be deployed at once. Speech-language therapists and pathologists can help patients maintain ways to communicate in the present and, because FTD is a progressive disorder, develop communication strategies that will work in the future. For example, they may help patients build banks of photographs of people and lists of words and phrases to point to when language deteriorates. Physical and occupational therapy can help relieve stiffness, soreness, and slowness for those with muscle involvement and movement problems.
There is no medication that has been shown to reverse, stop, slow, or prevent the decline that is the hallmark of FTD. However, drugs may be used to ameliorate specific cognitive and behavioral symptoms.
SSRIs, commonly used to treat depression and anxiety, are often prescribed to help FTD patients experiencing such symptoms as apathy, depression, anxiety, agitation, and obsessive-compulsive behavior.
Antipsychotic agents may be used to help patients control aggressive and agitated behavior.
Drugs that are used to treat memory and attention problems in patients with Alzheimer’s disease are also sometimes used in FTD patients.
An array of non-drug support services can help patients with FTD function. Physical and occupational therapy can help patients with movement and coordination problems. Speech therapy can support those with language difficulties.
Genetic testing can be helpful in families where a person has FTD. Those patients whose condition is associated with a genetic mutation of one of the neural proteins have a 50-50 chance of passing the disorder on to each child. Evaluation of genetic risk for the disorder may factor into childbearing decisions.
In addition, caregiver interventions can have a direct positive impact on patients as well as those tending to them. Caregiving to FTD patients can be demanding, and families of those with FTD may benefit from informational and emotional support groups offered by nonprofit organizations dedicated to FTD and local clinics. The diagnosis of FTD typically puts an emotional burden as well as a large socioeconomic burden on families. However, clinicians report that the years leading up to a diagnosis are usually also highly stressful for a spouse and other family members, creating marital strife, financial difficulties, and even estrangement from friends and family.