Frontotemporal dementia (FTD)
Frontotemporal dementia (FTD) refers to a group of neurodegenerative disorders primarily impacting the frontal and temporal lobes of the brain. These areas are crucial for regulating behavior, personality, and language skills. Individuals with FTD may experience significant behavioral changes, such as impulsivity, apathy, or loss of social awareness, alongside potential language difficulties like primary progressive aphasia or semantic dementia. The onset of symptoms typically occurs between the ages of 40 and 70, leading to a median survival of six to eight years post-diagnosis, although this can vary based on specific types, such as FTD with motor neuron disease, which is associated with a shorter survival time.
The exact cause of FTD is often linked to genetic factors, with about half of cases displaying a family history of the disorder. While there are currently no treatments available to halt disease progression, symptom management through speech therapy, caregiver support, and medications for behavioral symptoms are common approaches. Research is ongoing into the genetic underpinnings of FTD, with potential therapeutic interventions aimed at addressing the molecular changes associated with the disorder. Understanding FTD is critical not only for affected individuals and their families but also for healthcare providers to ensure accurate diagnosis and appropriate care planning.
Frontotemporal dementia (FTD)
ANATOMY OR SYSTEM AFFECTED: Brain, nervous system, psychic-emotional system
DEFINITION: Frontotemporal dementia is a descriptive term for a group of neurodegenerative disorders that affect the frontal and temporal lobes of the brain.
CAUSES: About half with family history, several genes identified
SYMPTOMS: Behavior changes (apathy, lack of inhibition, repetitiveness), speech and language changes (primary progressive aphasia and semantic dementia), motor neuron disease, Parkinson’s disease
DURATION: Eight to ten years until death; if with motor neuron disease, three to five years until death
TREATMENTS: None; therapy to manage symptoms
Causes and Symptoms
Frontotemporal dementias (FTDs) are a group of disorders characterized by degeneration of the frontal and of the brain. These areas in the are responsible for language, behavior, and personality. Magnetic resonance imaging (MRI) of the brain can show shrinkage of the brain in these areas (frontal and/or temporal lobes). FTDs can show symptoms depending on which parts of the brain may be affected. Most individuals have either behavior changes or language disturbances as their main feature.
Behavior changes associated with FTDs include dramatic personality changes, toward either impulsive and disinhibited or apathetic and listless. Frequently, verbal and facial social cues are unrecognizable to affected individuals. Additional behaviors can include isolation, lack of empathy and sympathy, distractibility, loss of insight, dietary changes (sweet food preferences), neglect of personal hygiene, repetitive behaviors, and decreased motivation. Language changes in FTDs are of two main types: loss of ability to speak as a result of difficulty with word recall (primary progressive aphasia) or loss of ability to understand language (semantic dementia).
Frequently, family members bring affected individuals to medical attention because of these behavioral changes, which go unrecognized to the individual. The onset of FTD can be from age forty to seventy; therefore, individuals can be living with the disease many years before family members notice personality and behavior changes or behaviors begin to interfere with activities of daily living.
There are a few rare types of FTDs that involve movement disorders in addition to dementia. One type is FTD with motor disease (MND). Classical MND is also called amyotrophic lateral sclerosis (ALS) or Lou Gehrig’s disease. FTD can also be seen with symptoms of Parkinson’s disease. Movement disorder-related symptoms can include tremor, weakness, difficulty swallowing, and poor coordination.
People can be misdiagnosed with psychiatric problems, especially with the young age of onset seen in FTDs. Others can be misdiagnosed with because physicians see this disease much more often.
Men and women are affected equally by FTD. Family history is the greatest risk factor for FTDs, with approximately 50 percent of all FTD cases showing familial inheritance. Mutations in several genes have been shown to cause several types of FTDs. Genetic testing may be offered. Individuals with FTD symptoms will undergo a variety of tests to try to rule out other illnesses that may mimic the symptoms of FTD. These tests may include blood count, electrolytes, liver function, thyroid function, and kidney function. Also, images of the brain via and may be obtained to rule out bleeding or tumors that can cause similar symptoms. Finally, neuropsychological testing may be used to help determine if there are language, memory, and/or reasoning deficits to aid in the diagnosis of FTD.
Treatment and Therapy
FTD is a degenerative disorder. There are no treatments to cure or slow the progression of the brain degeneration. The median duration of illness is six to eight years from onset to death, although the length of time can range from less than two years to more than ten years. Individuals with FTD-MND have a shorter survival time, with a median survival of only three years. Most therapy for individuals with FTDs focuses on managing the symptoms and behaviors seen in the disorder. Speech therapy can be helpful to learn new strategies to aid in verbal and written communication. Caregivers can help reduce behavior problems by avoiding behavior triggers (events or activities), anticipating needs, and maintaining a calm environment. Caregivers should focus on building a support network that includes social services, psychiatric care, support groups, respite care in adult care centers, and/or home health aids. Ultimately, individuals with FTDs will progress to require twenty-four-hour care, and nursing may be required. Many patients, if able, may wish to help family members with this planning ahead of time, making the transition for caregivers and family members easier knowing that the affected individual was part of the decision-making process.
Medications currently used to treat the behavioral symptoms of FTD include and antipsychotics. These drugs have not shown great success. Therapeutic research related to the genetic causes of FTDs, however, has shown promise. For example, the microtubule-associated protein tau (MAPT) gene can be altered to cause toxic clumps and tangles of MAPT protein. These MAPT tangles are seen in several forms of FTDs. Therapies and drugs designed to prevent or fix the MAPT tangles are currently being designed and tested in animal models. Additional testing and validation will be needed before clinical trials begin in humans.
Perspective and Prospects
FTD was originally described by Arnold Pick in the 1890s. He published a case series of patients in which he described the behavioral and language variants now part of the clinical criteria of FTD. In 1926, two neuropathologists, K. Onari and Hugo Spatz, described the brain findings commonly seen in FTD, including shrinkage of the frontal and temporal lobes and Pick bodies. In the 1980s, the term “frontolobe dementia” and “frontotemporal dementia” were derived in a group of papers trying to define the clinical criteria of FTD and help differentiate the disorder from Alzheimer’s disease. The recent discovery of several mutated genes that can cause FTD symptoms has helped physicians and scientists define the disorder and will only lead to improved diagnosis and treatments for the future.
Bibliography:
Antonioni, Annibale. "Frontotemporal Dementia, Where Do We Stand? A Narrative Review." International Journal of Molecular Sciences, 21 July 2023, doi.org/10.3390/ijms241411732. Accessed 1 Apr. 2024.
Bradley, Walter, et al., eds. Neurology in Clinical Practice. 6th ed. Boston: Butterworth Heinemann, 2012.
Cairns, Nigel J., et al. “Neuropathologic Diagnostic and Nosologic Criteria for Frontotemporal Lobar Degeneration: Consensus for the Consortium for Frontotemporal Lobar Degeneration.” Acta Neuropathologica 114 (2007): 5–22.
Carson-DeWitt, Rosalyn, and Rimas Lukas. "Dementia." Health Library, Sept. 27, 2012.
"Dementia." MedlinePlus, May 7, 2013.
"Frontotemporal Disorders: Information for Patients, Families, and Caregivers." National Institute on Aging, Mar. 13, 2013.
Kertesz, Andrew. “Frontotemporal Dementia/Pick’s Disease.” Archives of Neurology 61 (2004): 969–971.
Khan, Israr. "Frontotemporal Lobe Dementia." StatPearls, 12 Feb. 2023, www.statpearls.com/ArticleLibrary/viewarticle/91333. Accessed 1 Apr 2024.
"MAPT." Genetics Home Reference, May 13, 2013.
Neary, David, Julie Snowden, and David Mann. “Frontotemporal Dementia.” The Lancet Neurology 4 (2005): 771–780.
"NINDS Frontotemporal Dementia Information Page." National Institute of Neurological Disorders and Stroke, Mar. 20, 2013.