What is Frontotemporal Dementia?
Frontotemporal dementia (FTD) is a group of disorders caused by progressive cell degeneration in the brain’s frontal lobes (the areas behind your forehead) or its temporal lobes (the regions behind your ears). The cell damage caused by frontotemporal dementia leads to tissue shrinkage and reduced function in the brain’s frontal and temporal lobes, which control planning and judgment; emotions, speaking and understanding speech, and certain types of movement.
Symptoms of Frontotempral Dementia
FTD includes a range of specific disorders with different core symptoms. There is significant symptom overlap, especially as these disorders progress. The disorders grouped under FTD fall into three broad categories.
The Three Categories of FTD are:
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- Behavioral variant frontotemporal dementia (bvFTD): It takes its greatest toll on personality and behavior. It may begin with subtle changes that may be mistaken for depression. As bvFTD progresses people often develop disinhibition, a striking loss of restraint in personal relations and social life.
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- Primary progressive aphasia (PPA): It affects language skills in early stages, but often also affects behavior as it advances.The two chief forms of PPA have somewhat different symptoms:
- In semantic dementia, people speak easily, but their words convey less and less meaning. They tend to use broad general terms, such as “animal” when they mean “cat.” Language comprehension also declines.
- In progressive nonfluent aphasia, people lose their ability to generate words easily, and their speech becomes halting, “tongue-tied” and ungrammatical. Ability to read and write also may be impaired.
- Primary progressive aphasia (PPA): It affects language skills in early stages, but often also affects behavior as it advances.The two chief forms of PPA have somewhat different symptoms:
- FTD movement disorders: It affects certain involuntary, automatic muscle functions. These disorders also may impair language and behavior.The two primary FTD movement disorders are:
- Corticobasal degeneration (CBD), which causes shakiness, lack of coordination, and muscle rigidity and spasms.
- Progressive supranuclear palsy (PSP), which causes walking and balance problems, frequent falls, and muscle stiffness, especially in the neck and upper body. It also affects eye movements.
Symptoms of Frontotemporal Dementia
Major symptoms of FTD are:
- Dramatic change in personal and social conduct. The individual may lack initiative, seem unconcerned, and neglect domestic, financial and occupational responsibilities.
- Loss of empathy toward others.
- Patients may show shallow affect (flat facial expression or lack of emotional response). Or they may be inappropriately jocular and sing, dance, clap or recite phrases repeatedly.
- Rigid and inflexible thinking and impaired judgment.
- Loss of insight into personal and social misconduct, such as small sexual or moral transgressions.
- Stereotyped (i.e., repetitive) or compulsive behavior. For example, the person with FTD may become compulsive about rituals of hygiene and dress while at the same time neglecting proper hygiene. They may echo what others say, wander restlessly over a fixed route, or adhere to a fixed daily schedule.
- Hypochondriasis, including bizarre somatic complaints.
- Excessive eating or gluttony, food fads (especially a craving for sweet foods) and even excessive alcohol consumption. (The tendency of FTD patients to consume alcohol often leads to a misdiagnosis of alcohol-related dementia.) The person may refuse to eat, however, due to a behavioral pattern called “negativism†or to inability to use motor skills needed for eating.
- Decreased motor skills in later stages.
- Change in sleep patterns, with prolonged sleepiness shown, especially in those that present more apathetic behaviors.
Late Stage FTD Symptoms Include:
- A gradual reduction in speech, culminating in mutism.
- Hyperoral traits.
- Failure or inability to make motor responses to verbal commands.
- Akinesia (loss of muscle movement) and rigidity with death due to complications of immobility.
FTD Testing and Diagnosis:
FTD can be accurately diagnosed with brain scans or imaging. Computed tomography (CT scan) and magnetic resonance imaging (MRI) reveal cerebral atrophy in the frontotemporal regions. Degeneration of the corpus striatum, thalamus and other subcortical structures occurs. Functional brain imaging and single photon emission tomography may reveal dysfunction of the frontal lobes, decreased blood flow, and a selective reduced uptake of tracer in the anterior (front) cerebral hemispheres. Electroencephalography (EEG) remains normal, however, even in advanced stages. In autopsies, brain tissue changes include large neuronal cell loss with secondary spongiform change and astrocyctic gliosis.
Duration and Treatment
The length of FTD varies, with some patients declining rapidly over two to three years and others showing only minimal changes over a decade. Studies have shown persons with FTD to live with the disease an average of eight years, with a range from three years to 17 years. No medications are known currently to treat or prevent FTD. Serotonin-boosting medications may alleviate some behaviors.