Frontotemporal Dementia Clinical Symptoms
FTD Fact Sheet (PDF)
|William Hu, MD, PhD, has joined the Emory University faculty to acelerate the progress of research on biomarkers of Alzheimer's Disease and frontotemporal dementia.
Frontotemporal dementia (FTD) is the second most common dementing illness in those under the age of 65. In general, it affects a younger population than Alzheimer’s disease. Unlike Alzheimer’s disease, FTD is more likely to start in the 50s-70s than in the 80s.
FTD is an umbrella term, and your neurologist may give a more specific diagnosis based on each patient’s history and symptoms. According to the most severe or the earliest symptoms, neurologists can sometimes give a more specific FTD diagnosis. These possibilities include:
- Behavioral variant FTD – these patients have prominent, early changes in their behavior (such as being more impulsive or irritable), social interaction with others (kissing strangers, crude or explicit remarks), initiative to participate in hobbies (too much or too little), ability to control one’s own actions (excessive eating, pacing), or decision making abilities. In the past, bv-FTD may have been called Pick’s disease or FTD. Nowadays, the term Pick’s disease is reserved for a very specific type of change in the brain only detectable under a microscope, and FTD is used more broadly to include bv-FTD and other types of FTD.
- Primary Progressive Aphasia (PPA) – these patients have language abnormalities early in the disease course, although they can develop personality and behavior changes later. Depending on the type of language and speech problems in each patient, neurologists can further classify PPA into semantic variant PPA or semantic dementia, agrammatic/non-fluent PPA or progressive non-fluent aphasia, and logopenic progressive aphasia.
- Corticobasal syndrome (CBS) – these patients have troubles with planning and execution of certain actions, and may have a hard time using familiar objects, both simple (a fork) and complex (a computer keyboard). Some of these patients may walk or move like they have Parkinson’s disease, and some develop speech changes similar to PPA.
Other symptoms may emerge later in the disease course.
- Some bv-FTD and PPA patients develop troubles with walking and moving their eyes, and this combination of symptoms may suggest another related condition called progressive supranuclear palsy (PSP).
- About 10-15% of the patients can develop symptoms of amyotrophic lateral sclerosis (ALS, or Lou Gehrig’s disease).
Causes of FTD
Scientists believe that the cause of a patient’s dementia is related to the changes seen in his or her brain (the neuropathology). For example, when someone is diagnosed with Alzheimer’s disease, there is a 85-90% chance that changes seen in his or her brain are similar to the changes seen in other brains of patients diagnosed with Alzheimer’s disease. A number of unique neuropathologic changes have been identified in FTD, and many scientists at Emory and elsewhere are working on how to tell these changes apart by clinical examination, MRI, testing of blood or spinal fluid, or a combination of these tests.
As a group, when brains of patients with FTD are examined after death, we can divide them into main groups based on the changes seen under the microscope.
- 10-15% of patients have changes similar to patients with Alzheimer’s disease, even though their symptoms do not resemble the forgetfulness seen in those with Alzheimer’s disease. A spinal fluid test for Alzheimer’s disease may identify those in this group.
- Some patients show changes in a protein called TDP-43. These cases are referred to as “FTLD-TDP”.
- Some patients have changes associated with an abnormal form of the protein Tau. Neurologists and pathologists refer to these cases collectively as “FTLD-Tau” or “tauopathy”, although they may refine their diagnosis with more specific terms such as Pick’s disease, corticobasal degeneration (CBD), progressive supranuclear palsy (PSP), etc.
- A small group of patients have changes in a protein called FUS, and this group is known to have FTLD-FUS.
- A collection of other related diseases account for the remaining cases of FTD.
It is estimated that up to 40% of FTD patients have a family history of a progressive neurological disorder, and these diseases can include Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis (ALS) or Lou Gehrig’s disease, among others.
Mutations in a number of genes have been identified to cause multiple members in the same family to have FTD, including
- PGRN, which results in abnormal levels of the protein progranulin and abnormal deposition of TDP-43 (clinical testing available)
- TARDBP, which results in abnormal deposition of TDP-43
- MAPT, which results in abnormal accumulation of the protein tau (clinical testing available)
- VCP (valosin-containing protein) in rare families – members of these families often have involvement of the muscles and bone
The diagnosis of whether you have FTD and which subtypes (bv-FTD, PPA, etc) is made by your neurologist after a complete evaluation that may include:
- History from you and your family members or friends;
- Neurological examination;
- Neuropsychological testing to determine brain functions which may be more affected than others;
- Brain imaging such as MRI to look for areas of volume loss and other causes of dementia (such as strokes);
- Functional brain imaging such as a PET scan to look for changes in brain function;
- Blood tests to look for other disorders that can cause behavior and/or language changes;
- Lumbar puncture to look for other causes of behavior and/or language changes that are not detectable in the blood.
- There is currently no FDA-approved medication for FTD, although some are under investigation and researchers are developing others to target the main changes in the brain (TDP-43 or Tau).
- Medicines used in Alzheimer’s disease are variably effective in patients with FTD, and your neurologist may recommend trying one or more of these.
- Other medications may be used to treat specific symptoms such as irritability, sleep disturbance, and mood swings.