What is frontotemporal dementia (FTD)?
Frontotemporal dementia (FTD) is a group of disorders that result from damage to the frontal and temporal lobes of the brain. Depending on the location of the damage, the disorder causes changes in social behavior, personality, and/or loss of language skills. In addition, some people (between 10 and 20 percent) with FTD also develop neuromuscular and movement disorders, such as parkinsonism or motor neuron disease (also known as amyotrophic lateral sclerosis or Lou Gehrig’s disease).
FTD is a common cause of early dementia. Symptoms worsen over time as more parts of the brain are affected. Unlike typical Alzheimer’s disease, however, memory usually remains intact in the early stages of FTD.
FTD consists of three subtypes:
- Behavioral variant FTD – bvFTD (also called frontal variant FTD). This subtype accounts for about 50 percent of all cases of FTD. Persons with bvFTD experience progressive changes in personality, behavior, emotions, and planning and problem-solving skills.
- Nonfluent primary progressive aphasia (PPA) -- (also called agrammatic PPA). People with this subtype have difficulty forming and speaking words because the brain has trouble planning and performing the facial muscle movements needed to produce speech. They often seem to have problems with grammar, such as leaving out words or mixing up words, effortful speech, and communicate with shorter, simpler, sometimes incomplete phrases.
- Semantic variant PPA (also called temporal variant FTD or semantic dementia). People with this subtype slowly lose their ability to understand the meanings of words, recognize everyday objects and familiar faces, and/or use common items.
Who gets frontotemporal dementia (FTD)?
Approximately 60 percent of people with frontotemporal dementia (FTD) are between the ages of 45 and 64. It is estimated that about 10 percent of dementia cases are the result of FTD. Men and women are affected about equally.
What causes frontotemporal dementia (FTD)?
Frontotemporal dementia (FTD) occurs when abnormal proteins (there are many kinds) build up in the brain. This leads to death of brain cells and deterioration and shrinkage (atrophy) of the frontal and temporal lobes of the brain. Sometimes the disease is genetic, and passed down through families, but in most cases no specific cause can be found.
What functions are controlled by the frontal and temporal lobe of the brain?
The frontal lobes control executive functioning, meaning a person’s ability to plan in a step-by-step process, to choose priorities, to keep track of several tasks at one time, and make adjustments to one’s behavior. The frontal lobe also controls social and emotional responses. In addition, the frontal lobe helps in linking words to form sentences and is crucial making involuntary muscle movements.
The temporal lobes are the major language center, involved with speaking, reading, writing, understanding words and their meanings, and recognizing objects. The temporal lobe also plays a role in recognizing and responding to emotions and is a major memory center.
What are the symptoms of frontotemporal dementia (FTD)?
Early behavioral changes may include:
- Inappropriate social behavior and lack of social tact/manners. Examples include touching or kissing strangers, urinating in public, making rude or offensive comments, doing or saying things that others would find embarrassing or disgusting.
- Lack of empathy (interest in, or understanding of, what others feel), loss of interest in other people or activities, reduced affection, neglect of personal grooming and hygiene
- Changes in food preferences, overstuffing mouth with food, binge eating, eating food quickly, attempting to eat non-food items
- Becoming very obsessive or developing rituals, repeating things, collecting/hoarding items
Language problems may include:
- Difficulty with the ability to form words
- Problems with grammar, leaving words in a sentence out, causing speech to become effortful and shortened to simple, partial phrases
- Lack of understanding of the meanings of words
- Inability to recognize objects or familiar faces
Symptoms of neuromuscular disease or Parkinsonism (most often seen in patients with behavioral FTD) can include:
- Weakness in the arms and legs
- Weakness in the muscles of speech, such as lips and tongue
- Difficulty swallowing
- Muscle jerks or spasms
- Stiffness of muscles and slowness of movement
- Tremor, or shaking
- Problems with balance and walking
The types of symptoms and the order in which they appear can vary.