Definition and Overview
Frontotemporal dementia is a group of degenerative dementias caused by selective degeneration of the frontal and temporal lobes. Unlike Alzheimer's disease, which begins with a decline in recent memory, personality and behavioral changes and language disorders first appear in the early stages while memory is relatively maintained.
It is a common cause of early-onset dementia that occurs in people under the age of 65, and the average age of onset is about 58 years, which is earlier than Alzheimer's disease. It starts at a relatively young age and has a significant impact on career and family life.
In ICD-10, it is classified as G31.0 (localized brain atrophy) and includes the disease previously called Pick's disease.
Subtype
Behavioral variant (bvFTD)
Behavioral variant frontotemporal dementia (FTD) is the most common subtype, and its key focus is changes in personality and behavior due to damage to the frontal lobe. Disinhibition, apathy, decreased empathy, perseverative and compulsive behavior, and changes in eating habits appear, and memory is relatively preserved in the early stages.
Primary Progressive Aphasia (PPA)
Primary progressive aphasia is a subtype in which language function declines first. It is divided into the non-fluent type, where words cannot be found, speech becomes slurred, or grammar breaks down, and the semantic type, where the meaning of words is lost. Speech impairment increasingly interferes with everyday communication.
Causes and Pathophysiology
Frontotemporal dementia is based on frontotemporal lobar degeneration, in which abnormal proteins accumulate in nerve cells. The main pathological proteins are tau and TDP-43, and the clinical pattern and course vary depending on which protein is accumulated.
Many cases occur without a clear family history, but some are hereditary and involve genetic mutations such as MAPT, GRN, and C9orf72. In particular, C9orf72 mutation appears together with amyotrophic lateral sclerosis (ALS).
symptoms
Early symptoms of frontotemporal dementia vary depending on the area of damage.
- Personality/behavioral changes: disinhibition, apathy, decreased empathy, impulsive or socially inappropriate behavior
- Changes in eating habits: preference for sweet foods, overeating, compulsive eating
- Speech disorders: Difficulty finding words, decreased fluency in speech, loss of word meaning
- Decreased executive functioning: Decreased ability to plan, make judgments, and solve problems.
Memory decline is often not noticeable in the beginning but appears as it progresses, so it can easily be mistaken for a psychiatric disease.
diagnosis
Diagnosis is a combination of medical history, neuropsychological testing, and brain imaging.
- History taking: Check the time of onset and patterns of behavioral and language changes through guardians
- Neuropsychological testing: assessing selective decline in executive function, behavior, and language domains.
- Behavioral variant diagnostic criteria: Core items such as disinhibition, apathy, and decreased empathy are evaluated using the Rascovsky criteria revised in 2011.
- Brain MRI: confirms focal atrophy of the frontal and temporal lobes
- Functional imaging: Evaluation of decreased metabolism and blood flow in the relevant area
treatment
There is no cure, and symptom management and staying safe are the mainstays of treatment.
Cholinesterase inhibitors used for Alzheimer's disease have limited effectiveness and may worsen behavioral symptoms in some people. For behavioral symptoms, environmental adjustments and non-pharmacological approaches are given priority, and drugs are used cautiously when necessary. Speech rehabilitation is helpful for primary progressive aphasia.
Parental education and support are also important. Because the disease occurs at a relatively young age, the burden of care is high, so understanding behavioral symptoms and linking social support is necessary.