Frontotemporal dementia involves progressive damage to the frontal and/or temporal lobes of the brain. Symptoms often begin when people are in their 50's or 60's and sometimes earlier. There are two main presentations of frontotemporal dementia– frontal (involving behavioral symptoms and personality changes) and temporal (involving language impairments).
Because the frontal lobes of the brain control judgement and social behavior, people with frontotemporal dementia often have problems maintaining socially appropriate behavior. They maybe rude, neglect normal responsibilities, be compulsive or repetitive, be aggressive, show a lack of inhibition or act impulsively. There are two main forms of the temporal or language variant of frontotemporal dementia. Semantic dementia involves a gradual loss of the meaning of words, problems finding words and remembering people's names, and difficulties understanding language. Progressive non-fluent aphasia is less common and affects the ability to speak fluently. Frontotemporal dementia is sometimes called frontotemporal lobar degeneration (FTLD) or Pick's disease.