Frontotemporal dementia (FTD) or frontotemporal lobe dementia is a term used to describe a group of neurodegenerative disease which classically characterized by gradually progressive deterioration or changes in behaviour and/or language, as a result of neurodegeneration of frontal and/or temporal lobes. In FTD, early symptoms include impairment in cognition, and/or behavior and sometimes motor abnormalities. Unlike, Alzheimer’s disease (AD), which is also dementia, behavioral and/or language symptoms predominate in the early disease. Patients usually has impaired planning, judgement because of involved frontal lobe; language dues to temporal lobe. Memory is usually spared at the beginning.
There are several clinical variant of FTD, based on their predominant symptoms. This include behavior variant (bv-FTD), primary progressive aphasia (PPA), and semantic dementia/temporal variant (tv-FTD). As the name implies, bv-FTD has behavioral symptoms predominated, which include loss of proper social conduct, neglect of personal hygiene, obsession and compulsion, poor concentration and emotional blunting; they usually do not aware of these. In PPA however, there is gradually loss of the abilities in expressing a speech; expressive aphasia or non-fluent aphasia. For semantic dementia, victims has loss of the ability to understand the meaning of words, but their speech fluency is maintained.
In making diagnosis of FTD, usually depend on clinical judgment and supported by neuroimaging. Neary criteria is used to make clinical diagnosis and its has specificity of near 100% but sensitivity of 30% only. Neuroimaging on average has specificity and sensitivity ranging from 60-80%.
Picture obtained from http://brain.oxfordjournals.org/content/126/4/814/F3.expansion
Please read http://emedicine.medscape.com/article/1135164-overview for more information