Frontotemporal dementia is also one of the more common cognitive disorders, and the rate of consultation has been increasing in recent years. Since the onset of the disease is earlier than that of Alzheimer’s disease (commonly known as Alzheimer’s disease) and vascular dementia, and the burden is relatively heavier on the patient and his family, it is necessary to introduce some basic concepts of the disease here. Frontotemporal dementia (FTD), also known as frontotemporal lobe degeneration (FTLD), is a group of diseases characterized by behavioral and personality changes and aphasia. According to the epidemiological survey and pathological classification in the United States, frontotemporal lobe degeneration is the third type of dementia after Alzheimer’s disease (AD) and dementia with Lewy bodies (DLB). The age of onset is 45 to 70 years, with the vast majority of patients developing the disease before the age of 65. The duration of the disease ranges from 2 to 20 years, with an average of about 8 years.1,2 The presence of specific spherical silver-loving inclusions in neurons is known as Pick’s vesicles, which are tau protein-positive intraneuronal inclusions. For quite some time thereafter, frontotemporal lobe dementia has been referred to as Pick’s disease. Frontal and temporal pole atrophy is a typical morphological feature of frontotemporal lobe dementia, but in the early stage of the disease, these changes are not very obvious, and with the progression of the disease, the typical limited brain atrophy and hypometabolism can be seen in the imaging manifestations such as MRI or SPECT. In recent years, it has been found that frontotemporal lobe degeneration is a heterogeneous group of syndromes with heterogeneous clinical manifestations and pathological features. According to the 1998 Neary Diagnostic Criteria3 , frontotemporal lobe degeneration mainly includes behavioral variant frontotemporal dementia (bvFTD), which is narrowly defined as frontotemporal lobe dementia or frontotemporal lobe dementia, or frontotemporal lobe dementia. Dementia or frontotemporal dementia frontal lobe type, semantic dementia (SD) and progressive non-fluent aphasia (PNFA) are three clinical syndromes. Clinical features 1, frontotemporal lobe dementia behavioral abnormality type (bvFTD) The personality and behavioral abnormality accompanied by executive impairment is the prominent manifestation, and speech impairment may also be present, but it is usually not the prominent manifestation, and may be masked by personality changes and other more significant clinical symptoms. Personality changes and social dysfunction are the most prominent clinical manifestations, appearing early in the disease and continuing throughout the course of the disease. Perceptual abilities, spatial, utilization and memory functions are relatively preserved. Semantic dementia is the earliest and most severe form of semantic memory impairment, and MRI shows severe atrophy of the inferior lateral temporal lobe cortex, while the structure of the medial temporal lobe, i.e., the hippocampal system (including the hippocampus, parahippocampal gyrus, and inner olfactory cortex), is relatively normal; Alzheimer’s disease is characterized by diffuse cerebral atrophy, and there is no limited temporal lobe cortex atrophy. Therefore, the degree of temporal pole and inferior lateral temporal lobe atrophy is an imaging differential diagnostic feature between semantic dementia and Alzheimer’s disease. 3. Progressive nonfluent aphasia A dementia based on language impairment, characterized by disfluent speech, grammatical errors, and telegraphic speech. Progressive impairment of language is the only obvious area of impairment for at least the first two years of onset. Standardized neuropsychological tests of language function are useful for early identification of primary progressive aphasia (PPA).