Dementia is a clinical syndrome which characterized by progressive cognitive impairment,
behavior disturbance and dysfunction of daily activity. In aging population, Alzheimer's
dementia (AD) is the most common late onset dementia which occupied about 50-75%, the
vascular dementia, frontotemporal lobardegeneration (FTLD) and corticobasal syndrome is
followed. On the other hand, the young onset dementia (YOD), which represents the onset of
dementia before65 years old, is only about 1/10 to 1/100 proportion of late onset dementia.
The YOD is different from late onset dementia in the proportion of degenerative subtype (e.g.
the FTLD is more frequent than AD). Besides, frequent atypical presentation of clinical
syndrome in the YOD which characterize the different variant of AD made the early accurate
diagnosis of AD is more difficult. Currently, there is no available data to describe the
proportion of subtype in YOD in Taiwan. In AD dementia, two important biomarkers are amylod
plaque made by ß-amyloid protein and neurofibrillary tangle made by phosphorylation tau
protein. In the past, they only can be seen under the microscope findings at autopsy study.
Recently, the new amyloid tracer and tau tracer had been developed and could evaluate the
deposition of amyloid and tau protein in human brain. These progresses had substantially
improved the accurate diagnosis of degenerative dementia. A noval tau tracer [ 18F]PM-PBB3,
which had substantially improved the off-target binding and more clear background in human
brain than previous tau tracer. In current project, investigator will aim to consecutive
collect 50 YOD due to the neurodegeneration in 3 years using the NIA-AA research framework
system(ATN system) to achieve accurate diagnosis of the dementia subtype by the detail
clinical neurology study, neuropsychological examination, amyloid positron emission
tomography (PET) and tau PET study. In the first year, investigator will perform feasibility
study to explore the topographical tau distribution in different subtype of YOD. In the next
2 years, investigator will perform a large scale study in a group of YOD to understand the
amyloid and tau deposition and their association with clinical parameters. From current
project, investigator could understand the tau deposition in different YOD subtype.
Investigator also could understand the correlation between clinical phenotype and molecular
pathology. Investigator will use a mathematic model to construct the model of diffusion
kurtosis imaging from brain magnetic resonance imaging (MRI) and relate the white matter
integrity with amyloid and tau PET imaging.