Senile dementia of the neurofibrillary tangle type (tangle-only dementia): Neuropathological criteria and clinical guidelines for diagnosis

Senile dementia of the NFT type (SD-NFT) is a subset of dementia in the elderly, characterized by numerous NFT in the hippocampal region and absence or scarcity of senile plaques throughout the brain. Senile dementia-NFT has also been referred to as tangle-only dementia, NFT-predominant form of SD, SD with tangles, or limbic NFT dementia. Herein are proposed the criteria for neuropathological diagnosis of SD-NFT: (i) late-onset dementia with abundant NFT in the hippocampal region and absence or scarcity of senile plaques (amyloid beta protein deposits) throughout the brain; and (ii) exclusion of other dementias with NFT. Some elderly individuals suffering from memory disorder without obvious dementia have neuropathological findings similar to SD-NFT, and they would represent a condition in the process of formation of the SD-NFT pathology. Guidelines for the clinical diagnosis of SD-NFT are also proposed; development of reliable diagnostic tests is necessary to differentiate AD and other neurodegenerative dementias from SD-NFT.