Thioflavin T fluorescence kinetics and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) spectroscopy were used to classify tau aggregates from human brain homogenates.<h4>Results</h4>This method differentiated eight tauopathies, including Alzheimer's disease, Pick disease, progressive supranuclear palsy (PSP), corticobasal degeneration (CBD), argyrophilic grain disease (AGD), frontotemporal dementia with parkinsonism associated with chromosome 17 with N279K mutation (FTDP-17 N279K), and globular glial tauopathies types II and III. The gene discussed is MAPT; the disease is Parkinson disease.