TTTT is a non-invasive and new investigative examination, and a most important method of clinical diagnosis for many diseases, specially for orthostatic syncope, autonomic failure, intracranial hypertension, neurodegenerative diseases, CVAs and so on. At the same time, TCD technique for non-invasive monitoring of CBFV has also provided a new tool for investigating CA. In clinical circumstance, we may carry on assessment of dynamic CA by TTTT, and this kind of method has been proved to be appropriate to examine patients and monitor. we can choose different tilt positions by tilt-table according to the different demands for clinical diagnosis or researches, and record the different appearances of various index signs, we can take advantage of the technique of transfer function analysis of power spectrum between spontaneous changes in CBF and other factors (such as arterial pressure) to do research on the specific mechanism of impaired CA.