A mathematical model of autoregulation of cerebral circulation in the human body for obtaining additional information to make decisions about choosing a treatment plan has been presented in the paper. The fractal analysis methods based on wavelet leaders, which made it possible to expand the traditional approach to assessing the interaction between systemic arterial pressure and linear blood flow velocity formed the basis of the developed nonlinear model of autoregulation. The application of the developed methods to assessing the state of the autoregulation system in a healthy volunteer and a patient with cerebral pathology was exemplified.