Method for estimating a sensation felt by a subject, the sensation being only evaluable by the subject in term of numerical values, the method comprising: - at a first instant, the step of carrying out a method for obtaining a numerical model, the numerical model associating at least one objective measurement to a subjective sensation, an objective measurement being a measurement of a physical quantity representative of the activity of at least one area of the brain of a subject, the sensation being only evaluable by the subject in term of numerical values, the method for obtaining comprising the steps of: a) imaging the at least one area of the brain by using Doppler unfocused waves produced by a ultrasound probe, to obtain at least one acquired image of the activity of the area, b) evaluating a physical quantity representative of the activity of the at least one area based on each acquired image, to obtain at least one objective measurement, c) obtaining from the subject at least one numerical value representative of the subjective sensation, and d) determining the numerical model by using the obtained objective measurement and the obtained numerical value, and - at a second instant posterior to the first instant, the steps of: • imaging the at least one area of the brain by using unfocused waves produced by a ultrasound probe, to obtain at least one second acquired image of the activity of the area, • evaluating a physical quantity representative of the activity of the at least one area based on each second acquired image, to obtain at least one second objective measurement, and • estimating the sensation felt by the subject by using the numerical model applied on the second objective measurement, the numerical model being the model obtained at the first instant. - at a first instant, the step of carrying out a method for obtaining a numerical model, the numerical model associating at least one objective measurement to a subjective sensation, an objective measurement being a measurement of a physical quantity representative of the activity of at least one area of the brain of a subject, the sensation being only evaluable by the subject in term of numerical values, the method for obtaining comprising the steps of: a) imaging the at least one area of the brain by using Doppler unfocused waves produced by a ultrasound probe, to obtain at least one acquired image of the activity of the area, b) evaluating a physical quantity representative of the activity of the at least one area based on each acquired image, to obtain at least one objective measurement, c) obtaining from the subject at least one numerical value representative of the subjective sensation, and d) determining the numerical model by using the obtained objective measurement and the obtained numerical value, and an objective measurement being a measurement of a physical quantity representative of the activity of at least one area of the brain of a subject, the sensation being only evaluable by the subject in term of numerical values, the method for obtaining comprising the steps of: a) imaging the at least one area of the brain by using Doppler unfocused waves produced by a ultrasound probe, to obtain at least one acquired image of the activity of the area, b) evaluating a physical quantity representative of the activity of the at least one area based on each acquired image, to obtain at least one objective measurement, c) obtaining from the subject at least one numerical value representative of the subjective sensation, and d) determining the numerical model by using the obtained objective measurement and the obtained numerical value, and a) imaging the at least one area of the brain by using Doppler unfocused waves produced by a ultrasound probe, to obtain at least one acquired image of the activity of the area, b) evaluating a physical quantity representative of the activity of the at least one area based on each acquired image, to obtain at least one objective measurement, c) obtaining from the subject at least one numerical value representative of the subjective sensation, and d) determining the numerical model by using the obtained objective measurement and the obtained numerical value, and - at a second instant posterior to the first instant, the steps of: • imaging the at least one area of the brain by using unfocused waves produced by a ultrasound probe, to obtain at least one second acquired image of the activity of the area, • evaluating a physical quantity representative of the activity of the at least one area based on each second acquired image, to obtain at least one second objective measurement, and • estimating the sensation felt by the subject by using the numerical model applied on the second objective measurement, the numerical model being the model obtained at the first instant. • imaging the at least one area of the brain by using unfocused waves produced by a ultrasound probe, to obtain at least one second acquired image of the activity of the area, • evaluating a physical quantity representative of the activity of the at least one area based on each second acquired image, to obtain at least one second objective measurement, and • estimating the sensation felt by the subject by using the numerical model applied on the second objective measurement, the numerical model being the model obtained at the first instant.