1. A method of a real time medical or cognitive monitoring device for analyzing synchronizations of electroencephalography of an individual using a set of sensors starting from cerebral electromagnetic analysis of the individual, comprising: creating a database comprising: acquisition and digitization of electrophysiological signals output from the sensors, calculating a correlation of phase variations between all pairs of sensors recorded in an assembly protocol, in frequency bands between 0 and 2000 Hz, to build up the database of classes each characterizing a reference state of cerebral electromagnetic activity of said individual; statistical validation, by the real time medical or cognitive monitoring device, of a period analyzed in real time, which assigns the period to a class in the database; and detecting, by the real time medical or cognitive monitoring device, a specific period with a determined degree of synchronization.