An apparatus (1) for electrostimulation of biological tissues is proposed. The apparatus (1) comprises a signal generator (53) adapted to generate an electrical signal, an electrode (40) electrically connected to the signal generator (53) to receive the electrical signal generated by the signal generator (53), and a control unit (51) operatively connected to the signal generator (53) to adjust parameters of the generated electrical signal and to read the parameters of an electrical signal returning from the electrode (40). Advantageously, the control unit (51) is configured for determining (1001) the parameters of an electrical signal (stx), reading (1005) the electrical signal (sr) returning from the electrode (40), comparing (1009) at least one parameter of the return electrical signal (sr) with a corresponding parameter of an expected return signal, and if one or more of the parameters of the return electrical signal (sr) differ from the corresponding parameters of the expected return signal beyond a threshold value, then the control unit (51) is configured for modifying (1013) the parameters of the electrical signal (stx) and repeating steps b) to d).
