According to the document ANR 09 VTT VOLHAND Doc B, presented on October 2011, the research team in Gipsa-Lab is involved into the task 5.2 (T5.2) for the design of the the amplification curves that can be adapted to disabled people. The typical architecture of an Electric Power Assistance Steering (EPAS) system includes a static map to provide the correct amplification to the driver's exerted torque. In literature, it is generally known as booster curve. This document concerns a preliminary study of the current methods diffused in literature to provide this amplification and is based on the results published in [6] and [11]. The basic concepts of the Electric Power Steering (EPS) systems with a realistic model for the friction contact, that acts on the wheels are discussed. A relation between the assistance and the driver's torque is provided, under the hypothesis of a position-oriented control of the movement and the Stevens' power law. Finally, the simulation results proposed at the end of this paper validate the shape of the booster curves and are in accord with the initial hypothesis.