Figure 17: Illustration of the relation between hearing threshold LHS and response threshold L1. The linear extrapolation of the amplitude growth function (AGF) yields its zero crossing L0, which is in general different from the hearing threshold LHS (i.e. ΔL2≠ 0). The difference ΔL1 can be reduced by minimizing the residual noise. This does not hold for the difference ΔL2, which can depend on the type and origin of the signal to be detected, on the detection method and eventually on underlying pathologic processes.