System and methods are provided for determining a stimulation threshold for closed loop spinal cord stimulation (SCS). The system and methods provide a lead coupled to an implantable pulse generator (IPG). The system and methods deliver SCS pulses from the IPG to the lead electrodes in accordance with an SCS therapy and determine an evoked compound action potential (ECAP) amplitude based on an ECAP waveform resulting from the SCS therapy. The system and methods increase the SCS therapy by increasing at least one of an amplitude, a duration, and number of the SCS pulses associated with the SCS therapy. The system and methods also include iteratively repeat the delivering, determining and increasing operations until the ECAP amplitude exhibits a downward trend divergence. The system and methods define a stimulation threshold based on the ECAP amplitude at the trend divergence.
