Closed loop control in spinal cord stimulation

Abstract

Methods and systems for using sensed neural responses for informing aspects of stimulation therapy are disclosed. For example, features of evoked neural responses, such as evoked compound action potentials (ECAPs) can be used for closed-loop feedback control of stimulation parameters. Aspects of the disclosed methods and systems can differentiate between changes in the sensed neural responses that are caused by the environment at stimulating electrodes and changes in the neural responses that are caused by the environment at sensing electrodes. Embodiments determine changes in the morphology of the neural responses, which morphology changes indicate a degree of change in the stimulating environment. Algorithms and systems for assigning and tracking likelihoods for underlying electrode-tissue changes based on sensed neural responses are disclosed. The feedback control modality may be updated based on such likelihoods. Also disclosed are methods and systems for determining which features of evoked neural responses are more sensitive to changes in the stimulating environment and less sensitive to changes in the sensing environment.