Directional activation with electrical stimulation

A method comprising:

• controlling, by processing circuitry, stimulation generation circuitry to deliver, to a patient, multiphasic stimulation pulse that comprises a first phase and a second phase;
• determine, by the processing circuitry and with sensing circuitry, a composite evoked compound action potential (ECAP) signal elicited by the multiphasic stimulation pulse, wherein the composite ECAP signal comprises a summation of a first ECAP signal corresponding to the first phase of the multiphasic stimulation pulse and a second ECAP signal corresponding to the second phase of the multiphasic stimulation pulse;
• and
• determine, by the processing circuitry and based on the composite ECAP signal, a propagation characteristic associated with interference between the first ECAP signal and the second ECAP signal of the composite ECAP signal that is elicited by the multiphasic stimulation pulse.

A medical device comprising:

• stimulation generation circuitry configured to deliver a multiphasic stimulation pulse to a patient;
• sensing circuitry configured to sense a composite evoked compound action potential (ECAP) signal elicited by the multiphasic stimulation pulse;
• and
• processing circuitry electrically connected to the sensing circuitry and the stimulation generation circuitry, the processing circuitry being configured to:
• control the stimulation generation circuitry to deliver the multiphasic stimulation pulse that comprises a first phase and a second phase;
• and
• determine, based on the composite ECAP signal, a propagation characteristic, wherein the composite ECAP signal comprises a summation of a first ECAP signal corresponding to the first phase of the multiphasic stimulation pulse and a second ECAP signal corresponding to the second phase of the multiphasic stimulation pulse, and wherein the propagation characteristic is associated with interference between the first ECAP signal and the second ECAP signal of the composite ECAP signal that is elicited by the multiphasic stimulation pulse.