Objective measurement of cochlear implant operation is described which coordinates the delivery to a patient of an acoustic signal and an electrical signal including coordinating a delay time between the acoustic signal and the electrical signal. The acoustic signal is developed as an acoustic stimulation input to the ear canal of a patient, and the electrical signal is developed as an electrical stimulation input to intracochlear electrodes of a cochlear implant. The evoked response in the patient to the delivered signals is then measured including measuring a far field response associated with the skin surface of the patient.
