A system comprising: a memory storing instructions; and a processor communicatively coupled to the memory and configured to execute the instructions to: direct an acoustic stimulation generator to apply acoustic stimulation having a plurality of stimulus frequencies to a recipient of a cochlear implant during an insertion procedure in which an electrode lead (110, 600) communicatively coupled to the cochlear implant is inserted into a cochlea (200, 602) of the recipient, wherein the plurality of stimulus frequencies are concurrently applied to the recipient during the insertion procedure; direct the cochlear implant to use an electrode (112, 604) disposed on the electrode lead to record a plurality of evoked response signals during the insertion procedure, each evoked response signal included in the plurality of evoked response signals corresponding to a different stimulus frequency included in the plurality of stimulus frequencies and representative of evoked responses that occur within the recipient in response to the acoustic stimulation applied to the recipient; and determine, based on an amplitude and a phase of each of one or more evoked response signals included in the plurality of evoked response signals, an insertion state of the electrode lead within the cochlea of the recipient. a memory storing instructions; and a processor communicatively coupled to the memory and configured to execute the instructions to: direct an acoustic stimulation generator to apply acoustic stimulation having a plurality of stimulus frequencies to a recipient of a cochlear implant during an insertion procedure in which an electrode lead (110, 600) communicatively coupled to the cochlear implant is inserted into a cochlea (200, 602) of the recipient, wherein the plurality of stimulus frequencies are concurrently applied to the recipient during the insertion procedure; direct the cochlear implant to use an electrode (112, 604) disposed on the electrode lead to record a plurality of evoked response signals during the insertion procedure, each evoked response signal included in the plurality of evoked response signals corresponding to a different stimulus frequency included in the plurality of stimulus frequencies and representative of evoked responses that occur within the recipient in response to the acoustic stimulation applied to the recipient; and determine, based on an amplitude and a phase of each of one or more evoked response signals included in the plurality of evoked response signals, an insertion state of the electrode lead within the cochlea of the recipient. direct an acoustic stimulation generator to apply acoustic stimulation having a plurality of stimulus frequencies to a recipient of a cochlear implant during an insertion procedure in which an electrode lead (110, 600) communicatively coupled to the cochlear implant is inserted into a cochlea (200, 602) of the recipient, wherein the plurality of stimulus frequencies are concurrently applied to the recipient during the insertion procedure; direct the cochlear implant to use an electrode (112, 604) disposed on the electrode lead to record a plurality of evoked response signals during the insertion procedure, each evoked response signal included in the plurality of evoked response signals corresponding to a different stimulus frequency included in the plurality of stimulus frequencies and representative of evoked responses that occur within the recipient in response to the acoustic stimulation applied to the recipient; and determine, based on an amplitude and a phase of each of one or more evoked response signals included in the plurality of evoked response signals, an insertion state of the electrode lead within the cochlea of the recipient.