Patent Publication Number: US-11642525-B2

Title: Systems and methods for detecting a scalar translocation of an electrode lead within a cochlea of a cochlear implant patient

Description:
BACKGROUND INFORMATION 
     Cochlear implant systems are used to provide, restore, and/or improve hearing loss suffered by cochlear implant patients who use the cochlear implant systems. A key component of a cochlear implant system is an electrode lead that is inserted into a cochlea of the patient in a delicate surgical procedure referred to herein as an “insertion procedure.” Because insertion procedures are difficult and may result in cochlear trauma or other harm if not done with extreme care, surgeons and other people involved in insertion procedures may desire to carefully monitor and track the electrode lead by identifying its position and insertion path with respect to the cochlea during and after the insertion procedure. It may also be desirable to detect any trauma that may occur to the cochlea as a result of an insertion procedure. For example, trauma may occur when the electrode lead inadvertently translocates from one scala of the cochlea (e.g., the scala tympani) to another scala of the cochlea (e.g., the scala vestibuli) by penetrating through the basilar membrane. 
     By monitoring the electrode lead and trauma occurring as a result of its insertion, the surgeon or surgical team may be more likely to perform a safe, effective insertion of the electrode lead, thereby resulting in desirable hearing outcomes for patients. Moreover, by determining the final position and insertion path of an electrode lead (e.g., including whether the insertion path includes a scalar translocation), useful data may be determined and studied to improve and facilitate future insertion procedures (e.g., data showing correlation and/or causation between certain hearing outcomes and certain final electrode lead placements, etc.). 
     Unfortunately, current methods for detecting trauma and identifying the position and/or insertion path of an electrode lead within a patient typically involve imaging technology (e.g., x-ray technology, fluoroscopic technology, CT scanning technology, etc.) that is expensive, inconvenient, and may expose patients to undesirable risk. Moreover, these current methods may be impractical or impossible to employ in real time during insertion procedures, when detecting trauma and identifying the position and/or insertion path of an electrode lead may be of particular value for ensuring proper procedures and securing positive outcomes. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings illustrate various embodiments and are a part of the specification. The illustrated embodiments are merely examples and do not limit the scope of the disclosure. Throughout the drawings, identical or similar reference numbers designate identical or similar elements. 
         FIG.  1    illustrates an exemplary cochlear implant system according to principles described herein. 
         FIG.  2    illustrates a schematic structure of the human cochlea according to principles described herein. 
         FIG.  3    illustrates an exemplary implementation of the cochlear implant system of  FIG.  1    in which the cochlear implant system is implemented as an electro-acoustic stimulation (“EAS”) system according to principles described herein. 
         FIG.  4    illustrates an exemplary configuration in which a computing device is communicatively coupled to a sound processor of the cochlear implant system of  FIG.  1    according to principles described herein. 
         FIG.  5    illustrates an exemplary configuration in which the computing device of  FIG.  4    is implemented by a personal computer and a clinician&#39;s programming interface device according to principles described herein. 
         FIG.  6    illustrates a block diagram of exemplary components of a system for detecting scalar translocation of an electrode lead within a cochlea of a cochlear implant patient according to principles described herein. 
         FIG.  7    illustrates exemplary aspects of an electrode lead and of patient anatomy as an exemplary insertion procedure is performed according to principles described herein. 
         FIGS.  8 A- 8 B  illustrate graphs of amplitude measurements of exemplary evoked responses detected during exemplary insertion procedures according to principles described herein. 
         FIGS.  9 - 11    illustrate graphs of phase measurements of exemplary evoked responses detected during exemplary insertion procedures according to principles described herein. 
         FIG.  12    illustrates an exemplary method for detecting scalar translocation of an electrode lead within a cochlea of a cochlear implant patient according to principles described herein. 
         FIG.  13    illustrates an exemplary computing device according to principles described herein. 
     
    
    
     DETAILED DESCRIPTION 
     Systems and methods for detecting scalar translocation of an electrode lead within a cochlea of a cochlear implant patient are described herein. Detecting a scalar translocation of an electrode lead may assist in detecting trauma and/or identifying the position and/or insertion path of an electrode lead with respect to a cochlea that the electrode lead is inserted into (e.g., in a surgical insertion procedure). As used herein, a “scalar translocation” of an electrode lead refers to a translocation (i.e., a movement from one location to another) of an electrode lead (e.g., a distal end of the electrode lead, in particular) from one scala of the cochlea of a patient (e.g., the scala tympani) to another scala of the cochlea of the patient (e.g., the scala vestibuli). For example, during an insertion procedure whereby an electrode lead is inserted into a cochlea, the electrode lead may travel through the round window into the scala tympani of the cochlea but, instead of continuing to travel through the scala tympani, may inadvertently puncture the basilar membrane and/or other anatomy separating the scala tympani from the scala vestibuli to enter the scala vestibuli. Because such a scalar translocation may damage the basilar membrane (e.g., including hair cells disposed on the basilar membrane and associated with residual hearing of the patient), the translocation of the electrode lead may cause trauma to the cochlea. As such, it may be desirable to detect scalar translocation in real time during the insertion procedure (e.g., so that the scalar translocation may be corrected if possible) and/or after the fact (e.g., so that the scalar translocation may be associated with data being studied to help reduce trauma and improve outcomes in subsequent insertion procedures, or for other suitable purposes as will be described below). 
     To this end, as will be described in more detail below, an exemplary system for detecting scalar translocation of an electrode lead within a cochlea of a cochlear implant patient may be implemented by at least one physical computing device (e.g., by a computing system coupled to a cochlear implant system, by a sound processor included within a cochlear implant system, by a combination of a computing system and a sound processor included within a cochlear implant system, etc.). The system (e.g., the at least one physical computing device) may detect a first evoked response that occurs in response to acoustic stimulation applied to the cochlear implant patient. For example, the system may detect the first evoked response by way of an electrode configuration including at least one electrode disposed on the electrode lead while the electrode configuration is positioned at a first location along an insertion path of the electrode lead into the cochlea of the patient. The system may further detect a second evoked response that occurs in response to additional acoustic stimulation applied to the cochlear implant patient. For instance, the system may detect the second evoked response by way of the electrode configuration while the electrode configuration is positioned at a second location along the insertion path of the electrode lead into the cochlea (e.g., a second location deeper into the cochlea or nearer to the apex of the cochlea). 
     Based on the first and second evoked responses, the system may determine at least one of an amplitude change between the first and second evoked responses and a phase change between the first and second evoked responses. Accordingly, based on the amplitude change and/or the phase change, the system may determine whether a scalar translocation of the electrode lead from one scala of the cochlea (e.g., the scala tympani) to another scala of the cochlea (e.g., the scala vestibuli) has occurred. 
     In certain examples, as mentioned above, disclosed systems and methods may be employed to detect scalar translocation of an electrode lead in real time during an insertion procedure of the electrode lead into a cochlea of a cochlear implant patient. For example, at least one physical computing device included within such a system may, in real time during the insertion procedure, track trauma occurring to the cochlea during the insertion procedure by performing a sequence of scalar translocation determination operations. Specifically, each scalar translocation determination operation may include (e.g., may be implemented by performing) detecting a first evoked response that occurs in response to acoustic stimulation applied to the cochlear implant patient. For instance, the detecting of the first evoked response may be performed by way of an electrode nearest a distal end of the electrode lead at a first time during the insertion procedure while the electrode is positioned at a first location along an insertion path of the electrode lead into the cochlea. Each scalar translocation determination operation may further include detecting a second evoked response that occurs in response to additional acoustic stimulation applied to the cochlear implant patient. As with the detecting of the first evoked response, the detecting of the second evoked response may be performed by way of the same electrode (i.e., the electrode nearest the distal end of the electrode lead) at a second time during the insertion procedure while the electrode is positioned at a second location along the insertion path of the electrode lead into the cochlea. 
     Each scalar translocation determination operation may further include determining at least one of an amplitude change between the first and second evoked responses and a phase change between the first and second evoked responses, determining (e.g., based on the amplitude change and/or the phase change) whether a scalar translocation of the electrode lead from one scala of the cochlea to another scala of the cochlea has occurred, and determining (e.g., if the determination of whether the scalar translocation of the electrode lead has occurred indicates that the scalar translocation of the electrode lead has occurred) that trauma associated with the scalar translocation has occurred to the cochlea. 
     Along with performing the sequence of scalar translocation determination operations, the system may further provide a user interface for use by a user associated with the system (e.g., a surgeon or a member of a surgical team performing the insertion procedure), and may provide (e.g., to the user by way of the user interface) information representative of the tracked trauma occurring to the cochlea during the insertion procedure. For instance, the user interface may notify the user when a scalar translocation of the electrode lead has been detected, or may indicate to the user that no scalar translocation of the electrode lead has yet been detected (i.e., that the insertion procedure is so far proceeding without incident). 
     Disclosed systems and methods for detecting scalar translocation of an electrode lead within a cochlea of a cochlear implant patient may provide various benefits to cochlear implant patients, as well as to surgeons and others involved with insertion procedures. For example, by providing real time information about whether a scalar translocation of the electrode lead or other trauma is occurring during an insertion procedure, disclosed systems and methods may provide a surgeon performing the insertion procedure more information and perspective into the intricate insertion procedure, thereby allowing for a translocated electrode lead to be corrected (e.g., withdrawn and reinserted without scalar translocation) or for trauma to otherwise be mitigated to facilitate a successful outcome of the insertion procedure. 
     Along with providing perspective into the insertion procedure (e.g., informing surgeons and surgical team members which scala(s) an electrode lead being inserted is currently located in), disclosed systems and methods may further provide data representative of whether a scalar translocation of the electrode lead has occurred, which scala the electrode lead is currently located in, and so forth, to computer systems used to facilitate the insertion procedure. This may allow the computer systems to provide feedback or warnings (e.g., by way of user interfaces, lights, sounds, etc.) that may help the surgeon and other people involved in performing the insertion procedure to proceed with appropriate care at various stages of the procedure. Moreover, in situations where variables such as procedure time, electrode lead location (e.g., current insertion depth), and the like are being tracked along with the cochlear trauma, computer systems may log trauma events to correlate with these other variables to be used in subsequent procedures for other cochlear implant patients (e.g., to warn surgeons to take particular care at particular times or insertion depths, to perform particular actions when an electrode lead is coming up on a depth where a scalar translocation of the electrode lead has previously occurred, etc.). 
     Even after an insertion procedure is complete, disclosed systems and methods for detecting scalar translocation of electrode leads may be useful for providing insight into a final resting location at which the electrode lead has been inserted. As will be described below, this may be done by detecting evoked responses at two different electrodes located at different locations along the insertion path traveled by the electrode lead at arbitrary times (e.g., at the same time) while the electrode lead is stationary, rather than by the same electrode (e.g., the electrode nearest the distal end of the electrode lead) as the electrode moves from one location at one time to another location at a later time. For example, detecting a scalar translocation of a stationary electrode lead after the insertion procedure may provide useful data for studying effects of scalar translocation and other cochlear trauma on ultimate hearing outcomes such as residual hearing changes over time. Moreover, by using different electrodes (e.g., electrodes X and Y) along the electrode lead to detect evoked responses, an approximate location of a scalar translocation (e.g., a location such as between electrode X and electrode Y on the fully inserted electrode lead) may be determined, providing additional useful data for the patient and for improving insertion procedures to be performed on additional patients in the future. 
     Additionally, regardless of whether disclosed system and methods for detecting scalar translocation of an electrode lead are performed in real time during an insertion procedure or after the fact when the electrode lead is stationary, the detecting of scalar translocation without use of expensive, inconvenient, or risky imaging technology (e.g., x-ray technology, fluoroscopic technology, CT scanning technology, etc.) may be beneficial. For example, by detecting the scalar translocation of the electrode lead while avoiding these other technologies, patients may be less exposed to various risks, inconveniences, costs, and/or other undesirable aspects associated with such technology. 
     Various embodiments will now be described in more detail with reference to the figures. The disclosed systems and methods may provide one or more of the benefits mentioned above and/or various additional and/or alternative benefits that will be made apparent herein. 
       FIG.  1    illustrates an exemplary cochlear implant system  100 . As shown, cochlear implant system  100  may include a microphone  102 , a sound processor  104 , a headpiece  106  having a coil disposed therein, a cochlear implant  108 , and an electrode lead  110 . Electrode lead  110  may include an array of electrodes  112  disposed on a distal portion of electrode lead  110  and that are configured to be inserted into the cochlea to stimulate the cochlea after the distal portion of electrode lead  110  is inserted into the cochlea. It will be understood that one or more other electrodes (e.g., including a ground electrode, not explicitly shown) may also be disposed on other parts of electrode lead  110  (e.g., on a proximal portion of electrode lead  110 ) to, for example, provide a current return path for stimulation current generated by electrodes  112  and to remain external to the cochlea after electrode lead  110  is inserted into the cochlea. As shown, electrode lead  110  may be pre-curved so as to properly fit within the spiral shape of the cochlea. Additional or alternative components may be included within cochlear implant system  100  as may serve a particular implementation. 
     As shown, cochlear implant system  100  may include various components configured to be located external to a patient including, but not limited to, microphone  102 , sound processor  104 , and headpiece  106 . Cochlear implant system  100  may further include various components configured to be implanted within the patient including, but not limited to, cochlear implant  108  and electrode lead  110 . 
     Microphone  102  may be configured to detect audio signals presented to the user. Microphone  102  may be implemented in any suitable manner. For example, microphone  102  may include a microphone that is configured to be placed within the concha of the ear near the entrance to the ear canal, such as a T-MIC™ microphone from Advanced Bionics. Such a microphone may be held within the concha of the ear near the entrance of the ear canal by a boom or stalk that is attached to an ear hook configured to be selectively attached to sound processor  104 . Additionally or alternatively, microphone  102  may be implemented by one or more microphones disposed within headpiece  106 , one or more microphones disposed within sound processor  104 , one or more beam-forming microphones, and/or any other suitable microphone as may serve a particular implementation. 
     Sound processor  104  (i.e., one or more components included within sound processor  104 ) may be configured to direct cochlear implant  108  to generate and apply electrical stimulation (also referred to herein as “stimulation current”) representative of one or more audio signals (e.g., one or more audio signals detected by microphone  102 , input by way of an auxiliary audio input port, input by way of a CPI device, etc.) to one or more stimulation sites associated with an auditory pathway (e.g., the auditory nerve) of the patient. Exemplary stimulation sites include, but are not limited to, one or more locations within the cochlea, the cochlear nucleus, the inferior colliculus, and/or any other nuclei in the auditory pathway. To this end, sound processor  104  may process the one or more audio signals in accordance with a selected sound processing strategy or program to generate appropriate stimulation parameters for controlling cochlear implant  108 . Sound processor  104  may be housed within any suitable housing (e.g., a behind-the-ear (“BTE”) unit, a body worn device, headpiece  106 , and/or any other sound processing unit as may serve a particular implementation). 
     In some examples, sound processor  104  may wirelessly transmit stimulation parameters (e.g., in the form of data words included in a forward telemetry sequence) and/or power signals to cochlear implant  108  by way of a wireless communication link  114  between headpiece  106  and cochlear implant  108  (e.g., a wireless link between a coil disposed within headpiece  106  and a coil physically coupled to cochlear implant  108 ). It will be understood that communication link  114  may include a bi-directional communication link and/or one or more dedicated uni-directional communication links. 
     Headpiece  106  may be communicatively coupled to sound processor  104  and may include an external antenna (e.g., a coil and/or one or more wireless communication components) configured to facilitate selective wireless coupling of sound processor  104  to cochlear implant  108 . Headpiece  106  may additionally or alternatively be used to selectively and wirelessly couple any other external device to cochlear implant  108 . To this end, headpiece  106  may be configured to be affixed to the patient&#39;s head and positioned such that the external antenna housed within headpiece  106  is communicatively coupled to a corresponding implantable antenna (which may also be implemented by a coil and/or one or more wireless communication components) included within or otherwise associated with cochlear implant  108 . In this manner, stimulation parameters and/or power signals may be wirelessly transmitted between sound processor  104  and cochlear implant  108  via a communication link  114  (which may include a bi-directional communication link and/or one or more dedicated uni-directional communication links as may serve a particular implementation). 
     Cochlear implant  108  may include any type of implantable stimulator that may be used in association with the systems and methods described herein. For example, cochlear implant  108  may be implemented by an implantable cochlear stimulator. In some alternative implementations, cochlear implant  108  may include a brainstem implant and/or any other type of cochlear implant that may be implanted within a patient and configured to apply stimulation to one or more stimulation sites located along an auditory pathway of a patient. 
     In some examples, cochlear implant  108  may be configured to generate electrical stimulation representative of an audio signal processed by sound processor  104  (e.g., an audio signal detected by microphone  102 ) in accordance with one or more stimulation parameters transmitted thereto by sound processor  104 . Cochlear implant  108  may be further configured to apply the electrical stimulation to one or more stimulation sites (e.g., one or more intracochlear regions) within the patient via electrodes  112  disposed along electrode lead  110 . In some examples, cochlear implant  108  may include a plurality of independent current sources each associated with a channel defined by one or more of electrodes  112 . In this manner, different stimulation current levels may be applied to multiple stimulation sites simultaneously by way of multiple electrodes  112 . 
       FIG.  2    illustrates a schematic structure of the human cochlea  200  into which electrode lead  110  may be inserted. As shown in  FIG.  2   , cochlea  200  is in the shape of a spiral beginning at a base  202  and ending at an apex  204 . Within cochlea  200  resides auditory nerve tissue  206 , which is denoted by Xs in  FIG.  2   . The auditory nerve tissue  206  is organized within the cochlea  200  in a tonotopic manner. Relatively low frequencies are encoded at or near the apex  204  of the cochlea  200  (referred to as an “apical region”) while relatively high frequencies are encoded at or near the base  202  (referred to as a “basal region”). Hence, electrical stimulation applied by way of electrodes disposed within the apical region (i.e., “apical electrodes”) may result in the patient perceiving relatively low frequencies and electrical stimulation applied by way of electrodes disposed within the basal region (i.e., “basal electrodes”) may result in the patient perceiving relatively high frequencies. The delineation between the apical and basal electrodes on a particular electrode lead may vary depending on the insertion depth of the electrode lead, the anatomy of the patient&#39;s cochlea, and/or any other factor as may serve a particular implementation. 
       FIG.  3    illustrates an exemplary implementation of cochlear implant system  100  in which cochlear implant system  100  is implemented as an electro-acoustic stimulation (“EAS”) system  300 . EAS system  300  may be configured to operate similarly to cochlear implant system  100 , except that EAS system  300  may be further configured to provide acoustic stimulation to the patient (e.g., to acoustically stimulate residual hearing that the patient may retain along with electrically stimulating the patient as described above). 
     As shown, EAS system  300  may include, along with the same components described above with respect to cochlear implant system  100 , a loudspeaker  302 . Loudspeaker  302  may be in communication with an ear of the patient (e.g., located at an entrance or within the ear canal of the patient). In this configuration, sound processor  104  (which, in EAS system  300 , may be referred to as an “EAS sound processor”) may be configured to direct loudspeaker  302  to apply acoustic stimulation representative of audio content to one or more stimulation sites within the patient (e.g., within cochlea  200 , described above in relation to  FIG.  2   ). For example, loudspeaker  302  may generate the acoustic stimulation used to evoke the evoked responses that may be used to detect the scalar translocation of electrode leads, as described above. 
     Specifically, for example, a cochlear implant system associated with a particular scalar translocation detection system may be implemented as an EAS system (e.g., EAS system  300 ) communicatively coupled with the scalar translocation detection system. The EAS system may include a sound processor (e.g., sound processor  104 ) and a loudspeaker (e.g., loudspeaker  302 ) communicatively coupled to one another. In accordance with the scalar translocation detection operations described above, the scalar translocation detection system may thus direct the sound processor to direct the loudspeaker to apply the acoustic stimulation for the detection of the first evoked response, and direct the sound processor to direct the loudspeaker to apply the additional acoustic stimulation for the detection of the second evoked response. In some examples, a frequency of the acoustic stimulation and a frequency of the additional acoustic stimulation may be substantially the same. For example, the scalar translocation detection system may direct sound processor  104  to direct loudspeaker  302  to produce a tone at substantially the same frequency for both the acoustic stimulation and the additional acoustic stimulation. Or, as another example, the scalar translocation detection system may direct sound processor  104  to direct loudspeaker  302  to produce a single tone that acts as the acoustic stimulation and the additional acoustic stimulation for evoked responses that are detected simultaneously or closely in time to one another. 
     In some examples, at least one computing device (e.g., computing devices included within or implementing a scalar translocation detection system, a programming system, etc.) that is separate from (i.e., not included within) cochlear implant system  100  may be communicatively coupled to sound processor  104  for various purposes. For instance, a computing device may be employed to monitor cochlear trauma (e.g., scalar translocation of the electrode lead) during or after an insertion procedure, to otherwise facilitate proper insertion of electrode lead  110  into the cochlea of a patient (e.g., by tracking the insertion depth of the electrode lead or the like), to perform one or more programming or fitting operations with respect to cochlear implant system  100  (e.g., in a clinical setting after the electrode lead has been inserted), and/or for other suitable purposes as may serve a particular implementation. For example, during the insertion procedure, the at least one physical computing device may direct cochlear implant system  100  to perform operations (e.g., generating acoustic stimulation, detecting evoked responses in response to the acoustic stimulation, etc.) for detecting scalar translocation of the electrode lead within the cochlea of the patient. Subsequent to the insertion procedure, the at least one physical computing device may further be used to present audio clips to the patient by way of cochlear implant system  100  in order to facilitate evaluation of how well cochlear implant system  100  is performing for the patient. In other examples, any of these operations may be performed by components of cochlear implant system  100  (e.g., by sound processor  104 ) without interaction with an external computing device. 
     To illustrate,  FIG.  4    shows an exemplary configuration  400  in which a computing device  402  (e.g., a scalar translocation detection system, programming system, or the like) is communicatively coupled (e.g., by way of a wired or wireless communication channel) to sound processor  104 . Computing device  402  may be implemented by any suitable combination of physical computing and communication devices including, but not limited to, a fitting station or device, a programming device, a personal computer, a laptop computer, a handheld device, a mobile device (e.g., a mobile phone), a clinician&#39;s programming interface (“CPI”) device, and/or any other suitable component as may serve a particular implementation. 
     In some examples, computing device  402  may provide one or more user interfaces with which a user may interact. For example, a user interface may provide text, graphics, sounds, etc., to facilitate a successful insertion procedure of electrode lead  110  (e.g., by detecting a scalar translocation of the electrode lead) or effective programming of sound processor  104  as may serve a particular implementation. In some implementations, the user interface provided by computing device  402  may include a graphical user interface (“GUI”) that allows a user (e.g., a surgeon, a person assisting the surgeon during an insertion procedure, a clinician, etc.) to direct computing device  402  to perform operations for detecting a scalar translocation of the electrode lead within the cochlea. After performing the detection of the scalar translocation (i.e., after determining whether or not a scalar translocation of the electrode lead has occurred), the GUI may provide information representative of the determination by way of visual or audible feedback as may serve a particular implementation (e.g., a beep or red light if a scalar translocation of the electrode lead has occurred, silence or a green light if a scalar translocation of the electrode lead has not occurred, etc.). 
     As illustrated in  FIG.  4   , in certain examples, computing device  402  may be communicatively coupled to a loudspeaker  404 . As such, computing device  402  may use loudspeaker  404  to generate acoustic stimulation for evoking the evoked responses for non-EAS cochlear implant systems such as cochlear implant system  100  (i.e., systems that, unlike EAS system  300 , do not include a dedicated loudspeaker for applying acoustic stimulation to the patient). Specifically, in reference to the scalar translocation detection operations described above, computing device  402  may direct loudspeaker  404  to apply the acoustic stimulation for the detection of the first evoked response, and direct loudspeaker  404  to apply the additional acoustic stimulation for the detection of the second evoked response. Similar to EAS system  300  and loudspeaker  302  described above, in some examples, a frequency of the acoustic stimulation and a frequency of the additional acoustic stimulation may be substantially the same. For example, computing device  402  may direct loudspeaker  404  to produce a tone at substantially the same frequency for both the acoustic stimulation and the additional acoustic stimulation. Or, as another example, computing device  404  may direct loudspeaker  404  to produce a single tone that acts as the acoustic stimulation and the additional acoustic stimulation for evoked responses that are detected simultaneously or closely in time to one another. 
     While  FIG.  4    illustrates computing device  402  communicatively coupled with a cochlear implant system that is not an EAS system (e.g., a cochlear implant system similar to cochlear implant system  100 ), it will be understood that, in certain examples, computing device  402  or another computing device similarly implementing a scalar translocation detection system may instead be communicatively coupled with an EAS system such as EAS system  300 . In such examples, it may not be necessary for computing system  402  to be communicatively coupled to loudspeaker  404  since a loudspeaker included in the EAS system can be used to apply acoustic stimulation to the patient instead (as described above). 
       FIG.  5    illustrates an exemplary configuration  500  in which computing device  402  is implemented by a personal computer  502  and a CPI device  504 . As shown, personal computer  502  may be selectively and communicatively coupled to CPI device  504  by way of a cable  506 . Likewise, CPI device  504  may be selectively and communicatively coupled to sound processor  104  by way of a cable  508 . Cables  506  and  508  may each include any suitable type of cable that facilitates transmission of digital data between personal computer  502  and sound processor  104 . For example, cable  506  may include a universal serial bus (“USB”) cable and cable  508  may include any type of cable configured to connect to a programming port included in sound processor  104 . 
       FIG.  6    illustrates a block diagram of exemplary components of a scalar translocation detection system  600  (“system  600 ”). System  600  may be configured to perform any of the operations described herein for detecting scalar translocation of an electrode lead within a cochlea of a cochlear implant patient. To this end, as shown, system  600  may include an evoked response detection facility  602 , a processing facility  604 , and a storage facility  606 , which may be selectively and communicatively coupled to one another. It will be recognized that although facilities  602  through  606  are shown to be separate facilities in  FIG.  6   , facilities  602  through  606  may be combined into fewer facilities, such as into a single facility, or divided into more facilities as may serve a particular implementation. In some examples, system  600  may include, implement, or be implemented by a computing device such as computing device  402 , described above. Each of facilities  602  through  606  will now be described in more detail. 
     Evoked response detection facility  602  may include or be implemented by one or more physical computing devices (e.g., including hardware and/or software such as processors, memories, communication interfaces, instructions stored in memory for execution by the processors, etc.) such as computing device  402 , computing components included in sound processor  104 , and/or other suitable computing devices that perform various operations associated with detecting evoked responses that occur in response to acoustic stimulation being applied to a cochlear implant patient. For example, evoked response detection facility  602  may generate acoustic stimulation to be applied to the patient or direct a loudspeaker to generate and apply such acoustic stimulation (e.g., directly directing loudspeaker  402  to generate the acoustic stimulation as described in relation to  FIG.  4   , indirectly directing loudspeaker  302  to generate the acoustic stimulation by way of sound processor  104  as described in relation to  FIG.  3   , etc.). The acoustic stimulation may be applied to the patient when an electrode configuration (e.g., a single electrode configuration including the electrode nearest the distal end of an electrode lead, a multiple electrode configuration including at least two different electrodes along the electrode lead, etc.) is positioned at a particular location along an insertion path of the electrode lead into a cochlea of the patient. 
     As such, the acoustic stimulation may cause an evoked response to occur (e.g., to be involuntarily generated by the patient) that may be detected by the electrode configuration at the particular location. The evoked response may be any type of evoked response as may serve a particular implementation. For example, as used herein, an “evoked response” may refer to an electrocochleographic (“ECoG”) potential, an auditory nerve response, a brainstem response, a compound action potential, and/or any other type of neural or physiological response that may occur within a patient in response to application of acoustic stimulation to the patient. In some examples, evoked responses may originate from neural tissues, hair cell to neural synapses, inner or outer hair cells, or other sources. 
     Accordingly, evoked response detection facility  602  may detect, by way of the electrode configuration while the electrode configuration is positioned at a first location along the insertion path of the electrode lead into the cochlea, a first evoked response that occurs in response to the acoustic stimulation applied to the patient. Evoked response detection facility  602  may further detect, by way of the electrode configuration while the electrode configuration is positioned at a second location along the insertion path, a second evoked response that occurs in response to additional acoustic stimulation applied to the patient. For instance, evoked response detection facility  602  may detect the first evoked response by detecting a first ECoG potential occurring in response to the acoustic stimulation, and detect the second evoked response by detecting a second ECoG potential occurring in response to the additional acoustic stimulation. In some examples, the first and second ECoG potentials may be cochlear microphonic potentials. In other examples, other suitable ECoG potentials such as action potentials, summating potentials, or the like may be used in addition to or in place of the cochlear microphonic potentials. 
     Processing facility  604  may include or be implemented by one or more physical computing devices such as the same computing devices or similar (but separate) computing devices described above in relation to evoked response detection facility  602 . Based on evoked responses detected by evoked response detection facility  602  (e.g., the first and second evoked responses described above), processing facility  604  may be configured to determine at least one of an amplitude change between the first and second evoked response and a phase change between the first and second evoked responses. Moreover, based on the determined amplitude change and/or phase change, processing facility  604  may determine whether a scalar translocation of the electrode lead from one scala of the cochlea (e.g., the scala tympani) to another scala of the cochlea (e.g., the scala vestibuli) has occurred. Processing facility  604  may perform these determinations in any suitable way, such as will be described in more detail below. 
     In some examples, facilities  602  and  604  may perform some or all of the operations described above (e.g., the detections of the first and second evoked responses, the determination of the amplitude change and/or the phase change, the determination of whether the scalar translocation of the electrode lead has occurred, etc.) in real time during an insertion procedure of the electrode lead into the cochlea along the insertion path (e.g., while the surgical insertion procedure is ongoing). As used herein, an operation is considered to be performed in “real time” when the operation is performed immediately and without undue delay (e.g., in real time or near real time). Accordingly, operations may be said to be performed in real time and users of system  600  (e.g., surgeons, surgical team members, etc.) may be considered to receive real time information during the insertion procedure even if the information is provided after a small delay (e.g., up to a few seconds). 
     In these examples where system  600  is used to perform operations in real time during the insertion procedure, facilities  602  and  604  may be used to continuously and dynamically track trauma as it occurs during the insertion procedure. Specifically, for instance, if the determination by processing facility  604  as to whether the scalar translocation of the electrode lead has occurred indicates that the scalar translocation of the electrode lead has occurred, processing facility  604  may determine that trauma associated with the scalar translocation has occurred to the cochlea. As such, system  600  may track trauma occurring to the cochlea during the insertion procedure by performing a sequence of scalar translocation determination operations each including a respective performance of the detections of the first and second evoked responses (e.g., by evoked response detection facility  602 ), the determination of the amplitude change and/or the phase change (e.g., by processing facility  604 ), and the determination of whether the scalar translocation of the electrode lead has occurred (e.g., also by processing facility  604 ). 
     As mentioned above, system  600  (e.g., processing facility  604  or another facility not explicitly illustrated in  FIG.  6   ) may facilitate use of the information determined by system  600  by providing a user interface for use by a user associated with system  600  (e.g., using system  600 , receiving information from system  600 ), and by providing information representative of the determination of whether the scalar translocation of the electrode lead has occurred to the user by way of the user interface. This information may be provided in any of the ways described herein, such as by textual, graphical, color-based, audible, or other suitable means. 
     Storage facility  606  may maintain management data  608  and/or any other data received, generated, managed, maintained, used, and/or transmitted by facilities  602  and  604  in a particular implementation. Management data  608  may include data representative of evoked response measurements that have been made, or data used to make such measurements (e.g., data representative of acoustic stimulation levels, data representative of timing information for detecting voltages in response to generated acoustic stimulation, etc.), or the like. Additionally, management data  608  may include data representative of scalar translocations of electrode leads and/or other trauma that has been detected or data to facilitate such detections. Storage facility  606  may further include any other data as may serve a particular implementation of system  600  to facilitate performing one or more of the operations described herein. 
     In order to illustrate the context in which an insertion procedure is performed and how a scalar translocation of an electrode lead may occur,  FIG.  7    shows exemplary aspects of an electrode lead and of patient anatomy as an exemplary insertion procedure is performed. Specifically, as shown, an insertion procedure  702  is illustrated in which a distal portion of an electrode lead  704  is inserted into a cochlea  706  of a patient along an insertion path  708  (i.e., which is illustrated in part by a dashed curve but will be understood to including the entire path taken by electrode lead  704  within cochlea  706 ). It will be understood that, while only a distal portion of electrode lead  704  is illustrated in  FIG.  7   , a proximal portion of the electrode lead not explicitly shown may be coupled to a cochlear implant (also not shown) that may direct current into electrode lead  704 , receive and pass on data detected by electrode lead  704  (e.g., evoked response data or the like), and so forth. 
     As shown, electrode lead  704  may include various electrodes including a leading electrode  710  nearest a distal end of electrode lead  704  and several additional electrodes  712  disposed along the length of electrode lead  704 . Unless the context dictates otherwise, it will be understood that electrodes  712 , when referred to generally herein, may include all the electrodes disposed on electrode lead  704  including electrode  710  and/or electrodes not explicitly shown in  FIG.  7   . 
     As illustrated in  FIG.  7   , insertion procedure  702  may involve inserting electrode lead  704  through an entry point  714  (e.g., within a round window or cochleostomy of cochlea  706 , or another suitable location) and into a scala tympani  716  of cochlea  706 . Scala tympani  716  is a chamber of cochlea  706  that is separated by a basilar membrane  718  (e.g., as well as other membranes and anatomical structures not explicitly shown or labeled in  FIG.  7   ) from a scala vestibuli  720  of cochlea  706  (i.e., a separate chamber of the cochlea). As such, vibrations introduced at an oval window  722  of cochlea  706  may vibrate through fluid included in scala vestibuli  720  toward the apex of cochlea  706  and back toward the base of cochlea  706  through fluid included in scala tympani  716 . In other words, sound vibrations traveling on either side of basilar membrane  718  may be moving in opposite directions and, as such, may be out of phase with one another. As the vibrations travel through fluid in scala tympani  716 , the vibrations may be detected and encoded by hair cells along basilar membrane  718  (if undamaged hair cells are present in the particular patient). Additionally or alternatively, electrodes  712  disposed throughout scala tympani  716  may generate electrical stimulation to stand in for the function of damaged hair cells. Regardless, nerves associated with different depths (i.e., frequency regions) along cochlea  706  may send signals to the brain to effect a hearing sensation, as described above in relation to  FIG.  2   . 
       FIG.  7    illustrates electrode lead  704  within cochlea  706  at a particular moment during insertion procedure  702 . Specifically, at the moment depicted in  FIG.  7   , electrode lead  704  has translocated from scala tympani  716 , through basilar membrane  718 , and into scala vestibuli  720  at a translocation site  724 . This scalar translocation of electrode lead  704  may have occurred for any of a variety of reasons during insertion procedure  702 , but is most likely an undesirable occurrence because, as shown, the distal end of electrode lead  704  (i.e., at leading electrode  710 ) has physically penetrated basilar membrane  718 , thereby potentially causing trauma to basilar membrane  718  and/or any of various other parts of cochlea  706  associated with basilar membrane  718  (e.g., previously functional hair cells along basilar membrane  718 , other membranes or nerves associated with basilar membrane  718 , etc.). 
     To mitigate trauma caused by the scalar translocation of electrode lead  704  and/or to facilitate avoidance of similar scalar translocations in future insertion procedures, a scalar translocation detection system such as system  600  may detect the scalar translocation in any of the ways described herein. For instance, system  600  may detect first and second evoked responses by way of an electrode configuration that includes leading electrode  710  nearest the distal end of electrode lead  704 . The detection of the first evoked response may thus be performed by way of electrode  710  at a first time during insertion procedure  702  when electrode  710  is positioned at a first location along insertion path  708  (e.g., a location within scala tympani  716  prior to the moment during the insertion procedure when the scalar translocation of electrode lead  704  occurs). Thereafter, the detection of the second evoked response may be performed by way of electrode  710  at a second time during insertion procedure  702  when electrode  710  is positioned at a second location along insertion path  708  (e.g., the location of electrode  710  within scala vestibuli  720  at the moment depicted in  FIG.  7    after the scalar translocation of electrode lead  704  has occurred). 
     Alternatively, system  600  may, in certain examples, detect first and second evoked responses by way of an electrode configuration that includes a first electrode on electrode lead  704  and a second electrode on electrode lead  704 , rather than using the same electrode at two different times as described above. For example, if insertion procedure  702  were to be temporarily suspended or already completed while electrode lead  704  is arranged at the location shown in  FIG.  7   , system  600  may detect the scalar translocation of electrode lead  704  by way of a multiple-electrode electrode configuration while electrode lead  704  remains stationary. Specifically, system  600  may perform the detection of the first evoked response by way of leading electrode  710  (i.e., which, as shown, is located within scala vestibuli  720 ) and perform the detection of the second evoked response by way of another electrode  712  included on electrode lead  704  such as the electrode  712  nearest to electrode  710  (i.e., the electrode that, as shown, is located mostly within scala tympani  716  but is nearly breaching basilar membrane  718 ). 
     Both evoked responses may be detected simultaneously or at different times as long as electrode lead  704  is disposed, with respect to insertion path  708 , such that the distal-most electrode (i.e., electrode  710 ) is positioned at a first location along insertion path  708  and the other electrode (i.e., the second electrode  712  next to electrode  710 ) is positioned at a second location along insertion path  708 , where the first and second locations are in different chambers of cochlea  706  (e.g., the first location disposed in scala vestibuli  720  and the second location disposed in scala tympani  716 ). In other words, as used herein, the multiple-electrode electrode configuration that includes both the first and second electrodes may be said to be positioned at both the first location and the second location at the same time if the electrode configuration spans both locations (i.e., at least one electrode included within the multiple-electrode electrode configuration is positioned at each location). Thus, in certain examples, system  600  may detect a first evoked response by way of the multiple-electrode configuration while the electrode configuration is positioned at a first location and detect a second evoked response by way of the multiple-electrode configuration while the electrode configuration is positioned at a second location without the multiple-electrode configuration moving from one location to another (e.g., while the multiple-electrode configuration remains stationary after an insertion procedure is complete). 
     Regardless of the timeframe over which the first and second evoked responses are detected and/or whether the electrode configurations by way of which the evoked responses are detected use single or multiple electrodes, system  600  may determine an at least one of an amplitude change between the first and second evoked responses and a phase change between the first and second evoked responses. Based on the amplitude change and/or the phase change that has been determined, system  600  may determine that the scalar translocation of electrode lead  704  from scala tympani  716  to scala vestibuli  720  has occurred. System  600  may provide this information to a user to be used in any of the ways described herein. For example, the information may be used to inform a surgical team that electrode lead  704  should be backed out and reinserted to try to avoid the scalar translocation prior to completing insertion procedure  702 , the information may be stored for reference in later insertion procedures (e.g., to inform surgical teams to take extra care at particular times or depths during the later insertion procedures), the information may be used by researchers studying the effects of scalar translocations of electrode leads to inform the researchers that a scalar translocation has occurred with respect to cochlea  706 , and so forth as may serve a particular implementation. 
     In certain examples, the approximate depth of electrode lead  704  into cochlea  706  may be known or determined at a particular time. As such, because the scalar translocation of electrode lead  704  may be determined to have occurred between, for instance, electrode  710  and the electrode  712  adjacent to electrode  710 , system  600  may further determine approximately where scalar translocation site  724  is located within cochlea  706  (e.g., in terms of a cochlear depth, a frequency range, etc.). 
     As described above, system  600  may determine whether a scalar translocation of an electrode lead such as electrode lead  704  has occurred based on a determined amplitude change and/or phase change detected between a first evoked response detected at a first location and a second evoked response detected at a second location. This is because an evoked response may be expected to have a significantly different amplitude and phase if detected at a location within scala vestibuli  720  as compared to if the evoked response is detected at a location within scala tympani  716 . Specifically, as will be described and illustrated in more detail below, an evoked response detected by the electrode configuration at a translocated location within cochlea  706  (e.g., a location within scala vestibuli  720  in the example of  FIG.  7   ) may have a significantly lower amplitude and a phase approximately 180° offset from an evoked response detected by the electrode configuration at a non-translocated location within cochlea  706  (e.g., a location within scala tympani  716 , where electrode lead  704  is aimed to be kept during insertion procedure  702 ). 
     As such, in certain examples, system  600  may determine whether the scalar translocation of the electrode lead has occurred based on a notable drop off in amplitude and/or phase from one evoked response measurement to another. However, in other examples, this determination may be complicated by the fact that other factors may also cause amplitude and/or phase changes to be detected between different cochlear locations along the insertion path, even if no scalar translocation of the electrode lead has occurred. Specifically, for example, evoked responses at locations within the cochlea leading up to a depth associated with a particular frequency (e.g., a frequency at which acoustic stimulation is applied to evoke the evoked responses being detected) may be detected to have increasing amplitudes, while evoked responses at locations within the cochlea leading away from the location associated with the particular frequency may be detected to have decreasing amplitudes. 
     To illustrate,  FIG.  7    shows an exemplary depth  726  that may be associated with (i.e., may correspond to within the tonotopically arranged structure of the cochlea described above in relation to  FIG.  2   ) an exemplary frequency at which acoustic stimulation may be applied to the patient (e.g., to evoke the evoked responses being detected). Additionally,  FIG.  7    shows an exemplary depth  728  beyond depth  726  (i.e., nearer to the apex of cochlea  706 ) that may represent an anticipated final insertion depth of electrode lead  704  after insertion procedure  702  is complete. As the one or more electrodes included in the electrode configuration being used to detect evoked responses pass through entry point  714  and approach depth  726 , the amplitudes of evoked responses detected may be expected to grow increasingly larger. However, once the electrode configuration detecting the evoked responses passes depth  726  to continue on toward depth  728 , amplitudes of evoked responses detected may be expected to get increasingly smaller (e.g., dropping off by 1/e uV/mm in certain examples, where e represents Euler&#39;s number, which is approximately equal to 2.718). As such, a threshold used by system  600  to analyze whether a detected amplitude change may be indicative of a scalar translocation of the electrode lead may be dependent on both a frequency at which acoustic stimulation is applied to the patient to evoke the responses (e.g., the frequency associated with depth  726 ) as well as the ultimate depth (e.g., depth  728 ) and/or a current depth at which the evoked responses are being detected, insofar as the current depth may be determined. For example, if depth  728  is nearer to the apex of cochlea  706  than depth  726  as shown in  FIG.  7   , then a detected drop off in evoked response amplitudes detected by way of electrode  710  may indicate either that electrode  710  has passed depth  726  or that electrode  710  has translocated into scala vestibuli  720 . As such, the threshold against which amplitude measurements are compared may take this into account (e.g., allowing for an amplitude drop less than a particular threshold such as about 1/e uV/mm in some examples before determining that a scalar translocation of the electrode lead may have occurred). 
     To illustrate,  FIGS.  8 A- 8 B  show graphs  800  (i.e., graphs  800 - 1  in  FIG.  8 A and  800 - 2    in  FIG.  8 B ) of amplitude measurements  802  (e.g., amplitude measurements  802 - 1  in graph  800 - 1  and amplitude measurements  802 - 2  in graph  800 - 2 ) of exemplary evoked responses detected during exemplary insertion procedures. For example, graph  800 - 1  in  FIG.  8 A  may illustrate an exemplary insertion procedure in which no scalar translocation of the electrode lead occurs, while graph  800 - 2  in  FIG.  8 B  may illustrate a different exemplary insertion procedure (e.g., such as insertion procedure  702 ) in which a scalar translocation of the electrode lead does occur. 
     Both graphs  800 , as well as additional graphs that will be described in more detail below, illustrate measurements taken over a period of time indicated by the x-axis. For example, these graphs may represent measurements made by way of a single electrode (e.g., a leading electrode such as electrode  710 ) during an insertion procedure. During an insertion procedure, measurements of evoked responses (e.g., amplitude measurements, phase measurements, etc.) may be made automatically at a constant rate (e.g., once every 100-200 ms or at another suitable rate). As such, time may be closely tied to and/or may serve as a useful analog for insertion depth or electrode position within the cochlea because the electrode lead is being inserted deeper into the cochlea as time passes during the procedure. 
     In some insertion procedure examples, systems may be in place to detect real time insertion depth of a lead as the lead is being inserted into the cochlea, and to correlate that insertion depth with amplitude or other measurements of evoked responses. Hence, in such examples, amplitude graphs such as graphs  800  (e.g., and/or phase graphs such as will be described below) may be provided (e.g., to surgeons and/or others performing the insertion procedure) that represent measured amplitude and/or phase values with respect to insertion depth or electrode position within the cochlea, rather than (or in addition to) with respect to time. Similarly, it will be understood that principles described and illustrated herein with respect to time may apply with respect to measurements taken on a stationary electrode lead by way of different electrodes. Here again, the time at which such measurements are made may be less significant than the respective cochlear depths of the different electrodes performing the measurements. Hence, in these examples as well, graphs such as those illustrated in  FIGS.  8 A and  8 B , as well as other graphs illustrated below, may be drawn with respect to cochlear depth, electrode position within the cochlea, or something else other than time. 
     As shown in  FIG.  8 A , consecutive measurements  802 - 1  increase until the electrode configuration by way of which each measurement  802 - 1  is being made reaches a stimulation frequency depth (i.e., a depth within the cochlea associated with a frequency at which acoustic stimulation is being applied to the patient). For instance, depth  726  illustrated in  FIG.  7    and described above may represent one example of such a stimulation frequency depth. After continuing past the stimulation frequency depth, graph  800 - 1  shows that amplitude measurements  802 - 1  begin to drop off. However, because the drop off occurs at a rate less than a predetermined amplitude threshold  804  (i.e., causing measurements  802 - 1  to stay above or approximately with a rate represented by amplitude threshold  804 ), system  600  may recognize that this amplitude drop off does not indicate a scalar translocation of the electrode lead, but instead indicates that the stimulation frequency depth has been passed by the measuring electrode. 
     In scenarios where amplitude measurements  802 - 1  are being made during an insertion procedure (e.g., rather than with a stationary electrode lead after the insertion procedure) and where real-time lead insertion depth information is not available to correlate to measurements (e.g., but where time information is available), it will be understood that predetermined amplitude threshold  804  may be dependent on an average insertion speed for the particular insertion procedure. For example, predetermined amplitude threshold  804  may be a larger threshold (i.e., a steeper line) if a particular insertion procedure is progressing more rapidly than if the insertion procedure is progressing relatively slowly. Additionally, if measurements are made at a constant rate, it will be understood that changes between measurements (e.g., amplitude measurements  802 - 1 , as well as phase measurements described below) may be most useful (i.e., may yield the most accurate information) when the insertion speed of the lead into the cochlea remains relatively constant. Conversely, in scenarios where measurements are made while the electrode lead is stationary (e.g., and the measurements are thus represented with respect to insertion depth of the different electrodes rather than with respect to time), considerations such as insertion speed may not be relevant. 
     As shown, system  600  may determine whether the scalar translocation of the electrode lead has occurred by determining that an amplitude change  806 - 1  (also referred to as an amplitude drop  806 - 1 ) between first and second evoked responses is less than amplitude threshold  804 . For example, amplitude change  806 - 1  may be the difference between amplitude measurements  802 - 1  associated with two consecutive evoked responses that are measured by system  600  and amplitude threshold  804  may be associated with the stimulation frequency depth at which acoustic stimulation is being applied in order to evoke the responses represented by amplitude measurements  802 - 1 , and may be expressed as an amplitude rate of change with respect to time (e.g., based on a constant time between each measurement and an average insertion speed of a lead) or with respect to insertion depth (e.g., a constant rate such as 1/e uV/mm). System  600  may then determine (e.g., in response to the determination that amplitude change  806 - 1  is less than amplitude threshold  804 ) that the scalar translocation of the electrode lead has not occurred. In other words, system  600  may determine that, while the amplitude measurements  802 - 1  associated with amplitude change  806 - 1  do drop off significantly, the amplitude drop may be explained by passing the stimulation frequency depth and therefore is not considered to be indicative of a scalar translocation of the electrode lead. 
     Similarly, as shown in the example of graph  800 - 2  of  FIG.  8 B , consecutive measurements  802 - 2  increase until the electrode configuration reaches the stimulation frequency depth, and then, after continuing past the stimulation frequency depth, begin to drop off. However, in graph  800 - 2 , the rates of decrease between certain amplitude measurements  802 - 2  are much greater than the rates of decrease shown in graph  800 - 1 . For example, an amplitude change  806 - 2  (also referred to as an amplitude drop  806 - 2 ) between first and second evoked responses represented by amplitude measurements  802 - 2  associated with amplitude change  806 - 2  shows a drop off considerably more significant than the amplitude threshold  804  (i.e., causing measurements  802 - 2  to drop below the rate represented by amplitude threshold  804 ). Accordingly, system  600  may determine that this amplitude drop may indeed indicate that a scalar translocation of the electrode lead has occurred and may proceed to verify whether such a scalar translocation has occurred by analyzing a corresponding phase change associated with amplitude drop  806 - 2 . 
     It will be understood that in certain examples, the magnitude of amplitude drop  806 - 2  may, in and of itself, indicate that the scalar translocation of the electrode lead has occurred and system  600  may determine as much from amplitude measurements  802 - 2  alone. However, in other examples, it may be necessary or desirable to verify that the scalar translocation of the electrode lead has occurred by analyzing a corresponding phase change as will be described below. By the same token, it will be understood that, because the phase change of evoked responses may further indicate, along with the amplitude change, whether a scalar translocation is likely to have occurred, amplitude threshold  804  may be set so as to not take into account an amplitude drop expected after the electrode configuration passes the stimulation frequency depth. For example, amplitude threshold  804  may be set (i.e., predetermined at a level) such that both amplitude drops  806 - 1  and  806 - 2  would be greater than amplitude threshold  804  and would indicate the possibility of a scalar translocation of the electrode lead. Thus, in this example, an analysis of a phase change associated with each amplitude drop  806  could be used to determine whether the scalar translocation of the electrode lead has occurred or whether the stimulation frequency depth has merely been passed by the electrode configuration measuring the evoked responses. 
     To illustrate how a phase change corresponding to a threshold amplitude change may be used to determine whether (or verify that) a scalar translocation of the electrode lead has occurred,  FIGS.  9  through  11    show respective graphs of phase measurements of exemplary evoked responses detected during exemplary insertion procedures with respect to time. The threshold amplitude change illustrated in each of  FIGS.  9  through  11    may represent an amplitude drop greater than a predetermined amplitude threshold such as illustrated by amplitude drop  806 - 2  (or by an amplitude drop like  806 - 1  in examples where, as mentioned above, amplitude threshold  804  is set so as to not take into account an expected amplitude drop after the stimulation frequency depth is passed by the electrode configuration measuring the evoked responses). As such,  FIGS.  9  through  11    illustrate respective phase changes corresponding to such threshold amplitude changes. In other words, phase changes that may be analyzed by system  600  (i.e., due to a corresponding threshold amplitude change) are marked with boxes labeled “Threshold Amplitude Change ( 806 )” in  FIGS.  9  through  11   . 
     As mentioned above, if a scalar translocation of the electrode lead occurs, a phase change of approximately 180° (i.e., π radians) is expected to be detected between evoked responses associated with a location in one scala of the cochlea (e.g., the scala vestibuli) and evoked responses associated with a location in another scala of the cochlea (e.g., the scala tympani). However, detecting smaller phase changes between different locations within the same scala of the cochlea is also normally to be expected. Accordingly, system  600  may determine that the scalar translocation of the electrode lead has occurred only if a phase change (e.g., between two consecutive evoked response measurements) is detected to be approximately 180° for evoked responses that correspond to an amplitude drop that exceeds an amplitude threshold such as amplitude threshold  804 . For instance, system  600  may detect that the phase change is greater than one phase threshold (e.g., a phase threshold less than 180°) and, in some examples, that the phase change is also less than another phase threshold (e.g., a phase threshold greater than 180°). 
     For example, a graph  900  shown in  FIG.  9    illustrates a plurality of phase measurements  902  plotted along graph  900 . As described above in relation to  FIGS.  8 A and  8 B , while phase measurements  902  in graph  900  are plotted with respect to time (e.g., the time elapsing during an insertion procedure such as insertion procedure  702 ) in  FIG.  9   , it will be understood that, in other examples, phase measurements  902  may be plotted with respect to insertion depth. While not explicitly stated, it will be further understood that this may also be the case for other graphs depicting phase measurements described below in  FIGS.  10  and  11   . 
     As shown, a predetermined phase threshold  904  (e.g., a threshold large enough to allow for minor phase changes but small enough to be surpassed by a phase change of approximately 180°) is depicted relative to a first phase measurement  902  associated with the threshold amplitude change. A phase change  906  between that phase measurement  902  and the subsequent phase measurement  902  is also shown. Because phase change  906  is not greater than phase threshold  904 , system  600  may determine that a scalar translocation of the electrode lead has not occurred, but, rather, that the threshold amplitude change of amplitude drop  806  is caused by something other than a scalar translocation of the electrode lead (e.g., such as by the electrode configuration measuring the evoked responses passing the stimulation frequency depth). 
     In sum, system  600  may determine whether the scalar translocation of the electrode lead has occurred by, first, determining that an amplitude change (e.g., one of amplitude drops  806 ) is greater than a predetermined amplitude threshold associated with a frequency at which the acoustic stimulation is applied (i.e., amplitude threshold  804 ). Subsequently, in response to the determination that the amplitude change is greater than the predetermined amplitude threshold, system  600  may determine that phase change  906  is less than phase threshold  904 . Finally, in response to the determination that phase change  906  is less than phase threshold  904 , system  600  may determine that a scalar translocation of the electrode lead has not occurred. 
     In another example, a graph  1000  shown in  FIG.  10    illustrates a plurality of phase measurements  1002  plotted along graph  1000  with respect to time, similar to graph  900 . As shown, a predetermined phase threshold  1004 - 1  (e.g., a minimum threshold large enough to allow for minor phase changes but small enough to be surpassed by a phase change of approximately 180°) is depicted relative to a first phase measurement  1002  associated with the threshold amplitude change. Additionally, another predetermined phase threshold  1004 - 2  (e.g., a maximum threshold large enough to not be surpassed by a phase change of approximately 180° but small enough to be surpassed by a phase change of approximately 360°) is also shown. A phase change  1006  between the first phase measurement  1002  associated with the threshold amplitude change and the subsequent phase measurement  1002  is also illustrated. Because phase change  1006  is greater than phase threshold  1004 - 1 , system  600  may, in certain examples, determine that a scalar translocation of the electrode lead has occurred. However, because phase change  1006  is also greater than phase threshold  1004 - 2 , system  600  may instead, in other examples, determine that the threshold amplitude change of amplitude drop  806  is caused by something other than a scalar translocation of the electrode lead (e.g., such as by the electrode configuration measuring the evoked responses passing the stimulation frequency depth). This is because phase change  1006  is so large (approximately 360°) that it actually may represent a relatively minor phase change that only appears large due to an artifact of how evoked responses are measured and/or represented. In reality, a phase change of 360° may be identical to a phase change of 0°; thus, certain implementations may set both a minimum and a maximum phase threshold  1004  (i.e., minimum phase threshold  1004 - 1  and maximum phase threshold  1004 - 2 ) to ensure that phase change  1006  is within range of the 180° phase change that is expected to be measured if a scalar translocation of the electrode lead has occurred. 
     In yet another example, a graph  1100  shown in  FIG.  11    illustrates a plurality of phase measurements  1102  plotted along graph  1100  with respect to time, similar to graphs  900  and  1000 . As in graphs  900  and  1000 , a predetermined phase threshold  1104  (e.g., a threshold large enough to allow for minor phase changes but small enough to be surpassed by a phase change of approximately 180°) is depicted relative to a first phase measurement  1102  associated with the threshold amplitude change. In this example, phase threshold  1104  may represent a minimum phase threshold (i.e., analogous to phase threshold  1004 - 1 ). However, it will be understood that a maximum phase threshold analogous to phase threshold  1004 - 2  may additionally or alternatively be included in other similar examples. A phase change  1106  between the first phase measurement  1102  associated with the threshold amplitude change and the subsequent phase measurement  1102  is also shown. Because phase change  1106  is greater than phase threshold  1104 , system  600  may determine that a scalar translocation of the electrode lead has occurred. 
     In sum, system  600  may determine whether the scalar translocation of the electrode lead has occurred by, first, determining that an amplitude change (e.g., one of amplitude drops  806 ) is greater than a predetermined amplitude threshold associated with a frequency at which the acoustic stimulation is applied (i.e., amplitude threshold  804 ). Subsequently, in response to the determination that the amplitude change is greater than the predetermined amplitude threshold, system  600  may determine that phase change  1106  is greater than phase threshold  1104 . Finally, in response to the determination that phase change  1106  is greater than phase threshold  1104 , system  600  may determine that the scalar translocation of the electrode lead has occurred. 
       FIG.  12    illustrates a method  1200  for detecting scalar translocation of an electrode lead within a cochlea of a cochlear implant patient. One or more of the operations shown in  FIG.  12    may be performed by system  600  and/or any implementation thereof. While  FIG.  12    illustrates exemplary operations according to one embodiment, other embodiments may omit, add to, reorder, and/or modify any of the operations shown in  FIG.  12   . 
     In operation  1202 , a scalar translocation detection system associated with (e.g., communicatively coupled with, integrated by, etc.) a cochlear implant system may detect a first evoked response that occurs in response to acoustic stimulation applied to a cochlear implant patient. For example, the scalar translocation detection system may detect the first evoked response by way of an electrode configuration including at least one electrode disposed on an electrode lead included within the cochlear implant system and while the electrode configuration is positioned at a first location along an insertion path of the electrode lead into a cochlea of a cochlear implant patient. Operation  1202  may be performed in any of the ways described herein. 
     In operation  1204 , the scalar translocation detection system may detect a second evoked response that occurs in response to additional acoustic stimulation applied to the cochlear implant patient. For instance, the scalar translocation detection system may detect the second evoked response by way of the electrode configuration while the electrode configuration is positioned at a second location along the insertion path of the electrode lead into the cochlea. Operation  1204  may be performed in any of the ways described herein. 
     In operation  1206 , the scalar translocation detection system may determine at least one of an amplitude change and a phase change between the first and second evoked responses detected in operations  1202  and  1204 , respectively. Operation  1206  may be performed in any of the ways described herein. 
     In operation  1208 , the scalar translocation detection system may determine whether a scalar translocation of the electrode lead from one scala of the cochlea to another scala of the cochlea has occurred. In some examples, the scalar translocation detection system may determine whether the scalar translocation of the electrode lead has occurred based on the at least one of the amplitude change and the phase change determined in operation  1206 . Operation  1208  may be performed in any of the ways described herein. 
     In certain embodiments, one or more of the processes described herein may be implemented at least in part as instructions embodied in a non-transitory computer-readable medium and executable by one or more computing devices. In general, a processor (e.g., a microprocessor) receives instructions, from a non-transitory computer-readable medium (e.g., a memory, etc.) and executes the instructions, thereby performing one or more processes, including one or more of the processes described herein. Such instructions may be stored and/or transmitted using any of a variety of known computer-readable media. 
     A computer-readable medium (also referred to as a processor-readable medium) includes any non-transitory medium that participates in providing data (e.g., instructions) that may be read by a computer (e.g., by a processor of a computer). Such a medium may take many forms, including, but not limited to, non-volatile media, and/or volatile media. Non-volatile media may include, for example, optical or magnetic disks and other persistent memory. Volatile media may include, for example, dynamic random access memory (“DRAM”), which typically constitutes a main memory. Common forms of computer-readable media include, for example, a disk, hard disk, magnetic tape, any other magnetic medium, a compact disc read-only memory (“CD-ROM”), a digital video disc (“DVD”), any other optical medium, random access memory (“RAM”), programmable read-only memory (“PROM”), erasable programmable read-only memory (“EPROM”), electrically erasable programmable read-only memory (“EEPROM”), a Flash EEPROM device, any other memory chip or cartridge, or any other tangible medium from which a computer can read. 
       FIG.  13    illustrates an exemplary computing device  1300  that may be specifically configured to perform one or more of the processes described herein. As shown in  FIG.  13   , computing device  1300  may include a communication interface  1302 , a processor  1304 , a storage device  1306 , and an input/output (“I/O”) module  1308  communicatively connected via a communication infrastructure  1310 . While an exemplary computing device  1300  is shown in  FIG.  13   , the components illustrated in  FIG.  13    are not intended to be limiting. Additional or alternative components may be used in other embodiments. Components of computing device  1300  shown in  FIG.  13    will now be described in additional detail. 
     Communication interface  1302  may be configured to communicate with one or more computing devices. Examples of communication interface  1302  include, without limitation, a wired network interface (such as a network interface card), a wireless network interface (such as a wireless network interface card), a modem, an audio/video connection, and any other suitable interface. 
     Processor  1304  generally represents any type or form of processing unit capable of processing data or interpreting, executing, and/or directing execution of one or more of the instructions, processes, and/or operations described herein. Processor  1304  may direct execution of operations in accordance with one or more applications  1312  or other computer-executable instructions such as may be stored in storage device  1306  or another computer-readable medium. 
     Storage device  1306  may include one or more data storage media, devices, or configurations and may employ any type, form, and combination of data storage media and/or device. For example, storage device  1306  may include, but is not limited to, a hard drive, network drive, flash drive, magnetic disc, optical disc, RAM, dynamic RAM, other non-volatile and/or volatile data storage units, or a combination or sub-combination thereof. Electronic data, including data described herein, may be temporarily and/or permanently stored in storage device  1306 . For example, data representative of one or more executable applications  1312  configured to direct processor  1304  to perform any of the operations described herein may be stored within storage device  1306 . In some examples, data may be arranged in one or more databases residing within storage device  1306 . 
     I/O module  1308  may be configured to receive user input and provide user output and may include any hardware, firmware, software, or combination thereof supportive of input and output capabilities. For example, I/O module  1308  may include hardware and/or software for capturing user input, including, but not limited to, a keyboard or keypad, a touch screen component (e.g., touch screen display), a receiver (e.g., an RF or infrared receiver), and/or one or more input buttons. 
     I/O module  1308  may include one or more devices for presenting output to a user, including, but not limited to, a graphics engine, a display (e.g., a display screen), one or more output drivers (e.g., display drivers), one or more audio speakers, and one or more audio drivers. In certain embodiments, I/O module  1308  is configured to provide graphical data to a display for presentation to a user. The graphical data may be representative of one or more graphical user interfaces and/or any other graphical content as may serve a particular implementation. 
     In some examples, any of the facilities or systems described herein may be implemented by or within one or more components of computing device  1300 . For example, one or more applications  1312  residing within storage device  1306  may be configured to direct processor  1304  to perform one or more processes or functions associated with evoked response detection facility  602  or processing facility  604  within system  600 . Likewise, storage facility  606  within system  600  may be implemented by or within storage device  1306 . 
     In the preceding description, various exemplary embodiments have been described with reference to the accompanying drawings. It will, however, be evident that various modifications and changes may be made thereto, and additional embodiments may be implemented, without departing from the scope of the invention as set forth in the claims that follow. For example, certain features of one embodiment described herein may be combined with or substituted for features of another embodiment described herein. The description and drawings are accordingly to be regarded in an illustrative rather than a restrictive sense.