Patent Publication Number: US-2022233861-A1

Title: Use of one or more evoked response signals to determine an insertion state of an electrode lead during an electrode lead insertion procedure

Description:
RELATED APPLICATIONS 
     The present application claims priority to PCT International Application No. PCT/US2019/041136, filed Jul. 10, 2019, the contents of which are hereby incorporated by reference in their entirety. 
    
    
     BACKGROUND INFORMATION 
     During an insertion procedure in which an electrode lead is placed within the cochlea, it may be desirable to ascertain an insertion state of the electrode lead. For example, it may be desirable to determine and convey in real-time to a surgeon performing the insertion procedure when an electrode on the electrode lead passes a particular characteristic frequency location within the cochlea, when an electrode on the electrode lead is within a vicinity of a cluster of hair cells, and/or when the electrode lead is possibly causing trauma to a structure of the cochlea. 
    
    
     
       BRIEF DESCRIPTION OF THE DRA NGS 
       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 an exemplary configuration of the cochlear implant system of  FIG. 1 . 
         FIG. 3  illustrates an exemplary diagnostic system according to principles described herein. 
         FIGS. 4-5  illustrate exemplary implementations of the diagnostic system of  FIG. 3  according to principles described herein. 
         FIGS. 6A-6F  illustrate an exemplary insertion procedure in which an electrode lead is inserted into a cochlea of a recipient according to principles described herein. 
         FIGS. 7-11  show exemplary graphs of evoked response signals that may be generated according to principles described herein. 
         FIG. 12  illustrates an exemplary method according to principles described herein. 
         FIG. 13  illustrates an exemplary computing device according to principles described herein. 
     
    
    
     DETAILED DESCRIPTION 
     Systems and methods for use of one or more evoked response signals to determine an insertion state of an electrode lead during an electrode lead insertion procedure are described herein. For example, a diagnostic system may 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 communicatively coupled to the cochlear implant is inserted into a cochlea of the recipient. The diagnostic system may direct the cochlear implant to use an electrode 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 may correspond to a different stimulus frequency included in the plurality of stimulus frequencies and may be representative of evoked responses that occur within the recipient in response to the acoustic stimulation applied to the recipient. The evoked responses may each be an electrocochleographic (“ECoG”) potential (e.g., a cochlear microphonic potential, an action potential, a summating potential, etc.), an auditory nerve response, a brainstem response, a compound action potential, a stapedius reflex, and/or any other type of neural or physiological response that may occur within a recipient in response to application of acoustic stimulation to the recipient. Evoked responses may originate from neural tissues, hair cell to neural synapses, inner or outer hair cells, or other sources. 
     As will be described herein, attributes associated with the evoked response signals recorded by the electrode may be indicative of an insertion state of the electrode lead within the cochlea of the recipient. For example, an amplitude and/or a phase of one or more evoked response signals may be indicative of a particular insertion state. As used herein, “an insertion state” may correspond to any of a plurality of different insertion states that may be associated with insertion of the electrode lead into the cochlea of the recipient. For example, one or more insertion states may be associated with passing a characteristic frequency location of the cochlea, passing a cluster of hair cells or neurons, contacting a structure of the cochlea (e.g., the basilar membrane), causing trauma to the cochlea (e.g., passing through the basilar membrane), etc. Accordingly, the diagnostic system may determine an insertion state of the electrode lead within the cochlea of the recipient based on an amplitude and a phase of each of one or more evoked response signals included in the plurality of evoked response signals. 
     By using acoustic stimulation having a plurality of stimulus frequencies to facilitate determining an insertion state, the systems and methods described herein may optimize determination of an insertion state and/or facilitate determination of additional or alternative insertion states as compared to conventional methods. In addition, the systems and methods described herein may be used to provide real time feedback to a user (e,g., a surgeon) performing an insertion procedure to ensure proper placement of an electrode lead within a cochlea of a recipient. These and other benefits and advantages of the systems and methods described herein will be made apparent herein. 
       FIG. 1  illustrates an exemplary cochlear implant system  100  configured to be used by a recipient. As shown, cochlear implant system  100  includes a cochlear implant  102 , an electrode lead  104  physically coupled to cochlear implant  102  and having an array of electrodes  106 , and a controller  108  configured to be communicatively coupled to cochlear implant  102  by way of a communication link  110 . 
     The cochlear implant system  100  shown in  FIG. 1  is unilateral (i.e., associated with only one ear of the recipient). Alternatively, a bilateral configuration of cochlear implant system  100  may include separate cochlear implants and electrode leads for each ear of the recipient. In the bilateral configuration, controller  108  may be implemented by a single controller configured to interface with both cochlear implants or by two separate controllers each configured to interface with a different one of the cochlear implants. 
     Cochlear implant  102  may be implemented by any suitable type of implantable stimulator, For example, cochlear implant  102  may be implemented by an implantable cochlear stimulator. Additionally or alternatively, cochlear implant  102  may be implemented by a brainstem implant and/or any other type of device that may be implanted within the recipient and configured to apply electrical stimulation to one or more stimulation sites located along an auditory pathway of the recipient. 
     In some examples, cochlear implant  102  may be configured to generate electrical stimulation representative of an audio signal processed by controller  108  in accordance with one or more stimulation parameters transmitted to cochlear implant  102  by controller  108 . Cochlear implant  102  may be further configured to apply the electrical stimulation to one or more stimulation sites (e.g., one or more intracochlear locations) within the recipient by way of one or more electrodes  106  on electrode lead  104 . In some examples, cochlear implant  102  may include a plurality of independent current sources each associated with a channel defined by one or more of electrodes  106 . In this manner, different stimulation current levels may be applied to multiple stimulation sites simultaneously by way of multiple electrodes  106 . 
     Cochlear implant  102  may additionally or alternatively be configured to generate, store, and/or transmit data. For example, cochlear implant may use one or more electrodes  106  to record one or more signals (e.g., one or more voltages, impedances, evoked responses within the recipient, and/or other measurements) and transmit, by way of communication link  110 , data representative of the one or more signals to controller  108 . In some examples, this data is referred to as back telemetry data. 
     Electrode lead  104  may be implemented in any suitable manner. For example, a distal portion of electrode lead  104  may be pre-curved such that electrode lead  104  conforms with the helical shape of the cochlea after being implanted. Electrode lead  104  may alternatively be naturally straight or of any other suitable configuration. 
     In some examples, electrode lead  104  includes a plurality of wires (e.g., within an outer sheath) that conductively couple electrodes  106  to one or more current sources within cochlear implant  102 . For example, if there are n electrodes  106  on electrode lead  104  and n current sources within cochlear implant  102 , there may be n separate wires within electrode lead  104  that are configured to conductively connect each electrode  106  to a different one of the n current sources. Exemplary values for n are 8, 12, 16, or any other suitable number. 
     Electrodes  106  are located on at least a distal portion of electrode lead  104 . In this configuration, after the distal portion of electrode lead  104  is inserted into the cochlea, electrical stimulation may be applied by way of one or more of electrodes  106  to one or more intracochlear locations. One or more other electrodes (e.g., including a ground electrode, not explicitly shown) may also be disposed on other parts of electrode lead  104  (e.g., on a proximal portion of electrode lead  104 ) to, for example, provide a current return path for stimulation current applied by electrodes  106  and to remain external to the cochlea after the distal portion of electrode lead  104  is inserted into the cochlea. Additionally or alternatively, a housing of cochlear implant  102  may serve as a ground electrode for stimulation current applied by electrodes  106 . 
     Controller  108  may be configured to interface with (e.g., control and/or receive data from) cochlear implant  102 . For example, controller  108  may transmit commands (e.g., stimulation parameters and/or other types of operating parameters in the form of data words included in a forward telemetry sequence) to cochlear implant  102  by way of communication link  110 . Controller  108  may additionally or alternatively provide operating power to cochlear implant  102  by transmitting one or more power signals to cochlear implant  102  by way of communication link  110 . Controller  108  may additionally or alternatively receive data from cochlear implant  102  by way of communication link  110 . Communication link  110  may be implemented by any suitable number of wired and/or wireless bidirectional and/or unidirectional links. 
     As shown, controller  108  includes a memory  112  and a processor  114  configured to be selectively and communicatively coupled to one another. In some examples, memory  112  and processor  114  may be distributed between multiple devices and/or multiple locations as may serve a particular implementation. 
     Memory  112  may be implemented by any suitable non-transitory computer-readable medium and/or non-transitory processor-readable medium, such as any combination of non-volatile storage media and/or volatile storage media. Exemplary non-volatile storage media include, but are not limited to, read-only memory, flash memory, a solid-state drive, a magnetic storage device (e.g., a hard drive), ferroelectric random-access memory (“RAM”), and an optical disc. Exemplary volatile storage media include, but are not limited to, RAM (e.g., dynamic RAM). 
     Memory  112  may maintain (e.g., store) executable data used by processor  114  to perform one or more of the operations described herein. For example, memory  112  may store instructions  116  that may be executed by processor  114  to perform any of the operations described herein. Instructions  116  may be implemented by any suitable application, program (e.g., sound processing program), software, code, and/or other executable data instance. Memory  112  may also maintain any data received, generated, managed, used, and/or transmitted by processor  114 . 
     Processor  114  may be configured to perform (e.g., execute instructions  116  stored in memory  112  to perform) various operations with respect to cochlear implant  102 . 
     To illustrate, processor  114  may be configured to control an operation of cochlear implant  102 . For example, processor  114  may receive an audio signal (e.g., by way of a microphone communicatively coupled to controller  108 , a wireless interface (e.g., a Bluetooth interface), and/or a wired interface (e.g., an auxiliary input port)). Processor  114  may process the audio signal in accordance with a sound processing program (e.g., a sound processing program stored in memory  112 ) to generate appropriate stimulation parameters. Processor  114  may then transmit the stimulation parameters to cochlear implant  102  to direct cochlear implant  102  to apply electrical stimulation representative of the audio signal to the recipient. 
     In some implementations, processor  114  may also be configured to apply acoustic stimulation to the recipient. For example, a receiver (also referred to as a loudspeaker) may be optionally coupled to controller  108 . In this configuration, processor  114  may deliver acoustic stimulation to the recipient by way of the receiver. 
     The acoustic stimulation may be representative of an audio signal (e.g., an amplified version of the audio signal), configured to elicit an evoked response within the recipient, and/or otherwise configured. In configurations in which processor  114  is configured to both deliver acoustic stimulation to the recipient and direct cochlear implant  102  to apply electrical stimulation to the recipient, cochlear implant system  100  may be referred to as a bimodal hearing system and/or any other suitable term. 
     Processor  114  may be additionally or alternatively configured to receive and process data generated by cochlear implant  102 . For example, processor  114  may receive data representative of a signal recorded by cochlear implant  102  using one or more electrodes  106  and, based on the data, adjust one or more operating parameters of controller  108 . Additionally or alternatively, processor  114  may use the data to perform one or more diagnostic operations with respect to cochlear implant  102  and/or the recipient. 
     Other operations may be performed by processor  114  as may serve a particular implementation. In the description provided herein, any references to operations performed by controller  108  and/or any implementation thereof may be understood to be performed by processor  114  based on instructions  116  stored in memory  112 . 
     Controller  108  may be implemented by one or more devices configured to interface with cochlear implant  102 . To illustrate,  FIG. 2  shows an exemplary configuration  200  of cochlear implant system  100  in which controller  108  is implemented by a sound processor  202  configured to be located external to the recipient. In configuration  200 , sound processor  202  is communicatively coupled to a microphone  204  and to a headpiece  206  that are both configured to be located external to the recipient. 
     Sound processor  202  may be implemented by any suitable device that may be worn or carried by the recipient. For example, sound processor  202  may be implemented by a behind-the-ear (“BTE”) unit configured to be worn behind and/or on top of an ear of the recipient. Additionally or alternatively, sound processor  202  may be implemented by an off-the-ear unit (also referred to as a body worn device) configured to be worn or carried by the recipient away from the ear. Additionally or alternatively, at least a portion of sound processor  202  is implemented by circuitry within headpiece  206 . 
     Microphone  204  is configured to detect one or more audio signals (e,g., that include speech and/or any other type of sound) in an environment of the recipient. Microphone  204  may be implemented in any suitable manner, For example, microphone  204  may be implemented by 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 during normal operation by a boom or stalk that is attached to an ear hook configured to be selectively attached to sound processor  202 . Additionally or alternatively, microphone  204  may be implemented by one or more microphones in or on headpiece  206 , one or more microphones in or on a housing of sound processor  202 , one or more beam-forming microphones, and/or any other suitable microphone as may serve a particular implementation. 
     Headpiece  206  may be selectively and communicatively coupled to sound processor  202  by way of a communication link  208  (e.g., a cable or any other suitable wired or wireless communication link), which may be implemented in any suitable manner. Headpiece  206  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  202  to cochlear implant  102 . Headpiece  206  may additionally or alternatively be used to selectively and wirelessly couple any other external device to cochlear implant  102 . To this end, headpiece  206  may be configured to be affixed to the recipient&#39;s head and positioned such that the external antenna housed within headpiece  206  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 connected to cochlear implant  102 . In this manner, stimulation parameters and/or power signals may be wirelessly and transcutaneously transmitted between sound processor  202  and cochlear implant  102  by way of a wireless communication link  210 . 
     In configuration  200 , sound processor  202  may receive an audio signal detected by microphone  204  by receiving a signal (e.g., an electrical signal) representative of the audio signal from microphone  204 . Sound processor  202  may additionally or alternatively receive the audio signal by way of any other suitable interface as described herein. Sound processor  202  may process the audio signal in any of the ways described herein and transmit, by way of headpiece  206 , stimulation parameters to cochlear implant  102  to direct cochlear implant  102  to apply electrical stimulation representative of the audio signal to the recipient. 
     In an alternative configuration, sound processor  202  may be implanted within the recipient instead of being located external to the recipient, In this alternative configuration, which may be referred to as a fully implantable configuration of cochlear implant system  100 , sound processor  202  and cochlear implant  102  may be combined into a single device or implemented as separate devices configured to communicate one with another by way of a wired and/or wireless communication link. In a fully implantable implementation of cochlear implant system  100 , headpiece  206  may not be included and microphone  204  may be implemented by one or more microphones implanted within the recipient, located within an ear canal of the recipient, and/or external to the recipient. 
       FIG. 3  illustrates an exemplary diagnostic system  300  that may be configured to perform any of the operations described herein. As shown, diagnostic system  300  may include, without limitation, a storage facility  302  and a processing facility  304  selectively and communicatively coupled to one another. Facilities  302  and  304  may each include or be implemented by hardware and/or software components (e.g., processors, memories, communication interfaces, instructions stored in memory for execution by the processors, etc.). In some examples, facilities  302  and  304  may be distributed between multiple devices and/or multiple locations as may serve a particular implementation. 
     Storage facility  302  may maintain (e.g., store) executable data used by processing facility  304  to perform any of the operations described herein. For example, storage facility  302  may store instructions  306  that may be executed by processing facility  304  to perform any of the operations described herein. Instructions  306  may be implemented by any suitable application, software, code, and/or other executable data instance. Storage facility  302  may also maintain any data received, generated, managed, used, and/or transmitted by processing facility  304 . 
     Processing facility  304  may be configured to perform (e.g., execute instructions  306  stored in storage facility  302  to perform) various operations. For example, processing facility  304  may 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 communicatively coupled to the cochlear implant is inserted into a cochlea of the recipient, direct the cochlear implant to use an electrode 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. These and other operations that may be performed by processing facility  304  are described in more detail herein. 
     Diagnostic system  300  may be implemented in any suitable manner. For example,  FIG. 4  shows an exemplary configuration  400  in which diagnostic system  300  is implemented by a computing system  402  configured to communicatively couple to sound processor  202 . As shown, computing system  402  may include an acoustic stimulation generator  404  communicatively coupled to a speaker  406 . Computing system  402  is also communicatively coupled to a display device  408 , While computing system  402  is described herein as being be coupled to sound processor  202 , computing system  402  may be alternatively coupled to any other implementation of controller  108  as may serve a particular implementation. 
     Computing system  402  may be implemented by any suitable combination of hardware (e.g., one or more computing devices) and software. For example, computing system  402  may be implemented by a computing device programmed to perform one or more fitting operations with respect to a recipient of a cochlear implant, To illustrate, computing system  402  may be implemented by a desktop computer, a mobile device (e.g., a laptop, a smartphone, a tablet computer, etc.), and/or any other suitable computing device as may serve a particular implementation. As an example, computing system  402  may be implemented by a mobile device configured to execute an application (e.g., a “mobile app”) that may be used by a user (e.g., the recipient, a clinician, and/or any other user) to control one or more settings of sound processor  202  and/or cochlear implant  102  and/or perform one or more operations (e.g., diagnostic operations) with respect to data generated by sound processor  202  and/or cochlear implant  102 . 
     Acoustic stimulation generator  404  may be implemented by any suitable combination of components configured to generate acoustic stimulation. In some examples, the acoustic stimulation may include one or more tones having one or more stimulus frequencies. Additionally or alternatively, the acoustic stimulation may include any other type of acoustic content that has at least a particular stimulus frequency of interest. Speaker  406  may be configured to deliver the acoustic stimulation generated by acoustic stimulation generator  404  to the recipient. For example, speaker  406  may be implemented by an ear mold configured to be placed in or near an entrance to an ear canal of the recipient. 
     Display device  408  may be implemented by any suitable device configured to display graphical content generated by computing system  402 . For example, display device  408  may display one or more graphs of evoked responses recorded by an electrode disposed on electrode lead  104 . Display device  408  is shown in  FIG. 4  as an external device configured to display content generated by computing system  402 . Additionally or alternatively, computing system  402  may include display device  408  as an integrated display in certain implementations. 
       FIG. 5  shows another exemplary configuration  500  in which diagnostic system  400  is implemented by computing system  402 . In configuration  500 , acoustic stimulation generator  404  is included in sound processor  202 . For example, sound processor  202  may be implemented by a bimodal sound processor (i.e., a sound processor configured to direct cochlear implant  102  to apply electrical stimulation to a recipient and acoustic stimulation generator  404  to apply acoustic stimulation to the recipient). In some examples, speaker  406  may be implemented by an audio ear hook that connects to sound processor  202 . 
       FIGS. 6A-6F  illustrate an exemplary insertion procedure in which an electrode lead  600  is inserted into a cochlea  602  of a recipient. For illustrative purposes, cochlea  602  is depicted in  FIGS. 6A-6F  as being “unrolled” instead of its actual curved, spiral shape. Electrode lead  600  may be similar to electrode lead  104  and may include a plurality of electrodes (e.g., electrodes  604 - 1  through electrode  604 - 16 ) disposed thereon. Electrode  604 - 1  is a distal-most electrode on electrode lead  600  and electrode  604 - 16  is a proximal-most electrode on electrode lead  600 . 
     Various characteristic frequency locations within cochlea  602  are depicted by vertical dashed lines in each of  FIGS. 6A-6F . As shown, a first characteristic frequency location is associated with 4 kHz. Hence, electrical stimulation applied by an electrode positioned at this characteristic frequency location may result in the recipient perceiving sound having 4 kHz or the hair cell and neural structures there respond to 4 kHz acoustic stimulus.  FIGS. 6A-6F  also depict characteristic frequency locations associated with 2 kHz, 1 kHz, 500 Hz, and 250 Hz. As shown, the frequencies associated with the characteristic frequency locations are tonotopically arranged, with relatively higher frequencies being located towards the entrance (or base) of cochlea  602  and relatively lower frequencies being located towards the distal end (or apex) of cochlea  602 . 
       FIG. 6A  shows electrode lead  600  entering cochlea  602 . In this figure, electrode  604 - 1  is barely within cochlea  602 .  FIG. 6B  shows electrode lead  600  after electrode lead  600  has been advanced further into cochlea  602  such that electrode  604 - 1  is positioned at the characteristic frequency location corresponding to 4 kHz. 
       FIGS. 6C-6F  show electrode lead  600  after electrode lead  600  has been advanced further into cochlea  602  such that electrode  604 - 1  is positioned at the characteristic frequency location corresponding to 2 kHz ( FIG. 6C ), then 1 kHz ( FIG. 6D ), then 500 Hz ( FIG. 6E ), and then 250 Hz ( FIG. 6F ). 
     As mentioned, it is desirable to monitor an insertion state of an electrode lead as the electrode lead is inserted within a cochlea to ensure that the electrode lead is inserted properly. To that end, diagnostic system  300  may direct an acoustic stimulation generator (e.g., acoustic stimulation generator  404 ) to apply acoustic stimulation having a plurality of stimulus frequencies (i.e., concurrently) to a recipient of a cochlear implant during an insertion procedure in which an electrode lead communicatively coupled to the cochlear implant is inserted into a cochlea of the recipient. Diagnostic system  300  may direct the acoustic stimulation generator to apply the acoustic stimulation having the plurality of stimulus frequencies in any suitable manner. For example, diagnostic system  300  may direct the acoustic stimulation generator to continuously apply the acoustic stimulation during an insertion procedure, intermittently apply the acoustic stimulation during the insertion procedure, simultaneously apply different stimulus frequencies of the acoustic stimulation during the insertion procedure, sequentially apply the different stimulus frequencies of the acoustic stimulation during the insertion procedure, or apply the acoustic stimulation in any other suitable manner as may serve a particular implementation. 
     The acoustic stimulation may have any suitable plurality of stimulus frequencies as may serve a particular implementation. In certain examples, the acoustic stimulation may have four different stimulus frequencies that are concurrently applied during an insertion procedure. For example, in certain implementations the acoustic stimulation may include a first stimulus frequency corresponding to 2 kHz, a second stimulus frequency corresponding to 1 kHz, a third stimulus frequency corresponding to 500 Hz, and a fourth stimulus frequency corresponding to 250 Hz. In certain alternative implementations, the acoustic stimulation may have less than or more than four stimulus frequencies. 
     The acoustic stimulation is configured to produce a plurality of evoked responses during an insertion procedure that are useful in determining an insertion state. Accordingly, diagnostic system  300  may direct cochlear implant  102  to use an electrode to record a plurality of evoked response signals during an insertion procedure. Diagnostic system  300  may direct cochlear implant  102  to use any suitable electrode or combination of electrodes on an electrode lead to record the plurality of evoked response signals. For example, in certain implementations, diagnostic system  300  may direct the cochlear implant to use a distal-most electrode (e.g., electrode  604 - 1 ) to record the plurality of evoked response signals. Each evoked response signal included in the plurality of evoked response signals may correspond to a different stimulus frequency included in the plurality of stimulus frequencies. In addition, each evoked response signal included in the plurality of evoked response signals may be representative of evoked responses that occur within the recipient in response to the acoustic stimulation applied to the recipient. 
     In certain examples, the plurality of evoked response signals may be considered as being included as part of a single evoked response detected by diagnostic system  300  in response to the acoustic stimulation applied to the recipient. 
     Attributes of the plurality of evoked response signals may be indicative of an insertion state of the electrode lead as the electrode lead is inserted within the cochlea. 
     For example, as the electrode lead is inserted within the cochlea, an amplitude and/or a phase of one or more evoked response signals included in the plurality of evoked response signals may change in a manner that is indicative of a particular insertion state of the electrode lead. Accordingly, based on an amplitude and a phase of each of one or more evoked response signal included in the plurality of evoked response signals, diagnostic system  300  may determine an insertion state of the electrode lead within the cochlea of the recipient. 
     Diagnostic system  300  may determine any suitable number and/or type of insertion states as may serve a particular implementation. In certain examples, an insertion state may correspond to the electrode lead passing a particular characteristic frequency location within the cochlea. In such examples, diagnostic system  300  may determine that the electrode lead passes the particular characteristic frequency location when, within a predetermined amount of time, both an amplitude of a particular evoked response signal included in the plurality of evoked response signals decreases by at least an amplitude threshold amount and a phase of the particular evoked response signal changes by at least a phase threshold amount. The particular characteristic frequency location may correspond to a particular stimulus frequency that corresponds to the particular evoked response signal and that is included in the plurality of stimulus frequencies. Accordingly, diagnostic system  300  may determine an insertion state as passing a certain characteristic frequency location based on which evoked response signal has both a decrease in amplitude by at least an amplitude threshold amount and a phase change by at least a phase threshold amount. 
     To illustrate,  FIG. 7  shows an exemplary lead insertion procedure in which electrode lead  600  is advanced into cochlea  602 , Reference numbers P 1  through P 3  indicate positions of electrode lead  600 . For example, at position P 1 , electrode lead  600  is at a first position in which electrode  604 - 1  is at the characteristic frequency location that corresponds to 2 kHz. At position P 2 , electrode lead  600  is at a second position in which electrode  604 - 1  is at the characteristic frequency location that corresponds to 1 kHz. At position P 3 , electrode lead  600  is at a third position in which electrode  604 - 1  is at the characteristic frequency location that corresponds to 500 Hz. 
       FIG. 7  also shows a graph  702  of amplitudes  706  (e.g., amplitudes  706 - 1  through  706 - 3 ) of evoked response signals recorded by electrode  604 - 1  at different insertion times T (e.g., T 1  through T 3 ) during the lead insertion procedure. In addition,  FIG. 7  shows a graph  704  of phases  708  (e.g., phases  708 - 1  through  708 - 3 ) of the evoked response signals recorded by electrode  604 - 1  at different insertion times T during the lead insertion procedure. In this example, first, second, and third evoked response signals are generated in response to acoustic stimulation having stimulus frequencies of 2 kHz, 1 kHz, and 500 Hz, respectively. Hence, as shown in graph  702 , as electrode lead  600  advances towards the characteristic frequency location that corresponds to 2 kHz, the amplitude  706 - 1  of a first evoked response signal, which is generated in response to acoustic stimulation having a stimulus frequencies of 2 kHz, increases and peaks at insertion time T 1  when electrode lead  600  is positioned at position P 1 . As electrode lead  600  passes the characteristic frequency location that corresponds to 2 kHz, the first evoked response amplitude  706 - 1  decreases until it settles at a steady state value. As shown in graph  704 , as electrode lead  600  advances towards the characteristic frequency location that corresponds to 2 kHz, the phase  708 - 1  of the first evoked response signal remains at a relatively high level. However, the phase  708 - 1  suddenly changes to a relatively low level at insertion time T 1  as electrode lead  600  passes the characteristic frequency location that corresponds to 2 kHz. 
     As shown in  FIG. 7 , the decreasing of the first evoked response amplitude  706 - 1  and the changing of the phase  708 - 1  from the high level to the low level occur at substantially the same insertion time T 1 , and both occur as electrode  604 - 1  passes the characteristic frequency location that corresponds to 2 kHz. Hence, diagnostic system  300  may determine that electrode  604 - 1  passes the characteristic frequency location that corresponds to 2 kHz by detecting, within a predetermined time period, that both an amplitude  706 - 1  of the first evoked response signal recorded by electrode  604 - 1  decreases by at least an amplitude threshold amount and a phase  708 - 1  of the first evoked response signal recorded by electrode  604 - 1  changes by at least a phase threshold amount. The predetermined time period, the amplitude threshold amount, and/or the phase threshold amount may each be set by diagnostic system  300  to be any suitable value. For example, the predetermined time period may be set to be a relatively short time period (e.g., less than a few milliseconds) to ensure that the change in amplitude and in phase correspond to one another. In some examples, diagnostic system  300  may set the predetermined time period, the amplitude threshold amount, and/or the phase threshold in response to user input (e.g., by way of a graphical user interface). Additionally or alternatively, diagnostic system  300  may set the predetermined time period, the amplitude threshold amount, and/or the phase threshold automatically based on one or more factors, such as hearing loss, the stimulus frequency, recipient characteristics (e.g., age, gender, etc.), etc. 
     As is further shown in  FIG. 7 , after electrode lead  600  passes the characteristic frequency location that corresponds to 2 kHz, electrode lead  600  advances towards the characteristic frequency location that corresponds to 1 kHz. As electrode lead  600  advances toward the characteristic frequency location that corresponds to 1 kHz, the amplitude  706 - 2  of the second evoked response signal, which is generated in response to acoustic stimulation having a stimulus frequencies of 1 kHz, increases and peaks at insertion time T 2  when electrode lead  600  is positioned at position P 2 . As electrode lead  600  passes the characteristic frequency location that corresponds to 1 kHz, the second evoked response amplitude  706 - 2  decreases until it settles at a steady state value. As shown in graph  704 , as electrode lead  600  advances towards the characteristic frequency location that corresponds to 1 kHz, the phase  708 - 2  of the second evoked response signal remains at a relatively high level. However, the phase  708 - 2  suddenly changes to a relatively low level at insertion time T 2  as electrode lead  600  passes the characteristic frequency location that corresponds to 1 kHz. 
     The decreasing of the second evoked response amplitude  706 - 2  and the changing of phase  708 - 2  from the high level to the low level in  FIG. 7  occur at substantially the same insertion time T 2 , and both occur as electrode  604 - 1  passes the characteristic frequency location that corresponds to 1 kHz. Hence, diagnostic system  300  may determine that electrode  604 - 1  passes the characteristic frequency location that corresponds to 1 kHz by detecting, within an additional predetermined time period, that both an amplitude  706 - 2  of the second evoked response signal recorded by electrode  604 - 1  decreases by at least an amplitude threshold amount and a phase  708 - 2  of the second evoked response signal recorded by electrode  604 - 1  changes by at least a phase threshold amount. The additional predetermined time period, the amplitude threshold amount, and/or the phase threshold amount may each be set by diagnostic system  300  to be any suitable value, such as described herein. 
     As is further shown in  FIG. 7 , after electrode lead  600  passes the characteristic frequency location that corresponds to 1 kHz, electrode lead  600  advances towards the characteristic frequency location that corresponds to 500 Hz. As electrode lead  600  advances toward the characteristic frequency location that corresponds to 500 Hz, the amplitude  706 - 3  of the third evoked response signal, which is generated in response to acoustic stimulation having a stimulus frequencies of 500 Hz, increases and peaks at insertion time T 3  when electrode lead  600  is positioned at position P 3 . As electrode lead  600  passes the characteristic frequency location that corresponds to 500 Hz, the third evoked response amplitude  706 - 3  decreases until it settles at a steady state value. As shown in graph  704 , as electrode lead  600  advances towards the characteristic frequency location that corresponds to 500 Hz, the phase  708 - 3  of the third evoked response signal remains at a relatively high level. However, the phase  708 - 3  suddenly changes to a relatively low level at insertion time T 3  as electrode lead  600  passes the characteristic frequency location that corresponds to 500 Hz. 
     The decreasing of the third evoked response amplitude  706 - 3  and the changing of phase  708 - 3  from the high level to the low level in  FIG. 7  occur at substantially the same insertion time T 3 , and both occur as electrode  604 - 1  passes the characteristic frequency location that corresponds to 500 Hz. Hence, diagnostic system  300  may determine that electrode  604 - 1  passes the characteristic frequency location that corresponds to 500 Hz by detecting, within an additional predetermined time period, that both an amplitude  706 - 3  of the third evoked response signal recorded by electrode  604 - 1  decreases by at least an amplitude threshold amount and a phase  708 - 3  of the third evoked response signal recorded by electrode  604 - 1  changes by at least a phase threshold amount. The additional predetermined time period, the amplitude threshold amount, and/or the phase threshold amount may each be set by diagnostic system  300  to be any suitable value, such as described herein. 
     In certain examples, diagnostic system  300  may perform similar operations such as those described herein to determine when electrode lead passes other characteristic frequency locations that correspond to other frequencies (e.g., 4 kHz, 250 Hz, etc.). 
     In certain examples, diagnostic system  300  may determine that electrode lead  600  passes a characteristic frequency based on at least one of an amplitude of an additional evoked response signal included in the plurality of evoked response signals not decreasing by at least the amplitude threshold amount and a phase of the additional evoked response signal not changing by at least the phase threshold amount. For example, diagnostic system  300  may determine that electrode lead  600  passes the characteristic frequency location that corresponds to 1 kHz based on amplitude  706 - 3  of the third evoked response signal not decreasing by an amplitude threshold amount and/or phase  708 - 3  not changing by at least a phase threshold amount at insertion time T 2  in addition to amplitude  706 - 2  and phase  708 - 3  of the second evoked response signal changing by an amplitude threshold amount and a phase threshold amount at insertion time T 2 . 
     In  FIG. 7 , various aspects of electrode lead  600  and the illustrated anatomical features of the recipient are simplified for clarity of illustration. For instance, while cochlea  602  has been “unrolled” in  FIG. 7 , it will be understood that cochlea  602  has a curved, spiral-shaped structure and that electrode lead  600  curves to follow the spiral-shaped structure. Similarly, the anatomy of cochlea  602  omit many details and are not drawn to scale. 
       FIG. 7  does, however, illustrate at least one additional structure that may be associated with an insertion state that may be determined by diagnostic system  300 . In particular,  FIG. 7  also shows a basilar membrane  710  that extends along a length of cochlea  602 . As electrode lead  600  is inserted along cochlea  602 , electrode lead  600  may contact a structure of cochlea  602  such as basilar membrane  710 . In such examples, diagnostic system  300  may determine that electrode lead  600  is in contact with the structure of cochlea  602  when amplitudes of at least two of the evoked response signals included in the plurality of evoked response signals have decreased by at least an amplitude threshold amount and phases of the at least two of the evoked response signals have changed by at least a phase threshold amount. 
     In certain alternative examples, diagnostic system  300  may determine that electrode lead  600  is in contact with the structure of cochlea  602  when amplitudes of each of the evoked response signals included in the plurality of evoked response signals have decreased by at least an amplitude threshold amount and phases of each of the evoked response signals have changed by at least a phase threshold amount. 
     To illustrate,  FIG. 8  shows an exemplary electrode lead insertion procedure in which electrode lead  600  is advanced into cochlea  602 .  FIG. 8  also shows graph  702  of amplitudes  706  (e,g., amplitudes  706 - 1  through  706 - 4 ) of evoked response signals recorded by electrode  604 - 1  during the lead insertion procedure. In addition,  FIG. 8  shows graph  704  of phases  708  (e.g., phases  708 - 1  through  708 - 4 ) of the evoked response signals recorded by electrode  604 - 1  during the lead insertion procedure. In this example, first, second, third, and fourth evoked response signals are generated in response to acoustic stimulation having stimulus frequencies of 2 kHz, 1 kHz, 500 Hz, and 250 Hz, respectively. 
     As shown in  FIG. 8 , electrode lead  600  has come into contact with basilar membrane  710  at a position  802  along the length of basilar membrane  710 . Hence, as shown in graph  702 , amplitudes  706  of each of the first, second, third, and fourth evoked response signals increase and peak as a result of electrode lead  600  contacting basilar membrane  710  at position  802 . In addition, as shown in graph  704 , phase  708  of each of the first, second, third, and fourth evoked response signals change from a relatively high level to a relatively low level as a result of electrode lead  600  contacting basilar membrane  710  at position  802 . 
     As shown in  FIG. 8 , the decreasing of the first, second, third, and fourth evoked response amplitudes  706  and the changing of each of phases  708  from the high level to the low level occur at substantially the same time (e.g., within a predetermined time period), and each occur as electrode lead  600  contacts basilar membrane  710  and changes mechanical stiffness of basilar membrane  710 . Hence, diagnostic system  300  may determine that electrode lead  600  contacts a structure such as basilar membrane  710  by determining, within a predetermined time period, that the amplitudes of each of the evoked response signals included in the plurality of evoked response signals have decreased by at least the amplitude threshold amount and the phases of each of the evoked response signals have changed by at least the phase threshold amount. The predetermined time period, the amplitude threshold amount, and/or the phase threshold amount may each be set by diagnostic system  300  to be any suitable value, such as described herein. 
     In certain examples, diagnostic system  300  may be configured to determine a location and/or an amount of contact with respect to the structure of cochlea  602  based on amplitudes and phases of each of the evoked response signals. The location of the contact may be determined in any suitable manner. In addition, the amount of contact may be determined in any suitable manner. For example, amplitudes  706  of each of he first, second, third, and fourth evoked response signals shown in  FIG. 8  may be indicative of a first amount of contact with respect to basilar membrane  710  at position  802 . Relatively larger amplitudes  706  of each of the first, second, third, and fourth evoked response signals may be indicative of a second amount of contact with respect to basilar membrane  710  at position  802  that is relatively greater than the first amount of contact. Additionally or alternatively, an amount of phase change may be indicative of an amount of contact with respect to basilar membrane  710  at position  802 , For example, the amount of phase change shown in  FIG. 8  may be indicative of electrode lead  600  contacting basilar membrane  710  at a first amount of contact. The amount of phase change may increase with greater contact and/or in response to electrode lead  600  translocating basilar membrane  710 . 
     In certain examples, an insertion state of an electrode lead may be associated with an electrode lead passing a cluster of a particular type of cells (e.g., hair cells, neuron cells, etc.) within the cochlea. In such examples, diagnostic system  300  may determine that an electrode lead passes a cluster of a particular type of cells such as hair cells when amplitudes of one or more evoked response signals included in the plurality of evoked response signals have decreased by at least an amplitude threshold amount and phases of the one or more evoked response signals have not changed by at least a phase threshold amount. For example, diagnostic system  300  may determine that the electrode lead passes a cluster of hair cells when the amplitudes of the second, third, and fourth evoked response signals decrease by at least an amplitude threshold amount and the phases of the second, third, and fourth evoked response signals do not change by at least a phase threshold amount. 
     In certain alternative examples, diagnostic system  300  may determine that an electrode lead passes a cluster of a particular type of cells such as hair cells when amplitudes of each of the evoked response signals included in the plurality of evoked response signals have decreased by at least an amplitude threshold amount and phases of each of the evoked response signals have not changed by at least a phase threshold amount. To illustrate an example,  FIG. 9  shows an exemplary electrode lead insertion procedure in which electrode lead  600  is advanced into cochlea  602 .  FIG. 9  also shows graph  702  of amplitudes  706  (e.g., amplitudes  706 - 1  through  706 - 4 ) of evoked response signals recorded by electrode  604 - 1  during the lead insertion procedure. In addition,  FIG. 9  shows graph  704  of phases  708  (e.g., phases  708 - 1  through  708 - 4 ) of the evoked response signals recorded by electrode  604 - 1  during the lead insertion procedure. In this example, first, second, third, and fourth evoked response signals are generated in response to acoustic stimulation having stimulus frequencies of 2 kHz, 1 kHz, 500 Hz, and 250 Hz, respectively. 
     As shown in  FIG. 9 , electrode lead  600  passes a cluster of hair cells  902  along the length of cochlea  602 . As a result of passing cluster of hair cells  902 , an amplitude  706  of each of first, second, third, and fourth evoked response signals has peaked and dropped at an insertion time associated with passing cluster of hair cells  902 . However, as shown in graph  704 , phases  708  of each of the first, second, third, and fourth evoked response signals have not changed by at least a phase threshold amount as a result of passing cluster of hair cells  902 . Hence, diagnostic system  300  may determine that electrode lead  600  passes cluster of hair cells  902  when, within a predetermined time period, amplitudes of one or more evoked response signals included in the plurality of evoked response signals have decreased by at least an amplitude threshold amount and that phases of the one or more evoked response signals have not changed by at least a phase threshold amount. 
     In certain examples, an insertion state of an electrode lead may be associated with a possible occurrence of trauma (e.g., translocation from the scala tympani to the scala vestibuli (i.e., by penetrating through the basilar membrane)) to a structure of a cochlea of a recipient. Such trauma may be caused by the electrode lead penetrating the basilar membrane of the cochlea, inadvertently being placed within a wrong duct of the cochlea, and/or in any other suitable manner. In such examples, diagnostic system  300  may determine that the electrode lead has caused trauma to the cochlea based on a determination that amplitudes of evoked response signals included in a plurality of evoked response signals have decreased by at least an amplitude threshold amount and phases of the evoked response signals have changed by at least a phase threshold amount that is relatively larger than an additional phase threshold amount indicative of the electrode lead merely contacting a structure of the cochlea. In this regard, diagnostic system  300  may use different phase threshold amounts to determine different insertion states of electrode lead  600  in certain implementations. 
     To illustrate,  FIG. 10  shows an exemplary electrode lead insertion procedure in which electrode lead  600  is advanced into cochlea  602 .  FIG. 10  also shows graph  702  of amplitudes  706  (e.g., amplitudes  706 - 1  through  706 - 4 ) of evoked response signals recorded by electrode  604 - 1  during the lead insertion procedure. In addition, 
       FIG. 10  shows graph  704  of phases  708  (e.g., phases  708 - 1  through  708 - 4 ) of the evoked response signals recorded by electrode  604 - 1  during the lead insertion procedure. In this example, first, second, third, and fourth evoked response signals are generated in response to acoustic stimulation having stimulus frequencies of 2 kHz, 1 kHz, 500 Hz, and 250 Hz, respectively. 
     As shown in  FIG. 10 , electrode lead  600  has come into contact with and has punctured basilar membrane  710  at a position  1002  along the length of basilar membrane  710 . Hence, as shown in graph  702 , amplitudes  706  of each of the first, second, third, and fourth evoked response signals increase and peak decrease by at least an amplitude threshold amount with respect to each other as a result of electrode lead  600  puncturing basilar membrane  710  at position  1002 . As shown in graph  704 , phase  708  of each of the first, second, third, and fourth evoked response signals change from a relatively high level to a relatively low level as a result of electrode lead  600  puncturing basilar membrane  710 . The amount of phase change shown in  FIG. 10  is relatively larger than the amount of phase change shown in  FIG. 8 . This is because there is a relatively higher phase change threshold associated with electrode lead  600  causing trauma to cochlea  602  as compared to electrode lead  600  merely contacting basilar membrane  710 , as shown in  FIG. 8 . 
     As shown in  FIG. 10 , the decreasing of the first, second, third, and fourth evoked response amplitudes  706  by at least the amplitude threshold amount and the changing of each of phases  708  from the high level to the low level occur at substantially the same time, and each occur as electrode  604 - 1  punctures basilar membrane  710 . Hence, diagnostic system  300  may determine that electrode  604 - 1  has caused trauma to cochlea  602  based on diagnostic system  300  determining, within a predetermined time period, that the amplitudes of the evoked response signals included in the plurality of evoked response signals have decreased by at least the amplitude threshold amount and the phases of the evoked response signals changing have changed by at least a phase threshold amount that is relatively larger than an additional phase threshold amount indicative of the electrode lead contacting a structure of the cochlea, The phase threshold amount associated with causing trauma to cochlea  602  may be set by diagnostic system  300  to be any suitable value, such as described herein. 
     In certain examples, evoked response amplitudes (e.g., evoked response amplitudes  706 ) decreasing by different amounts with respect to each other may additionally or alternatively be indicative of an electrode lead causing trauma to the cochlea. Any suitable amount difference in the decrease of the amplitudes of the evoked response signals may be indicative of trauma to the cochlea. 
     In certain examples, diagnostic system  300  may be configured to provide a notification regarding an insertion state while an electrode lead is inserted into a cochlea. Such a notification may be provided in any suitable manner. For example, diagnostic system  300  may be configured to provide an audible notification, a text notification, and/or a graphical notification configured to inform a user (e.g., a surgeon) of the insertion state. In certain examples, the notification may include providing a graph of the evoked response signals for display in one or more graphs displayed by way of a display device (e.g., display device  408 ) associated with diagnostic system  300 . For example, diagnostic system  300  may direct a display device to display a graph of the evoked response signals in substantially real time as an insertion procedure is being performed by displaying each evoked response signal included in the plurality of evoked response signals such that, at any given time, multiple evoked response signals included in the plurality of evoked response signals are concurrently displayed by the display device. By displaying one or more graphs of the evoked response signals recorded by an electrode during the insertion procedure, diagnostic system  300  may provide real-time feedback to a user (e.g., a surgeon) performing the insertion procedure. This feedback may be used by the user to ensure proper placement of the electrode lead  600  within cochlea  602  and/or for any other purpose as may serve a particular implementation. 
     To illustrate, in the exemplary insertion procedure shown in  FIG. 10 , system  300  may be configured to provide a textual notification in a graphical user interface on a display screen to indicate that electrode lead  600  has punctured basilar membrane  710 . 
     In response to seeing such a notification appear within the graphical user interface, a user may stop the insertion procedure and/or take other remedial action (e.g., by pulling back the electrode lead outside the cochlea, changing electrode insertion angle, etc.). Any other type of notification (e.g., audible or visible notification) may additionally or alternatively be presented to the user as may serve a particular implementation. 
     In certain examples, diagnostic system  300  may direct a display device to display a first graph representative of the amplitudes of the evoked response signals and a second graph representative of the phases of the evoked response signals. For example, diagnostic system  300  may direct a display device to display graph  702  as a first graph and graph  704  as a second graph shown, for example, in  FIG. 10  in any suitable manner. In certain examples, diagnostic system  300  may direct a display device to concurrently display graphs  702  and  704  in a single graphical user interface. 
     Additionally or alternatively, a single graphical user interface that displays graphs  702  and  704  may also display a graphical representation of cochlea  602  and a graphical representation of electrode lead  600  being inserted within cochlea  602  during the insertion procedure similar to what is shown, for example, in  FIG. 8 . In such examples, the graphical representation of electrode lead  600  may be animated to facilitate depicting electrode lead  600  being inserted in real time into cochlea  602 . In addition, such a graphical representation of electrode lead  600  be animated to depict certain insertion states. For example, the graphical representation of electrode lead may be depicted as contacting a wall of cochlea  602  if diagnostic system  300  determines that an insertion state corresponding to contact of electrode lead  600  with a structure of cochlea  602  occurs. 
     In certain alternative implementations, diagnostic system  300  may direct a display device to display amplitudes and phases of evoked response signals for display in a single graph. To illustrate,  FIG. 11  shows an alternative implementation in which a single graph  1102  includes both amplitudes  706  and phases  708  of first, second, third, and fourth evoked response signals that may be generated in response to an insertion procedure in which electrode lead  600  passes cluster of hairs  902 . Graph  1102  may be provided for display to a user in any suitable graphical user interface to facilitate the user performing an insertion procedure. 
       FIG. 12  illustrates an exemplary method  1200 . The operations shown in  FIG. 12  may be performed by diagnostic system  300  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 diagnostic system directs 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 communicatively coupled to the cochlear implant is inserted into a cochlea of the recipient. Operation  1202  may be performed in any of the ways described herein, 
     In operation  1204 , the diagnostic system directs the cochlear implant to use an electrode 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. Operation  1204  may be performed in any of the ways described herein. 
     In operation  1206 , the diagnostic system determines, 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. Operation  1206  may be performed in any of the ways described herein. 
     In some examples, a non-transitory computer-readable medium storing computer-readable instructions may be provided in accordance with the principles described herein. The instructions, when executed by a processor of a computing device, may direct the processor and/or computing device to perform one or more operations, including one or more of the operations described herein. Such instructions may be stored and/or transmitted using any of a variety of known computer-readable media. 
     A non-transitory computer-readable medium as referred to herein may include any non-transitory storage medium that participates in providing data (e.g., instructions) that may be read and/or executed by a computing device (e.g., by a processor of a computing device). For example, a non-transitory computer-readable medium may include, but is not limited to, any combination of non-volatile storage media and/or volatile storage media. Exemplary non-volatile storage media include, but are not limited to, read-only memory, flash memory, a solid-state drive, a magnetic storage device (e.g. a hard disk, a floppy disk, magnetic tape, etc.), ferroelectric random-access memory (“RAM”), and an optical disc (e.g., a compact disc, a digital video disc, a Blu-ray disc, etc.). Exemplary volatile storage media include, but are not limited to, RAM (e.g., dynamic RAM). 
       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 one to another 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 and/or interpreting, executing, and/or directing execution of one or more of the instructions, processes, and/or operations described herein. 
     Processor  1304  may perform operations by executing computer-executable instructions  1312  (e.g., an application, software, code, and/or other executable data instance) stored in storage device  1306 . 
     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, any combination of the non-volatile media and/or volatile media described herein. Electronic data, including data described herein, may be temporarily and/or permanently stored in storage device  1306 . For example, data representative of computer-executable instructions  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 include one or more I/O modules configured to receive user input and provide user output. I/O module  1308  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 touchscreen component (e.g., touchscreen display), a receiver (e.g., an RF or infrared receiver), motion sensors, 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 systems, computing devices, and/or other components described herein may be implemented by computing device  1300 . For example, storage facility  302  may be implemented by storage device  1306 , and processing facility  304  may be implemented by processor  1304 . 
     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.