Patent Description:
Recognizing when the distal end of the electrode lead is at the basal turn of the cochlea may enable the surgeon to release the stylet from the electrode lead at an optimal time, as well as to lessen the force applied during insertion, thus reducing a risk of insertion trauma and maximizing a possibility of correct electrode lead placement in the cochlea. Late stylet release can cause the electrode tip to touch or otherwise impact the lateral wall at the basal turn, which may cause trauma to the recipient, whereas premature stylet release may increase the possibility of a tip fold over and/or translocation of the electrode lead.

<CIT>") discloses an intra-cochlear stimulating assembly insertion, and setting an angular insertion depth of a stimulating assembly during implantation into a recipient's cochlea. According to Risi, the angular insertion depth is monitored in real-time and advancement of the stimulating assembly is terminated when a selected angular insertion depth is achieved. Risi also discloses that a linear insertion depth that corresponds to a selected angular insertion depth is intraoperatively calculated and advancement of the stimulating assembly is terminated when the calculated linear insertion depth is achieved.

<CIT> relates to an example of monitoring of the position of an electrode lead of a cochlear implant when the electrode lead has been inserted into the cochlea, wherein a graphical representation of an intra-cochlear trajectory of electrodes is generated using electrical field imaging and wherein stimulation current is applied to one electrode and a resulting difference in impedance is recorded between two other electrodes. <CIT> relates to a similar example, wherein differential measurements between electrodes are performed to determine a distance between the electrode array and a wall of the cochlea.

The invention relates to a system as defined in claim <NUM> for determining when an electrode lead reaches a cochlear basal turn during a lead insertion procedure. For example, as described herein, an insertion management system directs a cochlear implant to apply electrical stimulation by way of a first electrode disposed on an electrode lead that is being inserted into a cochlea of a recipient. While the electrical stimulation is being applied by way of the first electrode, the insertion management system directs the cochlear implant to record a differential voltage signal representative of a differential voltage between a second electrode and a third electrode both disposed on the electrode lead and different than the first electrode. While the differential voltage signal is being recorded, the insertion management system determines that a signal characteristic of the differential voltage signal changes by at least a threshold amount. Based on the signal characteristic changing by at least the threshold amount, the insertion management system determines that a distal end of the electrode lead is positioned within a threshold distance of a basal turn of the cochlea.

The systems described herein may be used in connection with any suitable type of electrode lead. For example, the systems and methods described herein may be used in connection with an electrode lead that has a naturally pre-curved shape. This type of electrode lead may be referred to as a perimodiolar electrode lead and may be configured to hug a modiolar wall of a cochlea when inserted within the cochlea. The systems described herein may additionally or alternatively be used in connection with an electrode lead that has a naturally straight shape. This type of electrode lead may be referred to as a mid-scalar electrode lead, and may be configured to conform to the shape of the cochlea as the electrode lead is inserted into the cochlea.

The systems described herein may advantageously provide real-time feedback regarding a positioning of an electrode lead within the cochlea during a lead insertion procedure. This real-time feedback may optimize timing of stylet release and removal from an electrode lead being inserted into the cochlea, thereby reducing a risk of insertion trauma (e.g., trauma caused by scraping, piercing, irritating, and/or otherwise damaging a wall of the cochlea), maximizing a possibility of correct electrode lead placement in the cochlea, preventing tip-foldover, and providing an optimal insertion trajectory for the electrode lead into the cochlea. These and other advantages and benefits of the systems described herein will be made apparent herein.

<FIG> illustrates an exemplary cochlear implant system <NUM>: As shown, cochlear implant system <NUM> may include a microphone <NUM>, a sound processor <NUM>, a headpiece <NUM> having a coil disposed therein, a cochlear implant <NUM>, and an electrode lead <NUM>. Electrode lead <NUM> may include an array of electrodes <NUM> disposed on a distal portion of electrode lead <NUM> and that are configured to be inserted into a cochlea of a recipient to stimulate the cochlea when the distal portion of electrode lead <NUM> is inserted into the cochlea. One or more other electrodes (e.g., including a ground electrode, not explicitly shown) may also be disposed on other parts of electrode lead <NUM> (e.g., on a proximal portion of electrode lead <NUM>) to, for example, provide a current return path for stimulation current generated by electrodes <NUM> and to remain external to the cochlea after electrode lead <NUM> is inserted into the cochlea. As described herein, electrode lead <NUM> may be naturally pre-curved or straight. Additional or alternative components may be included within cochlear implant system <NUM> as may serve a particular implementation.

As shown, cochlear implant system <NUM> may include various components configured to be located external to a recipient including, but not limited to, microphone <NUM>, sound processor <NUM>, and headpiece <NUM>. Cochlear implant system <NUM> may further include various components configured to be implanted within the recipient including, but not limited to, cochlear implant <NUM> and electrode lead <NUM>.

Microphone <NUM> may be configured to detect audio signals presented to the user. Microphone <NUM> may be implemented in any suitable manner. For example, microphone <NUM> 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 during normal operation by a boom or stalk that is attached to an ear hook configured to be selectively attached to sound processor <NUM>. Additionally or alternatively, microphone <NUM> may be implemented by one or more microphones disposed within headpiece <NUM>, one or more microphones disposed within sound processor <NUM>, one or more beam-forming microphones, and/or any other suitable microphone as may serve a particular implementation.

Sound processor <NUM> may be housed within any suitable housing (e.g., a behind-the-ear ("BTE") unit, a body worn device, headpiece <NUM>, and/or any other sound processing unit as may serve a particular implementation). Sound processor <NUM> may be configured to direct cochlear implant <NUM> to generate and apply electrical stimulation (e.g., a sequence of stimulation pulses) by way of one or more electrodes <NUM>.

As shown, electrodes <NUM> may include a first electrode <NUM>-<NUM> that is most distally positioned on electrode lead <NUM> (i.e., closest to a distal end <NUM> of electrode lead <NUM>), a second electrode <NUM>-<NUM> adjacent to electrode <NUM>-<NUM>, a third electrode <NUM>-<NUM> adjacent to electrode <NUM>-<NUM>, etc. Any number of electrodes <NUM> (e.g., sixteen) may be disposed on electrode lead <NUM> as may serve a particular implementation. While electrodes <NUM> are shown as linearly positioned along a side of electrode lead <NUM> that faces a modiolar wall of cochlea <NUM>, other configurations for electrodes <NUM> may be implemented. For example, diametrically opposed electrodes <NUM> may be implemented (e.g., a first electrode and a second electrode may be positioned diametrically to one another, while a third and fourth electrode may be positioned diametrically to one another and linearly following first and second electrodes). As another example, the distal-most electrode may be a tip electrode (i.e., located a distal end <NUM> of electrode <NUM>).

In some examples, sound processor <NUM> may direct cochlear implant <NUM> to apply electrical stimulation representative of an audio signal presented to the recipient. The audio signal may be detected by microphone <NUM>, input by way of an auxiliary audio input port, input by way of a clinician's programming interface (CPI) device, and/or otherwise provided to sound processor <NUM>. Sound processor <NUM> may process the audio signal in accordance with a selected sound processing strategy or program to generate appropriate stimulation parameters for controlling cochlear implant <NUM>.

Additionally or alternatively, sound processor <NUM> (and/or any other suitable computing device) may direct cochlear implant <NUM> to generate and apply electrical stimulation that is not representative of audio signals to the patient. For example, as described herein, sound processor <NUM> and/or any other suitable computing device may direct cochlear implant <NUM> to apply a sequence of stimulation pulses by way of one or more electrodes <NUM> during a lead insertion procedure.

In some examples, sound processor <NUM> 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 <NUM> by way of a wireless communication link <NUM> between headpiece <NUM> and cochlear implant <NUM> (e.g., a wireless link between a coil disposed within headpiece <NUM> and a coil physically coupled to cochlear implant <NUM>). It will be understood that communication link <NUM> may include a bi-directional communication link and/or one or more dedicated uni-directional communication links.

Headpiece <NUM> may be communicatively coupled to sound processor <NUM> 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 <NUM> to cochlear implant <NUM>. Headpiece <NUM> may additionally or alternatively be used to selectively and wirelessly couple any other external device to cochlear implant <NUM>. To this end, headpiece <NUM> may be configured to be affixed to the recipient's head and positioned such that the external antenna housed within headpiece <NUM> 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 <NUM>. In this manner, stimulation parameters and/or power signals may be wirelessly transmitted between sound processor <NUM> and cochlear implant <NUM> via communication link <NUM>.

Cochlear implant <NUM> may include any suitable type of implantable stimulator. For example, cochlear implant <NUM> may be implemented by an implantable cochlear stimulator. Additionally or alternatively, cochlear implant <NUM> may include a brainstem implant and/or any other type of cochlear implant that may be implanted within a recipient and configured to apply stimulation to one or more stimulation sites located along an auditory pathway of a recipient.

In some examples, cochlear implant <NUM> may be configured to generate electrical stimulation in accordance with one or more stimulation parameters transmitted thereto by sound processor <NUM>. Cochlear implant <NUM> may be further configured to apply the electrical stimulation to one or more electrodes <NUM> disposed along electrode lead <NUM>. Such stimulation may be configured as monopolar stimulation (e.g., stimulation applied by way of a single electrode <NUM> with a remote electrode on a case of cochlear implant <NUM> or on a proximal portion of electrode lead <NUM> being used as a return electrode) or as multipolar stimulation (e.g., bipolar stimulation applied via by way of two electrodes <NUM>). In some examples, cochlear implant <NUM> may include a plurality of independent current sources each associated with a channel defined by one or more of electrodes <NUM>. In this manner, different stimulation current levels may be applied to multiple stimulation sites simultaneously by way of multiple electrodes <NUM>.

<FIG> illustrates a schematic structure of the human cochlea <NUM> into which electrode lead <NUM> may be inserted. As shown in <FIG>, cochlea <NUM> is in the shape of a spiral beginning at a base <NUM> and ending at an apex <NUM>. Within cochlea <NUM> resides auditory nerve tissue, which is denoted by Xs in <FIG>. The auditory nerve tissue is organized within the cochlea <NUM> in a tonotopic manner. Relatively low frequencies are encoded at or near the apex <NUM> of the cochlea <NUM> referred to as an "apical region" while relatively high frequencies are encoded at or near the base <NUM> in a basal region <NUM> of the cochlea <NUM>.

<FIG> illustrates a region of cochlea <NUM> referred to as a basal turn <NUM>. As shown, basal turn <NUM> is located at an end of basal region <NUM>. As described herein, the systems are configured to determine, in real-time during a lead insertion procedure, when distal end <NUM> of electrode lead <NUM> is within a threshold distance of basal turn <NUM> (e.g., when distal end <NUM> of electrode lead <NUM> is approaching but not yet at basal turn <NUM>, at basal turn <NUM>, or slightly past basal turn <NUM>). In so doing, it may be possible for an operator to begin removal of a stylet holding electrode lead <NUM> in a straightened configuration, as well as to avoid damage (e.g., scraping or puncture) of cochlea <NUM> by electrode lead <NUM> and/or the stylet.

<FIG> illustrates an exemplary insertion management system <NUM> ("system <NUM>") that may be configured to perform any of the operations described herein. As shown, system <NUM> may include, without limitation, a storage facility <NUM> and a processing facility <NUM> selectively and communicatively coupled to one another. Facilities <NUM> and <NUM> 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 <NUM> and <NUM> may be distributed between multiple devices and/or multiple locations as may serve a particular implementation.

Storage facility <NUM> may maintain (e.g., store) executable data used by processing facility <NUM> to perform any of the operations described herein. For example, storage facility <NUM> may store instructions <NUM> that may be executed by processing facility <NUM> to perform any of the operations described herein. instructions <NUM> may be implemented by any suitable application, software, code, and/or other executable data instance. Storage facility <NUM> may also maintain any data received, generated, managed, used, and/or transmitted by processing facility <NUM>.

Processing facility <NUM> may be configured to perform (e.g., execute instructions <NUM> stored in storage facility <NUM> to perform) various operations associated with determining when an electrode lead (e.g., electrode lead <NUM>) reaches a basal turn (e.g., basal turn <NUM>) of a cochlea (e.g., cochlea <NUM>) during an electrode lead insertion procedure in which the electrode lead is inserted into the cochlea. For example, processing facility <NUM> may direct a cochlear implant (e.g., cochlear implant <NUM>) to apply electrical stimulation by way of a first electrode (e.g., electrode <NUM>-<NUM>) disposed on the electrode lead while the electrode lead is being inserted into a cochlea of a recipient. While the electrical stimulation is being applied by way of the first electrode, processing facility <NUM> may direct the cochlear implant to record a differential voltage signal between a second electrode (e.g., electrode <NUM>-<NUM>) and a third electrode (e.g., electrode <NUM>-<NUM>) disposed on the electrode lead. While the differential voltage signal is being recorded, processing facility <NUM> may determine that a signal characteristic of the differential voltage signal changes by at least a threshold amount. Processing facility <NUM> may determine, based on the signal characteristic changing by at least the threshold amount, that a distal end <NUM> of the electrode lead is positioned within a threshold distance of a basal turn of the cochlea. These and other operations that may be performed by processing facility <NUM> (i.e., by system <NUM>) are described in more detail herein.

System <NUM> may be implemented in any suitable manner. For example, system <NUM> may be implemented entirely by sound processor <NUM>. Alternatively, system <NUM> may be implemented entirely by a computing device configured to be communicatively coupled to sound processor <NUM>. Alternatively, system <NUM> may be implemented by both sound processor <NUM> and a computing device configured to be communicatively coupled to sound processor <NUM>.

<FIG> shows an exemplary configuration <NUM> in which system <NUM> is at least partially implemented by a computing device <NUM> configured to communicatively couple to sound processor <NUM>. In some examples, computing device <NUM> may be configured to direct cochlear implant <NUM> to generate and apply electrical stimulation by way of one or more electrodes <NUM>.

Computing device <NUM> may be implemented by any suitable combination of hardware (e.g., one or more computing devices) and software. To illustrate, computing device <NUM> 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. In some examples, computing device <NUM> is included in a fitting system configured to be used to fit cochlear implant system <NUM> to a recipient.

As shown, computing device <NUM> is communicatively coupled to a display device <NUM>. While display device <NUM> is illustrated to be separate from computing device <NUM> in <FIG>, display device <NUM> may alternatively be integrated into computing device <NUM>. Display device <NUM> may be implemented by any suitable device configured to display graphical content generated by computing device <NUM>. For example, display device <NUM> may display one or more graphs of signals recorded by electrodes <NUM> disposed on electrode lead <NUM>.

<FIG> illustrate an exemplary insertion procedure in which electrode lead <NUM> of the cochlear implant <NUM> is inserted into a cochlea <NUM> of a recipient according to principles of the present disclosure. Electrode <NUM>-<NUM> is a distal-most electrode on lead <NUM> located closest to distal end <NUM> of lead <NUM>. The number of electrodes <NUM> shown as being disposed on lead <NUM> is exemplary only, and has been limited to simplify the following discussion. Any suitable number of electrodes <NUM> greater than or equal to <NUM> may be implemented on lead <NUM> without departing from the scope of the present disclosure. Moreover, although the electrodes <NUM> are sequentially numbered, proceeding linearly along a length of lead <NUM>, the term "a first electrode" does not necessarily mean electrode <NUM>-<NUM>, absent indication to the contrary, and the reference symbols are intended as referential, cardinal numbers.

<FIG> shows electrode lead <NUM> entering cochlea <NUM>. In this figure, electrodes <NUM>-<NUM> and <NUM>-<NUM> have barely entered cochlea <NUM>, while electrodes <NUM>-<NUM> to <NUM>-<NUM> remain outside cochlea <NUM>. <FIG> shows electrode lead <NUM> after electrode lead <NUM> has been advanced further into cochlea <NUM> such that electrodes <NUM>-<NUM> to electrodes <NUM>-<NUM> are positioned within cochlea <NUM>, while electrodes <NUM>-<NUM> to <NUM>-<NUM> (not labeled in <FIG>) remain outside of cochlea <NUM>. As shown in <FIG>, a distal end <NUM> of lead <NUM>, while nearing the basal turn of the cochlea <NUM>, has not yet arrived at this point.

<FIG> shows electrode lead <NUM> when electrode lead <NUM> has been advanced further into cochlea <NUM> such that distal end <NUM> of electrode lead <NUM> is positioned within a threshold distance of basal turn <NUM> of cochlea <NUM>. The threshold distance may be, for example, less than three millimeters or any other suitable distance. In some examples, the threshold distance may be set in response to user input, determined automatically based on one or more characteristics of the recipient (e.g., a pediatric recipient may be associated with a smaller threshold distance than an adult recipient), and/or determined in any other manner.

An exemplary manner in which system <NUM> may determine that distal end <NUM> is within the threshold distance of basal turn <NUM> will now be described with reference to <FIG>.

As electrode lead <NUM> is being inserted into cochlea <NUM>, system <NUM> may direct cochlear implant <NUM> to apply electrical stimulation by way of at least one electrode. The electrical stimulation may include, for example, a sequence of stimulation pulses applied at any suitable stimulation frequency. The stimulation pulses may have any suitable fixed current level as may serve a particular implementation.

In some examples, the electrical stimulation is monopolar. In these examples, the electrical stimulation is applied to only one of electrodes <NUM>, with a remote electrode (e.g., an electrode disposed on a case of cochlear implant <NUM> or on a proximal portion of electrode lead <NUM>) being used as a return electrode for the electrical stimulation. The single electrode <NUM> by way of which the monopolar stimulation is applied may be any one of electrodes <NUM>, but in many implementations, the single electrode is located more toward distal end <NUM> of electrode lead <NUM> (e.g., electrode <NUM>-<NUM>, electrode <NUM>-<NUM>, or electrode <NUM>-<NUM>).

In alternative examples, the electrical stimulation is bipolar. In these examples, the electrical stimulation is applied by way of two of electrodes <NUM>, with one of the two electrodes serving as the return electrode. For example, bipolar stimulation may be applied by way of electrodes <NUM>-<NUM> and <NUM>-<NUM>, electrodes <NUM>-<NUM> and <NUM>-<NUM>, or any other suitable combination of electrodes.

As used herein, the term "stimulating electrodes" refers to electrodes used to apply electrical stimulation. While the electrical stimulation is being applied by way of the stimulating electrode(s), system <NUM> may direct cochlear implant <NUM> to record a differential voltage signal representative of a differential voltage between two electrodes that are different than the stimulating electrodes. These electrodes used to record the differential voltage signal are referred to as "recording electrodes" herein. The two recording electrodes may be any combination of electrodes other than the stimulating electrodes. For example, if electrodes <NUM>-<NUM> and <NUM>-<NUM> serve as the stimulating electrodes, electrodes <NUM>-<NUM> and <NUM>-<NUM> may serve as the recording electrodes. As another example, if <NUM>-<NUM> and <NUM>-<NUM> serve as the stimulating electrodes, electrodes <NUM>-<NUM> and <NUM>-<NUM> may serve as the recording electrodes. In some implementations, the distal-most electrode <NUM>-<NUM> has to serve as either a stimulating electrode or as a recording electrode.

<FIG> illustrate various stimulating and recording electrode configurations that may be used in connection with the systems described herein. In each of the configurations shown in <FIG>, electrode lead <NUM> is positioned within cochlea <NUM> adjacent to cochlear tissue <NUM>. It will be recognized that configurations other than those illustrated in <FIG> may also be used in connection with the systems described herein.

In <FIG>, distal-most electrode <NUM>-<NUM> on electrode lead <NUM> is configured to be a stimulating electrode and electrodes <NUM>-<NUM> and <NUM>-<NUM> on electrode lead <NUM> are configured to be recording electrodes. In this configuration, monopolar stimulation is applied by way of electrode <NUM>-<NUM> while a differential voltage measuring circuit <NUM> uses electrodes <NUM>-<NUM> and <NUM>-<NUM> to record a differential voltage between electrodes <NUM>-<NUM> and <NUM>-<NUM>. Differential voltage measuring circuit <NUM> may be implemented by any suitable combination of components in cochlear implant <NUM> and/or sound processor <NUM>.

In <FIG>, distal-most electrode <NUM>-<NUM> and electrode <NUM>-<NUM> are configured to be stimulating electrodes and electrodes <NUM>-<NUM> and <NUM>-<NUM> are configured to be recording electrodes. In this configuration, bipolar stimulation is applied by way of electrodes <NUM>-<NUM> and <NUM>-<NUM> while differential voltage measuring circuit <NUM> uses electrodes <NUM>-<NUM> and <NUM>-<NUM> to record a differential voltage between electrodes <NUM>-<NUM> and <NUM>-<NUM>.

In <FIG>, electrodes <NUM>-<NUM> and <NUM>-<NUM> are configured to be stimulating electrodes and electrodes <NUM>-<NUM> and electrode <NUM>-<NUM> are configured to be recording electrodes. In this configuration, bipolar stimulation is applied by way of electrodes <NUM>-<NUM> and <NUM>-<NUM> while differential voltage measuring circuit <NUM> uses electrodes <NUM>-<NUM> and <NUM>-<NUM> to record a differential voltage between electrodes <NUM>-<NUM> and <NUM>-<NUM>.

While the differential voltage is being recorded, system <NUM> may determine that a signal characteristic of the differential voltage signal changes by at least a threshold amount. Based on the signal characteristic changing by at least the threshold amount, system <NUM> may determine that distal end <NUM> is positioned within the threshold distance of basal turn <NUM> of cochlea <NUM>.

The signal characteristic of the differential voltage signal may include any characteristic that may be indicative of an arrival of distal end <NUM> of electrode lead <NUM> at basal turn <NUM>. For example, the signal characteristic may be a slope associated with the differential voltage signal, a rate of change associated with the differential voltage signal, an amplitude associated with the differential voltage signal, and/or any other suitable characteristic associated with the differential voltage signal as may serve a particular implementation.

System <NUM> may determine the signal characteristic of the differential voltage signal in any suitable manner. For example, system <NUM> may process the differential voltage signal itself to determine the signal characteristic. Additionally or alternatively, system <NUM> may generate an impedance signal based on the differential voltage signal and then identify the signal characteristic based on the impedance signal. The impedance signal may be generated by, for example, dividing the differential voltage signal by the amplitude of the electrical stimulation in accordance with Ohm's law.

<FIG> shows an exemplary graph <NUM> of a signal <NUM> that may be representative of either a differential voltage signal or an impedance signal generated based on the differential voltage signal, and shows how an amplitude of signal <NUM> may increase as an insertion depth of electrode lead <NUM> increases during a lead insertion procedure in which electrode lead <NUM> is inserted into cochlea <NUM>. As shown, a slope of signal <NUM> remains relatively constant between insertion depth d1 and insertion depth d2. At insertion depth d2, the slope of signal <NUM> begins to decrease until it reaches a point of inflection <NUM> at insertion depth d3. After insertion depth d3, the slope goes slightly negative.

This change in slope correlates to when distal end <NUM> of lead <NUM> is within a threshold distance of basal turn <NUM>. Hence, system <NUM> may track the slope of signal <NUM> and determine, when the slope changes by at least a threshold amount, that distal end <NUM> of lead <NUM> is within a threshold distance of basal turn <NUM>. Other signal characteristics of signal <NUM> may be similarly tracked and used to determine when distal end <NUM> of lead <NUM> is within a threshold distance of basal turn <NUM>.

It will be recognized that graph <NUM> is merely illustrative and that signal <NUM> may have different characteristics compared to those shown in <FIG> (e.g., different slopes, shapes, etc.). For example, insertion of a naturally pre-curved electrode lead may result in a signal similar to signal <NUM> that peaks at an insertion depth that corresponds to when a distal end of the electrode lead is within the predetermined threshold of basal turn <NUM>. However, insertion of a naturally straight electrode lead may result in a signal that may not peak. In this case, the slope of the signal may still decrease by a certain amount when a distal end of the electrode lead is within the predetermined threshold of basal turn <NUM>. Hence, in some examples, the threshold amount by which the slope (and/or any other signal characteristic of signal <NUM>) has to change may be based on the type of electrode lead being used, one or more characteristics of the recipient, a current level of the electrical stimulation being used, etc..

Data representative of the threshold amount and/or threshold distance may be accessed by system <NUM> in any suitable manner. In some examples, system <NUM> may store data representative of the threshold amount and/or threshold distance in storage facility <NUM>, access such data stored remotely from system <NUM> (e.g., at a server connected to system <NUM> by way of a network), etc..

System <NUM> may perform various operations based on and/or in response to the determination that distal end <NUM> of electrode lead <NUM> is within the threshold distance of basal turn <NUM> of cochlea <NUM>. For example, system <NUM> may provide a notification (e.g., an alert) in substantially real-time that distal end <NUM> is within the threshold distance. As another example, in response to determining that distal end <NUM> of electrode lead <NUM> is within the threshold distance of basal turn <NUM> of cochlea <NUM>, system <NUM> may transmit one or more commands to a surgeon and/or a tool being used to perform the lead insertion procedure to release a stylet from electrode lead <NUM>, retract the stylet from the cochlea <NUM>, slow down an insertion rate of electrode lead <NUM> into cochlea <NUM>, and/or perform any other suitable operation as may serve a particular implementation.

In some examples, system <NUM> may plot, within an interface displayed on a display device, a graph associated with the differential voltage signal in substantially real time as the differential voltage signal is being recorded. In this manner, a user (e.g., a surgeon) may visually ascertain when electrode lead <NUM> is nearing basal turn <NUM>.

To illustrate, <FIG> illustrates an exemplary graphical user interface <NUM> that may be displayed by a display device (e.g., display device <NUM>) at the direction of system <NUM> according to embodiments of the present disclosure. As shown, graphical user interface <NUM> may include a graphical representation of graph <NUM>. In some examples, signal <NUM> is plotted in substantially real time as the differential voltage signal is being recorded.

In some examples, system <NUM> may additionally or alternatively present, within interface <NUM>, a progress indicator indicating a location of electrode lead <NUM> within cochlea <NUM> based on the signal characteristic being monitored by system <NUM>. For example, as shown in <FIG>, graphical user interface <NUM> may include a graphical representation of cochlea <NUM> that shows a graphical representation of electrode lead <NUM> being inserted into cochlea <NUM>. These graphical representations may serve as the progress indicator indicating a location of electrode lead <NUM> within cochlea <NUM>.

As mentioned, system <NUM> may provide a notification in response to determining that distal end <NUM> of electrode lead <NUM> has reached basal turn <NUM>. To illustrate, <FIG> shows that a graphical notification <NUM> may be presented within graphical user interface <NUM>. System <NUM> may additionally or alternatively provide an audible notification and/or any other type of notification as may serve a particular implementation.

In some examples, the real-time feedback provided during a lead insertion procedure as described herein may be used by system <NUM> to perform one or more other types of operations. For example, the real-time feedback provided by system <NUM> may be used by system <NUM> to determine a trajectory of insertion of electrode lead <NUM> into cochlea <NUM> until distal end <NUM> of electrode lead <NUM> reaches basal turn <NUM>. For example, based on a rate of change of a slope of signal <NUM>, a distance covered and/or time elapsed without a significant change in slope of signal <NUM>, and/or any other characteristic of signal <NUM>, system <NUM> may determine the trajectory of insertion and provide real-time feedback (e.g., by way of graphical user interface <NUM>) representative of the trajectory of insertion of lead <NUM>. This may be used by a user (e.g., a surgeon) to modify the trajectory of insertion as needed and/or desired.

In some examples, system <NUM> may additionally or alternatively determine, based on a signal characteristic of signal <NUM> changing by at least the threshold amount, a distance between a round window of a recipient and the basal turn of the recipient. For example, system <NUM> may use any suitable technique to determine a distance between d1 and d3 shown in <FIG> and designate this distance as the distance between the round window of the recipient and the basal turn of the recipient. Data representative of this distance may be used by system <NUM> to set one or more stimulation parameters for cochlear implant system <NUM> and/or for any other reason as may serve a particular implementation.

In some examples, once system <NUM> has determined that distal end <NUM> of electrode lead <NUM> has reached basal turn <NUM>, system <NUM> may switch to a new set of stimulating and recording electrodes in order to ascertain which and/or how many electrodes have passed basal turn <NUM> during the lead insertion procedure. For example, with references to <FIG>, system <NUM> may initially designate electrodes <NUM>-<NUM> and <NUM>-<NUM> as stimulating electrodes and electrodes <NUM>-<NUM> and <NUM>-<NUM> as recording electrodes. Once, distal end <NUM> of electrode lead <NUM> reaches basal turn <NUM>, system <NUM> may stop using electrodes <NUM>-<NUM> through <NUM>-<NUM> as stimulating and recording electrodes and instead use electrodes <NUM>-<NUM> and <NUM>-<NUM> as stimulating electrodes and electrodes <NUM>-<NUM> and <NUM>-<NUM> as recording electrodes. In this manner, system <NUM> may use the techniques described herein to determine when one or more of these electrodes (e.g., individual electrodes and/or groupings of multiple electrodes, such as groupings of three or four electrodes) are within the threshold distance of basal turn <NUM>. System <NUM> may provide real-time feedback regarding how many electrodes have passed basal turn <NUM> in any suitable manner (e.g., by way of graphical user interface <NUM>).

<FIG> illustrates an exemplary method according to principles described herein. The operations shown in <FIG> may be performed by system <NUM> and/or any implementation thereof. While <FIG> illustrates exemplary operations according to one embodiment, other embodiments may omit, add to, reorder, and/or modify any of the operations shown in <FIG>.

In operation <NUM>, an insertion management system directs cochlear implant to apply electrical stimulation by way of a first electrode disposed on an electrode lead that is being inserted into a cochlea of a recipient. Operation <NUM> may be performed in any of the ways described herein.

In operation <NUM>, the insertion management system directs the cochlear implant to record, while the electrical stimulation is being applied by way of the first electrode, a differential voltage signal representative of a differential voltage between a second electrode and a third electrode, both being disposed on the electrode lead, and the second and third electrodes different than the first electrode. Operation <NUM> may be performed in any of the ways described herein.

In operation <NUM>, the insertion management system determines, while the differential voltage signal is being recorded, that a signal characteristic of the differential voltage signal changes by at least a threshold amount. Operation <NUM> may be performed in any of the ways described herein.

In operation <NUM>, the insertion management system determines, based on the signal characteristic changing by at least the threshold amount, that a distal end <NUM> of the electrode lead is positioned within a threshold distance of a basal turn of the cochlea. Operation <NUM> may be performed in any of the ways described herein.

<FIG> illustrates another exemplary method according to principles described herein. The operations shown in <FIG> may be performed by system <NUM> and/or any implementation thereof. While <FIG> illustrates exemplary operations according to one embodiment, other embodiments may omit, add to, reorder, and/or modify any of the operations shown in <FIG>.

In operation <NUM>, an insertion management system directs cochlear implant to apply electrical stimulation by way of first and second electrodes disposed on an electrode lead that is being inserted into a cochlea of a recipient. The first and second electrodes may be any two of electrodes <NUM> described herein. Operation <NUM> may be performed in any of the ways described herein.

In operation <NUM>, the insertion management system directs the cochlear implant to record, while the electrical stimulation is being applied by way of the first and second electrodes, a differential voltage signal representative of a differential voltage between third and fourth electrodes disposed on the electrode lead. The third and fourth electrodes are different than the first and second electrodes. Operation <NUM> may be performed in any of the ways described herein.

<FIG> illustrates an exemplary computing device <NUM> that may be specifically configured to perform one or more of the processes described herein. As shown in <FIG>, computing device <NUM> may include a communication interface <NUM>, a processor <NUM>, a storage device <NUM>, and an input/output ("I/O") module <NUM> communicatively connected one to another via a communication infrastructure <NUM>. While an exemplary computing device <NUM> is shown in <FIG>, the components illustrated in <FIG> are not intended to be limiting. Additional or alternative components may be used in other embodiments. Components of computing device <NUM> shown in <FIG> will now be described in additional detail.

In some examples, any of the systems, computing devices, and/or other components described herein may be implemented by computing device <NUM>. For example, storage facility <NUM> may be implemented by storage device <NUM>, and processing facility <NUM> may be implemented by processor <NUM>.

Claim 1:
A system comprising:
a memory (<NUM>, <NUM>) storing instructions (<NUM>, <NUM>); and
a processor (<NUM>, <NUM>) communicatively coupled to the memory and configured to execute the instructions to:
direct a cochlear implant (<NUM>) to apply electrical stimulation by way of a first electrode (<NUM>-<NUM>) disposed on an electrode lead (<NUM>) that is being inserted into a cochlea (<NUM>) of a recipient;
direct the cochlear implant to record, while the electrical stimulation is being applied by way of the first electrode, a differential voltage signal representative of a differential voltage between a second electrode (<NUM>-<NUM>) and a third electrode (<NUM>-<NUM>) both disposed on the electrode lead, the second and third electrodes different than the first electrode;
determine, while the differential voltage signal is being recorded, that a signall characteristic of the differential voltage signal (<NUM>) changes by at least a threshold amount; and
determine, based on the signal characteristic changing by at least the threshold amount, that a distal end (<NUM>) of the electrode lead is positioned within a threshold distance of a basal turn (<NUM>) of the cochlea;
wherein the signal characteristic comprises a slope associated with the differential voltage signal, wherein the processor is further configured to execute the instructions to generate an impedance signal based on the differential voltage signal, and wherein the slope corresponds to the impedance signal.