Patent Publication Number: US-11642535-B2

Title: Systems and methods for gradually adjusting a control parameter associated with a cochlear implant system

Description:
RELATED APPLICATIONS 
     The present application is a continuation application of U.S. patent application Ser. No. 16/452,942, filed Jun. 26, 2019, which is a continuation application of U.S. patent application Ser. No. 15/500,494, filed Jan. 30, 2017 (now U.S. Pat. No. 10,376,698), which application is a U.S. National Stage Entry of PCT Application No. PCT/US2014/051087, filed Aug. 14, 2014. The contents of these applications are incorporated herein by reference in their respective entireties. 
    
    
     BACKGROUND INFORMATION 
     When a cochlear implant of a cochlear implant system is initially implanted in a patient, and during follow-up tests and checkups thereafter, it is usually necessary to fit the cochlear implant system to the patient. For example, during a fitting session, a clinician may utilize a fitting system to set various control parameters associated with (e.g., that govern an operation of) the cochlear implant system and/or otherwise configure the cochlear implant system for operation. 
     One of the control parameters that is often set during a fitting session for a cochlear implant patient is a most comfortable level (“M level”). An M level represents a stimulation current level required to achieve comfortable loudness to the patient. In other words, the M level represents a stimulation current level, which, when applied to a given set of one or more electrodes associated with the M level, produces a sensed perception of sound by the patient that is moderately loud, or comfortably loud, but not so loud that the perceived sound is uncomfortable. 
     An M level is typically determined by sequentially increasing the stimulation current level for the patient until the patient reports a comfortably loud sound on a subjective loudness scale. Because the M level anchors the patient&#39;s mapping function, defines the patient&#39;s electrical dynamic range (thereby impacting a host of perceptual attributes, such as loudness, sound-field-thresholds, spectral contrast, etc.), and is often used to derive other control parameters, accurately determining the M level is highly desirable. 
     It is a common observation that M levels are often under-fit (i.e., set to be lower than what the patient can actually tolerate) during the fitting process. This is at least in part due to the fact that the patient&#39;s tolerance of electrical stimulation is strongly influenced by sound exposure. Many cochlear implant patients have not had much, if any, exposure to loud sounds prior to being implanted with a cochlear implant. Hence, these patients may not initially be able to tolerate relatively high M levels, even though their ability to tolerate high M levels may increase over time as they are exposed to more loud sounds. 
     Unfortunately, however, M levels are only adjusted during fitting sessions (i.e., when the patient visits a clinic). This means that the M levels are held constant in between the fitting sessions, even though the ability of a patient to tolerate different electrical stimulation levels may fluctuate over time as the patient is exposed to different levels of sound. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings illustrate various embodiments and are a part of the specification. The illustrated embodiments are merely examples and do not limit the scope of the disclosure. Throughout the drawings, identical or similar reference numbers designate identical or similar elements. 
         FIG.  1    illustrates an exemplary cochlear implant system according to principles described herein. 
         FIG.  2    illustrates a schematic structure of the human cochlea according to principles described herein. 
         FIG.  3    shows an exemplary configuration in which a fitting system is communicatively coupled to the cochlear implant system shown in  FIG.  1    according to principles described herein. 
         FIG.  4    illustrates exemplary components of a sound processor according to principles described herein. 
         FIG.  5    shows a graphical representation of an adaption time course for a control parameter according to principles described herein. 
         FIG.  6    shows an exemplary look-up table that includes data representative of an adaption time course for a particular control parameter according to principles described herein. 
         FIG.  7    shows a graphical representation of an adaption time course for a control parameter according to principles described herein. 
         FIG.  8    illustrates an exemplary method of gradually adjusting a control parameter associated with a cochlear implant system. 
     
    
    
     DETAILED DESCRIPTION 
     Systems and methods for gradually adjusting a control parameter associated with a cochlear implant system are described herein. As will be described below, a sound processor included in a cochlear implant system associated with a patient may receive, from a fitting system while the sound processor is communicatively coupled to the fitting system, a command that sets a control parameter associated with the cochlear implant system to an initial value and data representative of a target value associated with the control parameter. The sound processor may subsequently enter a non-fitting state by being decoupled from the fitting system. While in the non-fitting state, the sound processor may gradually adjust the control parameter from the initial value towards the target value in accordance with an adaption time course associated with the control parameter. 
     As an example, a fitting system may be used by a clinician to initially fit a cochlear implant system to a patient subsequent to the patient being implanted with a cochlear implant. To this end, the clinician may connect a sound processor included in the cochlear implant system to the fitting system (e.g., by way of a clinician&#39;s programming interface (“CPI”) device). While the sound processor is connected to the fitting system, the clinician may perform one or more procedures to determine an initial value for an M level associated with the patient. As mentioned, this initial value for the M level may be under-fit (i.e., less than a target value for the M level that the patient should subsequently be able to tolerate after being exposed to sound over the course of a certain amount of time). To facilitate patient adaption to the target value of the M level, the clinician may use the fitting system to transmit, to the sound processor, a command that sets the M level to the initial value, data representative of a target value associated with the M level, and data representative of an adaption time course associated with the M level. As will be illustrated below, the adaption time course may specify a time course during which the M level is to be gradually adjusted by the sound processor from the initial value towards the target value. 
     After the fitting session is over, the sound processor may be decoupled from the fitting system (e.g., by being disconnected from the CPI device). The sound processor may detect this decoupling and, in response, enter a non-fitting state in which the sound processor may operate normally (e.g., by locking to the cochlear implant and, while locked, directing the cochlear implant to apply electrical stimulation representative of audio signals received and processed by the sound processor). 
     While in the non-fitting state, the sound processor may gradually adjust the M level from the initial value towards the target value in accordance with the adaption time course associated with the M level. For example, the sound processor may adjust the M level such that the M level trends upward towards the target value. As will be described below, incremental increases and decreases in the M level may occur during the trending upward towards the target value based on one or more other time-based and environmental-based factors. 
     The gradual adjustment of the M level may cease once the M level has reached the target level. Additionally or alternatively, the gradual adjustment of the M level may cease in response to user input provided by the patient. 
     By gradually adjusting a control parameter associated with a cochlear implant in this manner, the systems and methods described herein may facilitate patient adaption to a target value for the control parameter without requiring the patient to attend multiple fitting sessions. This may save the patient (and the clinician) time and resources. Moreover, the gradual adjustment of a control parameter as described herein may optimize cochlear implant system performance and allow for more accurate sound representation to the patient. Other benefits of the present systems and methods will be made apparent herein. 
     As used herein, a “control parameter” associated with a cochlear implant system may refer to any setting, stimulation parameter, and/or other parameter that governs an operation of one or more components included in the cochlear implant system. For example, a control parameter may be an M level, a threshold level (“T level”), an input dynamic range (“IDR”), a stimulation rate, and/or a pulse width. As described above, an M level represents a stimulation current level required to achieve comfortable loudness to the patient. A T level represents a minimum stimulation current level that produces a sensed perception of sound by the patient. IDR represents the difference (in SPL) between a sound amplitude producing T level stimulation and a sound amplitude producing M level stimulation. Stimulation rate refers to how many stimulation pulses per second may be applied by way of a given set of one or more electrodes. Pulse width refers to a width of each stimulation pulse that is applied by way of the given set of one or more electrodes. 
     Each of the control parameters described herein may be stimulation channel-specific. As used herein, a “stimulation channel” refers to a set of one or more electrodes by way of which electrical stimulation may be applied to a stimulation site within a cochlear implant patient. Because there may be multiple stimulation channels within a cochlear implant system, there may be multiple instances of a particular control parameter. For example, there may be a plurality of M levels each associated with a different stimulation channel. Alternatively, a single instance of a control parameter may be associated with all of the stimulation channels within a cochlear implant system. 
       FIG.  1    illustrates an exemplary cochlear implant system  100 . As shown, cochlear implant system  100  may include various components configured to be located external to a patient including, but not limited to, a microphone  102 , a sound processor  104 , and a headpiece  106 . Cochlear implant system  100  may further include various components configured to be implanted within the patient including, but not limited to, a cochlear implant  108  and a lead  110  (also referred to as an intracochlear electrode array) with a plurality of electrodes  112  disposed thereon. As will be described in more detail below, additional or alternative components may be included within cochlear implant system  100  as may serve a particular implementation. The components shown in  FIG.  1    will now be described in more detail. 
     Microphone  102  may be configured to detect audio signals presented to the patient. Microphone  102  may be implemented in any suitable manner. For example, microphone  102  may include a microphone that is configured to be placed within the concha of the ear near the entrance to the ear canal, such as a T-MIC™ microphone from Advanced Bionics. Such a microphone may be held within the concha of the ear near the entrance of the ear canal by a boom or stalk that is attached to an ear hook configured to be selectively attached to sound processor  104 . Additionally or alternatively, microphone  102  may be implemented by one or more microphones disposed within headpiece  106 , one or more microphones disposed within sound processor  104 , one or more beam-forming microphones, and/or any other suitable microphone as may serve a particular implementation. 
     Sound processor  104  (i.e., one or more components included within sound processor  104 ) may be configured to direct cochlear implant  108  to generate and apply electrical stimulation (also referred to herein as “stimulation current”) representative of one or more audio signals (e.g., one or more audio signals detected by microphone  102 , input by way of an auxiliary audio input port, etc.) to one or more stimulation sites associated with an auditory pathway (e.g., the auditory nerve) of the patient. Exemplary stimulation sites include, but are not limited to, one or more locations within the cochlea, the cochlear nucleus, the inferior colliculus, and/or any other nuclei in the auditory pathway. To this end, sound processor  104  may process the one or more audio signals in accordance with a selected sound processing strategy or program to generate appropriate stimulation parameters for controlling cochlear implant  108 . Sound processor  104  may include or be implemented by a behind-the-ear (“BTE”) unit, a body worn device, and/or any other sound processing unit as may serve a particular implementation. For example, sound processor  104  may be implemented by an electro-acoustic stimulation (“EAS”) sound processor included in an EAS system configured to provide electrical and acoustic stimulation to a patient. 
     In some examples, sound processor  104  may wirelessly transmit stimulation parameters (e.g., in the form of data words included in a forward telemetry sequence) and/or power signals to cochlear implant  108  by way of a wireless communication link  114  between headpiece  106  and cochlear implant  108 . It will be understood that communication link  114  may include a bi-directional communication link and/or one or more dedicated uni-directional communication links. 
     Headpiece  106  may be communicatively coupled to sound processor  104  and may include an external antenna (e.g., a coil and/or one or more wireless communication components) configured to facilitate selective wireless coupling of sound processor  104  to cochlear implant  108 . Headpiece  106  may additionally or alternatively be used to selectively and wirelessly couple any other external device to cochlear implant  108 . To this end, headpiece  106  may be configured to be affixed to the patient&#39;s head and positioned such that the external antenna housed within headpiece  106  is communicatively coupled to a corresponding implantable antenna (which may also be implemented by a coil and/or one or more wireless communication components) included within or otherwise associated with cochlear implant  108 . In this manner, stimulation parameters and/or power signals may be wirelessly transmitted between sound processor  104  and cochlear implant  108  via a communication link  114  (which may include a bi-directional communication link and/or one or more dedicated uni-directional communication links as may serve a particular implementation). 
     Cochlear implant  108  may include any type of implantable stimulator that may be used in association with the systems and methods described herein. For example, cochlear implant  108  may be implemented by an implantable cochlear stimulator. In some alternative implementations, cochlear implant  108  may include a brainstem implant and/or any other type of active implant or auditory prosthesis that may be implanted within a patient and configured to apply stimulation to one or more stimulation sites located along an auditory pathway of a patient. 
     In some examples, cochlear implant  108  may be configured to generate electrical stimulation representative of an audio signal processed by sound processor  104  (e.g., an audio signal detected by microphone  102 ) in accordance with one or more stimulation parameters transmitted thereto by sound processor  104 . Cochlear implant  108  may be further configured to apply the electrical stimulation to one or more stimulation sites within the patient via one or more electrodes  112  disposed along lead  110  (e.g., by way of one or more stimulation channels formed by electrodes  112 ). In some examples, cochlear implant  108  may include a plurality of independent current sources each associated with a channel defined by one or more of electrodes  112 . In this manner, different stimulation current levels may be applied to multiple stimulation sites simultaneously (also referred to as “concurrently”) by way of multiple electrodes  112 . 
       FIG.  2    illustrates a schematic structure of the human cochlea  200  into which lead  110  may be inserted. As shown in  FIG.  2   , the cochlea  200  is in the shape of a spiral beginning at a base  202  and ending at an apex  204 . Within the cochlea  200  resides auditory nerve tissue  206 , which is denoted by Xs in  FIG.  2   . The auditory nerve tissue  206  is organized within the cochlea  200  in a tonotopic manner. Relatively low frequencies are encoded at or near the apex  204  of the cochlea  200  (referred to as an “apical region”) while relatively high frequencies are encoded at or near the base  202  (referred to as a “basal region”). Hence, each location along the length of the cochlea  200  corresponds to a different perceived frequency. Cochlear implant system  100  may therefore be configured to apply electrical stimulation to different locations within the cochlea  200  (e.g., different locations along the auditory nerve tissue  206 ) to provide a sensation of hearing. 
       FIG.  3    shows an exemplary configuration  300  in which a fitting system  302  is communicatively coupled to cochlear implant system  100  by way of sound processor  104 . Fitting system  302  may be implemented by any suitable combination of computing and communication devices including, but not limited to, a fitting station, a personal computer, a laptop computer, a handheld device, a mobile device (e.g., a mobile phone), a clinician&#39;s programming interface (“CPI”) device, and/or any other suitable component or computing device as may serve a particular implementation. In some examples, fitting system  302  may provide one or more graphical user interfaces (“GUIs”) (e.g., by presenting the one or more GUIs by way of a display screen) with which a clinician or other user may interact. 
     Fitting system  302  may be selectively coupled to sound processor  104  in any suitable manner. While coupled to sound processor  104 , fitting system  302  may be used to perform various types of fitting procedures with respect to cochlear implant system  100 . For example, fitting system  302  may program sound processor  104  to operate in accordance with one or more sound processing programs, adjust one or more control parameters associated with cochlear implant system  100  (e.g., by transmitting a command to sound processor  104  that sets a particular control parameter to a particular value), and/or perform any other suitable operation with respect to cochlear implant system  100 . 
       FIG.  4    illustrates exemplary components of sound processor  104 . It will be recognized that the components shown in  FIG.  4    are merely representative of the many different components that may be included in sound processor  104  and that sound processor  104  may include additional or alternative components as may serve a particular implementation. 
     As shown in  FIG.  4   , sound processor  104  may include a processing facility  402  and a storage facility  404 , which may be in communication with one another using any suitable communication technologies. Processing facility  402  and/or storage facility  404  may include or be implemented by a computing device or processor configured to perform one or more of the functions described herein. 
     Storage facility  404  may maintain control parameter data  406 , adaption time course data  408 , and log data  410  received, generated, and/or used by processing facility  402 . Control parameter data  406  may include, but is not limited to, an initial value of a control parameter, a target value of the control parameter, and/or any other data associated with the control parameter. Adaption time course data  408  may include data representative of an adaption time course associated with a particular control parameter. Log data  410  may include data representative of a history of a gradual adjustment of a control parameter. Storage facility  404  may maintain additional or alternative data as may serve a particular implementation. 
     Processing facility  402  may perform various operations with respect to cochlear implant system  100  and/or fitting system  302 . For example, processing facility  402  may process an audio signal detected by microphone  102 , and, based on the processing, direct cochlear implant  108  to generate and apply electrical stimulation representative of the audio signal to one or more stimulation sites within the patient by way of one or more electrodes  112 . As another example, processing facility  402  may detect a coupling of sound processor  104  to fitting system  302 , and, in response, direct sound processor  104  to enter a “fitting state” in order to facilitate programming of sound processor  104  by fitting system  302 . Processing facility  402  may subsequently detect a decoupling of sound processor  104  from fitting system  302 , and, in response, direct sound processor to enter a “non-fitting state” in which sound processor  104  may operate normally. Various specific operations of processing facility  402  associated with gradually adjusting a control parameter will now be described. 
     As mentioned, it may be desirable to gradually and automatically adjust a control parameter associated with cochlear implant system  100  in between fitting sessions. For example, a cochlear implant patient may be initially able to tolerate a relatively low M level during a fitting session and shortly thereafter. However, after being exposed to sounds for an extended period of time (e.g., days or weeks), the patient may be able to tolerate a relatively higher M level. Hence, it may be desirable to dynamically increase the M level for the patient as the patient becomes more accustomed to sound without requiring the patient to participate in repeated fitting sessions (which would typically require the patient to make multiple trips to the clinic). 
     To this end, during a fitting session in which sound processor  104  is communicatively coupled to fitting system  302 , a clinician and/or the fitting system  302  itself may determine an initial value and a target value for a control parameter. The initial value may be determined in any suitable manner (e.g., in accordance with subjective feedback from the patient). Likewise, the target value may be determined in any suitable manner (e.g., by eliciting and measuring a stapedius reflex (“eSRT”) and/or any other objective measure, setting the target value to automatically be a predetermined percentage (e.g., twenty percent) higher than the initial value, and or in any other manner). The target value may be greater than or less than the initial value depending on the particular control parameter. For example, if the control parameter is an M level, the target value may be greater than the initial value. Alternatively, if the control parameter is pulse width, the target value may be less than the initial value. 
     Fitting system  302  may transmit a command to sound processor  104  that sets the control parameter to the initial value. Fitting system  302  may also transmit data representative of the target value to sound processor  104 . Processing facility  402  may receive the command that sets the control parameter to the initial value and the data representative of the target value in any suitable manner. 
     In some examples, the clinician and/or the fitting system  302  itself may also specify an adaption time course associated with the control parameter. Fitting system  302  may transmit data representative of the adaption time course to sound processor  104 . Processing facility  402  may receive the data representative of the adaption time course and store this data within storage facility  404  (e.g., in the form of adaption time course data  408 ). Alternatively, sound processor  104  may be pre-programmed with data representative of the adaption time course. 
     The adaption time adaption time course may specify a time course during which the control parameter is to be gradually adjusted by sound processor  104  from the initial value towards the target value. To illustrate,  FIG.  5    shows a graphical representation  500  of an adaption time course for a control parameter. In graphical representation  500 , line  502  represents the value of a particular control parameter as a function of time. As shown, as time progresses, the value of the control parameter gradually increases from an initial value towards a target value. In the particular example of  FIG.  5   , the gradual increase is linear. However, it will be recognized that other adaption time courses may specify that the control parameter increases and/or decreases in any other manner (e.g., the rate of increase for the control parameter may increase as time progresses). 
     Data representative of the adaption time course may be received and maintained by sound processor  104  in any suitable manner. For example, data representative of the adaption time course may be maintained by sound processor  104  in the form of a look-up table. To illustrate,  FIG.  6    shows an exemplary look-up table  600  that includes data representative of an adaption time course for a particular control parameter (e.g., an M level) and that may be maintained by sound processor  104 . 
     As shown, look-up table  600  specifies a plurality of time increments and a series of control parameter values. Each time increment represents an amount of elapsed time with respect to a start time (which may correspond to a time that the sound processor  104  is decoupled from fitting system  302 , a time that the sound processor  104  first locks to a cochlear implant subsequent to being decoupled from fitting system  302 , and/or a time associated with any other event as may serve a particular implementation). 
     Each control parameter value included in look-up table  600  represents a value that the control parameter is to be set to at each time increment. For example, look-up table  600  indicates that the control parameter is to be set by processing facility  402  to 1000 microamps at a time increment of zero hours (i.e., 1000 microamps is the initial value). After 12 hours have elapsed, the control parameter is to be increased by processing facility  402  to 1010 microamps. Likewise, after 24 hours have elapsed, the control parameter is to be increased by processing facility  402  to 1020 microamps. The control parameter may be gradually increased by processing facility  402  in this manner until the control parameter maxes out at the target value (which, in this example, is 1080 microamps and occurs at a time interval of 96 hours). By gradually increasing the control parameter in this manner, processing facility  402  may allow the patient to adapt to each increased value without even noticing that the control parameter is being adjusted. 
     Once the command to set the control parameter to the initial value and the data representative of the target value are transmitted to sound processor  104  during a fitting session, sound processor  104  may be decoupled from fitting system  302 . Processing facility  402  may detect this decoupling in any suitable manner. In response to the decoupling, processing facility  402  may direct sound processor  104  to enter a non-fitting state. While the sound processor  104  is in the non-fitting state, processing facility  402  may gradually adjust the control parameter from the initial value towards the target value in accordance with the adaption time course associated with the control parameter. This may be performed in any suitable manner. 
     For example, processing facility  402  may adjust the control parameter in accordance with the data included in look-up table  600 . To this end, processing facility  402  may track an elapsing of time (e.g., beginning with the decoupling of sound processor  104  from fitting system  302 ) and incrementally adjust the control parameter to a next value included in the series of values in response to an occurrence, within the elapsing of time, of each time increment included in the plurality of time increments. For example, in response to an elapsing of 12 hours, processing facility  402  may adjust the control parameter from 1000 microamps to 1010 microamps. This process may continue until the control parameter maxes out at the target value. 
     Processing facility  402  may track the elapsing of time in any suitable manner. For example, processing facility  402  may track the elapsing of time by tracking a total number of clock cycles that elapse subsequent to a starting event (e.g., an initial locking of sound processor  104  to cochlear implant  108 ). Additionally or alternatively, processing facility  402  may utilize a clock that tracks time in terms of any other suitable increment (e.g., seconds, minutes, hours, and/or days). 
     In some examples, processing facility  402  may adjust the control parameter while sound processor  104  is locked to cochlear implant  108  and abstain from adjusting the control parameter  104  while sound processor  104  is not locked to cochlear implant  108 . As used herein, the sound processor  104  may be “locked” to cochlear implant  108  while sound processor  104  is actively communicating with cochlear implant  108 . For example, sound processor  104  may lock to cochlear implant  108  each morning when the patient turns “on” sound processor  104 , but may not be locked to cochlear implant  108  after the patient turns the sound processor  104  “off” (e.g., at night while the patient sleeps). Processing facility  402  may detect that sound processor  104  is or is not locked to cochlear implant  108  in any suitable manner. 
     In cases where processing facility  402  only adjusts the control parameter while sound processor  104  is locked to cochlear implant  108 , the adaption time course may not take into account time periods during which sound processor  104  is not locked to cochlear implant  108 . In other words, the time intervals shown in look-up table  600  may only be tracked while sound processor  104  is locked to cochlear implant  108 . In some alternative embodiments, the adaption time course does take into account time periods during which sound processor  104  is not locked to cochlear implant  108 . In these alternative embodiments, the time intervals shown in look-up table  600  are tracked regardless of whether sound processor  104  is locked to cochlear implant  108 . 
     In some examples, processing facility  402  may adjust the control parameter until the control parameter reaches the target value. Processing facility  402  may detect that the control parameter has reached the target value and, in response, cease the adjustment of the control parameter. At any point before the control parameter reaches the target value, the patient may provide user input (e.g., by pressing a button on the sound processor  104 ) representative of a command to cease adjusting the control parameter. Processing facility  402  may detect this user input and, in response, cease the adjustment of the control parameter. Such user input may be provided, for example, if the user experiences pain and/or discomfort as a result of the gradual adjustment of the control parameter. 
     Processing facility  402  may take into account one or more other time-based and/or environmental-based factors while gradually adjusting the control parameter towards the target value. For example, processing facility  402  may take into account a time of day while gradually adjusting the M level (or any other control parameter) towards the target value. This is because electrical stimulation experienced by the patient early in the morning after a night of device deactivation is most likely perceived as being very loud compared to the same stimulation received later in the day when the patient has had more substantial exposure to sound. This is akin to a stereo sounding uncomfortably loud when it is turned on in the morning from a state that it was in during a loud party the previous night. 
     Hence, processing facility  402  may incrementally decrease the M level each morning when sound processor  104  locks to cochlear implant  108  so that sounds do not appear to be overly loud to the patient. Processing facility  402  may then increase the M level as the time of day progresses in accordance with the adaption time course. This is illustrated in  FIG.  7   , which shows a graphical representation  700  of an adaption time course that has been modified to take into account the time of day. Line  702  represents the value of a particular M level as a function of time. As shown, as time progresses, the value of the M level gradually trends upwards from an initial value towards a target value. However,  FIG.  7    shows that at times t 1  and t 2 , which correspond to times in the mornings of subsequent days when the sound processor  104  first locks to the cochlear implant  108 , processing facility  402  incrementally decreases the M level. 
     As mentioned, processing facility  402  may additionally or alternatively take into account one or more other environmental-based factors while gradually adjusting the control parameter towards the target value. For example, processing facility  402  may take into account an amount of sound exposure to the patient during a determined time period while gradually adjusting the M level (or any other control parameter) towards the target value. 
     For example, processing facility  402  may detect an amount of sound exposure to the patient within a predetermined time period and perform the gradual adjustment of the control parameter from the initial value towards the target value in accordance with the detected amount of sound exposure to the patient within the predetermined time period. The predetermined time period may be any suitable amount of time as may serve a particular implementation. For example, the predetermined time period may be relatively short when taking into account instantaneous sound exposure to the patient. Alternatively, the predetermined time period may be relatively long when taking into account average sound exposure to the patient. 
     Processing facility  402  may detect the amount of sound exposure to the patient in any suitable manner. For example, processing facility  402  may detect the amount of sound exposure to the patient by detecting a sound level (e.g., an amplitude) of an audio signal received by microphone  102  and average the sound level over the predetermined time period. 
     In some examples, if the detected amount of sound exposure is above a first threshold within the predetermined time period, processing facility  402  may increase the control parameter (e.g., by an incremental amount). Similarly, if the detected amount of sound exposure is below a second threshold (which may be the same as or less than the first threshold) within the predetermined time period, processing facility  402  may decrease the control parameter (e.g., by an incremental amount). 
     For example, if the patient enters and stays in an environment that has relatively loud sounds (e.g., a noisy restaurant), processing facility  402  may at least temporarily increase an M level associated with the patient. In some examples, the M level (or any other control parameter) may be temporarily adjusted (e.g., increased) only after the patient has been in the relatively loud environment for a predetermined amount of time (e.g., a few hours, a day, etc.). This would ensure that the patient has had sufficient exposure to the current value of the M level before further adjusting the M level. When the patient leaves the loud environment and enters a relatively quiet environment (e.g., the patient&#39;s home), processing facility  402  may decrease the M level associated with the patient (e.g., after a predetermined amount of time). It will be recognized that these incremental increases and decreases in response to changing sound exposure may be performed on top of (i.e., in addition to) the underlying gradual adjustment of the control parameter in accordance with the adaption time course. 
     In some examples, processing facility  402  may log a history of the gradual adjustment of the control parameter. Processing facility  402  may then detect a coupling of sound processor  104  to fitting system  302  subsequent to logging the history, and, in response, transmit data representative of the logged history to fitting system  302 . A clinician may then utilize fitting system  302  to perform one or more analysis operations with respect to the logged history in order to further optimize the control parameter. 
     In some examples, a cochlear implant system may include a bilateral configuration wherein separate cochlear implants are implanted for both ears of the patient. In this configuration, the patient may utilize a first sound processor for the first ear and a second sound processor for the second ear. In some examples, control parameters associated with each sound processor may be gradually adjusted in accordance with the systems and methods described herein. The sound processors may coordinate the adjustment of the control parameters (e.g., by way of a wireless link between the sound processors. 
     In some alternative examples, a cochlear implant system may be included in a bimodal configuration wherein the patient is fitted with a cochlear implant for his/her first ear and a hearing aid for his/her second ear. In this configuration, control parameters associated with both the cochlear implant system and the hearing aid may be gradually adjusted in accordance with the systems and methods described herein. The adjustment may be coordinated in any suitable manner. 
       FIG.  8    illustrates an exemplary method  800  of gradually adjusting a control parameter associated with a cochlear implant system. While  FIG.  8    illustrates exemplary steps according to one embodiment, other embodiments may omit, add to, reorder, and/or modify any of the steps shown in  FIG.  8   . One or more of the steps shown in  FIG.  8    may be performed by sound processor  104  and/or any implementation thereof. 
     In step  802 , a sound processor receives a command that sets a control parameter to an initial value and data representative of a target value associated with the control parameter. The sound processor may receive the command and data from a fitting system while the sound processor is communicatively coupled to the fitting system. Step  802  may be performed in any of the ways described herein. 
     In step  804 , the sound processor detects a decoupling of the sound processor from the fitting system, the decoupling resulting in the sound processor being in a non-fitting state. Step  804  may be performed in any of the ways described herein. 
     In step  806 , the sound processor gradually adjusts, while in the non-fitting state, the control parameter from the initial value towards the target value in accordance with an adaption time course associated with the control parameter. Step  806  may be performed in any of the ways described herein. 
     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.