Abstract:
Method, controller and system for an implantable medical device having a plurality of electrodes, the implantable medical device capable of delivering therapeutic stimulation to a patient, comprising a control module, a user interface operatively coupled to the control module, the user interface providing control of the control module by a medical professional or other user, and an electrode interface operatively coupled between the plurality of electrodes and the control module. The control module uses the electrode interface to obtain a plurality of measurements of impedance values for a plurality of selected pairs of individual ones of the plurality of electrodes. The control module flags electrodes using the plurality of measurements of impedance values of the selected pairs of individual ones of the plurality of electrodes comparative to a range, and the delivery of therapy on flagged electrodes is inhibited.

Description:
FIELD 
       [0001]    The present invention relates generally to controllers, systems and methods for implantable medical devices and, more particularly, to such controllers, systems and methods for implantable medical devices having therapeutic electrical stimulation electrodes. 
       BACKGROUND 
       [0002]    The medical device industry produces a wide variety of electronic devices for treating patient medical conditions. Depending upon medical condition, medical devices can be surgically implanted or connected externally to the patient receiving treatment. Medical professionals or other clinicians use medical devices alone or in combination with drug therapies and surgery to treat patient medical conditions. For some medical conditions, medical devices provide the best, and sometimes the only, therapy to restore an individual to a more healthful condition and a fuller life. Examples of implantable medical devices designed to deliver therapeutic electrical stimulation include neurological stimulators, pacemakers and defibrillators. 
         [0003]    Implantable medical devices configured to deliver therapeutic electrical stimulation commonly deliver therapy via electrodes positioned on one or more leads operatively connected to the implantable medical device. In some instances, the housing of the implantable medical device may also serve as an electrode or an electrode may be positioned on the housing of the implantable medical device. The electrode or electrodes are commonly positioned in the patient&#39;s body during the same surgical procedure in which the implantable medical device is implanted. Sometimes the electrode or electrodes are placed in a follow-up procedure. 
         [0004]    The positioning of electrodes, and associated leads, is often an inexact procedure and may commonly be dependent on the particular physiologic characteristics of the patient. In addition, electrodes may commonly be positioned within the patient without the medical professional or user conducting the procedure being capable of actually seeing where the electrodes are positioned. Instead, external aides such as fluoroscopes and/or endoscopes may commonly be employed to inform the medical professional or other user as to an approximate location of the electrodes. Electrodes may also be placed by stereotactic head frame which allows placement of the lead without direct visualization. Further, the ideal target is often not known a priori and time constraints may not allow for perfect targeting in the operating room. 
         [0005]    Due to the inherent uncertainty involved in the placement of electrodes for an implantable medical device, implantable medical devices and the external controllers that interface with the devices are commonly operable to perform a test on the leads and electrodes to verify that the leads and electrodes are functioning properly and are positioned correctly. A common test is to check the impedance between pairs of electrodes. During testing, an electrode can be driven with a signal having known electrical characteristics. The signal may be measured, e.g., on another electrode or electrodes, and the impedance computed between electrodes using known fundamental relationships. The measured impedance value can give a medical professional or other user information relating to whether the electrodes involved in the test are positioned correctly and operating properly. 
         [0006]    An external controller, e.g., a physician programmer, is commonly utilized in lead impedance tests. Physician programmers can be similar in size and composition to a large laptop computer. The physician programmer provides a user interface via a display screen, and is manipulated by a medical professional via a variety of inputs, such as buttons and touchscreens. The physician programmer commonly communicates with the implantable medical device via inductive telemetry. In order to accomplish this, a coil, operatively coupled to the controller, typically by a wire, is placed over a coil operatively coupled to the electronics in the implantable medical device producing an alternating current in the coil operatively coupled to the controller, thereby establishing an inductive link over which data may be passed in either direction. Because physician programmers are typically not sterilized, the physician programmer itself is placed outside of the sterile field, only the coil and its housing is taken inside the sterile field, e.g., using a sterile bag. 
         [0007]    For example, United States Patent Application Publication No. 2006/0036186, Goetz et al, Automatic Impedance Measurement of an Implantable Medical Device, discloses a method and controller for automating impedance measurements. An entry for each electrode pair is displayed on a user interface. Each electrode pair entry includes an identification of electrodes for an electrode pair, an associated value of impedance and a value of current that is measured between the electrodes of a pair. 
         [0008]    In another example, U.S. Pat. No. 5,891,179, Er et al, Method and Apparatus for Monitoring and Displaying Lead Impedance in Real-Time for an Implantable Medical Device, discloses a method and controller for displaying real-time graphical representations of variable lead impedance. Impedance values are calculated using Ohm&#39;s law or other related equations. The calculated impedance values are then output to a graphic display for presentation in graphical form or are output to a graphic printer, or both. 
         [0009]    In another example, United States Patent Application Publication No. 2003/0114899, Samuelsson et al, Programming System for Medical Devices, discloses a method and controller for displaying graphical representations of a quantity influenced by the operation of a medical device. Such quantities may include information derived from tests and diagnostics, such as an electrode impedance test. 
         [0010]    In another example, United States Patent Application Publication No. 2005/0033385, Peterson et al, Implantable Medical Device Programming Apparatus Having a Graphical User Interface, discloses graphical displays of the operation of a medical device, such as a test of a device lead. Results are organized according to the anatomical position of the lead, i.e., whether the lead is an atrial or ventricular lead, allowing the clinician to efficiently assess the functionally of all lead data by virtue of its grouping into precise anatomical categories. 
         [0011]    In another example, U.S. Pat. No. 6,721,600, Jorgenson et al, Implantable Lead Functional Status Monitor and Method, discloses a system for obtaining trend data on the status of leads of an implantable medical device. The lead status measurement derives its data from various sources including lead impedance, non-physiologic sensed events, percentage of time the device is in mode switch, the results of capture management operation, sensed events, reversion paced counts, and refractory sense counts. The lead status measurement employs a set of weighted sum rules used by algorithms to process data from all of the above-mentioned sources to arrive at easily interpreted messages accessible to clinicians via an external programmer. Data from these sources identify lead conductor/connector interface issues and electrode/tissue interface issues indicative of lead-related mechanisms suggestive of impending or actual lead failure. The weights are “interpreted” for the user in the following manner either by indicating (1) lead-related parameters are all within range or operating normally; (2) one or more of the lead parameters are out-of-range and, thus, leads should be investigated; or (3) a number of lead parameters are out-of-range and a safety problem exists. 
         [0012]    Messages to the user refer to three types of lead-related conditions: either lead/conductor/connector messages, lead insulation messages or biological interface messages. Examples of such messages include: (1) high impedance (&gt;4000 ohms, 2× increase over reference, among others); (2) increase in threshold(s) above preset or programmed limit; and (3) reduction in R-wave and P-wave amplitude below preset or programmed limits. 
         [0013]    Summary information from a variety of trend data is therefore presented for the use of a medical professional. 
       SUMMARY 
       [0014]    But none of the above documents show, disclose or suggest the physician programmer taking any automatic actions in response to an electrode integrity metric, such as an impedance measurement. The physician programmer may prevent or inhibit any attempt by a medial professional to program or utilize a non-functional or suspect electrode, thereby potentially preventing harm to the patient in the event the medical professional willfully or accidentally ignores or disregards the results. Like much of the above cited documents, the controller provides a range of impedance values considered normal, bounded on either end by values fixed, e.g., set by the user or learned from previous tests or adaptively determined from other values in the current test, for the test. 
         [0015]    In an embodiment, there is a controller for an implantable medical device having a plurality of electrodes. The implantable medical device is capable of delivering therapeutic stimulation to a patient using at least one of the plurality of electrodes. The controller has a control module, and an electrode interface operatively coupled between the plurality of electrodes and the control module. The control module uses the electrode interface to obtain a plurality of measurements of an integrity metric, such as an impedance value, for a plurality of selected sets of individual ones of the plurality of electrodes, and flags an individual one of the plurality of electrodes based on the plurality of measurements. 
         [0016]    In an embodiment, a subset of the plurality of electrodes is flagged. 
         [0017]    In an embodiment, the flagging is an indication of functionality of the individual one of the plurality of electrodes. 
         [0018]    In an embodiment, the flagging is a binary indication of functionality of the individual one of the plurality of electrodes. 
         [0019]    In an embodiment, the control module captures meta data related to the flagging of one of the plurality of electrodes. 
         [0020]    In an embodiment, the meta data is an indication related to when flagging of one of the plurality of electrodes occurred. 
         [0021]    In an embodiment, the control module inhibits delivery of the therapeutic stimulation on the individual one of the plurality of electrodes that is flagged. 
         [0022]    In an embodiment, the control module automatically inhibits delivery of the therapeutic stimulation on the flagged individual one of the plurality of electrodes. 
         [0023]    In an embodiment, the controller further comprises a user interface operatively coupled to the control module, the user interface providing control of the control module by a user. 
         [0024]    In an embodiment, the user interface notifying the user if a flagged electrode only if existing therapeutic settings include settings that use the flagged electrode. 
         [0025]    In an embodiment, the delivery of the automatically inhibited therapeutic stimulation may be overridden by the user via the user interface. 
         [0026]    In an embodiment, the delivery of the automatically inhibited therapeutic stimulation may be overridden by the user via the user interface after a second measurement of impedance values for a plurality of selected sets of individual ones of the plurality of electrodes has been obtained. 
         [0027]    In an embodiment, the flagging is based on an analysis of operational functionality of the plurality of electrodes using the plurality of measurements of impedance values of the selected sets of individual ones of the plurality of electrodes. 
         [0028]    In an embodiment, flagging of one of the plurality of electrodes is based upon a manual input by user instead of or in addition to being based upon a plurality of measurements. 
         [0029]    In an embodiment, there is a system for delivering therapeutic stimulation to a patient having an implantable medical device having a plurality of electrodes, and a controller. 
         [0030]    The controller includes a control module and an electrode interface. The electrode interface is operatively coupled between the plurality of electrodes and the control module. The control module uses the electrode interface to obtain a plurality of measurements of an integrity metric, such as an impedance value, for a plurality of selected sets of individual ones of the plurality of electrodes, and flags an individual one of the plurality of electrodes based on the plurality of measurements. 
         [0031]    In an embodiment, there is a method for delivering therapeutic stimulation to a patient using an implantable medical device having a plurality of electrodes. First, a plurality of measurements of an integrity metric, such as an impedance value, for a plurality of selected sets of individual ones of the plurality of electrodes is obtained. Then an individual one of the plurality of electrodes is flagged based on the plurality of measurements. 
         [0032]    In an embodiment, the flagging step flags a subset of the plurality of electrodes. 
         [0033]    In an embodiment, the flagging step flags the individual one of the plurality of electrodes based on functionality of the individual electrode. 
         [0034]    In an embodiment, the flag is a binary flag. 
         [0035]    In an embodiment, the flagging step captures meta data related to the flagging of one of the plurality of electrodes. 
         [0036]    In an embodiment, the meta data is an indication related to when the flagging occurred. 
         [0037]    In an embodiment, the method additionally has the step of inhibiting delivery of the therapeutic stimulation on the individual one of the plurality of electrodes that is flagged. 
         [0038]    In an embodiment, the method additionally has the step of automatically inhibiting delivery of the therapeutic stimulation on the individual one of the plurality of electrodes that is flagged. 
         [0039]    In an embodiment, the method additionally has the step of a user overriding the automatically inhibited delivery of the therapeutic stimulation. 
         [0040]    In an embodiment, the method additionally has the step of a user overriding the automatically inhibited delivery of the therapeutic stimulation after a second measurement of impedance values for a plurality of selected sets of individual ones of the plurality of electrodes has been obtained. 
         [0041]    In an embodiment, the method additionally has the step of analyzing the plurality of measurements of impedance values of the selected sets of individual ones of the plurality of electrodes, and wherein the flagging is based on the analysis. 
         [0042]    In an embodiment, the flagging step flags an electrode based upon manual input by a user instead of or in addition to being based upon an integrity metric. 
     
    
     
       DRAWINGS 
         [0043]      FIG. 1  shows an example of an implantable neurological stimulator implanted in the side of a patient, with electrodes positioned along the patient&#39;s sacral nerves; 
           [0044]      FIG. 2  shows an implantable neurological stimulator with a lead and lead extender and electrodes; 
           [0045]      FIG. 3  shows a cutaway diagram of a lead with electrodes, and a lead extender, for an implantable medical device; 
           [0046]      FIG. 4  shows a screen shot of a window for controlling an electrode impedance test of an implantable neurological stimulator; 
           [0047]      FIG. 5  shows a screen shot of a window for displaying out-of-range results of an electrode impedance test of an implantable neurological stimulator; 
           [0048]      FIG. 6  shows a screen shot of a window for displaying results of an electrode impedance test of an implantable neurological stimulator; 
           [0049]      FIG. 7  shows a block diagram of a controller for an implantable medical device; and 
           [0050]      FIG. 8  is a flow chart for conducting an electrode impedance test for an implantable medical device. 
       
    
    
     DESCRIPTION 
       [0051]      FIG. 1  shows the general environment of one rechargeable implantable medical device  20  embodiment. Implantable neurological stimulator  22  is shown, but other embodiments such as pacemakers and defibrillators and the like are also applicable. Implantable neurological stimulator  22  is implanted subcutaneously in side  28  of patient  30 . Lead  24  is operatively coupled to implantable neurological stimulator  22  at header  26 . Lead  24  is positioned along spinal chord  31  of patient  30 . Controller  32 , which may be a physician programmer or patient programmer or another device, may become transcutaneously coupled to implantable neurological stimulator  22  via an inductive communication link through the tissue of patient  30  when controller  32  is placed in proximity to implantable neurological stimulator  22 . 
         [0052]      FIGS. 2 and 3  show a closer view of implantable neurological stimulator  22  and lead  24 , operatively coupled by extender  36 . Electrodes  38  are mounted on distal end  37  of lead  24 . Electrodes  38  are comprised of a conductive material, in an embodiment, metal, that come into direct contact with tissue of patient  30 . Electrodes  38  are operatively coupled with implantable neurological stimulator  22  via header  26  through wires  39  comprised of conductive material that pass through the interior  41  of lead  24  and are operatively coupled with conductive wires  39  in the interior  40  of extender  36 . Insulation  42  is provided between wires  39  of lead  24 . 
         [0053]      FIG. 4  shows electrode impedance panel  42  for neurological stimulator  22 , in this case a deep brain stimulator. Pick menus  44  allow selection of different leads  24  to test. Pressing button  48  begins the test according to default parameters. Alternatively, the test may begin without the necessity of a button press. After the test has completed a summary of the results is displayed in window  50 , while buttons  52  give the medical professional or other user access to panel  60  ( FIG. 5 ) that displays all results that were out of the predetermined range and to panel  80  ( FIG. 6 ) that displays all results. 
         [0054]    In a typical electrode impedance test, each electrode  38  may be tested both in unipolar mode and bipolar mode. Each electrode  38  in unipolar mode is paired up with neurological stimulator case  23  and the impedance between each electrode  38  and implantable neurological stimulator case  23  is measured and stored. In addition, each electrode  38  in bipolar mode is paired up with every other electrode  38  and the impedance between each electrode  38  and every other electrode  38  is measured and stored. An exception may be that electrodes  38  that are located in different physiologic regions of the body, e.g., the head, the chest, are never paired and tested. 
         [0055]    While the electrode tests have been illustrated and described as being electrode impedance tests, it is to be recognized and understood that other forms of electrode integrity testing is also contemplated. In general, an integrity metric, which may be an impedance measurement, may be measured for a plurality of electrodes and the efficacy of each of the plurality of electrodes determined, at least in part. While electrode impedance is one such integrity metric, others are contemplated such as admittance, real or complex. Other integrity metrics could be the current into or out of a particular electrode or group of electrodes, voltage potential measured at an electrode due to stimulus on another electrode or electrodes, capacitance of an electrode with respect to another electrode or electrodes, inductance of an electrode with respect to another electrode or electrodes, frequency response of an electrode with respect to stimulus on another electrode or electrodes, measured reflection of a stimulus signal driven into an electrode (as in an electromagnetic transmission line). 
         [0056]      FIG. 5  shows out-of-range results panel  60  for displaying the results of testing initiated from electrode impedance panel  40 . Text  62  at top of out-of-range results panel  60  informs the medical professional or other user what test the current results pertain to by displaying which electrodes  38  were tested, in which mode electrodes  38  were tested and at which voltage amplitude electrodes  38  were tested. Possible open circuits window  64  lists possible locations, e.g., all possible locations, of open circuits that cause faults of tested electrodes  38 . Possible short circuits window  66  lists possible locations, e.g., all possible locations, of short circuits that cause faults. Buttons  68  provide access to out-of-range help panel  100  ( FIG. 6 ), all results panel  80  ( FIG. 5 ) and electrode impedance panel  40 , as well as a print command to print the data displayed on out-of-range results panel  60 . In an embodiment, results of electrode impedance tests are analyzed for selected sets of individual electrodes to determine operational functionality. 
         [0057]    Open circuits are typically detectable when all measured impedance values for one electrode  38  are higher than the allowable maximum value. As an example, assume that electrodes  38  include six electrodes designated “electrode one”, “electrode two”, and so on through “electrode six”. If all impedance values involving electrode two exceed the maximum value and all impedance values not involving electrode two are within the allowable value, the controller could conclude that an open circuit existed on the path along which electrode two was operatively coupled with implantable neurological stimulator  22 . Similarly, if all measured impedance values pertaining to electrodes ( 38 ) two and six exceeded the maximum value and all impedance values not involving electrodes  38  two and six are within the allowable values, the controller could conclude that both electrodes two and six were open. 
         [0058]    By contrast, short circuits are typically detectable when all measured impedance values involving those two electrodes  38  are lower than average and the measured impedance valve between the two electrodes  38  is below the minimum allowable value. For instance, if the average impedance between electrodes  38  is five hundred ohms, but between electrodes four and five, and four and six, in bipolar mode, and electrodes five and case  23  and six and case  23  were all four hundred ohms, and the impedance between electrodes five and six was below the allowable minimum value, controller  32  ( FIG. 1 ) could conclude that there is a short circuit between electrodes five and six. Such short circuits can occur, among other reasons, because the electrodes  38  in question are physically touching, or insulation  42  between wires  39  operatively coupling electrodes  38  with implantable neurological stimulator  22  have frayed. Other examples of possible electrodes shorts are crushing of the lead body causing conductive wires to contact each other or adjoining wires and fluid ingress to a connector, e.g., lead to lead extension, lead extension to implantable medical device, lead to implantable medical device, causing one or more of the electrodes to short. 
         [0059]    Occasionally, the results of testing may provide ambiguous results. For instance, if the impedance between electrodes zero and two, three and two and between electrode two and case are all greater than the maximum allowable value, but the impedance between electrodes one and two is within the allowable range, then it might not be clear what is the underlying cause of the issue. In circumstances where it is at least likely that a given individual electrode  38  or electrode  38  pair is not fully functional, an internal flag may be set in controller  32  corresponding to that electrode  38  or electrode  38  pair. Such an internal flag on an ambiguous result might be used to trigger further measurements or more aggressive measurements. Also, therapy on suspicious electrodes might be discourage, rather than prevented, in certain situations such as situations where the controller manages therapy creation or therapy settings. For example, a guided or wizard technique might try suspicious electrodes later in sequence or last. 
         [0060]    In an embodiment, fewer than all of the electrodes measured are flagged, i.e., a subset of all of the electrodes measured are flagged. 
         [0061]    In general, flagging consists of setting an internal flag associated with one or more of the plurality of electrodes measured. The flag thus set can be subsequently utilized by the controller to perform or to inhibit the performance of certain activities, such as inhibiting the use of a flagged electrode or electrode pair. The flag may also be communicated to a user who may then independently determine the use of the flagged electrode or electrode pair. In an embodiment, the user may only be notified of flagged electrodes if such flagged electrodes are included in currently selected therapeutic settings. 
         [0062]    Flagging may also involve the capture of meta data, i.e., data intrinsic to the electrode or electrode pair being flagged and/or intrinsic to the flagging operation. As an example, information related to when the electrode or electrode pair is flagged may be captured as meta data and subsequently used by the controller or communicated to the user. This information could be, for example, the date and/or time of day that the electrode or electrode pair was flagged or an indication of an elapsed time since the electrode or electrode was flagged. Other types of meta data are also contemplated such as the type of measurement used to discover the flag, e.g., impedance versus current, settings or parameters used to make the measurement or measurements, type of procedure, life cycle state of the implantable medical device in which flagging occurs, whether a flagging condition was reproducible across multiple or all measurements and the type of measurements, whether the flagged electrode had previously been flagged, whether the user opted to override the flag either currently or in the past and whether the flagged event impacted therapy, i.e., was the flagged electrode being used in therapy. 
         [0063]      FIG. 6  shows all results panel  80 , for displaying all results of testing initiated from electrode impedance panel  40 , regardless of whether testing resulted in an indication of failure or failures or not. Text  82  at the top of all results panel  80  informs the medical professional or other user to what test the current results pertain by displaying which electrodes  38  were tested, in which mode electrodes  38  were tested and at which voltage amplitude electrodes  38  were tested. Results are displayed in one of two windows  84 ,  86  depending on if the test mode was unipolar  84  or bipolar  86 . Buttons  88  provide access to electrode impedance panel  40  and a print command. 
         [0064]    Because an attempt to deliver therapy to patient  30  via a non-functional electrode  38  may cause undesirable consequences for the patient, including the possibility of injury and even death, controller  32  ( FIG. 1 ) may prevent therapy from being delivered on flagged electrode  38  or electrode  38  pair. Where a clear conclusion can be drawn from the data, controller  32  may impose outright restrictions on the ability of a user to utilize a non-functional or suspect electrode  38 . In the above example wherein electrodes five and six are shorted controller  120  may set an internal flag to prevent any programming of neurological stimulator  22  such that therapy is attempted to be delivered to patient  30  via electrodes five and six. Language may be appended to the result such as “Programming of electrodes five and six has been inhibited.” In an embodiment, therapy on the suspect electrode  38  may not be permitted until a new test has been conducted and controller  32  determines that no further issues exist with any of the previously suspect electrodes  38 . Note that in the above embodiment, where the internal flag has not been set then the electrode  38  pair may be taken to be functional and its use may not be automatically inhibited, thereby providing a binary indication of the functionality of the various electrodes  38 . 
         [0065]    Where a result is not considered sufficiently conclusive, or in situations where it is acceptable to allow a medical professional to override a determination of a suspect or non-functional electrode  38 , controller may prompt the medical professional “Do you wish to override inhibiting electrodes five and six?”. 
         [0066]    In an embodiment of the above example, where the medical professional chooses to override, electrodes  38  five and six would once again be eligible to deliver therapy to patient  30 . Where the medical professional gave a negative indication the inhibition may remain until either overridden by a medical professional, or a test indicating adequate functionality was run. 
         [0067]    In an alternative embodiment, where a result is not considered sufficiently conclusive, or in situations where it is acceptable to allow a medical professional to override a determination of a suspect or non-functional electrode  38 , controller may not automatically inhibit the programming of the suspect or non-functional electrodes  38 , but rather prompt the medical professional whether or not to inhibit the suspect or non-functional electrodes. For instance, continuing with the above example, the medical professional may be prompted, “Do you want to inhibit therapy on electrodes  5  and  6 ?” Where the medical professional selects “no”, the electrodes would not be inhibited. Where the medical professional selects “yes”, the electrodes would be inhibited, in an embodiment until either a medical professional removes the inhibition, or a test is run that indicates electrodes  38  five and six are functioning properly. In an alternative embodiment, controller  120  may allow the medical professional to opt whether or not to inhibit, but may first require further testing, such as a full measurement test or a different type of measurement or a measurement made using different parameters, to provide as much information as possible prior to allowing the medical professional the option of inhibiting or not. 
         [0068]      FIG. 7  shows a block diagram of the functional blocks of controller  32 . Control module  122  comprises a variety of off the shelf electronic components commonly found in a variety of commercial applications, such as personal computers. These electronic components include: a microprocessor, RAM, ROM and hard disks. These off the shelf components are integrated into control module  122  and additional operational features are added via custom electronics. These custom electronics are comprised of off the shelf integrated circuits and discrete components, and programmable components, such as Field Programmable Gate Arrays (FPGAs), Digital Signal Processors (DSPs), custom integrated circuits and Printed Circuit Boards (PCBs). 
         [0069]      FIG. 8  is a flow chart for conducting a standard electrode impedance test. In an embodiment, implantable neurological stimulator  22  performs an impedance measurement ( 160 ) involving minimal testing that still tests all electrode  38  pairs. In an alternative embodiment, impedance measurement ( 160 ) tests all electrodes  38  against all other electrodes  38 , in which case each individual electrode  38  may be independently characterized. In an embodiment, an analysis is performed ( 161 ) of impedance measurements of electrodes  38  to determine operational functionality. In an embodiment, if all of the resulting measured impedance values are within ( 162 ) the allowable range controller  32  indicates that no issue exists ( 164 ) in results window  50  ( FIG. 4 ), and the user may continue programming implantable neurological stimulator  22  ( 166 ) using controller  32 . 
         [0070]    In an embodiment, if any result is out of range, however, controller  32  indicates ( 168 ) the fault, and flags ( 170 ) the out-of-range electrodes  38 . In embodiments in which impedance measurement ( 160 ) involves minimal testing, then electrode  38  pairs may be flagged ( 170 ) and indicated ( 168 ) to the user. In embodiments in which impedance measurement ( 160 ) involves characterizing electrodes  38  individually, individual electrodes  38  may be flagged ( 170 ). In an embodiment the user may specify that the impedance test may be repeated to verify the fault. While the results of electrode impedance tests may be compared against a fixed allowable range, an adaptive algorithm that compares all measured impedance values against the average of the measured impedance values is contemplated. Electrodes  38  or electrode  38  pairs that vary from the average may be flagged as suspect, deserving of further analysis. 
         [0071]    In various embodiments, controller  32  may inhibit ( 172 ) delivery of therapeutic stimulation on electrodes  38  that have been flagged ( 170 ). In an embodiment, the inhibiting ( 172 ) is done automatically by controller  32 . In an embodiment, the user may override ( 174 ) the inhibition placed ( 172 ) on electrode  38 . In an alternative embodiment, the user may not be given the option of overriding ( 174 ). In an embodiment, controller  32  may require a second impedance measurement ( 176 ) of electrodes  38  before allowing the user to override ( 174 ). In alternative embodiments, the user may be prompted ( 178 ) whether to inhibit immediately after electrodes  38  are flagged ( 170 ). Optionally, meta data (as discussed above) may be stored ( 179 ). In either case, the user may continue programming implantable neurological stimulator  22  ( 166 ) using controller  32 . 
         [0072]    In an embodiment, an electrode or electrode pair, or any of the electrodes, may be flagged manually by a user, either instead of and/or in addition to the result of any measurement performed with respect to such electrode or electrode pair. For example, a medical professional may determine or suspect that a particular electrode or electrode pair may be providing non-advantageous results, such as unusual or abnormal behavior or intolerable side effects, and may manually flag such electrode or electrode pair to prevent, for example, the electrode or electrode pair to be subsequently utilized. This may be especially important because, in certain circumstances, the electrode or electrode may be technical functional, i.e., passing the integrity metric tests, such as impedance measurements, but still may be providing non-advantageous results. In an embodiment, testing by the controller, including prior, contemporaneous or subsequent testing, would not be allowed to remove the manually set flag. The reason an electrode or electrode has been manually flagged may be captured as meta data perhaps as well as the side effect caused or observed and the severity of such side effect. 
         [0073]    Thus, embodiments of the controller for flagging suspect electrodes, system and method therefore are disclosed. One skilled in the art will appreciate that the present invention can be practiced with embodiments other than those disclosed. The disclosed embodiments are presented for purposes of illustration and not limitation, and the present invention is limited only by the claims that follow.