Abstract:
A method and apparatus for displaying periodic signals generated by a medical device is disclosed. A method and apparatus for displaying quasi-periodic signals generated by a medical device also is disclosed.

Description:
PRIORITY CLAIM 
       [0001]    This is a continuation-in-part of U.S. application Ser. No. 13/838,563, titled “Method and Apparatus for Displaying Periodic Signals Generated by a Medical Device” and filed on Mar. 15, 2013, which is incorporated herein by reference in its entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    A method and apparatus for displaying periodic signals generated by a medical device is disclosed. A method and apparatus for displaying quasi-periodic signals generated by a medical device also is disclosed. 
       BACKGROUND OF THE INVENTION 
       [0003]    Electrocardiogram (EKG, also known as ECG) devices are well-known in the prior art. They measure the electrical activity of the human heart using electrodes and create tracings of the activity on paper or on a visual display. 
         [0004]      FIG. 1  depicts a prior art medical device  10  along with output  20 . In this particular exemplary depiction, medical device  10  is an EKG device and output  20  is EKG data. Notably, output  20  comprises either a graph printed on a scroll of paper or a graphical display on a screen that scrolls in real-time as the electrical activity is measured. Using prior art device  20 , a doctor or medical professional must read the scroll of paper or watch the tracings on a screen in real time. This can be a tedious and challenging exercise that contains the inherent risk that the doctor or medical professional will miss an important change in the monitored activity. 
         [0005]    Many medical devices create periodic signals as well that represent activity within the human body. For example, medical devices exist in the areas of electromyography (EMG) (to monitor muscle activity), electroencephalography (EEG) (to monitor brain activity), polysomnography (to monitor breathing activity during sleep), and other areas in which periodic signals are generated and monitored in real-time by a doctor or medical professional. 
         [0006]    In the electrical engineering field, oscilloscopes and other tools are well-known for displaying electrical signals on a screen. One technique used by such tools is to create an “eye diagram” for periodic signals. The technique involves superimposing the signal from one period over the signal from the next period and the next period, and so on. An exemplary eye diagram  30  is shown in  FIG. 2 . This allows the user to physically see multiple periods of the signal at one time in a limited amount of space and to readily view any differences or deviations in the signals. 
         [0007]    What is needed is a device for generating an eye diagram for periodic signals generated by medical devices and to identify any excursions from the mean values, expected values, or other thresholds. What is further needed is the ability to examine an excursion in more detail and to quickly see the data before and after the excursion occurred. 
         [0008]    What is further needed is the ability to apply these concepts to quasi-periodic signals generated by medical devices. 
       SUMMARY OF THE INVENTION 
       [0009]    The aforementioned problem and needs are addressed through an embodiment for generating an eye diagram of a periodic signal output from a medical device and for examining an excursion in more detail. Another embodiment provides the same benefit for quasi-periodic signals. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  depicts a prior art medical device and its output. 
           [0011]      FIG. 2  depicts a prior art eye diagram. 
           [0012]      FIG. 3  depicts an embodiment for generating an eye diagram using a periodic signal from a medical device. 
           [0013]      FIG. 4  depicts an embodiment for identifying and capturing one or more periods of data from a periodic signal from a medical device. 
           [0014]      FIG. 5  depicts an embodiment for generating an eye diagram using a periodic signal where the eye diagram shows an excursion in the signal. 
           [0015]      FIG. 6  depicts an embodiment for displaying an expanded version of the periodic signal in response to a user instruction after viewing the eye diagram of  FIG. 5 . 
           [0016]      FIG. 7  depicts an embodiment for generating an eye diagram using a quasi-periodic signal from a medical device. 
           [0017]      FIG. 8  depicts an embodiment for generating an eye diagram using a quasi-periodic signal where the eye diagram shows an excursion in the signal. 
           [0018]      FIG. 9  depicts an embodiment for displaying an expanded version of the quasi-periodic signal in response to a user instruction after viewing the eye diagram of  FIG. 8 . 
           [0019]      FIG. 10  depicts various display options for the eye diagram. 
           [0020]      FIG. 11  depicts an embodiment of display eyewear. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0021]    An embodiment will now be described with reference to  FIG. 3 . Medical device  10  is the same prior art device described previously with reference to  FIG. 1 . The output of medical device  10  is provided as an input to processing device  40 . In this particular example, the output is EKG data, but the same principles apply to any periodic data collected from a medical device. 
         [0022]    In one embodiment, processing device  40  is a computing device (such as a desktop, notebook, server, tablet, mobile device, or other computer) comprising a processor, memory, non-volatile storage (such as a hard disk drive or flash memory array), I/O connection (such as a USB connection) for communicating with a medical device, and an I/O connection for sending output to a display, printer, or other device. Optionally, processing device  40  can itself include a display (as might be the case if processing device  40  is a tablet or mobile device). Processing device  40  comprises software code for performing the functions described herein. 
         [0023]    Processing device  40  receives the periodic signal generated by medical device  10  and generates an output  50  that comprises an eye diagram of the signal by superimposing one period of the signal on top of another period of the signal, and so on. One of ordinary skill in the art will appreciate that output  50  is much easier to read and analyze than output  20  shown in  FIG. 1 . 
         [0024]    The periodic signal generated by medical device  10  can be either analog or digital. If the periodic signal is an analog signal, processing device  40  will perform analog-to-digital conversion using known techniques. If the periodic signal already is a digital signal, then no conversion is needed. 
         [0025]      FIG. 4  depicts a method for generating an eye diagram as shown in  FIG. 3 . Processing device  40  stores digital data in a buffer (step  200 ), where the buffer is contained within memory. The digital data is the data received from medical device  10  (if the data is digital) or is the digitized version of the data received from medical device  10  (if the data is analog). In the example of EKG data, the digital data represents the electrical impulses coming out of the heart Processing device  40  identifies peak values within a sequence of digital data stored in the buffer (step  210 ). This can be done simply by comparing all data points received within a time period t 1  that is several times larger than the expected period of a normal heartbeat. For example, t 1  can be 5 seconds. The peak value of each heartbeat will be approximately the same. Processing device  40  determines the number of data points B between peak values to determine the period of the data (step  220 ). The value of B will depend upon the patient&#39;s heart and the sampling rate of medical device  10  (if it generates digital data) or the sampling rate of the analog-to-digital converter of processing device  40  (if medical device  10  generates analog data). Processing device  40  optionally resamples the data to collect N data points per period (step  230 ). This might be desirable, for instance, if B is not a power of 2 (which is likely). For example, if B is 1157 (representing  1157  data points per period), one could choose N to be 1024, where 1024 data points are collected by resampling the B data points using known digital sampling techniques. Processing device  40  displays R periods of data on output  50  (step  240 ), where R is any integer value that represents the number of periods of data displayed in the eye-diagram at any given time. R optionally can be a very large number such that all of the data will be displayed on the eye-diagram. 
         [0026]    A baseline sequence representing one heart beat can be utilized. The baseline sequence can represent an ideal heart beat that is stored in non-volatile storage of processing device  40 , or the baseline sequence can be determined based on data collected from the patient&#39;s heart beat. For example, once processing device  40  has stored multiple periods of data for the patient&#39;s heart beat, it can determine the mean value for each data location within the sequence of data in one period over X periods of data. If X=50 and N=1024, for instance, processing device  40  will determine the mean value at each data location a i  (where i ranges from 1 to N or 1024 in this example) within 50 periods of data. The resulting sequence a will represent the baseline heartbeat. 
         [0027]    Once a baseline is determine, excursions can be automatically identified in the data obtained from medical device  10 . If we assume N is 1024, then each period will have 1024 data points, and the baseline sequence a i  will also have 1024 data points. A threshold L can be set, where L is a percentage of deviation. Each data point d hi  (where h ranges from 1 to T and T represents the number of periods of data captured to date, and i ranges from 1 to N, and i represents the location within the sequence as is the case with a i ) is compared to a i . If d hi  is 1% greater or less than a i , then d hi  represents an excursion. 
         [0028]    All data points representing excursions are recorded or flagged by processing device  40 . For example, processing device  40  can maintain a data structure for each data point d hi  that includes a flag bit, where a 0 represents no excursion and a 1 represents an excursion. In the alternative, processing device  40  can maintain a list of each data point d hi  that is an excursion. 
         [0029]    An embodiment is now shown in  FIG. 5 .  FIG. 5  is similar to  FIG. 3  except output  50  shows an graphical excursion  60  in one period of the signal. Graphical excursion  60  represents a deviation from the “norm” as shown in the eye diagram and comprises data points d hi  that were determined to be excursions, for example, by using the method described above. One of ordinary skill in the art will understand that graphical excursion  60  is much easier to identify than it would have been in the traditional tracings on a scroll of paper or tracings displayed on a screen that scrolls in real-time. 
         [0030]    Optionally, when an excursion is identified, processing device  40  can generate alert  70 . Alert  70  can appear on the display as part of output  50 , or it can be sent over email, SMS or MMS message, a phone call, a web-based message, etc. Processing device  40  can generate alert  70  based on any of the following: identification of an excursion as described above; statistically significant deviation from the mean value of the periodic signal at that location within the period; significant deviation from the expected value of the signal for a healthy individual; or a value above a pre-determined threshold specified by the user or programmed into processing device  40 . 
         [0031]    Optionally, processing device  40  can enable a user to request more information regarding graphical excursion  60  or any other portion of the eye diagram contained in output  50 . Such requests can be made through a mouse click on a display, through a keyboard, or using a voice command. 
         [0032]    If a user requests further information regarding graphical excursion  60  (such as by clicking on it using a mouse and a display), then optionally a traditional view will be created as shown in  FIG. 6 . 
         [0033]    In  FIG. 6 , processing device  40  generates output  70 , which resembles a traditional display of periodic signal. Graphical excursion  60  is shown, and the selected period  80  in which graphical excursion  60  appears is highlighted for the user, such as by drawing a box around the relevant portion of the signal as shown in  FIG. 6 , altering the color or brightness of that portion of the signal, or otherwise changing the appearance of that portion of the signal. The amount of data to be displayed before and after the excursion can be user controlled. Less amount of data display can lead to faster viewing whereas larger amount of data can be slower and appear cluttered on a limited viewing screen. 
         [0034]    One of ordinary skill in the art will understand that this combination of the prior art medical devise with the prior art eye diagram technique yields an invention that will enhance the ability of doctors and other medical professionals to analyze periodic signal from medical devices, such as EKG or ECG data, and to quickly identify any troublesome excursions in the data. 
         [0035]    The embodiments described thus far have utilized periodic signals generated by medical device  10 . Many of the same principles can be applied to quasi-periodical signals generated by medical device  15 . A quasi-periodic signal is a signal that represents measurements that are not periodic by nature (such as blood pressure, weight, blood sugar, etc.) but which are captured on a periodic basis (such as a measurement taken daily at 8 am or every few hours in a day). 
         [0036]    An embodiment is shown in  FIG. 7 . In  FIG. 7 , medical device  15  captures data from a patient that is not periodic in nature. Examples of medical device  15  include a scale to measure weight, a sphygmomanometer to measure blood pressure, a glucometer to measure blood sugar levels. 
         [0037]    Medical device  15  transmits data to processing device  40 , which is the same processing device  40  described with reference to other embodiments. Processing device  40  records the data, which in this example, comprises date/time and value information. For example, if medical device  15  is a scale, the data might be: 5-28-13 at 0801, 155 pounds. Over time, processing device  40  organizes the data into quasi-periodic groups. For instance, if processing device  40  receives a certain type of reading at approximately the same time each day, it will organize the data into a data structure and can optionally generate output  55  that depicts the readings of, for example, a patient&#39;s weight at 8 am on a daily basis. Even if the data is not obtained on a completely regular basis, for example at 8 am on one day, 10 am on another day etc., the dataset will still be assumed to be quasi-periodic. When the number of readings becomes too large to display on a single screen, the data can be shown as an eye-diagram as shown in  FIG. 7 . 
         [0038]    As with previous embodiments, a baseline can be generated (for example, by averaging the first F values), and processing device  40  can identify excursions from the baseline. The same methodology described previously can be used. This is depicted in  FIG. 8 , where graphical excursion  60  is shown in output  75 . 
         [0039]    With reference to  FIG. 9 , as with previous embodiments, a user can request further information about graphical excursion  60 , and once this occurs, the graphical excursion  60  and data that preceded and followed the graphical excursion will be displayed as output  75 , and the graphical excursion  60  can be highlighted for the user. 
         [0040]      FIG. 10  depicts various mechanisms for a user to view output  50 , output  55 , output  70 , output  75 , and other output that can be utilized for the embodiments described previously with reference to  FIGS. 3-9 . These mechanisms include a display  100  (such as an LCD), mobile device  110  (such as a tablet or mobile phone), and eyewear  120 . 
         [0041]      FIG. 10  depicts an example of eyewear  120 . Eyewear  120  comprises lenses  122  and frame  121  (just as with normal glasses). But it also includes display unit  130  and processing and transmission unit  140  (embedded within the frame  121 ). 
         [0042]    An example of eyewear  120  was recently announced by Google as the “Google Glass” product. Eyewear  120 , such as the Google Glass, comprises a display unit  130  that displays data that you could otherwise display on an LCD or other display. Display unit  130  can be used to display the eye diagrams discussed previously. 
         [0043]    The possible uses of eyewear  120  by physicians in conjunction with the display of periodic signals discussed above are numerous. For example, a physician could: (a) view a periodic signal during a patient examination, during a remote consultation, or during a collaborative session with a fellow physician (e.g., two physicians viewing the same EKG); (b) look at the patient in the physician&#39;s office while the display unit  130  displays a periodical signal; or (c) apply physical pressure to the patient or perform other techniques or tests and get instant visual feedback regarding the effect on heartbeat, etc. 
         [0044]    References to the present invention herein are not intended to limit the scope of any claim or claim term, but instead merely make reference to one or more features that may be covered by one or more of the claims. Materials, processes and numerical examples described above are exemplary only, and should not be deemed to limit the claims. It should be noted that, as used herein, the terms “over” and “on” both inclusively include “directly on” (no intermediate materials, elements or space disposed there between) and “indirectly on” (intermediate materials, elements or space disposed there between). Likewise, the term “adjacent” includes “directly adjacent” (no intermediate materials, elements or space disposed there between) and “indirectly adjacent” (intermediate materials, elements or space disposed there between). For example, forming an element “over a substrate” can include forming the element directly on the substrate with no intermediate materials/elements there between, as well as forming the element indirectly on the substrate with one or more intermediate materials/elements there between.