JP7614813B2 - Biological signal processing device and method performed by the biological signal processing device - Google Patents

Description

The present invention relates to a biological signal processing device and a method executed by the biological signal processing device , and more particularly to a biological signal processing device that handles data measured for sleep evaluation and a method executed by the biological signal processing device .

Sleep Apnea Syndrome (SAS) is of growing social interest. A definitive diagnosis of SAS requires a polysomnography (PSG) test, in which multiple sensors are attached to the subject to measure breathing and body movements while sleeping.

Measurements using PSG tests take a long time, resulting in a large amount of measurement data. For this reason, devices and systems that provide a function for efficiently evaluating data measured using PSG tests are known. For example, Patent Document 1 discloses a system that has an analysis means for determining the Apnea Hypopnea Index (AHI).

JP 2019-506920 A

Although the system described in Patent Document 1 is useful, there is a problem in that the system provides little information based on measurement data and is therefore not suitable for multifaceted consideration.

The present invention aims to provide a biosignal processing device and a method executed by the biosignal processing device that are capable of providing multifaceted information according to the user's wishes from data measured for sleep evaluation.

The above-mentioned object can be achieved by a biological signal processing device that handles measurement data measured for sleep evaluation, characterized in that it has a detection means for detecting a predetermined event related to sleep apnea syndrome (SAS) from the measurement data, and a control means for causing a display device to display a screen having an area for displaying a list of information related to the detected events by subject's body position, and an area for displaying information related to the detected events in more detail than the list display for a specific body position selected by the user.

According to the present invention, it is possible to provide a biosignal processing device and a method executed by the biosignal processing device that are capable of providing multifaceted information according to the user's wishes from data measured for sleep evaluation.

1 is a block diagram showing an example of a functional configuration of a biological signal processing apparatus according to an embodiment; FIG. 11 is a diagram showing an example of a waveform editing screen provided by the biological signal processing apparatus according to the embodiment. 4 is a flowchart relating to the operation of the biological signal processing apparatus according to the embodiment. 13A and 13B are diagrams showing an example of a display of a summary screen in an auxiliary information area of a waveform editing screen according to an embodiment. 13A and 13B are diagrams showing another display example of the summary screen in the auxiliary information area of the waveform editing screen according to the embodiment. 13A and 13B are diagrams illustrating an example of a histogram screen displayed in an auxiliary information area of the waveform editing screen according to the embodiment. 13A and 13B are diagrams showing another display example of a histogram screen in the auxiliary information area of the waveform editing screen according to the embodiment. 13A to 13C are diagrams showing examples of display of a histogram screen by position in the auxiliary information area of the waveform editing screen according to the embodiment.

The present invention will be described in detail below based on an exemplary embodiment with reference to the attached drawings. Note that the embodiment described below does not limit the present invention in any sense. Furthermore, not all of the configurations described in the embodiments are essential to the present invention. Furthermore, configurations included in different embodiments may be combined or replaced, except when clearly impossible or denied. Furthermore, in order to avoid redundant explanations, the same reference numbers are used throughout the attached drawings to the same or similar components.

Figure 1 is a block diagram showing an example of the functional configuration of a biosignal processing device 100 according to this embodiment. The biosignal processing device 100 can be realized, for example, by a programmable processor executing an application program that realizes the operations described below. Therefore, the biosignal processing device can be implemented in general electronic devices having a programmable processor, such as a personal computer.

In the following explanation, the biosignal processing device 100 will handle data measured and recorded by a simple PSG test device (also called a screening device). This is because simple PSG tests are frequently performed for measurements aimed at sleep evaluation. However, the present invention can also be implemented in a biosignal processing device that handles data measured by a PSG test that is not a simple test.

The data measured by the simplified PSG testing device may vary depending on the device, but in this embodiment, at least nasal or oral/nasal breathing (pressure) is measured as data related to breathing, and the type of body position (supine position) is measured as data related to the subject's movement. In addition, data on percutaneous arterial oxygen saturation (SpO2) is also measured. Other items such as abdominal and chest respiratory effort and temperature during nasal or oral/nasal breathing may also be measured.

The control unit 110 has a programmable processor, ROM, and RAM, and realizes the processing of the biosignal processing device 100, including the waveform editing processing described below, by loading programs stored in the ROM and the recording unit 130 into the RAM and executing them. The control unit 110 also executes processing in response to the operation of the operation unit 160, thereby enabling the user to interactively operate the biosignal processing device 100.

The external I/F 120 is an interface for the biosignal processing device 100 to communicate with an external device in a wired and/or wireless manner. The biosignal processing device 100 can acquire measurement data to be processed from an external device through the external I/F 120. The external I/F 120 can have a configuration conforming to one or more standards for communication between devices, such as USB, wireless LAN, wired LAN, Bluetooth (registered trademark), etc.

The recording unit 130 is a device for holding measurement data and the like, and may be an internal storage device such as an SSD or HDD, and/or a removable storage device such as a USB memory or memory card. The control unit 110 records data in the recording unit 130 and reads out data recorded in the recording unit 130.

The display unit 150 is a display device such as a liquid crystal display (LCD), and displays the user interface (GUI) of the biosignal processing device 100, measurement data, subject information, etc. The display unit 150 may be an external display device.

The operation unit 160 is a general term for input devices such as a keyboard, a pointing device, a touch panel, a switch, and a button that allow the user to input instructions to the biosignal processing device 100. If the display unit 150 is a touch display, the software keys displayed on the display unit 150 form part of the operation unit 160.

In this specification, operations on buttons, switches, menus, text boxes, etc. included in a graphical user interface (GUI) screen are pre-associated with operations on each input device. Unless otherwise specified, this association may be similar to the association adopted in a general operating system.

Figure 2 is a diagram showing an example of a screen (waveform editing screen 200) on which the biosignal processing device 100 displays measurement data, provides various information obtained from the measurement data, and provides a waveform editing function. The waveform editing function is a function for identifying measurement sections (also called artifact sections) in the measurement data that are unreliable or unnecessary, and for correcting the automatic analysis results of artifact sections and various events.

The waveform editing screen 200 is displayed on the display unit 150 by the biosignal processing device 100 executing a specific application program. Note that operations for starting an application and for calling up the waveform editing screen 200 after starting the application are similar to those generally performed on a personal computer, etc., and therefore details are omitted.

The waveform editing screen 200 has a list area 201, an auxiliary information area 202, and a waveform area 203. The size of each area and whether it is displayed or not may be changeable. Furthermore, the size of one area may change in conjunction with a change in the size of another area, or the size of one area may be changeable independently of the size of the other areas. In the latter case, multiple areas may be displayed in a superimposed manner.

The list area 201 is configured so that the display contents can be switched using tabs. In this embodiment, as an example, the display can be switched between an event list, a registered waveform list, and a task list. The event list is a list for searching for events assigned by the subject or measuring equipment, and for registering new events. The registered waveform list is a list of waveforms registered in response to events, etc. The task list is a list that displays task items corresponding to the steps to be executed in waveform editing.

The auxiliary information area 202 is an area that displays an auxiliary information screen that displays various information useful for diagnosis obtained from the measurement data, a setting screen for the display of the waveform area 203, a screen that displays information about the device that measured the data, and the like. The screen displayed in the auxiliary information area 202 can be switched by selecting tab 202A. The auxiliary information screens include a trend screen that reduces the entire measurement interval to a single screen, a summary screen that consolidates information on the number of times an event occurs, and a histogram (graph) screen that displays the frequency of event occurrence.

The waveform area 203 is an area that displays the measurement data along the time axis and accepts waveform editing operations for the measurement data. In addition to the measurement data, the waveform area 203 displays events registered by the subject during measurement, events and artifact sections assigned by automatic analysis, and events and artifact sections set by the user of the biosignal processing device 100 using the waveform editing function.

Figure 3 is a flowchart of the operation of the biosignal processing device 100. The control unit 110 can execute the operation shown in Figure 3 in response to an instruction from the recording unit 130 to read measurement data while an application is running.

In S301, the control unit 110 reads out measurement data from a measurement data file stored in the recording unit 130, for example, a file designated by the user through a file selection GUI. The read-out measurement data is temporarily stored in a buffer memory such as the RAM of the control unit 110. Note that the measurement data can be read in predetermined processing units, and does not have to be read all at once.

In S303, the control unit 110 applies a detection process for events and artifact sections to the measurement data. In this detection process, the control unit 110 detects SAS events (apnea events and hypopnea events) and their classification, oxygen desaturation events, body movement events, and artifact sections (sensor improper attachment sections, pre-sleep sections, wake-up sections, etc.) based on predetermined criteria. The control unit 110 stores the detected events and their associated information (occurrence time, duration, classification, section start time, end time, type, etc.) in association with the measurement data. The control unit 110 also calculates predetermined indices (AHI, ODI, etc.) to be displayed in the auxiliary information area 202 (described later) based on the detection results and measurement data, and stores them in association with the measurement data.

In S305, if there is a user instruction, the control unit 110 provides a waveform editing function through the waveform editing screen 200, and accepts editing (deletion, change of type, change of period, etc.) of the events and sections automatically detected in S303, and addition of user events. The control unit 110 reflects the waveform editing results in the automatic detection results.

In S307, the control unit 110 updates the events detected in S303, their associated information, indexes, etc., by reflecting the waveform editing results. Various numerical values used to display the summary screen, histogram screen, etc. described below are either calculated by automatic detection in S303 or updated in S307.

FIG. 4 shows a state in which the summary screen is displayed in the auxiliary information area 202 of the waveform editing screen 200.
The summary screen has a detail display area 2020 and a comparison area by body position 2025. One or more of apnea/hypopnea, SpO2 and pulse rate, body movement, and user events can be displayed in the detail display area 2020, and items for which the corresponding checkboxes of the display item checkboxes 2026 are in an ON state are displayed in the detail display area 2020. In the example of Fig. 4, all the checkboxes are in an ON state.

The display item check boxes 2026 further include a check box for switching whether or not the position-specific comparison area 2025 is displayed. In this case, the check box is ON, so the position-specific comparison area 2025 is displayed.

The aggregation target interval selection menu 2021 is a GUI element for setting the interval of measurement data for which a summary is to be aggregated. A combo box is used here, and all time, waveform display interval, and specified range can be set. All time refers to the entire measurement interval from the start to the end of measurement. The waveform display interval refers to the interval displayed in the waveform area 203. The specified range refers to a range of the entire interval that is separately specified. Figure 4 shows the state where all time has been selected.

In addition, a check box 2022 can be used to specify whether or not to exclude a section set as an artifact section from the section set in the tabulation section selection menu 2021. The artifact section is, for example, a section where the sensor is not properly attached, a section before falling asleep, or a section when waking up, and is set by automatic analysis or user instruction.

The posture specification menu 2023 is a GUI element for limiting the measurement data for which values to be displayed in the detailed display area 2020 are calculated, by posture. Here, it is possible to set any of the following postures: full body position, supine position, left lateral position, right lateral position, prone position, standing/sitting position, and total lateral position.

When "Total position" is set, the position is not limited. When other options are set, only the measurement data while the set position is detected is collected. When "Side-lying position total" is set, the measurement data while either the right lateral position or the left lateral position is detected is collected. It has been pointed out that the frequency of occurrence of OSA (obstructive type), which is the most common type of apnea and hypopnea, differs between the supine and lateral positions. Therefore, by making it possible to collect data from the right lateral and left lateral positions together, it becomes easier to compare with the supine position.

The comparison area by body position 2025 is an area that displays a list of the occurrence frequency of SAS events (apnea/hypopnea events and oxygen desaturation (ODI) events) and body movement events by body position. As an example, apnea and hypopnea (AH) events and apnea (A) events are displayed as apnea/hypopnea events. The body movement index is the occurrence frequency of body movement events. The decrease rate (%) that is regarded as an ODI event is a predetermined value (e.g., 3%).

Although not shown in the example of FIG. 4, the sum of the values for the left lateral position and the right lateral position may be displayed as a separate position value (lateral position total) in the position-by-position comparison area 2025. In particular, by displaying the lateral position total value adjacent to the supine position value, it is possible to easily compare the frequency of event occurrence in the supine position and the lateral position, which is useful.

The position comparison area 2025 also displays the percentage of each position in the section in which the position was detected. In the example of FIG. 4, the percentage of the supine position is 98.2%, and it can be seen that the subject was in the supine position for the majority of the measurement.

The detailed display area 2020 displays information according to the state of the display item checkboxes 2026, but when displaying a hypopnea/apnea event, more detailed information is displayed than what is displayed in the list in the comparison area by body position 2025.

Specifically, for each of apnea/hypopnea (AH), apnea (A), and hypopnea (H),
The number of events occurring per hour, total number of occurrences, maximum duration and occurrence time, and average duration (seconds) are displayed for each of the types total (total of obstructive, central, and mixed), obstructive (O), and central (C). In addition, the number of events occurring per hour and total number of occurrences are displayed for mixed (M). Note that obstructive, central, and mixed types are displayed only when an apnea/hypopnea event has such a classification.

In addition, for ODI, the number of events occurring per hour, total number of occurrences, maximum duration and occurrence time, and average duration are displayed for oxygen sum saturation events including those edited manually, and for oxygen desaturation levels of 2%, 3%, 4%, and 5% from automatic measurement results. Since there is no set percentage threshold for oxygen desaturation levels, a variety of needs can be met by displaying a list for different percentages.

For SpO2 and pulse rate, the maximum value and the time of occurrence, the minimum value and the time of occurrence, and the average value are displayed.

For the body movement index (number of body movement events per hour), the total number of occurrences, maximum duration and time of occurrence, and average duration are displayed.

A user event is an event added by the user of the biosignal processing device 100, and an event can be added for each measurement data. The detailed display area 2020 displays the number of occurrences per hour, total number of occurrences, maximum duration, occurrence time, and average duration for three types of user events: all user events and the top two types of user events by frequency. For the top two types of user events by frequency, the measurement data type is also displayed.

As explained above, the items displayed in the detailed display area 2020 can be changed by the user at will by operating the display item checkboxes 2026. The user can also change the aggregation period at will by operating the aggregation period selection menu 2021 and checkboxes 2022. Furthermore, it is also possible to display values limited to a specific body position by operating the body position designation menu 2023.

In this way, the summary screen of this embodiment is capable of displaying a list of the occurrence frequency of apnea/hypopnea events for each body position, while providing the user with more detailed information about specific body positions. In addition, since it is easy to compare cases where artifact sections are included in the measurement section with cases where they are not, it is also easy to understand the extent to which artifact sections affect apnea/hypopnea events and ODI events.

Figure 5(a) shows an example of a state in which the body movement and user events check boxes in the display item check boxes 2026 are unchecked in the display state shown in Figure 4, and the display in the detailed display area 2020 is limited to values in the supine position. Also, Figure 5(b) shows an example of a state in which the state of Figure 5(a) has been switched to displaying the total in the lateral position. Note that Figures 4 to 5(b) are intended to show examples of display states, and are not intended to display the same measurement data.

Figure 6 shows the state in which the histogram screen is displayed in the auxiliary information area 202 by operating tab 202A (Figure 2). The aggregation target interval selection menu 2021 and check boxes 2022 are the same as those in the summary screen. In addition, the display item check boxes 2027 are check boxes for selecting items to be displayed on the histogram screen, and are the same as the display item check boxes 2026 on the summary screen.

Here, it is possible to display histograms of apnea/hypopnea events, oxygen desaturation events (ODI events), user events, body movement events, and SpO2. Of these, for SpO2, a histogram is displayed showing the frequency of measured values within the target interval, and for other items (events), a histogram is displayed showing the time series frequency within the target interval and the frequency of occurrence of duration.

For SpO2, the frequency of measurements falling into the ranges of less than 50% and 50%-100% in 5% increments is displayed as a histogram, as a percentage of the total number of measurements. The percentages are also displayed numerically. In the example of Figure 6, it can be seen that values between 95% and 100% account for 74% of the measurements.

For various events, the horizontal axis represents the target interval (time range), and the number of times an event occurred in each of 60 divided intervals is displayed as a histogram. In addition, for duration, body movement events are divided into 10 ms intervals, and other events are divided into 1 s intervals, and the number of times the event occurred for each divided interval is displayed as a histogram. In this way, histograms showing the change over time in the frequency of event occurrence in the measurement interval and the frequency distribution of event duration are displayed so that events can be compared.

Note that the division units on the horizontal axis are all examples, and may be other values or may be changeable by the user. The scale (maximum value) of the vertical axis of the histogram for events is automatically adjusted according to the highest frequency, and may be changeable by the user. As SpO2 is a percentage, the scale of the vertical axis is fixed at 0-100%.

For apnea/hypopnea events and user events, the histograms for which are displayed can be changed by operating the corresponding menus 2028 and 2029.

In the apnea/hypopnea event menu 2028, it is possible to select from apnea/hypopnea (default value), obstructive apnea/hypopnea, central apnea/hypopnea, mixed apnea/hypopnea, apnea, obstructive apnea, central apnea, mixed apnea, hypopnea, obstructive hypopnea, and central hypopnea. Note that if classification into obstructive, central, and mixed is not performed, classification cannot be selected.
In addition, in the user event menu 2029, in addition to user events (all) (default value), it is possible to select measurement data to which one or more user events have been added.

Of the numerical values displayed on the summary screen and the frequencies displayed on the histogram screen, the values that can be displayed in the initial state can be calculated by the control unit 110 when the measurement data is first read, and stored, for example, in ROM. This allows for a more responsive screen display than if the values were calculated at the time of screen display.

Figure 7 is a diagram showing an example of a histogram display screen 202' that allows display by body position. In Figure 7, the same components as those in the histogram display screen 200 in Figure 6 are given the same reference numerals. The histogram display screen 202' has a body position designation menu 2023 described with reference to Figure 4. When a body position other than the overall body position is designated by the body position designation menu 2023, the control unit 110 displays the frequency of events that occurred in the designated body position on the histogram display screen. In Figure 7, the supine position is designated by the body position designation menu 2023, so the frequency distribution when the body position is supine is displayed for apnea/hypopnea events, oxygen desaturation events, user events, and body movement events.

In this way, being able to display the frequency of events occurring by position is useful because it makes it easy to understand the frequency of events occurring in a particular position and how that frequency changes over time.

In addition, when "all positions" is specified in the position specification menu 2023, the bars showing the frequency of each bin in the histogram may be displayed divided by position. FIG. 8 shows an example of the display of the bars when "all positions" is specified in the position specification menu 2023.

Figure 8 (a) shows an example of a histogram display of apnea/hypopnea events as an example of an event, with the bar display color being different depending on the body position. 2030 indicates the sitting and standing positions, 2032 indicates the supine position, and 2034 indicates the lateral position (right lateral position and left lateral position). Note that if events for multiple body positions exist in the same bin, a single bar may be displayed in a different color according to the frequency of occurrence for each body position, as shown in Figure 8 (b).

In this way, when displaying the frequency distribution for all body positions, by displaying the frequency for each body position in a way that makes it possible to understand at a glance which body positions are most likely to have events, as well as to distinguish invalid events (events that occur in the standing or sitting position).

The duration distribution can also be displayed by body position, in the same way as the occurrence frequency. This makes it easy to understand in which body position events with long durations (high severity) are likely to occur. Note that on a histogram display screen without a body position designation menu 2023 as in FIG. 6, a display showing the body positions as shown in FIG. 8 may also be displayed.

As described above, the biosignal processing device 100 of this embodiment is capable of providing multifaceted information according to the user's wishes from data measured by PSG testing. For example, the occurrence frequency of SAS events (apnea/hypopnea events and oxygen desaturation events) is displayed in a list by body position, while displaying further details of apnea/hypopnea events and oxygen desaturation events for a specific body position, as well as other information such as SpO2 and body movement. Therefore, it is possible to check detailed information about a specific body position while grasping each body position and the occurrence frequency of an event in the list display, which is easy to use.

In addition, by treating the left lateral position and the right lateral position as a single body position, it is easy to compare the supine position and the lateral position. Furthermore, since it is possible to easily switch whether or not to include the artifact section in the effective measurement section used when calculating the occurrence frequency of SAS events (SAS event index), the effect of the artifact section on the occurrence frequency of SAS events can be easily understood.

In addition, histograms showing the change in event occurrence frequency over time in the measurement section and the frequency distribution of event durations can be displayed in a way that allows comparison between events, allowing users to evaluate event occurrence trends from multiple perspectives.

The biosignal processing device according to the present invention can also be realized by executing a program (application software) that executes the display described with reference to Figures 2 to 6 on a commonly available electronic device capable of executing a program, such as a personal computer, smartphone, or tablet terminal. Therefore, such a program that causes a computer to function as the biosignal processing device according to the embodiment, and a storage medium that stores the program (optical storage medium such as a CD-ROM or DVD-ROM, magnetic storage medium such as a magnetic disk, semiconductor memory card, etc.), also constitute the present invention.

100... biosignal processing device, 110... control unit, 120... external I/F, 130... recording unit, 150... display unit, 160... operation unit

Claims (13)

A biological signal processing device that handles measurement data measured for sleep evaluation,
A detection means for detecting a predetermined event related to sleep apnea syndrome (SAS) from the measurement data;
a control means for controlling a display device to display a screen having an area for displaying a list of information on the detected events by body position of the subject, and an area for displaying information on the detected events in more detail than the list display for a specific body position selected by a user;
A biological signal processing device comprising: The biosignal processing device according to claim 1, characterized in that the subject's body positions include a lateral position that combines the left lateral position and the right lateral position. The biosignal processing device according to claim 2, characterized in that the supine position and the lateral position are adjacent to each other in the list display. The biosignal processing device according to claim 1, characterized in that in the detailed display area, a combination of all body positions can be selected as the specific body position. the events include apnea events, hypopnea events, and desaturation events;
the information about the event includes a number of occurrences of the event per hour ;
a switch is provided for determining whether or not a section set as an artifact section is included in the length of the measurement section used to calculate the number of events occurring per hour;
5. The biological signal processing device according to claim 1, wherein the biological signal processing device is a biological signal processing device. The biosignal processing device according to any one of claims 1 to 5, characterized in that information about the duration of the event is not displayed in the list display area, but is displayed in the detailed display area. The biosignal processing device according to claim 6, characterized in that the information about the duration includes the maximum duration, its occurrence time, and the average duration. The biosignal processing device according to any one of claims 1 to 7, characterized in that the control means further causes the display device to display a screen including a histogram showing the change over time in the occurrence frequency of the event. The biosignal processing device according to any one of claims 1 to 8, characterized in that the control means further causes the display device to display a screen including a histogram showing a frequency distribution of the durations of the events. 10. The biological signal processing device according to claim 8, wherein the control means causes the display device to display a screen including the histogram for a specific body position selected by a user. The biosignal processing device according to claim 8 or 9, characterized in that the control means generates the histogram so that the body position can be identified. A method for processing measurement data measured for sleep evaluation, the method being executed by a biological signal processing device, comprising:
A detection step of detecting a predetermined event related to sleep apnea syndrome (SAS) from the measurement data;
a control step of displaying on a display device a screen having an area for displaying a list of information related to the events detected in the detection step by body position of the subject, and an area for displaying information related to the events detected in the detection step in more detail than the list display for a specific body position selected by a user ;
The method according to claim 1, further comprising: A program that causes a computer to function as each of the means possessed by the biosignal processing device according to any one of claims 1 to 11.

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