Pulse analysis device and information display device

Abstract

This pulse analysis device (25) for analyzing a subject's pulse comprises a control unit (25). The control unit executes: a first analysis process (S31) for calculating, on the basis of a frequency analysis of the subject's pulse, LF indicating the magnitude of a low-frequency component of variations in the pulse, and HF indicating the magnitude of a high-frequency component of the variations in the pulse; a second analysis process (S32) for performing a Lorentz plot analysis of the pulse; and an index value calculation process (S33) for calculating a stress index value of the subject on the basis of the LF, the HF, and the analysis result of the Lorentz plot analysis.

Description

Pulse analyzer and information display device

[0001] This disclosure relates to a pulse analysis device and an information display device.

[0002] Pulse wave meters are known for measuring the pulse waves of subjects. For example, Patent Document 1 discloses a pulse wave measuring device in which the pulse wave sensor is less likely to tilt relative to the radial artery of the subject.

[0003] Japanese Patent Publication No. 2025-30808

[0004] It is desirable to obtain index values ​​indicating the subject's condition in real time or retrospectively, based on the measured pulse wave of the subject. Furthermore, it is desirable that the obtained index values ​​be displayed in a manner that makes it easy to understand the subject's condition.

[0005] This disclosure aims to provide a technology that can effectively acquire and / or present indicator values ​​representing the subject's condition.

[0006] A pulse analyzer is provided for analyzing the pulse of a subject, comprising a control unit, the control unit performing: a first analysis process for calculating LF, which indicates the magnitude of the low-frequency component of the pulse fluctuations, and HF, which indicates the magnitude of the high-frequency component of the pulse fluctuations, based on a frequency analysis of the subject's pulse; a second analysis process for performing a Lorentz plot analysis of the pulse; and an index value calculation process for calculating a stress index value of the subject based on the analysis results of LF, HF, and the Lorentz plot analysis.

[0007] A second aspect of the present disclosure is provided, an information display device for displaying information relating to a subject's pulse, comprising a control unit that performs an image generation process to generate an image to be displayed on a display unit, wherein the image includes: a region for displaying a waveform based on the subject's pulse wave; a region for displaying the time series progression of at least one index value based on the pulse wave; a first object for displaying information indicating an autonomic nervous system index value based on the pulse wave; and a second object for displaying information indicating an arterial system index value based on the pulse wave.

[0008] The technology of this disclosure makes it possible to obtain and / or present indicator values ​​that show the condition of a subject in an effective manner.

[0009] Figure 1 is a block diagram showing the configuration of a pulse wave analysis system, which is one embodiment of the system. Figure 2 is a flowchart of an example of the measurement and display operation performed by the pulse wave analysis system. Figure 3 is a flowchart of an example of the stress index value calculation process performed by the control unit. Figure 4 is an example of a scatter plot obtained by the control unit in the nonlinear analysis process. Figure 5 is an example of an image generated by the control unit in the image generation process. Figure 6 is another example of an image generated by the control unit in the image generation process. Figure 7 is another example of an image generated by the control unit in the image generation process. Figure 8 is another example of an image generated by the control unit in the image generation process. Figure 9 is another example of an image generated by the control unit in the image generation process.

[0010] <Embodiment> The pulse wave analysis system 100 (Figure 1) according to an embodiment of the present disclosure will be described with reference to Figures 1 to 9.

[0011] [Configuration of the pulse wave analysis system 100] As shown in Figure 1, the pulse wave analysis system 100 includes a pulse wave meter 10 and a terminal device 20. The pulse wave meter 10 and the terminal device 20 are connected in a manner that enables communication by wire or wireless.

[0012] The pulse wave meter 10 is a measuring device for measuring the pulse wave of a subject. In this embodiment, the pulse wave meter 10 measures the subject's pulse wave using a non-invasive method, such as tonometry. The pulse wave meter 10 may, for example, be equipped with a strain gauge (not shown), and the pressure pulse wave of the subject's radial artery may be measured using the strain gauge. The pulse wave meter 10 may be any measuring device capable of measuring the subject's pulse wave. The pulse wave meter 10 is not limited to a device that performs measurement using a non-invasive method, nor is it limited to a device that performs measurement based on tonometry.

[0013] The terminal device 20 also serves as a control device for controlling the operation of the pulse wave meter 10, an analysis device for analyzing the pulse waves measured by the pulse wave meter 10, and a display device for displaying the pulse waves measured by the pulse wave meter 10. The terminal device 20 may be configured as part of a general-purpose device such as a tablet terminal, smartphone, or personal computer. Alternatively, the terminal device 20 may be configured as a dedicated device.

[0014] As shown in Figure 1, the terminal device 20 includes a communication unit 21, an input unit 22, a display unit 23, a storage unit 24, and a control unit 25 (an example of a "pulse analyzer" or "information display device"). In addition, the terminal device 20 may also include an audio output unit (not shown; specifically, a speaker, for example) that outputs predetermined sounds according to the control of the control unit 25.

[0015] The communication unit 21 is a communication interface for wired or wireless communication between the pulse wave meter 10 and the terminal device 20. The communication method for wired communication and the communication method for wireless communication are arbitrary. The communication unit 21 may be configured to perform either wired or wireless communication.

[0016] The input unit 22 is a device that receives operation input from the user of the pulse wave analysis system 100 (i.e., a person who intends to obtain information about a subject's pulse wave using the pulse wave analysis system 100; specifically, for example, a doctor, nurse, caregiver, or the subject themselves), and transmits information indicating said operation input to the control unit 25. Specifically, the input unit 22 may be, for example, a keyboard or mouse.

[0017] The display unit 23 is a device that displays an image based on the control instructions of the control unit 25. Specifically, the display unit 23 may be, for example, a liquid crystal display. The input unit 22 and the display unit 23 may be configured as a single unit. Specifically, for example, the input unit 22 and the display unit 23 can be configured as a single unit using a touch panel.

[0018] The memory unit 24 is a storage device that stores various data necessary for the operation of each part of the terminal device 20. The memory unit 24 may be any storage device and may include non-volatile memory such as ROM and volatile memory such as RAM.

[0019] The storage unit 24 stores at least an application program AP (hereinafter simply referred to as "app AP"). The app AP is a program that describes the processing related to pulse wave analysis and output of analysis results. The app AP may also include a program that describes the processing related to user registration and user authentication functions (e.g., password-based login authentication).

[0020] The storage unit 24 may store user information UI and / or log data LD. User information UI may include, for example, "information for identifying (and authenticating) the user" such as the user ID, name, and login password of the pulse wave analysis system 100, and "user-configurable setting information" such as the design of the display screen, whether or not to display various parameters (various index values), and / or the display position. Log data LD may include at least one of log data of the pulse wave itself acquired from the pulse wave meter 10 in the past, and log data of parameters (index values) obtained by analyzing the pulse wave. The log data may be stored in a format that allows the subject being measured and / or the user of the terminal device 20 to be identified.

[0021] The control unit 25 is a control device that comprehensively controls the terminal device 20. The control unit 25 may be composed of, for example, a CPU, an MPU, etc. The control unit 25 executes various processes described in the application AP by reading and executing the application AP stored in the storage unit 24. Details of the various processes will be described later.

[0022] [Operation of the Pulse Wave Analysis System 100] An example of the measurement and display operation in which the pulse wave analysis system 100 measures the pulse wave of a subject using the pulse wave meter 10 and displays various information acquired based on the measurement on the display unit 23 is as follows. The measurement and display operation described below is realized by the control unit 25 reading and executing one or more applications AP stored in the storage unit 24.

[0023] As shown in the flowchart in Figure 2, the measurement and display operations performed by the pulse wave analysis system 100 include a measurement step S1, an information calculation step S2, a stress index value calculation step S3, an image generation step S4 (an example of "image generation processing"), and a display step S5.

[0024] [Measurement Step S1] In measurement step S1, the pulse wave meter 10 measures the pulse wave of the subject. The pulse wave meter 10 sends the pulse wave data acquired by the measurement to the control unit 25 via the communication unit 21.

[0025] [Information Calculation Process S2] In the information calculation process S2, the control unit 25 calculates various types of information (e.g., waveform, index value, etc.) based on the pulse wave data received from the pulse wave meter 10. The types of information calculated by the control unit 25 can be set arbitrarily, but specifically, they may include at least one of the following. Note that each of the following types of information can be calculated by any known method, so a detailed explanation of the calculation method will be omitted. The index values ​​(4) to (10) below are examples of "at least one index value based on pulse waves" and are also examples of "arterial system index values".

[0026] (1) Pulse wave data: Data of a waveform indicating the state of change in arterial pressure according to the heartbeat (the pulsation of the heart) of the subject. (2) First derivative wave (velocity pulse wave) data: Data obtained by differentiating the pulse wave data once. (3) Second derivative wave (acceleration pulse wave) data: Data obtained by differentiating the pulse wave data twice. (4) R-R interval: The time interval between heartbeats. For example, it can be calculated as the reciprocal of the number of heartbeats per minute (BPM). The detection of arrhythmia, respiratory rate, stress index value, etc. can be estimated from the variation of the R-R interval. (5) SNR (Signal Noise Ratio): A numerical value representing the stability of pulse wave measurement. The higher the value, the higher the stability of pulse wave measurement. (6) PW50 (Peak Width 50%): The peak half-value width (time) of the first derivative wave. The smaller the value, the higher the ejection ability of the heart. (7) rAI (radial Augmentation Index): The ratio of the peak (P1) of the ejection wave to the peak (P2) of the reflected wave of the pulse wave. The value becomes larger as the blood vessels become stiffer and arteriosclerosis progresses. (8) aoPWV (aortic Pulse Wave Velocity): An estimated value of the aortic pulse wave propagation velocity. The value becomes larger as arteriosclerosis progresses. (9) Vascular Age: The value becomes larger as the blood vessels become stiffer and arteriosclerosis progresses. (10) CBP (Central Blood Pressure): Central blood pressure, that is, the blood pressure at the origin of the aorta.

[0027] The control unit 25 stores the calculated respective information in the storage unit 24.

[0028] [Stress index value calculation step S3] In the stress index value calculation step S3, the control unit 25 calculates a stress index value indicating the state of the autonomic nervous system of the subject (more specifically, the degree of stress felt by the subject) based on the pulse wave data received from the pulse wave meter 10. Specifically, for example, the control unit 25 calculates the stress index value according to the following procedure.

[0029] As shown in the flowchart of FIG. 3, the calculation of the stress index value executed by the control unit 25 includes a frequency analysis step S31 (an example of "first analysis processing") for performing frequency analysis of the pulse wave, a non-linear analysis step S32 (an example of "second analysis processing") for performing non-linear analysis of the pulse wave, and a calculation step S33 (an example of "index value calculation processing") for calculating the stress index value of the subject.

[0030] In the frequency analysis step S31, the control unit 25 performs Fourier transform of the sphygmogram, calculates the power spectrum, LF (Low Frequency) indicating the magnitude of the low-frequency component of the subject's heart rate variability, HF (High Frequency) indicating the magnitude of the high-frequency component of the subject's heart rate variability, and LF / (LF + HF). The specific frequency bands of LF and HF may be defined by general definitions in pulse wave analysis. For example, LF may indicate the magnitude of frequency components less than 0.15 Hz, and HF may indicate the magnitude of frequency components of 0.15 Hz or more. More specifically, LF may indicate the magnitude of frequency components of 0.04 Hz or more and less than 0.15 Hz, and HF may indicate the magnitude of frequency components of 0.15 Hz or more and less than 0.4 Hz.

[0031] LF is an index value indicating the activity levels of both the sympathetic nerve and the parasympathetic nerve of the subject, and the larger LF is, the higher the activity levels of the sympathetic nerve and the parasympathetic nerve are indicated. HF is an index value indicating the activity level of the parasympathetic nerve of the subject, and the larger HF is, the higher the activity level of the parasympathetic nerve is indicated. LF / (LF + HF) is an index value indicating the activity ratio of the sympathetic nerve in the entire autonomic nerve, and the higher LF / (LF + HF) is, the higher the activity ratio of the sympathetic nerve is, in other words, the more stress the subject is feeling.

[0032] Since the power spectrum, LF, HF, and LF / (LF + HF) can be calculated by any known method, a specific description of the calculation method is omitted.

[0033] In the nonlinear analysis step S32, the control unit 25 performs a Lorentz plot analysis to create a scatter plot SD (Figure 4) and calculates the CSI (Cardiac Sympathetic Index) and CVI (Cardiac Vagal Index).

[0034] In the scatter plot SD shown in Figure 4, the horizontal axis represents the R-R interval, which is the time interval between the Nth pulse and the (N+1)th pulse, and the vertical axis represents the R-R interval, which is the time interval between the (N-1)th pulse and the Nth pulse. CSI is the ratio of the ellipse length L to the ellipse thickness T (= T / L) in the scatter plot SD. CSI is an index value indicating the activity level of the sympathetic nervous system; a larger value indicates a higher activity level of the sympathetic nervous system. CVI is the product of the ellipse length L and the ellipse thickness T (= T × L). CVI is an index value indicating the activity level of the parasympathetic nervous system; a larger value indicates a higher activity level of the parasympathetic nervous system.

[0035] Since the creation of scatter plot SD, calculation of CSI, and calculation of CVI can be performed by any known method, a detailed explanation will be omitted.

[0036] In calculation step S33, the control unit 25 calculates the stress index value SI based on LF / (LF+HF) calculated in frequency analysis step S31 and CSI and CVI calculated in nonlinear analysis step S32. The stress index value SI is an estimated value indicating the magnitude of stress felt by the subject, and a larger stress index value SI indicates that the subject is experiencing greater stress. Specifically, the control unit 25 calculates the stress index value SI by, for example, the following procedure.

[0037] The control unit 25 first performs scaling on the calculated LF / (LF+HF), CSI, and CVI, and sets the scaling value SV ＬＦ／（ＬＦ＋ＨＦ） , SV ＣＳＩ , and SV ＣＶＩ This obtains the scaling value SV, which is equal in scale to LF / (LF+HF), CSI, and CVI, which have different scales. ＬＦ／（ＬＦ＋ＨＦ） , SV ＣＳＩ , SV ＣＶＩ Converted to: Scaling value SV ＬＦ／（ＬＦ＋ＨＦ） , SV ＣＳＩ, SV ＣＶＩ Since they have equal scales, comparison and arithmetic operations between them can be significantly performed.

[0038] Next, the control unit 25 weights the scaling values SV ＬＦ／（ＬＦ＋ＨＦ） , SV ＣＳＩ , SV ＣＶＩ to calculate the index values IV ＬＦ／（ＬＦ＋ＨＦ） , IV ＣＳＩ , IV ＣＶＩ . Specifically, the index value IV ＬＦ／（ＬＦ＋ＨＦ） which is the product of the scaling value SV ＬＦ／（ＬＦ＋ＨＦ） and the weight W ＬＦ／（ＬＦ＋ＨＦ） , the index value IV ＣＳＩ which is the product of the scaling value SV ＣＳＩ and the weight W ＣＳＩ , and the index value IV ＣＶＩ which is the product of the scaling value SV ＣＶＩ and the weight W ＣＶＩ are calculated. The values of the weights W ＬＦ／（ＬＦ＋ＨＦ） , the weights W ＣＳＩ , and the weights W ＣＶＩ can be set as appropriate.

[0039] Next, the control unit 25 calculates the stress index value SI using the following formula (1), and stores the calculated value in the storage unit 24.

[0040] [Image generation step S4, display step S5] In the image generation step S4, the control unit 25 generates an image (image data) for displaying the various information calculated in the information calculation step S2 and the stress index value calculation step S3 on the display unit 24 based on the various information. In the display step S5, the control unit 25 displays the image generated in the image generation step S4 on the display unit 23.

[0041] The following describes specific embodiments of images generated by the control unit 25 in the image generation process S4 and displayed on the display unit 23 by the control unit 25 in the display process S5. In each specific embodiment, the content of the information contained in the image can be sequentially updated based on various information sequentially calculated by the control unit 25 in the information calculation process S2 and the stress index value calculation process S3. That is, the content of the image can change in real time in accordance with the measurement by the pulse wave meter 10 and the calculation of various information by the control unit 25. Operations on GUIs such as buttons and checkboxes included in each specific embodiment can be performed, for example, by operating a cursor via the input unit 22 if the display unit 23 is a liquid crystal display or the like. Alternatively, if the input unit 22 and the display unit 23 are integrated as a touch panel, operations can be performed, for example, by directly touching the GUI.

[0042] Figure 5 shows image IM1, which is an example of a specific embodiment. The control unit 25 generates image IM1 and displays it on the display unit 24 during the period when the pulse wave meter 10 is measuring the subject's pulse wave. Image IM1 includes regions AR101 to AR110.

[0043] Region AR101 is located above the vertical center of image IM1, excluding the area near the right edge. Graph G11, which displays the pulse wave waveform WF, the first derivative waveform (not shown), and the second derivative waveform (not shown), is located within region AR101. The horizontal axis of graph G11 represents time, and the vertical axis represents amplitude. Graph G11 is an example of a "region displaying waveforms based on the subject's pulse wave."

[0044] A pull-down button PB11 is located in the lower right corner of graph G11. When the pull-down button PB11 is operated, the control unit 25 changes the display width of graph G11 (i.e., the range of the horizontal axis; 5 [s] in Figure 5) to the width selected by the pull-down button PB11.

[0045] Region AR102 is located to the right of region AR101. Region AR102 contains the pressure pulse wave selection button B11, the first differential wave selection button B12, and the second differential wave selection button B13.

[0046] When the pressure pulse wave selection button B11 is operated, the control unit 25 switches the waveform displayed on graph G11 to the pressure pulse wave waveform WF. When the first derivative wave selection button B12 is operated, the control unit 25 switches the waveform displayed on graph G11 to the first derivative wave waveform. When the second derivative wave selection button B13 is operated, the control unit 25 switches the waveform displayed on graph G11 to the second derivative wave waveform. Figure 5 shows the state after the pressure pulse wave selection button B11 was last operated, and the control unit 25 is displaying the pressure pulse wave waveform WF on graph G11.

[0047] Region AR103 is located below region AR101. Region AR103 contains graph G12, which displays line graphs LG1 for the R-R interval, LG2 for SNR, LG3 for PW50, LG4 for rAI, and LG5 for aoPWV. The horizontal axis of graph G12 represents time, and the vertical axis represents the magnitude of each indicator value. Each line graph shows the pulse-by-pulse progression of the corresponding indicator value. Graph G12 is an example of a "region that displays the time-series progression of at least one indicator value based on pulse waves."

[0048] A pull-down button PB12 is located in the lower right corner of graph G12. When the pull-down button PB12 is operated, the control unit 25 changes the display width of graph G12 (i.e., the range of the horizontal axis; 30 [beats] in Figure 5) to the width selected by the pull-down button PB12.

[0049] Area AR104 is located to the right of area AR103. The index value display unit D11 is located in area AR104.

[0050] In the example shown in Figure 5, the indicator value display unit D11 displays the moving average values ​​of BPM, R-R interval, SNR, PW50, rAI, and aoPWV, respectively. The moving average interval for each moving average value is arbitrary and may be set for each indicator value.

[0051] Region AR105 is located to the right of region AR104. Checkboxes CB1 to CB5 are located in region AR105.

[0052] The checkbox CB1 is located to the right of the area on the indicator value display unit D11 that displays the moving average value of the R-R interval. The control unit 25 displays the line graph LG1 of the R-R interval on graph G12 when the checkbox CB1 is checked, and does not display the line graph LG1 of the R-R interval on graph G12 when the checkbox CB1 is unchecked.

[0053] The checkbox CB2 is located to the right of the area on the indicator value display unit D11 that displays the moving average value of SNR. The control unit 25 displays the SNR line graph LG2 on graph G12 when the checkbox CB2 is checked, and does not display the SNR line graph LG2 on graph G12 when the checkbox CB2 is unchecked.

[0054] The checkbox CB3 is located to the right of the area on the indicator value display unit D11 where the moving average value of PW50 is displayed. The control unit 25 displays the line graph LG3 of PW50 on graph G12 when the checkbox CB3 is checked, and does not display the line graph LG3 of PW50 on graph G12 when the checkbox CB3 is unchecked.

[0055] The checkbox CB4 is located to the right of the area on the indicator value display unit D11 that displays the moving average value of rAI. The control unit 25 displays the line graph LG4 of rAI on graph G12 when the checkbox CB4 is checked, and does not display the line graph LG4 of rAI on graph G12 when the checkbox CB4 is unchecked.

[0056] The checkbox CB5 is located to the right of the area on the indicator value display unit D11 that displays the moving average value of aoPWV. The control unit 25 displays the aoPWV line graph LG5 on graph G12 when the checkbox CB5 is checked, and does not display the aoPWV line graph LG5 on graph G12 when the checkbox CB5 is unchecked.

[0057] Region AR106 is located below region AR103 and to the left of the left-right center of image IM1. A record file name input unit IN11 is located in region AR106. The user can input a record file name into the record file input unit IN11, for example, via the input unit 22. The record file name will be described later.

[0058] Area AR107 is located to the right of area AR106. Area AR107 contains a record period selection unit RS (an example of a "record period selection unit"). In this specific example, the record period selection unit RS is a drum-roll type GUI. The record period will be discussed later.

[0059] Region AR108 is located to the right of region AR107. Region AR108 contains a systolic blood pressure input unit IN12 (an example of a "region where numerical values ​​are entered") and a diastolic blood pressure input unit IN13 (an example of a "region where numerical values ​​are entered"). The user can, for example, input the subject's systolic blood pressure value into the systolic blood pressure input unit IN12 and the subject's diastolic blood pressure value into the diastolic blood pressure input unit IN13 via the input unit 22. The control unit 25 stores the inputted systolic and diastolic blood pressure values ​​in the storage unit 24 and uses them to calculate CBP (central blood pressure) in the information calculation step S2. The inputted systolic and diastolic blood pressure values ​​may be measured by any method, such as using a widely used upper arm blood pressure monitor. Alternatively, the control unit 25 may calculate the systolic and diastolic blood pressure values ​​based on the measurement data from the pulse wave meter 10 and automatically input the calculated values ​​into the systolic blood pressure input unit IN12 and the diastolic blood pressure input unit IN13.

[0060] Area AR109 is located to the right of Area AR108. Area AR109 contains a stress system analysis result display button B14 (an example of an object for displaying information indicating autonomic nervous system index values ​​(first object)) and an arterial system analysis result display button B15 (an example of a second object for displaying information indicating arterial system index values).

[0061] When the stress system analysis result display button B14 is operated, the control unit 25 displays an image (specifically, for example, image IM3 described later) showing the results of the stress system analysis on the display unit 24. When the arterial system analysis result display button B15 is operated, the control unit 25 displays an image (specifically, for example, image IM2 described later) showing the results of the arterial system analysis on the display unit 24.

[0062] Area AR110 is located to the right of area AR109. Area AR110 contains the waveform display start button B16 and the record start button B17 (an example of an object for instructing the recording of information displayed in the image).

[0063] When the waveform display start button B16 is operated, the control unit 25 starts displaying various information in image IM1. For example, image IM1 can be displayed on the display unit 24 even when the pulse wave meter 10 has not measured the subject's pulse wave and the control unit 25 has not calculated various information about the subject. In this case, image IM1 does not include various waveforms that can be displayed on graph G11, various line graphs that can be displayed on graph G12, or various moving average values ​​that can be displayed on the index value display unit D11. In this state, when the waveform display disclosure button B16 is operated, the control unit 25 starts the measurement process S1 to measure the subject's pulse wave using the pulse wave meter 10, calculates various information in the information calculation process S2 and the stress index value calculation process S3, generates image IM1 containing the calculated information in the image generation process S4, and displays the generated image IM1 on the display unit 23 in the display process S5.

[0064] When the record start button B17 is operated, the control unit 25 starts recording various information contained in the image IM1. For example, if a user wants to record various information displayed by the image IM1 and save it as log data, they enter a record file name in the record file name input unit IN11, specify a record period by operating the record period selection unit RS, and then operate the record start button B17. As a result, the control unit 25 stores the various information displayed by the image IM1 (and consequently the information calculated by the control unit 25 in the information calculation process S2 and the stress index value calculation process S3) in the storage unit 24 over the specified record period, and makes it log data with the record file name entered in the record file name input unit IN1.

[0065] Figure 6 shows image IM2, which is another example of a specific embodiment. The control unit 25 switches the display content of the display unit 24 from image IM1 to image IM2 based on the operation of the arterial system analysis result display button B15 in image IM1. Alternatively, the control unit 25 may superimpose image IM2 on image IM1 as a pop-up screen based on the operation of the arterial system analysis result display button B15 in image IM1. Image IM2 includes regions AR201 to AR203.

[0066] Region AR201 is located approximately in the center of image IM2. Region AR201 contains graph G21 (an example of a "region for displaying average pulse waves") which displays the subject's average pulse wave waveform AWF, the average waveform AWF1 of the first derivative wave, and the average waveform AWF2 of the second derivative wave.

[0067] The average waveform AWF of the pressure pulse wave is a waveform that shows the average shape of multiple unit waveforms (i.e., waveforms corresponding to one heartbeat) included in the pressure pulse wave waveform WF acquired over a predetermined period. The average waveform AWF1 of the first derivative wave is a waveform that shows the average shape of multiple unit waveforms included in the first derivative wave waveform acquired over a predetermined period, and the average waveform AWF2 of the second derivative wave is a waveform that shows the average shape of multiple unit waveforms included in the second derivative wave waveform acquired over a predetermined period. The predetermined period may be any period, but in this example, it is the record period set via the record period selection unit RS. That is, in this example, the average waveform AWF of the pressure pulse wave, the average waveform AWF1 of the first derivative wave, and the average waveform AWF2 of the second derivative wave for one log data created by operating the record start button B17 are displayed on graph G21.

[0068] Region AR202 is located above region AR201. Region AR202 contains the pressure pulse wave selection button B21, the first differential wave selection button B22, and the second differential wave selection button B23.

[0069] When the pressure pulse wave selection button B21 is ON, the control unit 25 displays the average waveform AWF of the pressure pulse wave on graph G21, and does not display the average waveform AWF of the pressure pulse wave on graph G21 when the pressure pulse wave selection button B21 is OFF. When the first-order differential wave selection button B22 is ON, the control unit 25 displays the average waveform AWF1 of the first-order differential wave on graph G21, and does not display the average waveform AWF1 of the first-order differential wave on graph G21 when the first-order differential wave selection button B22 is OFF. When the second-order differential wave selection button B23 is ON, the control unit 25 displays the average waveform AWF2 of the second-order differential wave on graph G21, and does not display the average waveform AWF2 of the second-order differential wave on graph G21 when the second-order differential wave selection button B23 is OFF.

[0070] Area AR203 is located to the right of area AR201. Area AR203 contains an index value display unit D21 (an example of an area that displays information indicating arterial system index values).

[0071] In the example shown in Figure 6, the indicator value display unit D21 displays the mean and standard deviation of BPM, the mean and standard deviation of R-R interval, the mean SNR, the mean and standard deviation of PW50, the mean and standard deviation of rAI, the mean and standard deviation of aoPWV, the mean Vascular Age, and the mean CBP. Each mean value is the mean value over a predetermined period, and the standard deviation is the standard deviation over a predetermined period. The predetermined period can be any period, but in this specific example, it is the record period set via the record period selection unit RS. That is, in this specific example, the mean and standard deviation of each indicator value for one log data created by operating the record start button B17 are displayed on the indicator value display unit D21.

[0072] Figure 7 shows image IM3, which is another example of a specific embodiment. The control unit 25 switches the display content of the display unit 24 from image IM1 to image IM3 based on the operation of the stress system analysis result display button B14 in image IM1. Alternatively, the control unit 25 may superimpose image IM3 on image IM1 as a pop-up screen based on the operation of the stress system analysis result display button B14 in image IM1. Image IM3 includes regions AR301 to AR303.

[0073] Region AR301 is located in the upper left of image IM3. Region AR301 contains a power spectrum display unit D31 and an index value display unit D32.

[0074] The power spectrum display unit D31 displays the power spectrum calculated in the frequency analysis step S31. The index value display unit D32 displays LF, HF, and LF / (LF+HF) calculated in the frequency analysis step S31. The power spectrum, LF, HF, and LF / (LF+HF) are examples of "information indicating the analysis results of the frequency analysis." "Information indicating the analysis results of the frequency analysis" also includes other information that directly or indirectly indicates the analysis results of the frequency analysis.

[0075] Region AR302 is located in the upper right of image IM3. Region AR302 contains a scatter plot display unit D33 and an index value display unit D34.

[0076] The scatter plot display unit D33 displays the scatter plot SD calculated in the nonlinear analysis process S32. The index value display unit D34 displays the CSI, CVI, and ellipse thickness T calculated in the nonlinear analysis process S32. The scatter plot SD, CSI, CVI, ellipse thickness T, and ellipse length L are examples of "information indicating the analysis results of the Lorentz plot analysis." "Information indicating the analysis results of the Lorentz plot analysis" also includes other information that directly or indirectly indicates the analysis results of the Lorentz plot analysis.

[0077] Region AR303 is located in the lower center of image IM3. A stress index value display unit D35 is located in region AR303.

[0078] The stress index value display unit D35 displays the gauge chart in a manner corresponding to the stress index value SI calculated in the calculation step S33.

[0079] Figure 8 shows an example of image IM3 when the subject is in a relaxed state. At this time, the LF / (LF+HF) displayed on the indicator value display unit D32 and the CSI displayed on the indicator value display unit D34 are relatively small values, while the CVI displayed on the indicator value display unit D34 is a relatively large value. In the stress indicator value display unit D35, the needle of the gauge chart points towards the relaxed side.

[0080] Figure 9 shows an example of image IM3 when the subject is under stress. At this time, the LF / (LF+HF) displayed on the indicator value display unit D32 and the CSI displayed on the indicator value display unit D34 are relatively large values, while the CVI displayed on the indicator value display unit D34 is a relatively small value. In the stress indicator value display unit D35, the needle of the gauge chart points towards the stress side.

[0081] Based on the display in the stress index value display unit D35, the user can intuitively determine whether or not the subject is experiencing stress. Furthermore, based on the displays in the power spectrum display unit D31, index value display unit D32, scatter plot display unit D33, and index value display unit D34, the user can gain a more detailed understanding of the subject's autonomic nervous system state.

[0082] The advantageous effects of the pulse wave analysis system 100 of this embodiment are summarized below.

[0083] In the pulse wave analysis system 100 of this embodiment, the control unit 25 calculates the subject's stress index value SI using the HF and LF calculated by frequency analysis and the analysis results of the Lorentz plot analysis. Therefore, the pulse wave analysis system 100 of this embodiment can obtain an index value indicating the subject's condition with good accuracy. Specifically, the pulse wave analysis system 100 of this embodiment can calculate the stress index value SI with high accuracy.

[0084] In the pulse wave analysis system 100 of this embodiment, the control unit 25 performs scaling and weighting of LF, HF calculated by frequency analysis, and CVI, CSI obtained by Lorentz plot analysis in the calculation step S33. Therefore, the pulse wave analysis system 100 of this embodiment can calculate the stress index value SI with higher accuracy.

[0085] In the pulse wave analysis system 100 of this embodiment, the image IM1 generated by the control unit 25 in the image generation step S4 and displayed on the display unit 23 in the display step S5 includes a graph G11 that displays either the pressure pulse wave waveform WF, the first derivative wave waveform, or the second derivative wave waveform, a graph G12 that displays the time-series transition of various indicator values, a stress system analysis result display button B14, and an arterial system analysis result display button B15. Users of the pulse wave analysis system 100 can simultaneously view information indicating the subject's condition from multiple perspectives and switch the information display, thus easily grasping the subject's condition. Thus, the pulse wave analysis system 100 of this embodiment can present indicator values ​​indicating the subject's condition in a good manner by generating an image that includes an area for displaying a waveform based on the subject's pulse wave, an area for displaying the time-series transition of at least one indicator value based on the pulse wave, and at least one of a first object for displaying information indicating autonomic nervous system indicator values ​​based on the pulse wave and a second object for displaying information indicating arterial system indicator values ​​based on the pulse wave.

[0086] In the pulse wave analysis system 100 of this embodiment, the image IM2 generated by the control unit 25 in the image generation step S4 and displayed on the display unit 23 in the display step S5 includes a graph G21 that displays the average waveform AWF of the subject's pressure pulse wave, the average waveform AWF1 of the first derivative wave, and the average waveform AWF2 of the second derivative wave, and an index value display unit D21 that displays various index values. Users of the pulse wave analysis system 100 can simultaneously grasp the waveform and numerical information indicating the subject's condition, and easily understand the subject's condition.

[0087] <Modification> In the above embodiment, the following modified form can also be used.

[0088] In the stress index value calculation step S3 of the above embodiment, the control unit 25 may use LF / HF instead of LF / (LF+HF). Specifically in this case, for example, the control unit 25 calculates LF / HF instead of LF / (LF+HF) in the frequency analysis step S31. In the stress index value calculation step S33, the control unit 25 performs scaling processing using LF / HF instead of LF / (LF+HF) and calculates the scaled value SV ＬＦ／ＨＦ , SV ＣＳＩ , and SV ＣＶＩ The control unit 25 then obtains the scaling value SV ＬＦ／ＨＦ , SV ＣＳＩ , SV ＣＶＩ Weighting is applied to the index value IV ＬＦ／ＨＦ , IV ＣＳＩ , IV ＣＶＩ The following formula (2) is used to calculate the stress index value SI.

[0089] In the stress index value calculation step S3 of the above embodiment, the control unit 25 may calculate the stress index value SI using the following (Equation 3) instead of (Equation 1). Alternatively, the control unit 25 may calculate the stress index value SI using the following (Equation 4) instead of (Equation 2).

[0090] Equations (3) and (4) are calculation formulas for calculating the stress index SI using a weighted power mean, respectively. Note that when p = 1, equations (3) and (4) are equal to equations (1) and (2), respectively, and the stress index SI corresponds to the weighted arithmetic mean. When p = 2, the stress index SI corresponds to the weighted mean square. When p → 1, the stress index SI corresponds to the weighted geometric mean. When p → -1, the stress index SI corresponds to the weighted harmonic mean.

[0091] In the stress index value calculation step S3 of the above embodiment, the control unit 25 may use information other than CVI and CSI as analysis results of the Lorentz plot analysis to calculate the stress index value SI. Specifically, for example, RMSSD, which is the root mean square of the difference between adjacent R-R intervals, has a high correlation with the ellipse thickness T. Therefore, RMSSD can be used as an index value representing the activity level of the parasympathetic nervous system of the subject, either in place of CVI or together with CVI. In addition, for example, the area of ​​an ellipse obtained based on the scatter plot SD has a correlation with HF. Therefore, the area of ​​an ellipse can be used as an index value representing the activity level of the parasympathetic nervous system, either in place of CVI or together with CVI. Furthermore, for example, if the horizontal axis of the scatter plot SD is the x-axis, the vertical axis is the y-axis, and the intersection of the x and y axes is the origin, and the average distance m is the average distance along the y=x axis (i.e., the axis obtained by rotating the x-axis counterclockwise by 45°, or the axis obtained by rotating the y-axis clockwise by 45°) between each point plotted on the scatter plot SD and the origin, then the average distance m correlates with HF. Therefore, the average distance m can be used as an index value representing the activity level of the parasympathetic nervous system, either in place of or in conjunction with CVI. In addition, for example, a superellipse can be obtained based on the ellipse length L and ellipse thickness T, and index values ​​(width, length, etc.) based on the shape of the superellipse can be used as the analysis result of the Lorentz plot analysis. The area of ​​the ellipse obtained based on CVI, CSI, RMSSD, and scatter plot SD, the average distance m, and index values ​​based on the shape of the superellipse are examples of "numerical values ​​obtained as the analysis result of the Lorentz plot analysis."

[0092] In the stress index value calculation step S3 of the above embodiment, the control unit 25 performs both scaling and weighting for LF / (LF+HF), CSI, and CVI, but is not limited to this. It may perform only at least one of scaling and weighting.

[0093] The image generated by the control unit 25 in the image generation step S4 of the above embodiment can be modified as appropriate. For example, in image IM1, at least one of the elements (i.e., graphs, GUIs, display areas, etc.) arranged in each of regions AR101 to AR110 may be omitted. The number of waveforms, line graphs, etc. that can be selectively displayed in the graph can be changed as appropriate. The arrangement of regions AR101 to AR110 within image IM1 may also be changed. Multiple elements arranged in one region of regions AR101 to AR110 in image IM1 may be distributed and arranged in different regions. The same applies to images IM2 and IM3.

[0094] In the image generation step S4 of the above embodiment, the image IM3 generated by the control unit 25 may include an area in place of, or in addition to, the systolic blood pressure input unit IN12 and / or diastolic blood pressure input unit IN13, in which any numerical value can be input. The control unit 25 may store the numerical value input in the area in the storage unit 24, and may use it in the calculation of the index value in the information calculation step S2.

[0095] In the image generation step S4 of the above embodiment, the image IM3 generated by the control unit 25 does not necessarily have to include at least one of the power spectrum display unit D31, index value display unit D32, scatter plot display unit D33, and index value display unit D34. In this case as well, the user can understand in detail the state of the subject's autonomic nervous system based on the stress index value SI and at least one of the analysis results of the frequency analysis and the analysis results of the Lorentz plot analysis. Furthermore, the stress index value display unit D35 may display the stress index value SI as an arbitrary image such as an icon, in addition to or instead of a gauge chart, or it may be displayed as a numerical value. Gauge charts, arbitrary images, and numerical displays are examples of "information indicating the stress index value." "Information indicating the stress index value" also includes other information that directly or indirectly indicates the stress index value.

[0096] Furthermore, "information indicating arterial system index values" includes any information that directly or indirectly indicates arterial system index values. In addition, "information indicating autonomic nervous system index values" includes "information indicating the results of frequency analysis," "information indicating the results of Lorentz plot analysis," and "information indicating stress index values." "Information indicating autonomic nervous system index values" further includes any information that directly or indirectly indicates autonomic nervous system index values.

[0097] In the pulse wave analysis system 100, the terminal device 20 may be a device that displays pulse waves and the results of pulse wave analysis, and the pulse wave analysis may be performed by a separate control device. Specifically, for example, the control unit 25 may be divided into a first control unit that executes the information calculation process S2 and the stress index value calculation process S3, and a second control unit that executes the image generation process S4 and the display process S5, and the first control unit may be an external device separate from the terminal device 20. In this case, the memory unit of the external device stores an application for pulse wave analysis, and the external device performs pulse wave analysis by executing the application. The external device then transmits the analysis results to the terminal device 20. The terminal device 20 displays the analysis results received from the external device on the display unit 23.

[0098] In the pulse wave analysis system 100 of the above embodiment, the control unit 25 does not have to perform at least one of the information calculation step S2, the image generation step S4, and the display step S5. For example, if the control unit 25 does not perform any of the information calculation step S2, the image generation step S4, and the display step S5, but only performs the measurement step S1 and the stress index value calculation step S3, the control unit 25 of the pulse wave analysis system 100 functions as an analyzer that calculates the subject's stress index value based on the subject's pulse rate.

[0099] In the pulse wave analysis system 100 of the above embodiment, the control unit 25 may perform the stress index value calculation step S3 based on the heart rate obtained based on the measurement of a heart rate monitor (not shown) different from the pulse wave meter 10. In this disclosure and the present invention, "pulse" and "heart rate" are collectively referred to as "pulsation".

[0100] As long as the features of the present invention are maintained, the present invention is not limited to the embodiments described above, and other forms conceivable within the scope of the technical idea of ​​the present invention are also included within the scope of the present invention.

[0101] 10 Pulse wave meter; 20 Terminal device; 21 Communication unit; 22 Input unit; 23 Display unit; 24 Storage unit; 25 Control unit; 100 Pulse wave analysis system

Claims

1. A pulse analysis device for analyzing the pulse of a subject, comprising a control unit, wherein the control unit performs: a first analysis process for calculating LF, which indicates the magnitude of the low-frequency component of the pulse fluctuations, and HF, which indicates the magnitude of the high-frequency component of the pulse fluctuations, based on frequency analysis of the subject's pulse; a second analysis process for performing Lorentz plot analysis of the pulse; and an index value calculation process for calculating a stress index value of the subject based on the analysis results of LF, HF, and the Lorentz plot analysis.

2. The pulsation analyzer according to claim 1, wherein the control unit, in the index value calculation process, obtains a numerical value obtained as an analysis result of the Lorentz plot analysis, obtains LF / (LF+HF) or LF / HF based on LF and HF, and performs at least one of scaling the LF / (LF+HF) or LF / HF and the numerical value obtained as an analysis result of the Lorentz plot analysis, and weighting the LF / (LF+HF) or LF / HF and the numerical value obtained as an analysis result of the Lorentz plot analysis.

3. The numerical values obtained as the analysis results of the Lorentz plot analysis are CVI and CSI. When the control unit uses the acquired LF / (LF + HF) or LF / HF as X in the index value calculation process, the control unit scales the X, the CVI, and the CSI to the same scale to obtain SV Ｘ , SV ＣＶＩ , and SV ＣＳＩ , and acquires the obtained SV Ｘ , the SV ＣＶＩ , the SV ＣＳＩ , respectively, multiplies the weights W Ｘ , the weight W ＣＶＩ , the weight W ＣＳＩ to accumulate IV Ｘ , IV ＣＶＩ , IV ＣＳＩ , and calculates the stress index value by the following formula using the stress index value as SI The pulsation analysis device according to claim 2.

4. The pulsation analyzer according to any one of claims 1 to 3, wherein the control unit performs a display process to display the stress index value on the display unit.

5. The pulsation analyzer according to claim 4, wherein the control unit performs an image generation process to generate an image to be displayed on the display unit, and the image includes at least one of information showing the analysis results of the frequency analysis and information showing the analysis results of the Lorentz plot analysis, and information showing the stress index value.

6. The pulsation analyzer according to claim 5, wherein the image includes a spectrum which is information showing the results of the frequency analysis, a scatter plot which is information showing the results of the Lorentz plot analysis, and information showing the stress index value.

7. The pulse analysis apparatus according to claim 5 or 6, wherein the control unit generates a secondary image in the image generation process, and the secondary image includes: a region for displaying a waveform based on the pulse wave of the subject; a region for displaying the time series progression of at least one index value based on the pulse wave; and an object for displaying information indicating an autonomic nervous system index value based on the pulse, and the control unit displays the image on the display unit based on the selection of the object.

8. An information display device for displaying information relating to a subject's pulse, comprising a control unit that performs an image generation process to generate an image to be displayed on a display unit, wherein the image includes: a region for displaying a waveform based on the subject's pulse wave; a region for displaying the time series progression of at least one index value based on the pulse wave; a first object for displaying information indicating an autonomic nervous system index value based on the pulse wave; and a second object for displaying information indicating an arterial system index value based on the pulse wave.

9. The information display device according to claim 8, wherein the image includes an object for selectively displaying in the image any of the following waveforms based on the pulse wave of the subject: a pressure pulse wave waveform, a first derivative wave waveform, and a second derivative wave waveform.

10. The information display device according to claim 8 or 9, wherein the image includes an area into which a numerical value used for calculating at least one index value based on the pulse wave is input, and the control unit calculates at least one index value based on the pulse wave based on the numerical value input into the area into which the numerical value is input.

11. The information display device according to any one of claims 8 to 10, further comprising: an object for instructing the recording of information displayed in the image; and a recording period selection unit for selecting a period for recording.

12. The information display device according to any one of claims 8 to 11, wherein the control unit generates a secondary image in the image generation process, the secondary image includes an area for displaying information indicating the arterial system index value and an area for displaying an average pulse wave which is the average waveform of a plurality of pulse wave waveforms of the subject corresponding to each of the plurality of pulses of the subject, and the control unit displays the secondary image on the display unit based on the fact that the second object has been manipulated in the image.

Images