JP2013208287A - Biosignal display device and method for controlling the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a biological information display device capable of easily grasping the posture of a subject during sleep.
A biological information display device acquires biological information related to a subject's sleep and determines the posture of the subject when the biological information is acquired. The acquired biological information and the determined posture information are recorded in a storage medium in association with each other. The biological information display device reads biological information and posture information from a storage medium, displays a waveform based on the biological information, and displays an icon representing the posture type at a position synchronized with the waveform in time.
[Selection] Figure 6

Description

  The present invention relates to a biological signal display device and a control method thereof.

  Sleep Apnea (Hypopnea) Syndrome (SAS or SAHS) is associated with excessive daytime somnolence due to sleep disruption, and 5 apneas / hour or more It is a disease that occurs 30 times / 7 hours or more. Hereinafter, for convenience, SAS and SAHS are simply referred to as SAS.

  SAS can be broadly classified into obstructive sleep apnea syndrome (OSAS), central sleep apnea syndrome (CSAS), and mixed sleep apnea syndrome (MSAS). ing. In addition, since MSAS shifts from CSAS to OSAS, it may be regarded as OSAS.

  Among these, OSAS is considered to occur when the sleep muscles deepen, the airway muscles relax, and the tongue sinks under its own weight to block the airways. In an obstructed state, it falls into an oxygen deficient state, so that sleep becomes shallow (sleep deprivation), and the muscles of the airways become tense and the obstruction and oxygen deficiency are alleviated or eliminated. Then, sleep deepens and falls into an obstructed state again. Since this cycle is repeated many times during sleep, even if he intended to have enough sleep, he did not actually get enough sleep, resulting in intense sleepiness during non-sleep, Or cause trouble.

Conventionally, sleep polygraphy is known as an apparatus for measuring whether or not symptoms such as sleep apnea are actually observed for a patient suspected of having SAS (see, for example, Patent Document 1). Polysomnography measures and records blood oxygen saturation (SpO ₂ ), chest breathing, abdominal breathing, electrocardiogram, snoring, body position, mouth-nose airflow, etc. over the entire sleep time. Larger devices may also measure brain waves, eye movements, chin electromyograms, limb electromyograms, and the like.

  It is known that posture is greatly related to respiratory stoppage during sleep. For example, in the supine position, even when the upper airway stenosis due to tonsil enlargement, obesity, or the like leads to respiratory arrest, in the supine position, respiratory arrest is often not achieved. For this reason, many polysomnography measures posture (posture).

Japanese National Patent Publication No. 11-504840

  The information on the measured posture is displayed in synchronization with the time axis waveform of various measurement values as described above. Conventionally, such posture information has been displayed as a transition diagram or a color bar. However, the conventional transition diagram and color bar display have a problem that the type of posture cannot be known at a glance. There are some that display the type of posture on a tool bar or the like by holding the mouse cursor on the displayed color bar, but it takes time to operate the mouse.

  The present invention has been made in view of the above-described problems of the prior art, and an object thereof is to provide a biological information display device that can easily grasp the posture of a subject during sleep.

  That is, the gist of the present invention is a posture measurement apparatus that is attached to a subject and measures the posture of the subject, and is orthogonal to a static acceleration sensor that measures the magnitude of static acceleration in three orthogonal directions. The posture measuring apparatus includes a signal generating unit that generates a signal representing the posture of the subject based on the relationship between the magnitudes of the static accelerations in the three directions.

  Another gist of the present invention resides in a biological information display device that includes the posture measuring apparatus of the present invention and records the posture measured using the posture measuring apparatus together with other biological information.

  With such a configuration, according to the present invention, it is possible to provide a biological information display device that can easily grasp the posture of the subject during sleep.

The block diagram which shows the structural example of the sleep polygraphy which concerns on embodiment. The figure explaining the example of arrangement | positioning of an acceleration sensor. The figure which shows the specific structural example of the body posture measurement part 190. FIG. The figure explaining the determination method of the threshold value in FIG. The figure which shows the example of the table for determining the body position of a subject. The figure which shows the example of the waveform display screen in embodiment. The figure which shows the example of the conventional waveform display screen.

Hereinafter, the present invention will be described in detail based on preferred embodiments with reference to the drawings.
FIG. 1 is a block diagram illustrating a configuration example of polysomnography as an example of a biological information display device according to the present embodiment.

  The operation of the polysomnography 100 is controlled by the control unit 110. The control unit 110 includes, for example, a CPU, a ROM, and a RAM. The CPU has a control program stored in the ROM, thereby realizing a function as polysomnography. The display unit 120 is an LCD, for example, and displays various setting screens, messages, operation states, and the like. The operation unit 130 includes input devices such as keys and buttons, and is used by the user to input setting values, personal information, and the like, and to give instructions to the apparatus.

  The A / D conversion unit 140 converts analog output values of various sensors and measuring devices connected to digital data with a predetermined accuracy and outputs the digital data to the control unit 110. In the present embodiment, the sensors connected to the A / D converter 140 are an electrocardiogram electrode 150, a pulse oximeter 160, for example, an oronasal breathing / snoring sensor 170 including a cannula and a pressure sensor, and a chest respiratory sensor 180. And the posture measuring unit 190.

The electrocardiogram electrode 150 is attached to the subject's chest and outputs an electrocardiogram signal. The pulse oximeter 160 is attached to the subject's finger and outputs a signal representing blood oxygen saturation (SpO ₂ ). The mouth-nose breathing / snoring sensor 170 outputs a signal representing an air flow rate in the mouth and nose of the subject and a snoring sound. The chest respiration sensor 180 outputs a signal representing a change in the chest circumference accompanying chest respiration. The body position measurement unit 190 outputs a signal representing the body position (posture) of the subject using, for example, a static acceleration sensor.

  The recording unit 195 is a reader / writer that uses, for example, a semiconductor memory card as a recording medium, and sequentially records measurement data supplied from the control unit 110 on the recording medium.

  In the present embodiment, since a portable polysomnography is assumed, a configuration for measuring an electroencephalogram or an eye movement is not shown, but the posture measuring apparatus of the present embodiment is a portable, stationary device. Applicable to any polysomnography regardless of type. Moreover, it is not essential to record all the above-described biological information, and other biological information may be recorded.

  Next, the posture measuring unit 190 will be described. In the present embodiment, the posture measurement unit 190 performs posture measurement using an acceleration sensor that changes electrical characteristics according to acceleration, specifically, an electrical resistance or an output voltage, instead of a mechanical switch.

  An acceleration sensor that can be suitably used in the present embodiment is an acceleration sensor (static acceleration sensor) capable of measuring so-called static acceleration. Examples of such a static acceleration sensor that can be obtained include a piezoresistive triaxial acceleration sensor. The piezoresistive three-axis acceleration sensor has a basic structure in which a weight is supported by a plurality of thin beams (beams), and a piezoresistive element is provided on each beam.

  Since the basic structure can be obtained by etching the silicon substrate, a small acceleration sensor can be realized using semiconductor manufacturing technology. Further, since no mechanical contact is used, the lifetime is semi-permanent.

  When acceleration is applied to the sensor and the weight moves, distortion is applied to the piezoresistive element on the beam according to the direction and magnitude of the acceleration, and the resistance value changes. By detecting this change in resistance value as a change in voltage, the acceleration in the XYZ orthogonal axis direction can be detected. Static acceleration (tilt against gravity, centrifugal acceleration, etc.) is continuously detected by forming a resistive network with piezoresistive elements on the beam and detecting changes in output potential while inputting a constant potential. be able to. Specific examples of such a piezoresistive triaxial acceleration sensor include the H48 series manufactured by Hitachi Metals, and ML8950 manufactured by Oki Electric.

  In the present embodiment, as shown in FIG. 2, the acceleration sensor is used by being placed on the subject's trunk, specifically the chest. Then, the orthogonal axes of XYZ are used so as to be in the directions shown in FIG.

  Note that FIG. 2 is merely an example of a possible arrangement of the acceleration sensor. As long as the posture of the subject can be measured based on the amount of static acceleration in the XYZ-axis directions, the placement position of the acceleration sensor and the trunk of the subject. The relative relationship between the XYZ axis directions and the like can be arbitrarily determined.

FIG. 3 is a diagram illustrating a specific configuration example of the body posture measuring unit 190 in the present embodiment.
The posture measuring unit 190 includes an acceleration sensor 200, a temperature sensor 210, a temperature correction circuit 220, amplifiers 231 to 233, and comparators 241 to 246. For convenience, the acceleration sensor 200 is described as having acceleration sensors 202, 204, and 206 that independently measure accelerations in the Z, X, and Y axis directions. An output representing the acceleration in each axial direction is obtained from one acceleration sensor.

  The semiconductor piezoresistive acceleration sensor as described above has a characteristic that the sensitivity and the output voltage at zero G (gravity acceleration) change (drift) with temperature. Therefore, in the present embodiment, a temperature sensor 210 and a temperature correction circuit 220 are provided to compensate for temperature characteristics. The temperature correction circuit 220 is realized by an amplifier having a characteristic opposite to the temperature drift characteristic of the acceleration sensor 200 measured in advance. Specifically, the gain of the amplifier that amplifies the sensor output is adjusted according to the value referring to the compensation table according to the output of the temperature sensor 210.

  Some acceleration sensors have a temperature compensation function. When such an acceleration sensor is used, it is not necessary to provide the temperature sensor 210 or the correction circuit 220. As an acceleration sensor incorporating a temperature compensation function, for example, there is a three-axis acceleration sensor H48C manufactured by Hitachi Metals.

  Returning to FIG. 3, the voltage signals corresponding to the acceleration in the Z-, X-, and Y-axis directions output from the temperature correction circuit 220 are amplified by the amplifiers 231 to 233, and then the two threshold values Th ( +) And Th (-).

  The threshold values Th (+) and Th (−) are threshold values for positive and negative accelerations. The comparators 241, 243, and 245 to which the threshold value Th (+) is input as the reference voltage output a predetermined level voltage only when the output of the acceleration sensor 200 (amplifiers 231 to 233) is equal to or higher than Th (+). To do. The comparators 242, 244, and 246 to which the threshold value Th (−) is input as the reference voltage output a voltage of a predetermined level only when the output of the acceleration sensor 200 (amplifiers 231 to 233) is equal to or less than Th (−). To do.

  Since the posture during sleep is considered to be basically stable in any of the lateral position, the supine position, or the prone position, in this embodiment, the potentials of the thresholds Th (+) and Th (-) are detected so that these positions can be detected. Is stipulated. That is, the state in which any of the X, Y, and Z axis directions detected by the acceleration sensor is substantially parallel to the direction of gravity, in other words, the static acceleration in any of the X, Y, and Z axis directions is shown in FIG. As shown in the figure, determinations are made so that the states of approximately + 1G and -1G can be detected.

  The outputs of the comparators 241 to 246 are converted into 1 or 0 digital data by the A / D converter 140 and then input to the controller 110. The control unit 110 determines the posture of the subject based on the digital data with reference to a table as shown in FIG. In the example of FIG. 5, the position is determined to be one of the supine position, the prone position, the right-side prone position, the left-side prone position, the standing position, and the inverted standing position, depending on which position of the 6 bits stands.

  In addition, when the value after A / D conversion of all the comparator outputs is 0, such as the state of transition from one posture to another, it is determined that the state is the transition state. Data representing the determined body position is transferred to the recording unit 195 and recorded, as with other measurement values.

Note that the posture measuring unit 190 of the present embodiment is configured to use the comparators 241 to 246 to give the control unit 110 only the result of whether or not the static acceleration in the X, Y, and Z axis directions is ± 1 G. It was. However, the number of thresholds may be increased, and the magnitude of static acceleration in the X, Y, and Z axis directions may be multivalued and output.
Moreover, although the example using the threshold values Th (+) and Th (−) common to a plurality of comparators has been described in the above-described embodiment, Th (+) and Th (−) may be different depending on the comparator. Good. In other words, threshold values that differ by the number of comparators may be used.

  Further, the comparators 241 to 246 are not provided in the posture measuring unit 190, and a voltage value indicating the magnitude of the static acceleration in the X, Y, and Z axis directions is input to the control unit 110 as it is (A / D conversion). It may be. In this case, after the controller 110 performs the same process as the comparators 241 to 246, the posture may be determined.

  Alternatively, the control unit 110 may handle the output values (6-bit data) of the comparators 241 to 246 after A / D conversion as data representing the type of posture. In this case, it can be considered that the posture determination is substantially performed by the posture measurement unit 190.

  As described above, in the present embodiment, the body position of the subject is measured based on the direction and the magnitude of the static acceleration using the static acceleration sensor that can detect the static acceleration based on the change in electrical characteristics. Thereby, highly accurate and reliable posture measurement can be realized. However, the present invention is not limited to a specific posture measurement method, and other known posture measurement methods may be used.

  As described above, the data as the biological information related to the sleep of the subject from the various sensors and the information on the posture obtained by the posture measuring unit 190 at the time of acquiring the biological information are associated with each other. Then, it is recorded on the recording medium by the recording unit 195 as measurement data.

  After the measurement is completed, the measurement data can be read from the recording medium and the waveform of the data from various sensors can be displayed by a specific operation via the operation unit 130. FIG. 6 shows an example of a waveform display screen displayed on the display unit 120. In the example of FIG. 6, two types of waveforms are displayed on the waveform display unit 61 for convenience, but all waveforms from each sensor may be displayed on each stage here. Further, the waveform from each sensor may be analyzed to display the result of SAS type determination (for example, OSAS / MSAS determination) in a graph. The time axis scale and amplitude scale of the displayed waveform can be arbitrarily changed by a user operation.

  At the bottom of the waveform display section 61, a body position information display section 62 for displaying the body position information obtained by the above-described body position measurement is provided. In the present embodiment, the type of posture is displayed by an icon in synchronization with the time scale of the waveform displayed on the waveform display unit 61. For example, the icon 63 indicates the supine position, the icon 64 indicates the left position, the icon 65 indicates the prone position, and the icon 66 indicates the right position.

  FIG. 7 shows a conventional example of body position information display. FIG. 7 shows the position types displayed by color bars. However, in such a display using a color bar, the type of body position is not known at a glance. To know what each color represents, it is necessary to refer to the legend as shown at 72. Further, since it is necessary to provide an area for displaying such a legend 72, the area of the waveform display portion is narrowed. It can be configured to display the type of posture on a tool bar or the like by holding the mouse cursor on the displayed color bar, but in this case, the operation of the mouse is required.

  On the other hand, according to the example of FIG. 6 according to the present embodiment, the type of posture can be recognized at a glance by the icon. In addition, since it is not necessary to provide a legend, the area of the waveform display portion can be made wider than before.

Claims (2)

An acquisition means for acquiring biological information related to sleep of the subject;
Discriminating means for discriminating the posture of the subject at the time of obtaining the biological information;
Recording means for associating the biological information acquired by the acquisition means and the information on the posture determined by the determination means with each other and recording them on a storage medium;
An icon that reads out the biological information and the posture information from the storage medium, displays a waveform based on the biological information, and temporally synchronizes with the waveform to indicate the type of posture based on the posture information. Display means for displaying
A biological information display device characterized by comprising: A control method for a biological information display device, comprising:
An obtaining means for obtaining biological information related to sleep of the subject;
A step of determining a body position of the subject at the time of acquiring the biological information;
Recording means for associating the acquired biological information and the information on the determined body position with each other and recording them on a storage medium;
The display means reads the biological information and the posture information from the storage medium, displays a waveform based on the biological information, and temporally synchronizes with the waveform to determine the posture based on the posture information. Displaying an icon representing the type;
A control method for a biological information display device, comprising: