JP7629341B2 - Care recipient monitoring system and care recipient monitoring program - Google Patents

Description

The present invention relates to a monitoring system and program that can grasp the condition of a person receiving care.

In hospitals and nursing care facilities, when a person receiving care tries to get out of bed by themselves (so-called getting out of bed), there is a risk that the person may fall out of bed, stumble and trip when they stand up, or fall shortly after starting to walk, so caregivers must constantly monitor the person to see if they will get out of bed.

In view of this, a system for determining the posture of a care recipient has been proposed, as disclosed in, for example, Japanese Patent Laid-Open No. 2003-233696.
According to this system, the patient's posture is captured using images taken by a camera attached to the bed, and by acquiring images at regular distances, posture determination is made without the influence of the duvet.

Patent document 2 also discloses a device that places two vibration sensors on a bed, calculates a waveform from the vibrations detected by the vibration sensors, and determines the posture of the subject from the characteristics of the waveform.

JP 2018-082745 A JP 2019-098069 A

Image-based assessments such as those in the above-mentioned Patent Document 1 can determine posture when the upper body is raised, but cannot determine posture in bed, and cannot detect in advance situations where the person rolls over and falls under the bed without raising the upper body.

In addition, with devices such as that described in Patent Document 2, the sensor needs to be installed in an appropriate position according to the physique of the care recipient, which poses the problem that the sensor installation position must be changed for each care recipient.

The present invention was made to solve the above problems, and its purpose is to provide a system and program that can reduce the caregiver's workload and accurately grasp the posture of the person being cared for.

According to the present invention, a care recipient monitoring system includes a pressure distribution sensor arranged to cover the entire bed of the care recipient and having a plurality of detection units; a control device which receives pressure data detected by each detection unit of the pressure distribution sensor and performs the functions of creating a color-coded pressure distribution image for each detection unit based on the value of the input pressure data and determining the condition of the care recipient based on the input pressure data; and a monitor which displays the pressure distribution image created by the control device . The control device creates unit space data for each of the care recipient's postures, namely supine, lateral, and sitting, based on parameters including at least the average value of pressure data input from the plurality of detection units in the pressure distribution sensor, the number of detection units that detected, and the number of detection units that detected in the longitudinal direction of the bed, and calculates the Mahalanobis distance between the created unit space data and the pressure data input from the plurality of detection units in the pressure distribution sensor, and determines the posture of the care recipient .
By adopting this configuration, the caregiver can check the body pressure distribution of the care recipient through an image, and the condition of the care recipient can be determined based on the pressure data, so the caregiver can accurately grasp the condition of the care recipient. In addition, by using a pressure distribution sensor that covers the entire bed, it is not necessary to adjust the sensor to fit the physique of the care recipient, which saves the caregiver time.
Furthermore, with this configuration, it is possible to reduce errors in determining the posture of the care recipient based on past data, regardless of the experience of the caregiver.

The control device may further comprise a notification means for notifying the user of the determined state of the care recipient.
The notification means here includes display on a monitor and output of voice or warning sound from a speaker etc. This allows the caregiver to more quickly recognize the condition of the care recipient.

The control device may also be characterized in that it distinguishes between a plurality of types of the condition of the person being cared for, sets one or more of the plurality of types of conditions as a dangerous condition, and if the distinguished condition is the set dangerous condition, issues a warning by the notification means.
According to this configuration, a dangerous condition of the care recipient can be recognized quickly.

In addition, when multiple types of dangerous states are set, the control device may be characterized in that it sets danger levels for the multiple types of dangerous states in stages and issues different warnings for each stage via the notification means.
With this configuration, the caregiver can grasp the gradual danger level of the condition and can respond to the person being cared for in accordance with the danger level, thereby reducing the burden on the caregiver.

The control device may be characterized in that it receives pressure data from a plurality of pressure distribution sensors and performs control so that the pressure distribution images of the pressure distribution sensors are split and displayed on one monitor.
According to this configuration, even if there are multiple care recipients in a care facility or the like, the conditions of the multiple care recipients can be grasped at once.

The control device may also be characterized by having a transmission function capable of transmitting the determined information to an external device by wireless communication.
With this configuration, the determined information can be sent to the mobile terminal device carried by each caregiver, allowing the caregiver to grasp the condition of the person being cared for even when not staring at the monitor.

The present invention reduces the burden on caregivers and allows them to accurately grasp the condition of the person being cared for.

FIG. 1 is an explanatory diagram showing the overall configuration of a monitoring system. FIG. 2 is a plan view showing a schematic configuration of a pressure distribution sensor. FIG. 2 is a block diagram showing a schematic internal configuration of a control device. FIG. 2 is an explanatory diagram showing the arrangement of a detection unit in a bed. FIG. 4 is an explanatory diagram showing an example of a pressure distribution image displayed on a monitor. 4 is a flowchart showing a first embodiment of state determination. 10 is a flowchart showing a Mahalanobis distance calculation process in a second embodiment of state determination. 13 is a flowchart of bed exit determination using the MT method. 13 is a flowchart showing a sleep onset determination in a third embodiment of the state determination. 13 is a flowchart showing a determination in a pre-sleep state in a third embodiment of the state determination. 13 is a flowchart showing a determination in a post-sleep state in a third embodiment of the state determination method. FIG. 13 is a block diagram showing how the state determination result is displayed on a mobile terminal device carried by a caregiver.

(Overall system configuration)
FIG. 1 shows a schematic overall configuration of a care recipient monitoring system.
The care recipient monitoring system 10 of this embodiment comprises a bed 11 on which the care recipient sleeps, a pressure distribution sensor 20 arranged to cover the entire bed 11, a control device 30 to which pressure data from the pressure distribution sensor 20 is input, and a monitor 32 to display data from the control device 30.
The bed 11 may have any structure and may be of any ordinary construction.

A single control device 30 is capable of acquiring and processing pressure data from pressure distribution sensors 20 from multiple beds 11. In FIG. 1, only three beds 11 and pressure distribution sensors 20 are shown as an example, but it is preferable to acquire and process pressure data from up to about 16 pressure distribution sensors 20, for example.

Pressure data from the multiple pressure distribution sensors 20 is wirelessly transmitted to one router 29 with each pressure distribution sensor 20 acting as a Wi-Fi slave, and then wirelessly transmitted from the router 29 to the control device 30 .
However, the method of transmitting pressure data from the pressure distribution sensor 20 is not limited to Wi-Fi communication using the router 29, but may also employ Bluetooth (registered trademark) or a wired transmission method.

1, a data storage area may be provided on the cloud, and the pressure data, statistical value data calculated from the pressure data, and state determination data determined from the statistical value data may be stored in the storage area on the cloud. Furthermore, the storage of the pressure data, statistical value data, and state determination data is not limited to the storage area on the cloud, and may be an external storage connected to the control device 30.
In this way, by storing past pressure data, statistical value data, and state determination data, it becomes possible to obtain even more accurate statistics in the future by utilizing the past data.

(Pressure distribution sensor)
Next, a pressure distribution sensor that covers the entire bed of the care recipient will be described.
The pressure distribution sensor is preferably made of flexible fabric, which is low cost and does not cause discomfort when the care recipient sleeps on it, and for example, a pressure distribution sensor as shown in Fig. 2 can be used. Note that Fig. 2 is not illustrated as a pressure distribution sensor that covers the entire bed, but is merely a schematic diagram for explaining the structure.

The pressure distribution sensor 20 in FIG. 2 is configured by arranging a plurality of strip-shaped first electrode cloths 22 at predetermined intervals on the surface of a conductive cloth 21, and arranging a plurality of strip-shaped second electrode cloths 23 at predetermined intervals on the back surface of the conductive cloth 21 in a direction perpendicular to the arrangement direction of the first electrode cloths 22.

According to the pressure distribution sensor 20 as described above, the intersection area of the first electrode cloth 22 and the second electrode cloth 23 is configured as a detection section 25 that detects pressure. The detection sections 25 are arranged in a matrix pattern over the entire bed area, but only one detection section 25 is shown in FIG.
When pressure due to the weight of the person being cared for is applied to the detection unit 25, the electrical resistance value of the first electrode cloth 22 and the second electrode cloth 23 via the conductive cloth 21 changes in the detection unit 25, and by measuring this resistance value, it is possible to detect pressure data.

Furthermore, a signal line 26 is connected to one end in the longitudinal direction of each of the first electrode cloth 22 and the second electrode cloth 23 .
The signal line 26 is connected to a controller 27. The controller 27 measures the resistance value of the detection unit 25 at a predetermined time interval (for example, every 1 second), A/D converts the resistance value, performs a predetermined calculation to convert it into pressure data, and outputs it to the control device 30 via a router 29.
The controller 27 is provided with a wireless communication device such as a wireless LAN, and can output pressure data to the router 29 via wireless communication, and can output pressure data to the control device 30 via wireless communication. However, as described above, the transmission of pressure data from the controller 27 to the control device 30 is not limited to wireless communication, and may be performed via wired communication.
In addition, the controller 27 may output pressure data based on a request signal from the control device 30.

By adopting the pressure distribution sensor 20 configured as described above, it can be constructed from inexpensive cloth material, making it possible to enlarge the pressure distribution sensor 20 without incurring costs, and making it possible to measure the entire bed 11.

(Control device)
The configuration of the control device 30 will be described with reference to FIG.
The control device 30 may be a general computer. The monitor 32 may also be a general one that is connected to a computer. The monitor 32 may be a simple liquid crystal panel or a touch panel, or may have any other structure. A plurality of monitors 32 may be connected to one control device 30.
The control device 30 includes a communication device 33 that receives pressure data from the controllers 27 of the multiple pressure distribution sensors 20, a control unit 34 composed of a central processing unit (CPU), ROM, RAM, etc., a memory unit 35 in which programs and data are stored, and an input unit 36 composed of a mouse and keyboard.

The control unit 34 reads out and executes the data processing program P1 stored in the memory unit 35, thereby performing the function of creating a color-coded pressure distribution image for each of the pressure distribution sensors 20 based on the magnitude of the pressure values of the multiple pressure data from each of the multiple pressure distribution sensors 20.

In addition, the control unit 34 reads out and executes the data processing program P1, thereby executing the function of determining the condition of the care recipient based on the pressure data measured by each detection unit 25 of each pressure distribution sensor 20.
To determine the condition of the person being cared for, at least three parameters can be used: the magnitude of the pressure value, the pressure distribution on the pressure distribution sensor, and the amount of change in the magnitude of the pressure value and the pressure distribution over time, but these are not limited to these three parameters.

The control unit 34 is capable of determining at least the lying down and sitting positions as the posture of the care recipient, and by measuring the center of gravity position and body movement in each posture, it can determine the state of the care recipient, such as getting out of bed, being careful of falling, getting up, no body movement, and excessive body movement.
The control unit 34 may output an alarm if the care recipient is in a dangerous state, or may determine the dangerous state in stages according to the degree of danger and output a different alarm depending on the stage.

For example, the highest urgency of the condition of the care recipient is set to getting out of bed, followed by caution against falling, and then excessive body movement, which is set to a low urgency.
In this case, if the person being cared for has left the bed, there is a possibility that the person has already fallen, and therefore the level of urgency is highest, so the monitor 32 will display the person leaving the bed in red and an alarm will be sounded from a speaker (not shown: same below).
In addition, when the person being cared for is in a lying position at the end of the bed, there is a risk of the person falling off the bed, so a warning about falling is displayed in yellow on the monitor 32 as a level of urgency that is one level lower than getting out of bed, and a warning sound different from that for getting out of bed is output from the speaker.
Furthermore, in the case of excessive body movement, although the urgency is low, there is a risk and caregivers need to be prepared for this in advance, so excessive body movement is displayed in green on the monitor 32 as a level of urgency one step lower than the fall warning, and a warning sound different from the bed leaving and fall warning sounds is output from the speaker.

The positions of the multiple detection units 25 of one pressure distribution sensor 20 are expressed by coordinates as shown in FIG. 4. For example, in this embodiment, the width direction of the human body in the pressure distribution sensor 20 is set as the Y axis, the height direction of the human body is set as the X axis, and the head side on the left side of the human body is set as the origin. In the example of FIG. 4, there are 16 detection units 25 in the Y axis direction and 32 detection units 25 in the X axis direction, so each detection unit is specified as X and Y coordinates of (X1, Y1), (X2, Y2), ... (X32, Y16). However, the number of detection units 25 is not limited to the above numbers.

FIG. 5 shows an example of a color-coded pressure distribution image that is created by the control unit 34 and displayed on the monitor 32.
The control unit 34 divides the entire bed 11 into a matrix of areas of the detection units 25 configured in the pressure distribution sensor 20, and corresponds each detection unit 25 ((X1, Y1), (X2, Y2), ... (X32, Y16)) to each of the divided areas (hereinafter, these areas may be referred to as cells), displays the values of the pressure data detected by each detection unit 25 in different colors, and creates a pressure distribution image.

For example, in the pressure distribution image, the control unit 34 sets the colors of the cells displayed on the monitor 32 in the order of blue, green, yellow-green, yellow, orange, and red for the cells with a pressure value of 0 in the pressure data, and blue, green, yellow, orange, and red for the cells with increasing pressure value in the pressure data. This order of colors corresponds to the order of shortest wavelengths in natural light, but is not limited to this order.

In addition, since the pressure data from each controller 27 is transmitted to the control device 30 at a predetermined time interval (for example, every second), the control unit 34 sets the display color of each cell based on the value of the pressure data at the predetermined time interval.

The control unit 34 may also increase the saturation of the color of each section of the pressure distribution image with the same hue as the pressure value of the pressure data increases, or may increase the brightness with the same hue as the pressure value of the pressure data increases. In any case, as long as it is extremely easy to clearly distinguish between areas with high and low pressure values, any color coding may be used.

The caregiver stores in advance user information 37 of the user using each bed 11 in the storage unit 35. The user information may include the bed number, the name, age, and sex of the care recipient. The control unit 34 may display the user information on the monitor 32 together with the pressure distribution image.
In the example of Figure 5, the image serial number, bed number, the name of the care recipient from the user information, a pressure distribution image, and an indication of the determined condition of the care recipient are displayed for one bed, but the display content is not limited to this example.

In this embodiment, user information and a pressure distribution image are displayed on the monitor 32, so that the caregiver can clearly see what posture the person being cared for is currently in and can respond immediately if the person is about to enter a dangerous state.
However, as described below, if the control unit 34 is able to determine the posture state of the care recipient in more detail, the caregiver's workload can be further reduced.

(First embodiment of determining the condition of a care recipient)
Next, the determination of the condition of the care recipient will be described.
The control unit 34 loads and executes the data processing program P1 to perform the following calculations from the pressure data from each pressure distribution sensor 20 and to determine the state of the care recipient.
The control unit 34 calculates the maximum pressure, average pressure, number of responses (number of detection units 25 that responded), X-direction center of pressure, Y-direction center of pressure, and amount of change in the center of pressure for each pressure distribution sensor 20, date, and time, based on the pressure data.

The control unit 34 judges the condition of the care recipient based on the above-mentioned calculation items, and the judgment contents include getting out of bed, caution against falling, no body movement, excessive body movement, etc. In this embodiment, all of these judgment contents are judged, but it is also possible to judge one or more of these items.

Next, a determination method executed by the control unit 34 will be described with reference to FIG.
After the state determination is started, first, it is determined whether the care recipient has left the bed.
In step S100, the control unit 34 calculates how many of all the detection units 25 in the pressure distribution sensor 20 are detecting pressure, and compares the result with a preset first threshold value. For example, if the first threshold value is set to 2, and two or more detection units 25 are detecting pressure, the control unit 34 determines that the patient has not left bed and proceeds to step S200, and if the number of detection units 25 detecting pressure is less than two, the control unit 34 proceeds to step S102.

In addition, if a first threshold value for the number of detection units 25 detecting pressure is set in step S100, there is a possibility that even if the person being cared for has left the bed, the pressure will be detected due to the weight of the futon or pillow, and it will be erroneously determined that the person has not left the bed.
Therefore, for example, a minimum reaction pressure may be set as the magnitude of the pressure value in addition to the first threshold value, and the bed may be determined to have been left only when the magnitude of the detected pressure value is equal to or greater than the minimum reaction pressure and the number of detection units 25 detecting the pressure is equal to or greater than the first threshold value. The minimum reaction pressure may be, for example, 5 mmHg.
Furthermore, in order to prevent a case where pressure is detected due to the weight of a futon or pillow even when the care recipient has left the bed, and thus a false determination that the care recipient has not left the bed, the first threshold value may be set to a load obtained by multiplying the average value of the pressure values in each detection unit 25 by the reaction area, rather than the number of detection units 25 detecting the pressure. In this case, if a load less than the first threshold value is detected, it can be determined that the care recipient has left the bed.

In step S102, the control unit 34 judges whether the state where the number of the detection units 25 detecting pressure is less than two continues for a time period equal to or greater than a preset second threshold value. For example, if the second threshold value is set to three seconds, and the state where the number of the detection units 25 detecting pressure is one or less continues for three seconds or more, the control unit 34 judges that the care recipient has left the bed, and causes the monitor 32 to display that the care recipient has left the bed.
The display of getting out of bed is preferably in a color (e.g., red) that the caregiver can immediately recognize. The control unit 34 may output a voice or a warning sound when the care recipient has gotten out of bed. In this case, the control device 30 requires a speaker (not shown) that outputs a predetermined voice signal by the control unit 34.

In step S102, if the state in which there are less than two detection units 25 detecting pressure does not continue for longer than the second preset threshold value, the control unit 34 determines that this is a malfunction caused by noise or the like, and returns to the start of state determination.

In step S200, when the number of detection units 25 detecting pressure is equal to or greater than the first threshold, the control unit 34 compares the distance from the edge of the bed to the third threshold. As described above, the Y direction is the width direction of the bed, and this step is for determining that there is a risk of falling if the Y direction pressure center position is too far from the Y direction center.

For example, if the number of detection units 25 in the Y direction in the pressure distribution sensor 20 is 16 as shown in FIG. 4 and the third threshold value is 3, then when the position of the Y direction pressure center is less than 3, that is, Y1 to Y2 or Y15 to Y16, the position of the Y direction pressure center is determined to be within a predetermined distance range from the bed end, and the process proceeds to step S202.
Furthermore, if the position of the Y direction pressure center is at a distance from the bed edge that is equal to or greater than the third threshold value, that is, in the range of Y3 to Y14, it is determined that the position of the Y direction pressure center is not near the bed edge and the process proceeds to step S300.

In step S202, the control unit 34 determines whether the state in which the center of pressure in the Y direction is close to the edge of the bed continues for a time period equal to or greater than a fourth threshold value set in advance. For example, if the fourth threshold value is set to 3 seconds, and the state in which the center of pressure in the Y direction is close to the edge of the bed continues for 3 seconds or more, the process proceeds to step S204 for determining the sleeping posture.

In step S202, if the state in which the Y-direction pressure center position is close to the bed end does not continue for the fourth threshold value or more, the control unit 34 determines that this is a malfunction due to noise or the like, and returns to the start of the state determination.

In step S204, the control unit 34 executes a sleeping posture determination as to whether the shape detected by the multiple detection units 25 detecting the pressure is a supine or lateral position, or a sitting position. In the supine or lateral position, the detection units 25 corresponding to the entire body of the care recipient from head to feet detect pressure, whereas in the sitting position, since the care recipient is sitting beside the bed 11, only the detection units 25 corresponding to the buttocks detect pressure.
Therefore, the control unit 34 can determine that the subject is in a supine or lateral position when the X-direction length of the multiple detection units 25 detecting pressure is equal to or greater than a predetermined length, and can determine that the subject is in a sitting position when the X-direction length is less than the predetermined length.

If the control unit 34 determines that the X-direction length of the multiple detection units 25 is equal to or longer than a predetermined length and that the patient is in a supine or lateral position, there is a risk of falling, so it displays a fall warning on the monitor 32.
The fall warning is preferably displayed in a color that can be easily recognized by the caregiver. The control unit 34 may also output a fall warning for the care recipient by voice or alarm sound. In this case, the control device 30 requires a speaker (not shown) that outputs a predetermined audio signal by the control unit 34.

When the control unit 34 determines that the length in the X direction of the multiple detection units 25 is less than a predetermined length and that the care recipient is in a sitting position, the care recipient is sitting beside the bed 11 and may stand up, which may pose a risk of the care recipient standing up, etc. Therefore, the control unit 34 displays a warning to stand up on the monitor 32.
The control unit 34 may also be configured to output a voice or a warning sound to warn the care recipient not to stand up. In this case, the control device 30 requires a speaker (not shown) that outputs a predetermined audio signal by the control unit 34.

In addition, in step S202, if the position of the Y-direction pressure center near the bed edge continues for a time period equal to or longer than a fourth preset threshold, the control unit 34 may not proceed to step S204 of determining the sleeping posture, but may instead display a warning about falling on the monitor 32 as there is a possibility of falling, and end the posture determination (the area indicated by the dashed line in Figure 6).

In step S300, which is reached when the position of the Y-direction pressure center is not at the bed end, no body movement or excessive body movement is determined based on whether the pressure center position (not limited to the Y-direction pressure center) is moving.
Since pressure data is transmitted at predetermined intervals, the control unit 34 determines whether the pressure center position of the previously received pressure data and the pressure center of the currently received pressure data have moved less than a predetermined distance (fifth threshold value) or more than a predetermined distance (fifth threshold value).

For example, if the preset fifth threshold value is set to 1, when the position of the center of pressure has moved to a distance of one or more detection units 25 away in either the X direction or the Y direction from the position of the center of pressure measured last time, the process proceeds to step S303.
If the position of the center of pressure has moved in either the X direction or the Y direction away from the previously measured position of the center of pressure by a distance less than one detection unit 25 (i.e., if it has not moved), proceed to step S302.

In step S302, the control unit 34 determines whether the state in which the position of the center of pressure has moved less than a predetermined distance in either the X direction or the Y direction from the previously measured position of the center of pressure continues for a time period equal to or greater than a preset sixth threshold. For example, if the sixth threshold is set to 3 seconds, and the state in which the position of the center of pressure has moved less than a predetermined distance in either the X direction or the Y direction from the previously measured position of the center of pressure continues for 3 seconds or more, the process proceeds to step S304 for determining no body movement.

In step S302, if the state in which the position of the center of pressure has moved less than a predetermined distance in either the X direction or the Y direction from the previously measured position of the center of pressure has not continued for a period of at least a preset sixth threshold value, the control unit 34 determines that this is a malfunction due to noise or the like, and returns to the start of state determination.

In the non-body movement determination in step S304, the control unit 34 determines that there is non-body movement if the state in which the position of the center of pressure has moved less than a predetermined distance in either the X direction or the Y direction from the previously measured position of the center of pressure continues for a time period equal to or longer than a preset seventh threshold value.
An example of the seventh threshold value is 3600 seconds.
When the control unit 34 determines that the care recipient is not moving, the control unit 34 causes the monitor 32 to display that the care recipient is not moving.
The control unit 34 may also be configured to output the physical movement of the care recipient by voice or warning sound. In this case, the control device 30 requires a speaker (not shown) that outputs a predetermined voice signal by the control unit 34.

In the non-motion determination in step S304, the control unit 34 determines that the subject is at rest if the state in which the position of the center of pressure has moved less than a predetermined distance in either the X direction or the Y direction from the previously measured position of the center of pressure continues for a time less than a preset seventh threshold.
If it is determined that the subject is at rest, the process proceeds to step S306.

In step S306, the control unit 34 executes a sleeping posture determination as to whether the shape detected by the multiple detection units 25 detecting the pressure is a supine or lateral position, or a sitting position. In the supine or lateral position, the detection units 25 corresponding to the entire body of the care recipient from head to feet detect pressure, whereas in the sitting position, since the care recipient is sitting beside the bed 11, only the detection units 25 corresponding to the buttocks detect pressure.
Therefore, the control unit 34 can determine that the subject is in a supine or lateral position when the X-direction length of the multiple detection units 25 detecting pressure is equal to or greater than a predetermined length, and can determine that the subject is in a sitting position when the X-direction length is less than the predetermined length.

When the length in the X direction of the multiple detection units 25 is equal to or greater than a predetermined length and the control unit 34 determines that the subject is in a supine or lateral position, the subject is at rest and causes the monitor to display that fact. When the subject is at rest, there is no need for the caregiver to take any particular notice, and therefore there is no need to output a voice or warning sound to indicate that the subject is at rest.

When the length in the X direction of the multiple detection units 25 is less than a predetermined length, the control unit 34 determines that the person is in a sitting position and has sat up (with only the upper body raised), and causes the monitor to display that fact.
In the case of getting up, since this is normal before falling asleep, no warning is required, but after falling asleep there is a risk of falling off the bed 11 or getting up, so it is better to give a warning that the person is getting up. Therefore, it is preferable for the control unit 34 to determine whether it is before or after falling asleep using a method described below, and then determine whether the person is getting up, and if the person is getting up after falling asleep, to give a warning such as outputting a voice or warning sound.

In the non-body movement determination in step S304, if the state in which the position of the center of pressure has moved less than a predetermined distance in either the X direction or the Y direction from the previously measured position of the center of pressure continues for a time less than a preset seventh threshold, the control unit 34 may determine that the subject is at rest, and then may end the posture determination by displaying on the monitor that the subject is at rest, without proceeding to step S306 for determining the sleeping posture (the area indicated by the dashed line in FIG. 6).

Next, the operation after step S303 will be described when the position of the center of pressure has moved a predetermined distance in either the X direction or the Y direction from the previously measured position of the center of pressure.
In step S303, the control unit 34 judges whether the state in which the position of the center of pressure has moved a predetermined distance or more in either the X direction or the Y direction from the previously measured position of the center of pressure continues for a time period equal to or longer than a preset eighth threshold value. For example, if the eighth threshold value is set to 3 seconds, and the state in which the position of the center of pressure has moved a predetermined distance or more in either the X direction or the Y direction from the previously measured position of the center of pressure continues for 3 seconds or more, the process proceeds to step S305 for determining excessive body movement.

In step S303, if the state in which the position of the center of pressure has moved a predetermined distance or more in either the X direction or the Y direction from the previously measured position of the center of pressure has not continued for at least the eighth preset threshold value, the control unit 34 determines that this is a malfunction due to noise or the like, and returns to the start of the state determination.

In the excessive body movement determination in step S305, the control unit 34 determines that there is excessive body movement if the state in which the position of the center of pressure has moved a predetermined distance or more in either the X direction or the Y direction from the previously measured position of the center of pressure continues for a time period equal to or greater than a preset ninth threshold, and determines that there is simple body movement if the state in which the position of the center of pressure has moved a predetermined distance or more in either the X direction or the Y direction from the previously measured position of the center of pressure continues for a time period less than the preset ninth threshold.
The ninth threshold value in step S305 may be, for example, 60 seconds.

When the control unit 34 determines that the body movement is excessive, it causes the monitor 32 to display that the care recipient is moving excessively.
The control unit 34 may also output excessive body movement of the care recipient by voice or warning sound. In this case, the control device 30 requires a speaker (not shown) that outputs a predetermined voice signal by the control unit 34.

When the control unit 34 determines in the excessive body movement determination in step S305 that the body movement is normal, it causes the monitor 32 to display that the care recipient is making normal body movements.
Since this normal body movement does not pose any particular danger, there is no need to output a voice or warning sound to inform the user that this is a normal body movement.

(Second embodiment of determining the condition of a care recipient)
The Mahalanobis distance is used to determine the state of the care recipient. The Mahalanobis distance is a method of creating unit space data for each posture in advance, comparing the distance in each posture of the signal space data based on the actually measured data with the distance in each posture of the unit space data, and determining that the posture is different from the posture when the distance in the signal space data is far from the distance in the unit space data. This method is also called the MT method.

The average value of pressure data input from the multiple detection units 25 in the pressure distribution sensor 20 in multiple postures of the care recipient, the number of detected detection units, the aspect ratio (XY) of the detected detection units, and the number of detected detection units in the longitudinal direction (X direction) of the bed are defined as feature quantities, and unit space data is created for each of the postures of the care recipient, namely supine, lateral, and sitting, based on the parameters of these feature quantities.
The feature amount may include at least the average value of the pressure data, the number of detection parts that detected, and the number of detection parts that detected in the length direction (X direction) of the bed.
It is preferable to collect as much pressure data as possible, since the greater the amount of data, the less likely it is that a judgment will be made.

First, a method for creating unit space data will be described with reference to FIG.
The control unit 34 defines the four feature quantities as the average value of the pressure data, the number of detected detection parts, the aspect ratio (XY) of the detected detection parts, and the number of detected detection parts in the longitudinal direction (X direction) of the bed in each posture, and calculates the average value and standard deviation of each feature quantity in each posture.
Next, the control unit 34 calculates a correlation coefficient for each feature amount based on the average value and standard deviation of each feature amount. The correlation coefficient is a coefficient that indicates the correlation when two of the four feature amounts are compared.

Then, the control unit 34 calculates the inverse matrix of the correlation matrix using the calculated correlation coefficients as the correlation matrix. Furthermore, the control unit 34 normalizes the four feature amounts in each posture. The normalization can be calculated by (measurement data-average value)/standard deviation.
Next, the control unit 34 calculates the matrix product of the standardized data and the inverse matrix. Then, the control unit 34 calculates the distance from the standardized determinant, the matrix product, and the number of features. This allows the Mahalanobis distance in the unit space data for each of the supine, lateral, and sitting positions to be calculated.

On the other hand, for pressure data that is used to determine which posture the care recipient is in, the Mahalanobis distance is calculated in the same manner as in the method shown in FIG.
Specifically, the control unit 34 sets the actually measured pressure data as four feature quantities, namely, the average pressure data, the number of detected detection parts, the aspect ratio (XY) of the detected detection parts, and the number of detected detection parts in the longitudinal direction of the bed (X direction), normalizes these as signal space data, calculates the inverse matrix, calculates the matrix product of the normalized determinant and the determinant of the inverse matrix, and calculates the Mahalanobis distance.
This allows the Mahalanobis distance to be calculated for pressure data with an unknown orientation.

A determination method using the Mahalanobis distance of pressure data with an unknown posture will be described.
As described above, the storage unit 35 stores the Mahalanobis distances in the unit space data for each of the supine, lateral, and sitting positions that have been calculated in advance.
The control unit 34 calculates the Mahalanobis distance of the pressure data to be judged, and compares it with the Mahalanobis distance in the unit space data of each of the pre-set positions of supine, lateral, and sitting.
The control unit 34 compares the Mahalanobis distance of the object to be determined with the Mahalanobis distances in the unit space data for each of the supine, lateral, and sitting positions, and determines the posture with the shortest distance as the posture of the object to be determined.

The control unit 34 may detect the care recipient getting out of bed by a posture determination method based on the MT method, and output a bed-getting alarm to the monitor 32. The bed-getting determination method based on the MT method will be described with reference to FIG.
Since a cared-for person usually gets out of bed from a lying position such as a supine or lateral position, a threshold value is set for the Mahalanobis distance in a lying position calculated in advance, and the control unit 34 determines that the cared-for person has moved from a sitting position to getting out of bed when the Mahalanobis distance to be judged exceeds the threshold value.

When the control unit 34 determines that the care recipient has left the bed, the control unit 34 causes the monitor 32 to display an alarm indicating that the care recipient has left the bed.
As in the first embodiment, the display of getting out of bed is preferably in a color (e.g., red) that the caregiver can immediately recognize. The control unit 34 may output a voice or a warning sound that the care recipient has gotten out of bed. In this case, the control device 30 requires a speaker (not shown) that outputs a predetermined voice signal or a warning sound by the control unit 34.

(Third embodiment of determining the condition of a care recipient)
A third embodiment of the state determination will be described with reference to FIGS.
In this embodiment, sleep onset determination is performed first.
In the sleep determination, the control unit 34 first determines whether the shape of the care recipient detected by the multiple detection units 25 detecting the pressure is a lying position, including a supine position or a lateral position, or a position other than the lying position, as in step S400. Positions other than the lying position include sitting and getting out of bed. In the lying position, the detection units 25 corresponding to the entire body of the care recipient from head to feet detect pressure, and in the position other than the lying position, the number of detection units 25 detecting pressure in the X direction is extremely small compared to the lying position. Therefore, the control unit 34 can determine that the care recipient is in a lying position when the length in the X direction of the multiple detection units 25 detecting pressure is equal to or greater than a predetermined length, and can determine that the care recipient is in a position other than the lying position when the length in the X direction is less than the predetermined length.

When the control unit 34 determines that the care recipient is in a lying position, it proceeds to step S402 and measures the duration of the lying position. The control unit 34 pre-sets a threshold for the duration as a tenth threshold, and determines that the care recipient has fallen asleep if the duration is equal to or greater than the tenth threshold, and determines that the care recipient has not fallen asleep if the duration is less than the tenth threshold. The tenth threshold can be set to, for example, 300 seconds.

If it is determined in step S400 that the care recipient is in a position other than the lying position, or if it is determined in step S402 that the care recipient is before falling asleep, the process proceeds to the flow of determining the state of the care recipient before falling asleep shown in FIG.
When it is determined in step S402 that the care recipient has fallen asleep, the process proceeds to a flow of determining the state of the care recipient after falling asleep, as shown in FIG.

Next, the state determination of the care recipient before falling asleep will be described with reference to FIG.
In step S500, the control unit 34 performs bed exit determination based on the load applied to the entire pressure distribution sensor 20. The control unit 34 sets the load threshold as an eleventh threshold in advance, and determines that the patient is in bed (not exiting) when the load is equal to or greater than the eleventh threshold, and determines that the patient is exiting when the load is less than the eleventh threshold. The eleventh threshold can be set to, for example, 10 kg.

When the control unit 34 determines that the patient has left the bed, it controls the monitor 32 to display that the patient has left the bed and to output a warning sound from the speaker. The display on the monitor 32 is displayed in a color (e.g., red) different from other displays so that the warning stands out.

After determining that the patient is in bed, the process proceeds to step S502, where the control unit 34 compares the distance from the edge of the bed to the 12th threshold value for the position of the center of pressure in the Y direction. As described above, the Y direction is the width direction of the bed, and this step is for determining that there is a risk of falling if the position of the center of pressure in the Y direction is too far from the center in the Y direction.

For example, if the number of Y-direction detection units 25 in the pressure distribution sensor 20 is 16 as shown in FIG. 4 and the 12th threshold value is 3, when the position of the Y-direction pressure center is less than 3, that is, Y1-Y2 or Y15-Y16, the position of the Y-direction pressure center is determined to be within a predetermined distance range from the end of the bed, so that a warning about falling is displayed on the monitor 32, and a warning sound is output from the speaker.
Since the fall warning has a lower degree of urgency than the bed exit warning, the fall warning is displayed on the monitor 32 in a color different from the other warnings and in a color (e.g., yellow) different from that for the bed exit warning, so that the warning stands out. The warning sound is also different from that for the bed exit warning.

Furthermore, if the position of the center of pressure in the Y direction is a distance from the end of the bed that is equal to or greater than the twelfth threshold, that is, in the case of Y3 to Y14, it is determined that the position of the center of pressure in the Y direction is not near the end of the bed and the process proceeds to step S504.
In step S504, no body movement or excessive body movement is determined based on whether the pressure center position (not limited to the Y-direction pressure center) is moving.
Since pressure data is transmitted at predetermined intervals, the control unit 34 determines whether the pressure center position of the previously received pressure data and the pressure center of the currently received pressure data have moved less than a predetermined distance (a pre-set 13th threshold value) or more than a predetermined distance (a pre-set 13th threshold value).

For example, if the preset 13th threshold is set to 0.5 cells, if the position of the center of pressure has moved a distance of 0.5 or more, in terms of the number of detection units 25, in either the X direction or the Y direction from the position of the center of pressure measured previously, the process proceeds to step S506.
If the position of the center of pressure has moved a distance less than 0.5 in terms of the number of detection units 25 in either the X direction or the Y direction from the previously measured position of the center of pressure (i.e., if it has not moved), proceed to step S505.

In step S505, the control unit 34 judges whether the subject is motionless or at rest. The control unit 34 judges the subject to be motionless if the state in which the position of the center of pressure is less than the 13th threshold continues for a period of time equal to or longer than a preset 14th threshold, and judges the subject to be at rest if the state in which the position of the center of pressure is less than the 13th threshold continues for a period of time less than a preset 14th threshold. The 14th threshold can be set to, for example, 10,800 seconds.
The results of being determined to be motionless and quiet are displayed on the monitor 32. In these cases, since there is no particular urgency, there is no need to output audio from the speaker.

In step S506, the control unit 34 judges whether the body movement is excessive or merely body movement. The control unit 34 judges that the body movement is excessive when the state in which the position of the pressure center is equal to or greater than the 13th threshold continues for a period equal to or greater than the 15th threshold set in advance, and judges that the body movement is excessive when the state in which the position of the pressure center is equal to or greater than the 13th threshold continues for a period less than the 15th threshold set in advance. The 15th threshold can be set to, for example, 10 seconds.
The result of the determination that there is body movement is displayed on the monitor 32. When there is excessive body movement, the result is displayed on the monitor 32 and an alarm sound is output from the speaker.
Since excessive body movement is less urgent than getting out of bed or being careful not to fall, the display on the monitor 32 is made to stand out as a warning by using a color (e.g., green) different from other displays and a color different from the warnings for getting out of bed and being careful not to fall. The warning sound is also made to be different from the warnings for getting out of bed and being careful not to fall.

After the pre-sleep state determination shown in FIG. 10 is completed, the control unit 34 returns to the sleep onset determination shown in FIG. 9 and repeats the sleep onset determination process.

Next, the state determination of the care recipient after falling asleep will be described with reference to FIG.
In step S600, the control unit 34 performs bed exit determination based on the load applied to the entire pressure distribution sensor 20. The control unit 34 preliminarily sets a load threshold as a 16th threshold, and determines that the patient is in bed (not exiting) when the load is equal to or greater than the 16th threshold, and determines that the patient is exiting when the load is less than the 16th threshold. The 16th threshold can be set to, for example, 10 kg.

When the control unit 34 determines that the patient has left the bed, it controls the monitor 32 to display that the patient has left the bed and to output a warning sound from the speaker. The display on the monitor 32 is displayed in a color (e.g., red) different from other displays so that the warning stands out.

After determining that the patient is in bed, the process proceeds to step S601, where the control unit 34 compares the position of the center of pressure in the Y direction from the edge of the bed with the 17th threshold value. As described above, the Y direction is the width direction of the bed, and this step is for determining that there is a risk of falling if the position of the center of pressure in the Y direction is too far from the center in the Y direction.

For example, if the number of Y-direction detection units 25 in the pressure distribution sensor 20 is 16 as shown in FIG. 4 and the 17th threshold value is 3, when the position of the Y-direction pressure center is less than 3, that is, Y1-Y2 or Y15-Y16, the position of the Y-direction pressure center is determined to be within a predetermined distance range from the end of the bed, so that a warning about falling is displayed on the monitor 32, and a warning sound is output from the speaker.
Since the fall warning has a lower degree of urgency than the bed exit warning, the fall warning is displayed on the monitor 32 in a color different from the other warnings and in a color (e.g., yellow) different from that for the bed exit warning, so that the warning stands out. The warning sound is also different from that for the bed exit warning.

Furthermore, if the position of the center of pressure in the Y direction is a distance from the end of the bed that is equal to or greater than the 17th threshold, that is, in the range of Y3 to Y14, it is determined that the position of the center of pressure in the Y direction is not near the end of the bed and the process proceeds to step S602.
In step S602, whether the care recipient is in a lying or sitting position is determined based on the shape of the multiple detection units 25 detecting the pressure of the care recipient. In the lying position, the detection units 25 corresponding to the entire body of the care recipient from head to feet detect pressure, and in the sitting position, the number of detection units 25 detecting pressure in the X direction is extremely small compared to the lying position. Therefore, the control unit 34 can determine that the care recipient is in a lying position when the length in the X direction of the multiple detection units 25 detecting pressure is equal to or greater than a predetermined length (a preset 18th threshold value), and can determine that the care recipient is in a position other than lying position when the length in the X direction is less than the predetermined length (a preset 18th threshold value).

When the control unit 34 determines that the care recipient is in a sitting position, the care recipient is sitting in the center of the bed 11 and may get up, which may pose a risk of falling, etc. Therefore, the control unit 34 displays a warning to the care recipient not to get up on the monitor 32 and outputs a warning sound from the speaker.
The warning to get up is less urgent than the warning to get out of bed, so the warning is displayed on the monitor 32 in a color different from the other warnings and in a color (e.g. purple) different from that for getting out of bed so that the warning stands out. The warning sound is also different from that for getting out of bed.

In step S602, no body movement or excessive body movement is determined based on whether the pressure center position (not limited to the Y-direction pressure center) is moving.
Since pressure data is transmitted at predetermined intervals, the control unit 34 determines whether the pressure center position of the previously received pressure data and the pressure center of the currently received pressure data have moved less than a predetermined distance (19th threshold value) or more than a predetermined distance (19th threshold value).

For example, if the preset 19th threshold is set to 0.5 cells, if the position of the center of pressure has moved a distance of 0.5 or more, in terms of the number of detection units 25, in either the X direction or the Y direction from the previously measured position of the center of pressure, the process proceeds to step S606.
If the position of the center of pressure has moved a distance less than 0.5 in terms of the number of detection units 25 in either the X direction or the Y direction from the previously measured position of the center of pressure (i.e., if it has not moved), proceed to step S605.

In step S605, the control unit 34 judges whether the subject is motionless or at rest. The control unit 34 judges the subject to be motionless if the state in which the position of the center of pressure is less than the 19th threshold continues for a preset 20th threshold or more, and judges the subject to be at rest if the state in which the position of the center of pressure is less than the 19th threshold continues for a preset 20th threshold or less. The 20th threshold can be set to, for example, 10,800 seconds.
The results of being determined to be motionless and quiet are displayed on the monitor 32. In these cases, since there is no particular urgency, there is no need to output audio from the speaker.

In step S606, the control unit 34 judges whether the body movement is excessive or merely body movement. The control unit 34 judges that the body movement is excessive when the state in which the position of the pressure center is equal to or greater than the 19th threshold continues for a period equal to or greater than the preset 21st threshold, and judges that the body movement is excessive when the state in which the position of the pressure center is equal to or greater than the 19th threshold continues for a period less than the preset 21st threshold. The 21st threshold can be set to, for example, 10 seconds.
The result of the determination that there is body movement is displayed on the monitor 32. When there is excessive body movement, the result is displayed on the monitor 32 and an alarm sound is output from the speaker.
Since excessive body movement is less urgent than getting out of bed or being careful not to fall, the display on the monitor 32 is made to stand out as a warning by using a color (e.g., green) different from other displays and a color different from the warnings for getting out of bed and being careful not to fall. The warning sound is also made to be different from the warnings for getting out of bed and being careful not to fall.

Even after the pre-sleep state determination shown in FIG. 11 is completed, the control unit 34 repeatedly executes the post-sleep state change determination.
However, if it is determined that the patient has left the bed, the process returns to the sleep onset determination shown in FIG. 9 and repeats the steps of sleep onset determination.

In the third embodiment, as in the first embodiment, if the state in each judgment step does not continue for a predetermined time, it is judged to be a malfunction due to noise or the like, and each judgment step returns to the start of the judgment. If the judgment result continues after measuring for a predetermined time, it is determined that the judgment result has been confirmed, and each judgment result is displayed on the monitor 32 and an alarm sound is output from the speaker.

Furthermore, in the third embodiment, when the judgment result indicates a highly urgent state, a warning sound is output, but as in the first embodiment, a warning sound or voice output may be output.

(Output of status judgment results to external device)
In the above-described first to third embodiments, the case where the result of determining the state of the care recipient is displayed on the monitor 32 of the control device 30 has been described.
However, the result of determining the condition of the care recipient may be displayed on a mobile terminal device carried by the caregiver.

A schematic diagram of an embodiment in which the state determination result is displayed on a mobile terminal device carried by a caregiver is shown in Fig. 12. Note that the same components as those in the above-described embodiment are given the same reference numerals and the description thereof will be omitted.
In this embodiment, the control unit 34 of the control device 30 transmits the condition of the person being cared for determined by the first to third embodiments described above via the communication device 33 to multiple mobile terminal devices 40 carried by multiple caregivers respectively.

The mobile terminal device 40 may be a so-called smartphone, tablet, or the like, but is not limited to a specific device.
In this way, the condition of the person being cared for can be received by the mobile terminal device 40 carried by the caregiver, so the caregiver does not need to constantly look at the display on the monitor 32 and can check the condition of the person being cared for wherever he or she is.

REFERENCE SIGNS LIST 10 Monitoring system 11 Bed 20 Pressure distribution sensor 21 Conductive cloth 22 First electrode cloth 23 Second electrode cloth 25 Detection unit 26 Signal line 27 Controller 29 Router 30 Control device 32 Monitor 33 Communication device 34 Control unit 35 Memory unit 36 Input unit 37 User information 40 Portable terminal device P1 Data processing program

Claims (12)

A pressure distribution sensor having a plurality of detection units, the pressure distribution sensor being arranged so as to cover the entire bed of the care recipient;
a control device that receives pressure data detected by each detection unit of the pressure distribution sensor, and executes a function of creating a color-coded pressure distribution image for each detection unit based on the value of the input pressure data, and a function of determining the state of the care recipient based on the input pressure data;
a monitor for displaying a pressure distribution image created by the control device ;
The control device includes:
creating unit space data for each of the supine, lateral and sitting positions of the care recipient based on parameters including at least an average value of pressure data input from the multiple detection units in the pressure distribution sensor, the number of detection units that detected, and the number of detection units in the length direction of the bed;
A care recipient monitoring system characterized by calculating the Mahalanobis distance between pressure data input from multiple detection elements in a pressure distribution sensor and the created unit space data, and determining the posture of the care recipient . The care recipient monitoring system according to claim 1, characterized in that the control device is equipped with a notification means for notifying the determined condition of the care recipient. The control device is characterized in that it classifies the condition of the person being cared for into multiple types, sets one or more of the multiple types of conditions as a dangerous condition, and if the determined condition is the set dangerous condition, it issues a warning by the notification means. The care-receiver monitoring system of claim 3, characterized in that when multiple types of dangerous conditions are set, the control device sets danger levels for the multiple types of dangerous conditions in stages, and issues different warnings according to the stages using the alarm means . The control device includes:
A care recipient monitoring system as described in any one of claims 1 to 4 , characterized in that pressure data from a plurality of pressure distribution sensors is input, and the pressure distribution images of each pressure distribution sensor are controlled so as to be divided and displayed on a single monitor. The control device includes:
The care receiver monitoring system according to any one of claims 1 to 5, further comprising a transmission function capable of transmitting the determined information to an external device by wireless communication. A computer-readable program to which pressure data detected by each detection unit of a pressure distribution sensor having a plurality of detection units arranged to cover the entire bed of a care recipient is input,
A function to create a color-coded pressure distribution image for each detector based on the input pressure data value;
a function of creating unit space data for each of the postures of the care recipient, namely supine, lateral and sitting, based on parameters including at least an average value of pressure data input from the multiple detection units in the pressure distribution sensor, the number of detection units that detected, and the number of detection units that detected in the longitudinal direction of the bed, and calculating a Mahalanobis distance between the created unit space data and the pressure data input from the multiple detection units in the pressure distribution sensor, and determining the posture of the care recipient;
A care recipient monitoring program that causes a computer to execute a function of displaying the created pressure distribution image and the determined condition of the care recipient on a monitor connected to the computer. 8. The care receiver monitoring program according to claim 7, further comprising a function of informing the determined condition of the care receiver on the computer. The care recipient monitoring program of claim 8, characterized in that the computer is caused to execute a function of classifying the condition of the care recipient into multiple types, setting one or more of the multiple types of conditions as dangerous conditions , and notifying the care recipient as a warning if the determined condition is the set dangerous condition. The care recipient monitoring program of claim 9, characterized in that when multiple types of dangerous conditions are set, the program causes the computer to execute a function of setting danger levels for the multiple types of dangerous conditions in stages and issuing different warnings for each stage. A care recipient monitoring program as described in any one of claims 7 to 10, characterized in that the program causes a computer to execute a control function in which pressure data from a plurality of pressure distribution sensors is input and each pressure distribution image of each pressure distribution sensor is split and displayed on a single monitor. The program for monitoring a care recipient according to any one of claims 7 to 11 , characterized in that the program causes a computer to execute a transmission function capable of transmitting the determined information to an external device by wireless communication.

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