Patent Publication Number: US-2020289786-A1

Title: Measurement apparatus and measurement system

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims priority to and the benefit of Japanese Patent Application No. 2017-207479 filed on Oct.  26 ,  2017  and Japanese Patent Application No. 2018-109734 filed on Jun. 7, 2018, the entire disclosures of which are incorporated herein by reference. 
     TECHNICAL FIELD 
     The present disclosure relates to a measurement apparatus and a measurement system. 
     BACKGROUND 
     Measurement apparatuses that are worn on the human body to measure biological information are conventionally known. For example, PTL  1  discloses an ear-worn type apparatus that is worn at the ears, detects biological information, and calculates a blood flow state value based on the detected biological information. 
     CITATION LIST 
     Patent Literature 
     PTL 1: JP 2005-192581 A 
     SUMMARY 
     A measurement apparatus according to an aspect comprises: 
     a wearing portion configured to be worn at an auricle of a subject; 
     a body portion joined to the wearing portion; 
     a first measurement portion joined to the body portion, and configured to be worn by the subject and measure oxygen saturation; and 
     a second measurement portion joined to the body portion, and configured to be in contact with the subject in a state in which the wearing portion is worn and measure body temperature. 
     A measurement apparatus according to another aspect comprises: 
     a wearing portion configured to be worn at an auricle of a subject; 
     a body portion including a connector configured to removably connect a measurement instrument capable of measuring biological information of the subject; and 
     a body temperature measurement portion joined to the body portion, and configured to be in contact with the subject in a state in which the wearing portion is worn and measure body temperature. 
     A measurement system according to an aspect comprises: 
     a measurement apparatus including: a wearing portion configured to be worn at an auricle of a subject; a body portion including a connector; and a body temperature measurement portion joined to the body portion, and configured to be in contact with the subject in a state in which the wearing portion is worn and measure body temperature; and 
     a measurement instrument configured to be removably connected to the connector, and measure biological information of the subject. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the accompanying drawings: 
         FIG. 1  is a schematic external perspective view of a measurement apparatus according to an embodiment; 
         FIG. 2  is a schematic external perspective view of the measurement apparatus in  FIG. 1  as seen from a different direction; 
         FIG. 3  is a schematic view illustrating an example of a state of wearing the measurement apparatus in  FIG. 1 ; 
         FIG. 4  is a schematic external perspective view illustrating the measurement apparatus in the state in which a measurement instrument is connected to a connector; 
         FIG. 5  is a schematic view illustrating an example of a state of wearing a measurement apparatus according to an embodiment; 
         FIG. 6  is a functional block diagram illustrating a schematic structure of the measurement apparatus and the measurement instrument in  FIG. 4 ; 
         FIG. 7  is a flowchart illustrating an example of a process performed by the measurement apparatus in  FIG. 6 ; 
         FIG. 8  is a flowchart illustrating an example of a process performed by a measurement apparatus according to an embodiment; and 
         FIG. 9  is a functional block diagram illustrating a schematic structure of a measurement system according to an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     In the case of measuring biological information using a conventional measurement apparatus, a different measurement apparatus needs to be used depending on which biological information is to be measured. Hence, a subject needs to wear a plurality of measurement apparatuses in sequence according to the order in which biological information is measured, which is often considered inconvenient. The present disclosure relates to provision of a measurement apparatus and a measurement system capable of improving convenience. According to the present disclosure, a measurement apparatus and a measurement system capable of improving convenience can be provided. An embodiment will be described in detail below, with reference to the drawings. 
       FIG. 1  is a schematic external perspective view of a measurement apparatus  10  according to an embodiment.  FIG. 2  is an external perspective view of the measurement apparatus  10  in  FIG. 1  as seen from a different direction. That is,  FIGS. 1 and 2  are external perspective views of the same measurement apparatus  10  as seem from different directions. 
     The measurement apparatus  10  is used in a state of being worn by a subject. The measurement apparatus  10  may be worn at any position where biological information of the subject can be measured. Non-limiting examples of the position at which the measurement apparatus  10  is worn include the head, the neck, the arms, the wrists, the abdomen, the shoulders, the waist, the hips, the legs, the ankles, and the fingers and toes. This embodiment describes an example in which the measurement apparatus  10  is worn on the head of the subject. Specifically, the measurement apparatus  10  according to this embodiment is worn at the auricles of the subject. 
     The measurement apparatus  10  measures biological information of the subject, in a state of being worn at the auricles of the subject. The biological information is any information about the organism, and may include, for example, oxygen saturation, body temperature, pulse rate, breathing rate, perfusion index (PI) value, blood flow amount, and blood pressure. The biological information may also include, for example, the degree of relaxation indicating the degree of physical and mental relaxation of the organism. The measurement apparatus  10  may estimate the state of the subject based on the measured biological information. The state of the subject is any state of the organism of the subject, and includes, for example, the possibility of developing mountain sickness. 
     The measurement apparatus  10  includes a first wearing portion  110 R, a second wearing portion  110 L, and a joining portion  120 . 
     The first wearing portion  110 R is worn at the right auricle of the subject. That is, when the subject wears the measurement apparatus  10 , the first wearing portion  110 R is in contact with the root of the right auricle of the subject on the side closer to the top of the head, and maintains the wearing state of the measurement apparatus  10 . The second wearing portion  110 L is worn at the left auricle of the subject. That is, when the subject wears the measurement apparatus  10 , the second wearing portion  110 L is in contact with the root of the left auricle of the subject on the side closer to the top of the head. For example, in the state in which the subject wears the measurement apparatus  10 , the measurement apparatus  10  is supported by the first wearing portion  110 R and the second wearing portion  110 L worn at the auricles, as illustrated in  FIG. 3 . 
     The first wearing portion  110 R and the second wearing portion  110 L may have curved shapes as illustrated in  FIGS. 1 and 2  as an example, so as to be easily supported respectively by the right auricle and the left auricle when the subject wears the measurement apparatus  10 . The first wearing portion  110 R and the second wearing portion  110 L may be symmetrically shaped. Herein, the first wearing portion  110 R and the second wearing portion  110 L are collectively referred to as wearing portions  110  when they are not distinguished from each other. 
     The joining portion  120  joins the first wearing portion  110 R and the second wearing portion  110 L. The joining portion  120  has a curved shape, and is configured to be located at the back of the head of the subject in the wearing state of the measurement apparatus  10 . The first wearing portion  110 R, the second wearing portion  110 L, and the joining portion  120  may be symmetrically shaped. 
     The joining portion  120  may be shaped so as not to interfere with the subject wearing another apparatus on the head. For example, the subject may wear a helmet, glasses, a cap, or the like as another apparatus. The joining portion  120  may be shaped so that the subject can wear a helmet, glasses, a cap, or the like even when he or she wears the measurement apparatus  10 . For example, the joining portion  120  may be shaped so as to be located closer to the neck of the subject than the back of the head of the subject in the wearing state of the measurement apparatus  10 . The joining portion  120  may be shaped so as to cover the top of the head. 
     The joining portion  120  is provided with a body portion  130  that includes a substrate for controlling a measurement process by the measurement apparatus  10 . In detail, the body portion  130  is joined to the wearing portions  110  via the joining portion  120 , and supported by the wearing portions  110  in the wearing state of the measurement apparatus  10 . The body portion  130  may have a thin platelike shape. With such a body portion  130 , the subject can easily wear the measurement apparatus  10 . Moreover, such a body portion  130  is unlikely to cause discomfort to the subject in the wearing state of the measurement apparatus  10 . 
     A body temperature measurement portion  140  is joined to the body portion  130 . For example, the body temperature measurement portion  140  may be shaped to project from the body portion  130 . The body temperature measurement portion  140  may be joined to the body portion  130  so as to be in contact with the mastoid part of the subject in the state in which the subject wears the measurement apparatus  10 . That is, in the wearing state of the measurement apparatus  10 , a tip  141  of the projecting body temperature measurement portion  140  is in contact with the mastoid part of the subject. The mastoid part is a part between the auricle and the back of the head. For example, the tip  141  of the projecting body temperature measurement portion  140  includes a thermistor, and the body temperature measurement portion  140  can measure the body temperature of the subject by the thermistor. In this embodiment, the tip  141  of the body temperature measurement portion  140  is configured to be in contact with the left mastoid part of the subject, as illustrated in  FIG. 3  as an example. The body temperature measurement portion  140  may be configured to measure the body temperature by detecting infrared light. The body temperature measurement portion  140  may be joined to the body portion  130  so as to be in contact with a part other than the mastoid part of the subject in the state in which the subject wears the measurement apparatus  10 . The body temperature measurement portion  140  may measure the body temperature of the subject without being in contact with the subject in the state in which the subject wears the measurement apparatus  10 , in the body portion  130 . 
     The body temperature measurement portion  140  may be configured to be biased toward the mastoid part of the subject in the wearing state of the measurement apparatus  10 . For example, the body temperature measurement portion  140  may be joined to the body portion  130  via a spring, and configured to be biased toward the mastoid part by the elastic force of the spring. The body temperature measurement portion  140  may be configured to be biased toward the mastoid part by a mechanism other than a spring. The force for biasing the body temperature measurement portion  140  may be, for example, such that the subject wearing the measurement apparatus  10  feels no pain. The force for biasing the body temperature measurement portion  140  may be, for example, such that the tip  141  of the body temperature measurement portion  140  does not separate from the mastoid part. 
     The body portion  130  includes a connector  150  to which a measurement instrument capable of measuring biological information of the subject is removably connectable. For example, the connector  150  may be formed as a female connector. The connector  150  may have a shape conforming to a predetermined standard. The connector  150  may be connected with, for example, a measurement instrument capable of measuring predetermined biological information depending on the state of the subject to be measured (or estimated). This embodiment describes an example in which the connector  150  is connected with a measurement instrument capable of measuring the oxygen saturation of the subject. 
       FIG. 4  is a schematic external perspective view illustrating the measurement apparatus  10  in the state in which a measurement instrument  20  is connected to the connector  150 . The measurement instrument  20  may be, for example, an instrument having a function corresponding to a pulse oximeter, which is capable of measuring oxygen saturation. For example, the measurement instrument  20  is capable of measuring, as the oxygen saturation of the subject, percutaneous oxygen saturation (SpO 2 , S: saturation, p: percutaneous or pulse oximetry, O 2 : oxygen). The biological information measured by the measurement instrument  20  is, however, not limited to SpO 2  and blood flow amount. Hereafter, percutaneous oxygen saturation (SpO 2 ) is also simply referred to as oxygen saturation. One value indicating oxygen saturation is SaO 2  (S: saturation, a: artery, O 2 : oxygen), and SaO 2  represents a measured value of the oxygen saturation of arterial blood. By measuring SpO 2 , SaO 2  can be measured indirectly. If measurement conditions are right, the two values are approximate to each other. 
     The measurement instrument  20  in  FIG. 4  includes a connector  210  connectable to the connector  150  in the measurement apparatus  10 , a measurement portion  220  capable of measuring biological information at a measured part, and a cable  230  joining the connector  210  and the measurement portion  220 . 
     The connector  210  may be formed as, for example, a male connector of a shape removably connectable to the connector  150  in the measurement apparatus  10 . 
     The measurement portion  220  may be configured to, for example, sandwich the measured part to be worn at the measured part. For example, the measurement portion  220  is configured to sandwich the earlobe as the measured part to be worn at the earlobe. For example, the biological information may be measured at, as the measured part, the earlobe of the auricle on the side opposite to the body temperature measurement portion  140 . In the case of using the measurement apparatus  10  illustrated in  FIGS. 1 to 4 , the measurement portion  220  can acquire the biological information from the earlobe of the right ear as the measured part. The measurement portion  220  may acquire the biological information from the earlobe of the left ear as the measured part, or acquire the biological information from the earlobes of both the right and left ears as the measured part. 
     The measurement portion  220  includes two light sources, i.e. a first light source and a second light source, as illustrated in  FIG. 6  described later. The first and second light sources emit light of different wavelengths. The first light source emits light of a first wavelength, and the second light source emits light of a second wavelength different from the first wavelength. The first wavelength is a wavelength at which the difference between the absorbance of hemoglobin combined with oxygen (hereafter also referred to as “oxygenated hemoglobin”) and the absorbance of hemoglobin not combined with oxygen (hereafter also referred to as “reduced hemoglobin”) is large. For example, the first wavelength is a wavelength of 600 nm to 700 nm, and the light emitted from the first light source is red light. The second wavelength is a wavelength at which the difference between the absorbance of oxygenated hemoglobin and the absorbance of reduced hemoglobin is small as compared with the first wavelength. For example, the second wavelength is a wavelength of 800 nm to 1000 nm, and the light emitted from the second light source is near-infrared light. 
     The measurement portion  220  further includes an optical detector capable of receiving light transmitted through the body&#39;s tissues (measured part) from among the light emitted from the first and second light sources. The optical detector outputs a signal corresponding to the intensity of the received light, to the body portion  130 . The measurement portion  220  may include two optical detectors, i.e. a first optical detector and a second optical detector, respectively capable of receiving the transmitted light of the light emitted from the first and second light sources, or include one optical detector capable of receiving the transmitted light of the light emitted from the first and second light sources. This embodiment describes an example in which the measurement portion  220  includes one optical detector. 
     In the body portion  130 , for example, the below-described controller calculates SpO 2  based on the signal acquired from the optical detector. Specifically, the controller calculates SpO 2  based on the difference in received light intensity in the optical detector between when the first light source irradiates the measured part and when the second light source irradiates the measured part. The controller can further calculate the pulse rate, based on the temporal change in received light intensity in the optical detector. Specifically, the controller can calculate the period of received light intensity from the temporal change in received light intensity, and calculate the pulse rate per unit time based on the period. The controller can further calculate the PI value, based on the temporal change in received light intensity in the optical detector. The PI value is also referred to as “perfusion index”, and is expressed as the proportion of the pulsatile component to the non-pulsatile component in the blood flow. The controller can calculate PI, by calculating the proportion of the pulsatile component to the non-pulsatile component in the blood flow from the temporal change in received light intensity. The controller can further calculate the breathing rate, based on the temporal change in received light intensity in the optical detector. For example, the controller calculates the breathing rate by extracting the low frequency component of the temporal change in received light intensity in the optical detector. 
     Referring back to  FIGS. 1 and 2 , the joining portion  120  may include a battery holder  121 . The battery holder  121  includes a battery for driving each functional part included in the measurement apparatus  10 . 
     The body portion  130  and the battery may be arranged in the joining portion  120  so that the force exerted from the first wearing portion  110 R on the right auricle and the force exerted from the second wearing portion  110 L on the left auricle are approximately equal. That is, the body portion  130  and the battery may be arranged in the joining portion  120  so that the right-left weight balance is approximately equal in the wearing state of the measurement apparatus  10 . Herein, the phrase “approximately equal” includes a range in which the subject wearing the measurement apparatus  10  feels no discomfort in terms of weight balance. That is, the phrase “approximately equal” includes a range in which the subject does not feel that the right and left weights are not balanced in the wearing state of the measurement apparatus  10 . The body portion  130  and the battery may be, for example, arranged at corresponding positions on the left and the right in the joining portion  120 . In the example illustrated in  FIGS. 1 and 2 , the battery is located near the first wearing portion  110 R, and the body portion  130  is located near the second wearing portion  110 L. 
     The measurement apparatus  10  according to this embodiment further includes a sound output interface  160  that causes the subject wearing the measurement apparatus  10  to hear sound. In this embodiment, the sound output interface  160  is located on the tip side of the wearing portion  110  not joined to the joining portion  120 . In this embodiment, the sound output interface  160  is configured to be located at the harmony crevice or temple of the subject in the wearing state of the measurement apparatus  10 . The sound output interface  160  may be formed by, for example, a bone conduction speaker for causing the subject to hear sound by vibration transmission to the human body. In this case, for example, the sound output interface  160  vibrates based on a control signal from the controller in the body portion  130 . As a result of the vibration of the sound output interface  160  propagating to the skull of the subject, the subject can hear sound. In this case, the measurement apparatus  10  can make the subject hear sound without covering the ear of the subject, so that the subject can hear ambient sound. The sound output interface  160  may be configured to be located at any position of the body of the subject, such as the temporal region, the forehead, any other part of the head, or the neck, in the wearing state of the measurement apparatus  10 . 
     The sound output interface  160  may not necessarily be formed by a bone conduction speaker. The sound output interface  160  may be formed by an apparatus for transmitting sound to a user by air vibration, such as an earphone or a speaker. In this case, the sound output interface  160  outputs sound based on a control signal from the controller. In the present disclosure, a bone conduction speaker and an apparatus for transmitting sound to a user by air vibration may be used together. That is, the sound output interface  160  may be any combination of a bone conduction speaker and an apparatus for transmitting sound to a user by air vibration. 
       FIG. 5  is a view illustrating the state in which the subject wears the measurement apparatus  10  in the case where the sound output interface  161  is formed by an earphone, a speaker, or the like. The measurement apparatus  10  in  FIG. 5  has the same structure as the measurement apparatus  10  in  FIG. 3 , except that the sound output interface  160  in the measurement apparatus  10  in  FIG. 3  has been replaced with a sound output interface  161 . In the case where the sound output interface  160  is formed by a bone conduction speaker, there is no need to cover the ear of the subject when causing the subject to hear sound, as described earlier with reference to  FIG. 3 . In the case where the sound output interface  161  is formed by an earphone, a speaker, or the like, on the other hand, the portion of the sound output interface  161  from which sound is output may be close to the auricle or external ear canal hole of the subject, as illustrated in  FIG. 5 . For example, in the case where the sound output interface  161  is formed by a speaker, the portion of the sound output interface  161  from which sound is output may be configured to abut on any part of the auricle of the subject (e.g. near the external ear canal hole). For example, in the case where the sound output interface  161  is formed by an earphone, at least part of the portion (e.g. earpiece) of the sound output interface  161  from which sound is output may be configured to be inserted in the external ear canal hole of the subject. In the case where the sound output interface  161  is formed by an earphone, a speaker, or the like as illustrated in  FIG. 5 , the subject may find it harder to hear ambient sound, but can easily concentrate on the sound output from the sound output interface  161 . 
     In the example illustrated in  FIGS. 1 and 2 , the sound output interface  160  is provided on the tip side of each of the first wearing portion  110 R and the second wearing portion  110 L. The sound output interface  161 , on the other hand, may be provided on the tip side of only one of the first wearing portion  110 R and the second wearing portion  110 L, or provided at any position of the measurement apparatus  10  other than the tip side of the wearing portion. In the following description, the sound output interface  160  is replaceable with the sound output interface  161  as appropriate. 
     The measurement apparatus  10  according to an embodiment can perform measurement by at least one of the measurement instrument  20  and the body temperature measurement portion  140  while the sound output interface  160  is outputting predetermined sound. In the measurement apparatus  10  according to an embodiment, the sound output interface  160  can output predetermined sound based on information measured by at least one of the measurement instrument  20  and the body temperature measurement portion  140 . In the measurement apparatus  10  according to an embodiment, the sound output by the sound output interface  160  may be sound having a psychological and/or physiological action on the subject using the measurement apparatus  10 . For example, in the measurement apparatus  10  according to an embodiment, the sound output by the sound output interface  160  may be sound including solfeggio frequencies. 
     Herein, the solfeggio frequencies are sound frequencies considered to have some kind of effect on the human mind and/or body. For example, the following are known as sounds of frequencies considered to have effect on the human mind and/or body based on past studies. Sound of 174 Hz is considered to be effective in pain alleviation. Sound of 285 Hz is considered to be effective in expansion and promotion of consciousness from multidimensional domain. Sound of 396 Hz is considered to be effective in release from guilt, trauma, and fear. Sound of 417 Hz is considered to be effective in recovery from negativity and promotion of transformation. Sound of 528 Hz is considered to be effective in conversion to ideals, miracle, and cell recovery. Sound of 639 Hz is considered to be effective in repair of human connections and relationships. Sound of 741 Hz is considered to be effective in expressiveness improvement and problem solution. Sound of 852 Hz is considered to be effective in raising intuition and awareness. Sound of 963 Hz is considered to be effective in connection with high-dimensional, cosmic consciousness. For example, while the sound output interface  160  is outputting sound of 396 Hz, the measurement apparatus  10  can perform measurement by at least one of the measurement instrument  20  and the body temperature measurement portion  140  on the subject who is in a relaxed state. 
     In the measurement apparatus  10  according to an embodiment, the sound output by the sound output interface  160  may be, for example, sound constituting music (typically, sound including melody), or predetermined sound effects such as environmental sound (typically, sound not including melody). The predetermined sound effects such as environmental sound may include, for example, sound of leaves rustling in the wind with occasional sound of chirping birds, which conjure images of forests. The predetermined sound effects such as environmental sound may include, for example, sound of waves, which conjures images of beaches. In the measurement apparatus  10  according to an embodiment, the sound output by the sound output interface  160  may be, for example, a mixture of sound constituting music (typically, sound including melody) and predetermined sound effects such as environmental sound (typically, sound not including melody). 
     In the measurement apparatus  10  according to an embodiment, the sound output by the sound output interface  160  may be sound having a favorable action on the subject using the measurement apparatus  10 , such as the subject&#39;s favorite music. While the sound output interface  160  is outputting such sound, the measurement apparatus  10  can perform measurement by at least one of the measurement instrument  20  and the body temperature measurement portion  140  on the subject who is in a favorable state. 
       FIG. 6  is a functional block diagram illustrating a schematic structure of the measurement apparatus  10  and the measurement instrument  20  in  FIG. 4 . The measurement apparatus  10  includes a controller  101 , a memory  103 , the body temperature measurement portion  140 , and the sound output interface  160  as functional parts, as illustrated in  FIG. 6 . 
     The controller  101  includes at least one processor  102  that controls and manages the whole measurement apparatus  10 , e.g. each functional block in the measurement apparatus  10  and the measurement instrument  20 . The controller  101  includes at least one processor  102  such as a CPU (Central Processing Unit) that executes a program defining a control procedure, to achieve its functions. Such a program is, for example, stored in the memory  103  or an external storage medium connected to the measurement apparatus  10 . 
     In various embodiments, at least one processor  102  may be implemented as a single integrated circuit (IC), or as a plurality of ICs and/or discrete circuits communicably connected to one another. At least one processor  102  can be implemented according to various known technologies. 
     In one embodiment, the processor  102  includes, for example, one or more circuits or units configured to perform one or more data calculation procedures or processes by executing instructions stored in related memory. In another embodiment, the processor  102  may be firmware (e.g. a discrete logic component) configured to perform one or more data calculation procedures or processes. 
     In various embodiments, the processor  102  may include one or more processors, controllers, microprocessors, microcontrollers, application specific integrated circuits (ASICs), digital signal processors, programmable logic devices, field programmable gate arrays, or any combination of these devices or structures, or any combination of other known devices or structures, to perform the functions of the controller  101  described below. 
     The controller  101  controls biological information measurement processes. For example, the controller  101  controls a process of measuring the body temperature of the subject by the body temperature measurement portion  140 . For example, the controller  101  controls a process of measuring the SpO 2  of the subject by the measurement instrument  20 . The controller  101  may simultaneously perform the body temperature measurement process by the body temperature measurement portion  140  and the SpO 2  measurement process by the measurement instrument  20 . The controller  101  can thus measure the body temperature and SpO 2  at the same time. 
     The controller  101  may transmit a control signal to the sound output interface  160  to cause the subject to hear sound such as music described above, while performing the body temperature measurement process by the body temperature measurement portion  140  and the SpO 2  measurement process by the measurement instrument  20 . This helps the subject relax, and not be conscious of the fact that biological information is being measured. Consequently, the measurement apparatus  10  can measure more accurate biological information. 
     The controller  101  may estimate the state of the subject based on the measured information. In this embodiment, for example, the controller  101  may estimate the possibility of the subject developing mountain sickness (also referred to as altitude sickness), based on the measured body temperature and SpO 2  of the subject. Mountain sickness tends to be developed as a result of a decrease in SpO 2 . Moreover, with mountain sickness, the body temperature is higher than in normal time. The controller  101  can therefore estimate the possibility of the subject developing mountain sickness, based on body temperature and SpO 2 . The controller  101  may estimate the possibility of developing mountain sickness by, for example, weighing body temperature and SpO 2  using a predetermined algorithm. Conventionally, in the case of measuring body temperature and SpO 2  by, for example, wearing a thermometer and a pulse oximeter in sequence, it is impossible to measure body temperature and SpO 2  at the same time. It is therefore difficult to estimate the possibility of developing mountain sickness based on two types of information, i.e. body temperature and SpO 2 . With the measurement apparatus  10  according to this embodiment, however, body temperature and SpO 2  can be measured simultaneously, so that the possibility of developing mountain sickness can be estimated based on two indices, i.e. body temperature and SpO 2 . The measurement apparatus  10  according to this embodiment thus achieves higher estimation accuracy than in the case of estimating the possibility of developing mountain sickness based on any one index. 
     The controller  101  may notify the subject of the measured biological information and/or the information about the estimated possibility of developing mountain sickness via the sound output interface  160 , by controlling the sound output interface  160 . This allows the subject to learn the information. For example, in the case where the subject is notified that his or her possibility of developing mountain sickness is high, the subject can take measures to prevent mountain sickness beforehand. 
     The memory  103  may be formed by semiconductor memory, magnetic memory, or the like. The memory  103  stores various information, programs for operating the measurement apparatus  10 , and the like. The memory  103  may function as working memory. For example, the memory  103  may store the body temperature and SpO 2  of the subject calculated by the controller  101 , as historical information. The memory  103  may store information about the possibility of developing mountain sickness estimated by the controller  101 . 
     In an embodiment, the memory  103  may store information of the sound output by the sound output interface  160 . The information of the sound stored in the memory  103  may be, for example, an audio file in any format such as an MP3 (MPEG-1 Audio Layer-3) file or a WAV file. The information of the sound stored in the memory  103  may be, for example, any data that can be supplied to each type of synthesizer or sequencer, such as an MIDI (Musical Instrument Digital Interface) data. In an embodiment, the memory  103  may store information of each type of sound depending on the state of the subject using the measurement apparatus  10 . 
     The structures and functions of the body temperature measurement portion  140  and the sound output interface  160  are as described above, and accordingly their detailed description is omitted here. 
     The measurement instrument  20  includes, in the measurement portion  220 , a first light source  201 , a second light source  202 , and an optical detector  203  as functional parts. The structures and functions of the first light source  201 , the second light source  202 , and the optical detector  203  are as described above, and accordingly their detailed description is omitted here. The measurement instrument  20  has a function corresponding to a pulse oximeter, and measures the SpO 2  of the subject. 
       FIG. 7  is a flowchart illustrating an example of a process performed by the measurement apparatus  10 . For example, when the subject connects the measurement instrument  20  to the measurement apparatus  10 , wears the measurement apparatus  10 , and performs an input operation for executing the measurement process, the measurement apparatus  10  starts the process in the flowchart in  FIG. 7 . 
     First, the controller  101  in the measurement apparatus  10  controls the sound output interface  160  to output sound (step S 11 ). In step S 11 , the controller  101  transmits a control signal for outputting predetermined sound, to the sound output interface  160 . Consequently, for example in the case where the sound output interface  160  is formed by a bone conduction speaker, the sound output interface  160  vibrates to cause the subject to hear the sound. The sound output from the sound output interface  160  in step S 11  may be, for example, such sound that puts the subject in a relaxed state. 
     The measurement apparatus  10  then measures biological information (step S 12 ). In this embodiment, specifically, the measurement apparatus  10  measures the body temperature of the subject by the body temperature measurement portion  140 , and measures the SpO 2  of the subject by the measurement instrument  20 . Information about the measured body temperature and SpO 2  is transmitted to the controller  101 . Thus, the measurement apparatus  10  according to an embodiment may perform measurement by at least one of the body temperature measurement portion  140  and the measurement instrument  20  while the sound output interface  160  is outputting the predetermined sound. In step S 12 , the measurement apparatus  10  according to an embodiment may store the result of the measurement by at least one of the body temperature measurement portion  140  and the measurement instrument  20  in, for example, the memory  103 . 
     By accumulating measurement results obtained while causing the subject using the measurement apparatus  10  to hear various sounds in the memory  103 , the measurement apparatus  10  may determine a tendency of specific sound influencing a specific subject. For example, the measurement apparatus  10  may determine that, when a specific subject is caused to hear specific music, the subject tends to relax, from past information accumulated in the memory  103 . This suggests that, for example in the case where the specific subject is estimated to be under stress, the measurement apparatus  10  may be able to effectively alleviate the stress of the subject by causing the specific subject to hear the specific music. The measurement apparatus  10  according to an embodiment can thus perform measurement on the subject in a relaxed, natural state by causing the subject to hear the predetermined sound and relax. Therefore, the measurement apparatus  10  according to an embodiment can appropriately measure the biological information of the subject. 
     The controller  101  in the measurement apparatus  10  estimates the state of the subject based on the measured biological information (step S 13 ). In this embodiment, specifically, the controller  101  estimates the possibility of the subject developing mountain sickness based on the body temperature and SpO 2  of the subject. 
     In step S 13 , the controller  101  in the measurement apparatus  10  according to an embodiment may estimate the state of the subject, based on information measured by at least one of the body temperature measurement portion  140  and the measurement instrument  20 . For example, the controller  101  may estimate that the possibility of the subject developing mountain sickness is high, in the case where a predetermined condition, such as both of the body temperature and SpO 2  of the subject exceeding predetermined thresholds, is satisfied. For example, the controller  101  may estimate that the subject is in a predetermined healthy state, in the case where the body temperature of the subject is within a first predetermined range and the SpO 2  of the subject is within a second predetermined range. 
     In step S 13 , the controller  101  in the measurement apparatus  10  according to an embodiment may estimate the state of the subject, based on information measured by at least one of the body temperature measurement portion  140  and the measurement instrument  20  and satisfying a predetermined condition. For example, only in the case where the measurement result of the body temperature measurement portion  140  and/or the measurement instrument  20  is within a predetermined range, the controller  101  in the measurement apparatus  10  according to an embodiment may use the measurement result in the estimation of the state of the subject. In an embodiment, in the case where the measurement result of the body temperature measurement portion  140  and/or the measurement instrument  20  is outside the predetermined range, the controller  101  may not use the measurement result in the estimation of the state of the subject. For example, suppose it is estimated beforehand that the subject is in a predetermined state if the measurement result of the body temperature measurement portion  140  and/or the measurement instrument  20  is within the predetermined range. In this case, the state of the subject may be estimated using only the measurement result of the body temperature measurement portion  140  and/or the measurement instrument  20  that is within the predetermined range. In particular, a high body temperature range exceeding the body temperature of a specific subject in a healthy state, a body temperature range in which the specific subject is developing hypothermia, and the like may be determined beforehand. 
     The controller  101  in the measurement apparatus  10  according to an embodiment may take into account at least one of time information and position information when estimating the state of the subject in step S 13 . The time information may be supplied from outside the measurement apparatus  10 , or be information of the time determined by the controller  101 . The position information may be supplied from outside the measurement apparatus  10 , or supplied from a position information acquisition device such as the GPS included in the measurement apparatus  10 . For example, in the case where the subject is determined to be in a state of running, e.g. jogging, from the position information, the controller  101  may estimate the state of the subject by taking into account the exercise state of the subject. For example, in the case where the subject is determined to be in a state of being still from the position information, the controller  101  may estimate the state of the subject by taking into account that the subject is not exercising. Further, the controller  101  may estimate the state of the subject, for example, by taking into account which of morning, noon, night, and midnight the current time is, from the time information. By taking into account other information in this way, the state of the subject can be estimated more accurately. 
     The controller  101  transmits a control signal to the sound output interface  160 , to notify the subject of information via the sound output interface  160  (step S 14 ). For example, the controller  101  notifies the subject of the information by causing the subject to hear predetermined alarm sound or voice. 
     Instead of or in addition to step S 14 , the controller  101  in the measurement apparatus  10  according to an embodiment may change the sound output by the sound output interface  160  depending on the state of the subject estimated in step S 13 . For example, in the case where the subject is estimated to be under stress in step S 13 , the controller  101  may output such sound that alleviates the stress of the subject in step S 14 . For example, in the case where the body temperature of the subject is estimated to be in a slightly low state in step S 13 , the controller  101  may output such sound that lifts the subject&#39;s mood in step S 14 . For example, the state in which the body temperature of the subject is slightly low may be a state in which the body temperature is 1% lower than the average body temperature of the subject or a healthy person or a state in which the body temperature is 2% lower than the average body temperature of the subject or a healthy person. As the state in which the body temperature of the subject is slightly low, the proportion in which the body temperature is lower than the average body temperature of the subject or a healthy person is not limited to 1% or 2%, and may be any value. 
     Thus, the controller  101  in the measurement apparatus  10  according to an embodiment may change the sound output by the sound output interface  160 , based on information measured by at least one of the body temperature measurement portion  140  and the measurement instrument  20 . With the measurement apparatus  10  according to an embodiment, for example, causing the subject to hear the predetermined sound when the result of measuring the subject is deteriorating is expected to be effective in prevention of the physical condition of the subject from worsening or in recovery in an initial stage. 
     The measurement apparatus  10  may continuously cause the subject to hear the predetermined sound via the sound output interface  160  at least during step S 12 . 
     The measurement apparatus  10  may repeat steps S 12  and S 13  or steps S 12 , S 13 , and S 14  periodically, non-periodically, or continuously. The measurement apparatus  10  can thus successively acquire a history of the biological information of the subject and the state of the subject. 
     In step S 14 , the measurement apparatus  10  may notify the subject of the information by a means other than the sound output interface  160 . For example, the measurement apparatus  10  may include a vibrator, and notify the subject of the information by vibrating the vibrator. For example, the measurement apparatus  10  may include a display, and notify the subject of the information by displaying the information on the display. The measurement apparatus  10  may notify the subject of the information by any other means that can be recognized by the subject. 
     Thus, the measurement apparatus  10  according to this embodiment can simultaneously measure a plurality of types of biological information by the body temperature measurement portion  140  included in the measurement apparatus  10  and the measurement instrument  20  connected to the connector  150 . In the embodiment described above, the measurement apparatus  10  can simultaneously measure the body temperature and SpO 2  of the subject. With the measurement apparatus  10  according to this embodiment, a plurality of types of biological information can be simultaneously measured using one apparatus, so that convenience can be improved. Moreover, at least one of the body temperature measurement portion  140  included in the measurement apparatus  10  and the measurement instrument  20  connected to the connector  150  may perform measurement while the sound output interface  160  is outputting predetermined sound in the measurement apparatus  10 . The measurement apparatus  10  according to this embodiment can thus serve to measure the biological information of the subject appropriately and accurately and also maintain or restore the healthy state of the subject. 
     The measurement apparatus  10  also estimates the state of the subject using the plurality of types of biological information measured simultaneously. With such a measurement apparatus  10 , the accuracy of estimating the state of the subject is improved as compared with the case where the state of the subject is estimated based on one type of biological information or the case where the state of the subject is estimated based on the plurality of types of biological information measured at different timings. 
     The measurement apparatus  10  is worn on the head, so that both hands of the subject are free in the wearing state of the measurement apparatus  10 . Since the subject can use both hands even when wearing the measurement apparatus  10 , the safety of the subject is easily ensured. The subject can work using both hands while wearing the measurement apparatus  10 . 
     The foregoing embodiment describes the case where the body portion  130  includes the connector  150  and the measurement instrument  20  capable of measuring SpO 2  is removably connectable to the connector  150 . Alternatively, the measurement apparatus  10  may include, for example, a functional part capable of measuring SpO 2  and corresponding to the measurement instrument  20 . That is, the measurement apparatus  10  may include the functional part capable of measuring SpO 2  and corresponding to the measurement instrument  20 , in a form of being not removably connectable. Even in this case, the measurement apparatus  10  can simultaneously acquire the plurality of types of biological information of the subject by the functional part capable of measuring SpO 2 , which functions as a first measurement portion, and the body temperature measurement portion  140  capable of measuring body temperature, which functions as a second measurement portion. Therefore, in this case, too, the measurement apparatus  10  achieves the same effects as above. 
     The foregoing embodiment describes the case where the body temperature measurement portion  140  is joined to the body portion  130 . Alternatively, the body temperature measurement portion  140  may not be joined to the body portion  130 . For example, the body portion  130  may further include another connector different from the connector  150 , and a body temperature measurement instrument having the same function as the body temperature measurement portion  140  may be removably connectable to the other connector. In this case, too, the measurement apparatus  10  achieves the same effects as above. 
     The foregoing embodiment describes the case where the body portion  130  is located near the second wearing portion  110 L, but the position of the body portion  130  is not limited to such. The body portion  130  can be located at any position where the body portion  130  does not interfere with biological information measurement, in the joining portion  120 . 
     The foregoing embodiment describes the case where the body temperature measurement portion  140  measures the body temperature at the mastoid part of the subject, but the part at which the body temperature is measured is not limited to the mastoid part. The body temperature may be measured at other parts such as the back of the neck or the forehead. The body temperature measurement portion  140  may measure the body temperature at a part where the body temperature of the subject can be accurately measured. The part where the body temperature can be accurately measured is, for example, a part that is less affected by external air. 
     The foregoing embodiment describes the case where the measurement apparatus  10  measures body temperature and SpO 2  as biological information, but the biological information measured by the measurement apparatus  10  is not limited to such. The measurement apparatus  10  may be configured to acquire necessary biological information as appropriate depending on the test object of the subject. Hence, for example, the measurement apparatus  10  need not necessarily include the body temperature measurement portion  140 . In the case of not measuring the body temperature of the subject, the body temperature measurement portion  140  may be omitted from the measurement apparatus  10 . 
     The foregoing embodiment describes the case where the measurement apparatus  10  includes two wearing portions, i.e. the first wearing portion  110 R and the second wearing portion  110 L, but the measurement apparatus  10  need not necessarily include two wearing portions. For example, the measurement apparatus  10  may include only one wearing portion  110 . In this case, the subject uses the measurement apparatus  10 , for example with the wearing portion  110  being worn at one auricle. The measurement apparatus  10  is supported by one ear in this case. 
     The foregoing embodiment describes the case where the measurement apparatus  10  includes the sound output interface  160 , but the measurement apparatus  10  need not necessarily include the sound output interface  160 . Even without the sound output interface  160 , the measurement apparatus  10  can measure biological information as long as it includes a measurement portion for measuring biological information. 
     The measurement apparatus  10  according to the foregoing embodiment outputs sound from the sound output interface  160  (step S 11 ) before measuring biological information (step S 12 ), as illustrated in  FIG. 7 . Alternatively, the measurement apparatus  10  according to an embodiment may start measurement of biological information in a state in which sound is not output from the sound output interface  160 . 
       FIG. 8  is a flowchart illustrating an example of a process performed by the measurement apparatus  10  according to an embodiment. For example, when the subject connects the measurement instrument  20  to the measurement apparatus  10 , wears the measurement apparatus  10 , and performs an input operation for executing the measurement process, the measurement apparatus  10  according to an embodiment starts the process in the flowchart in  FIG. 8 , as in the embodiment in  FIG. 7 . In the following, the same description as that with reference to  FIG. 7  is simplified or omitted as appropriate. 
     When the process illustrated in  FIG. 8  starts, the controller  101  in the measurement apparatus  10  first measures biological information as in step  12  in  FIG. 7  (step S 21 ). The controller  101  then estimates the state of the subject as in step  13  in  FIG. 7  (step S 22 ). 
     After the state of the subject is estimated in step S 22 , the controller  101  controls the sound output interface  160  to output predetermined sound corresponding to the estimated state of the subject (step S 23 ). For example, in the case where the subject is estimated to be under stress in step S 22 , the controller  101  may output such sound that alleviates the stress of the subject in step S 23 , as in step S 14  in  FIG. 7 . For example, in the case where the body temperature of the subject is estimated to be in a slightly low state in step S 22 , the controller  101  may output such sound that lifts the subject&#39;s mood in step S 23 , as in step S 14  in  FIG. 7 . 
     Thus, in an embodiment, the sound output interface  160  may output predetermined sound depending on the state of the subject. In this case, the controller  101  may select the predetermined sound output by the sound output interface  160 , depending on the estimated state of the subject. Moreover, the memory  103  may store information of the predetermined sound output by the sound output interface  160  depending on the state of the subject. The controller  101  may then select the predetermined sound output by the sound output interface  160  depending on the state of the subject, and read the information of the predetermined sound from the memory  103 . With such a measurement apparatus  10  according to an embodiment, too, for example, causing the subject to hear the predetermined sound when the result of measuring the subject is deteriorating is expected to be effective in prevention of the physical condition of the subject from worsening or in recovery in an initial stage. 
     The measurement apparatus  10  according to the foregoing embodiment may be connected to another information processing apparatus in an information communicable state.  FIG. 9  is a functional block diagram illustrating a schematic structure of a measurement system  1  according to an embodiment. The measurement system  1  in  FIG. 9  includes the measurement apparatus  10 , the measurement instrument  20  connected to the measurement apparatus  10 , and an information processing apparatus  30 . The measurement apparatus  10  and the information processing apparatus  30  are connected so as to be communicable with each other. 
     In the example illustrated in  FIG. 9 , the measurement apparatus  10  includes the controller  101 , the memory  103 , a communication interface  104 , the body temperature measurement portion  140 , and the sound output interface  160 . The structures and functions of the controller  101 , the memory  103 , the body temperature measurement portion  140 , and the sound output interface  160  are as described above, and accordingly their detailed description is omitted here. 
     The communication interface  104  transmits and receives various information through communication with the information processing apparatus  30 . The communication interface  104  can perform information transmission and reception using a wireless network, a wire network, or a combination thereof. The communication interface  104  can perform communication using, for example, Bluetooth® (Bluetooth is a registered trademark in Japan, other countries, or both), infrared, NFC, wireless LAN, wire LAN, or any other communication medium, or any combination thereof. For example, the communication interface  104  transmits biological information measured by the measurement apparatus  10  and/or information about the state of the subject estimated by the measurement apparatus  10 , to the information processing apparatus  30 . 
     The functional blocks included in the measurement instrument  20  are the same as those described in the foregoing embodiment, and accordingly their detailed description is omitted here. 
     The information processing apparatus  30  is formed, for example, by a computer. The information processing apparatus  30  can acquire various information from the measurement apparatus  10 , store the acquired information, and perform information processing based on the acquired information. The information processing apparatus  30  includes a controller  301 , a memory  303 , and a communication interface  304 . 
     The controller  301  includes at least one processor  302  that controls and manages the whole information processing apparatus  30 , e.g. each functional block in the information processing apparatus  30 . The controller  301  includes at least one processor  302  such as a CPU that executes a program defining a control procedure, to achieve its functions. Such a program is, for example, stored in the memory  303  or an external storage medium connected to the information processing apparatus  30 . Specific structures of the processor  302  that can be used include those described with regard to the processor  102 . 
     The memory  303  may be formed by semiconductor memory, magnetic memory, or the like. The memory  303  stores various information, programs for operating the information processing apparatus  30 , and the like. The memory  303  may function as working memory. The memory  303  may store information acquired from the measurement apparatus  10 . 
     The communication interface  304  transmits and receives various information through communication with the measurement apparatus  10 . 
     The communication interface  304  can perform information transmission and reception using a wireless network, a wire network, or a combination thereof. The communication interface  304  can perform communication using, for example, Bluetooth® (Bluetooth is a registered trademark in Japan, other countries, or both), infrared, NFC, wireless LAN, wire LAN, or any other communication medium, or any combination thereof. For example, the communication interface  304  receives biological information measured by the measurement apparatus  10  and/or information about the state of the subject estimated by the measurement apparatus  10 , from the measurement apparatus  10 . 
     In the case where the presently disclosed techniques are implemented as the measurement system  1  as illustrated in  FIG. 9 , for example, the measurement apparatus  10  can transmit biological information measured by the measurement apparatus  10  and/or information about the state of the subject estimated by the measurement apparatus  10 , to the information processing apparatus  30 . For example, the measurement apparatus  10  can transmit information about the body temperature and SpO 2  of the subject and/or information about the possibility of the subject developing mountain sickness, to the information processing apparatus  30 . Having received the measured biological information and/or the information about the state of the subject estimated by the measurement apparatus  10 , the information processing apparatus  30  may store the received information in the memory  303 . Here, the information processing apparatus  30  may store the information received from the measurement apparatus  10  in the memory  303 , in association with information identifying the measurement apparatus  10  that has transmitted the information. In this way, the information processing apparatus  30  can accumulate information of a plurality of measurement apparatuses  10 . 
     In the case where the presently disclosed techniques are implemented as the measurement system  1  as illustrated in  FIG. 9 , for example, the information processing apparatus  30  can perform at least part of the processes performed by the measurement apparatus  10  in the foregoing embodiment. For example, the measurement apparatus  10  performs the processes in steps S 11  and  12  in  FIG. 7 . The measurement apparatus  10  transmits biological information measured in step S 12 , to the information processing apparatus  30 . The information processing apparatus  30  can then perform the process of estimating the state of the subject in step S 13  in  FIG. 7 , based on the information acquired from the measurement apparatus  10 . The information processing apparatus  30  transmits information about the estimated state of the subject to the measurement apparatus  10 . The measurement apparatus  10  can notify the subject of information, based on the state of the subject estimated by the information processing apparatus  30 . In this case, since part of the processes in  FIG. 7  is performed by the information processing apparatus  30 , the processing load of the measurement apparatus  10  can be reduced. 
     Although the above describes the case where the measurement portion  220  is configured to, for example, sandwich the measured part to be worn at the measured part, the structure of the measurement portion  220  is not limited to such. For example, the measurement portion  220  may be configured to be worn on the arm, the leg, the head, the wrist, the ankle, or the like by a fixture such as a band, a seal, a bandage, an adhesive, or a fixation mechanism, and irradiate blood vessels in the arm, the leg, the head, the wrist, the ankle, or the like with light to measure SpO 2  or blood flow amount. 
     REFERENCE SIGNS LIST 
       1  measurement system 
       10  measurement apparatus 
       20  measurement instrument 
       30  information processing apparatus 
       101 ,  301  controller 
       102 ,  302  processor 
       103 ,  303  memory 
       104 ,  304  communication interface 
       110  wearing portion 
       110 R first wearing portion 
       110 L second wearing portion 
       120  joining portion 
       121  battery holder 
       130  body portion 
       140  body temperature measurement portion 
       141  tip 
       150  connector 
       160 ,  161  sound output interface 
       201  first light source 
       202  second light source 
       203  optical detector 
       210  connector 
       220  measurement portion 
       230  cable