Symptom determination device and symptom determination program

Abstract

[Problem] To evaluate objectively a symptom related to a mental disorder, without resorting to the subjective view of a person that carries out the evaluation. [Solution] A symptom evaluation device 20 comprises a brain wave characteristics detection unit 212 and a symptom evaluation unit 214. The brain wave characteristics detection unit 212 detects one or a plurality of frequency components of a brain wave in a specific brain region of a person being examined. On the basis of the intensity of the brain wave frequency component detected by the brain wave characteristics detection unit 212, the symptom evaluation unit 214 evaluates a symptom of depression in the person being examined. In this case, for instance, the symptom evaluation unit 214 evaluates the symptom of depression in the person being examined on the basis of a correlation between the frequency component detected by the brain wave characteristics detection unit 212 and a brain wave frequency component serving as a reference for evaluating a symptom of depression.

Description

[Technical Field]

[0001] The present invention relates to a symptom determination device and a symptom determination program. [Background technology]

[0002] Conventionally, the diagnosis of symptoms related to mental illnesses such as depression has been mainly carried out by assessors such as doctors, etc. For example, the assessor may have a conversation with a subject and determine the symptoms related to mental illnesses based on the subject's state during the conversation, the content of the subject's responses, etc. An example of a technology for supporting such evaluators is disclosed in Patent Document 1. The technology disclosed in Patent Document 1 supports the evaluator to take the initiative in assessing the symptoms of a subject in a remote location by establishing a communication connection between a server used by the evaluator and a terminal used by the subject. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-066317 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when the evaluator is the main person in assessing symptoms as described above, the subjective opinion of the evaluator is inevitably reflected in the assessment results, which may result in different assessment results depending on the evaluator.

[0005] The present invention has been made in view of the above circumstances, and an object of the present invention is to objectively assess symptoms related to mental illness without relying on the subjectivity of the assessor. [Means for solving the problem]

[0006] In order to solve the above problem, a symptom determination device according to one embodiment of the present invention comprises: an electroencephalogram (EEG) detecting means for detecting one or more frequency components of an electroencephalogram in a specific brain region of a subject; a depressive symptom determination means for determining a depressive symptom in the subject based on the intensity of the frequency components of the electroencephalogram detected by the electroencephalogram detection means; The present invention is characterized by comprising: [Effects of the Invention]

[0007] According to the present invention, symptoms of mental illness can be objectively assessed without relying on the subjectivity of the assessor. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a block diagram showing an example of the overall configuration of a symptom determination system according to an embodiment of the present invention. [Figure 2] 1 is a block diagram showing an example of the configuration of an electroencephalogram measuring device according to one embodiment of the present invention. [Figure 3] 1 is a block diagram showing an example of the configuration of a symptom determination device according to an embodiment of the present invention; [Figure 4] 10 is a flowchart showing the flow of a measurement process executed by the electroencephalogram determination device according to one embodiment of the present invention. [Figure 5] 10 is a flowchart showing the flow of a reference data generation process executed by the symptom determination device according to one embodiment of the present invention. [Figure 6] 3 is a flowchart showing the flow of a symptom determination process executed by a symptom determination device according to an embodiment of the present invention. [Figure 7] 10 is a graph showing the results of a comparison of electroencephalogram features between healthy subjects and patients with depression in one embodiment of the present invention. [Figure 8] 10 is an enlarged graph showing the results of a comparison of electroencephalogram characteristics between a healthy subject and a patient with depression in one embodiment of the present invention. [Figure 9] 10 is a graph showing the results of a comparison of electroencephalogram features between healthy subjects and patients with depression in terms of relative values ​​in an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] An example of an embodiment of the present invention will now be described with reference to the accompanying drawings.

[0010] [System Configuration] Fig. 1 is a block diagram showing the overall configuration of a symptom determination system S according to this embodiment. As shown in Fig. 1, the symptom determination system S includes an electroencephalogram (EEG) measurement device 10 and a symptom determination device 20. Fig. 1 also shows a user U who is the target of processing performed by the symptom determination system S (i.e., a subject whose symptoms are to be determined).

[0011] The electroencephalogram measuring device 10 and the symptom determination device 20 are connected to each other so that they can communicate with each other. The communication between these devices may be performed in accordance with any communication method, and the communication method is not particularly limited. The communication connection may be a wired connection or a wireless connection. Furthermore, the communication between the devices may be performed directly or via a network including a relay device. In this case, the network is realized by, for example, a network such as a LAN (Local Area Network), the Internet, or a mobile phone network, or a network that combines these.

[0012] The symptom determination system S objectively determines symptoms of a mental illness using a user U as a subject, without relying on the subjectivity of the determiner. The inventor of the present invention conducted extensive testing and research into the determination of symptoms of a mental illness and found a correlation between the symptoms of a mental illness and electroencephalograms. This led to the idea that it is possible to determine symptoms of such mental illnesses based on electroencephalograms, leading to the creation of the present invention. Accordingly, in this embodiment, as an example for explanation, it is assumed that the symptom determination system S determines symptoms of depression, which is one of the diseases accompanied by a mental illness. Here, the determination of symptoms of depression includes determining whether the user U is suffering from depression and, if so, determining the severity of the depressive symptoms. However, depression is merely one example of a disease accompanied by a mental disorder, and the use of depression as an example is not intended to limit the scope of application of the present invention to depression.

[0013] The EEG measuring device 10 generates data (hereinafter referred to as "measurement data") corresponding to the brain waves of the user U by processing such as measuring fluctuations in the electric potential in the head of the user U (i.e., brain waves in a specific brain region of the user U). The EEG measuring device 10 is configured as a headset-type electroencephalograph that includes a pair of electrodes or a larger number of multiple electrodes for measuring the brain waves of the user U, and each of these electrodes is electrically contacted with a predetermined part of the user U. The EEG measuring device 10 generates measurement data by performing processing such as measuring the brain waves of the user U with each of these electrodes. The EEG measuring device 10 also transmits the generated measurement data to the symptom determination device 20.

[0014] The symptom determination device 20 determines symptoms related to depression of the user U based on the measurement data generated by the electroencephalogram measurement device 10. The symptom determination device 20 is realized by, for example, a personal computer or a server device. As a specific process, the symptom determination device 20 detects one or more frequency components of electroencephalograms in a specific brain region of the subject user U. Furthermore, the symptom determination device 20 determines the depressive symptoms of the subject user U based on the intensity of the frequency components of the detected electroencephalograms.

[0015] In this way, the electroencephalogram (EEG) measuring device 10 measures electroencephalograms in a specific brain region of the subject, i.e., user U. The symptom determination device 20 determines depressive symptoms in the subject based on an objective index, i.e., the electroencephalograms in the specific brain region of the subject. Therefore, according to the symptom determination system S of this embodiment, it is possible to objectively determine symptoms related to mental illness, without relying on the subjectivity of the determiner.

[0016] Furthermore, the symptom determination system S can solve the general problems of the prior art by objectively determining symptoms related to mental illness in this way. For example, as described above, when the assessor is the main person in determining symptoms, the subjectivity of the assessor inevitably ends up being reflected in the result of the determination.

[0017] Next, the configurations of the electroencephalogram measuring device 10 and the symptom determination device 20 for realizing such processing will be described in more detail. In the following, for clarity of explanation, a user (corresponding to user U in FIG. 1) who is the target of processing performed by the symptom determination system S will be referred to as a "subject" as appropriate. On the other hand, a user (not shown) who uses the symptom determination system S to determine the symptoms of the subject will be referred to as an "evaluator" as appropriate.

[0018] [Configuration of EEG measuring device] Next, the configuration of the electroencephalogram measuring device 10 will be described with reference to Fig. 2. Fig. 2 is a block diagram showing an example of the configuration of the electroencephalogram measuring device 10. 2, the electroencephalogram measuring device 10 includes a CPU (Central Processing Unit) 11, a ROM (Read Only Memory) 12, a RAM (Random Access Memory) 13, a communication unit 14, a storage unit 15, an input unit 16, and a measuring unit 17. These units are connected by signal lines and send and receive signals to and from each other.

[0019] The CPU 11 executes various processes (for example, measurement processes described later) according to a program recorded in the ROM 12 or a program loaded from the storage unit 15 into the RAM 13. The RAM 13 also stores data and the like necessary for the CPU 11 to execute various processes.

[0020] The communication unit 14 controls communication so that the CPU 11 can communicate with other devices (for example, the symptom determination device 20). The storage unit 15 is configured with a semiconductor memory such as a DRAM (Dynamic Random Access Memory), and stores various data. The input unit 16 is made up of various buttons and the like, and inputs various information in response to user instructions.

[0021] The measurement unit 17 measures fluctuations in the potential of the head of a subject (here, a person suspected of being a patient or a data provider to the symptom determination system S) as the subject's electroencephalogram. In this embodiment, as an example of a measurement method, it is assumed that the measurement unit 17 measures unipolar electroencephalograms using a reference electrode derivation method. In this case, one end of a pair of electrodes provided in the measurement unit 17 is brought into contact with a position where the potential is close to zero (e.g., the subject's earlobe) to serve as the reference electrode. The other end is brought into contact with a predetermined position on the subject's head (e.g., a position corresponding to Fp1 in the left prefrontal cortex defined by the International 10-20 System) to serve as the probe electrode. The measurement unit 17 then measures fluctuations in the potential difference between the reference electrode and the probe electrode over time at a predetermined sampling frequency (e.g., 512 Hz) as the electroencephalogram in a predetermined region of the subject's brain.

[0022] As described above, the EEG measuring device 10 has a headset-type configuration, and when the subject wears the EEG measuring device 10, the pair of electrodes provided in the measuring unit 17 are positioned at positions suitable for measurement (for example, a position in contact with the earlobe and a position in contact with a part corresponding to Fp1). In this regard, if a typical EEG device is used in which an electrode net is placed over the subject's head, the subject feels pressured, resulting in noise in the EEG due to tension. In contrast, the EEG measuring device 10 has a headset-type configuration, and therefore can perform measurement without causing such pressure and while suppressing tension in the subject. Therefore, the EEG measuring device 10 can suppress noise due to tension in the subject and perform accurate measurement.

[0023] In the electroencephalogram measuring device 10, these units cooperate to perform the "measurement process." Here, the measurement process is a series of processes that measure the brain waves of the subject and perform predetermined pre-processing on the measured brain waves.

[0024] When the measurement process is executed, as shown in FIG. 2, a measurement control unit 111, a preprocessing unit 112, and a measurement data transmission unit 113 function in the CPU 11. Including cases not specifically mentioned below, data required to realize processing is transmitted and received between these functional blocks at appropriate times.

[0025] The measurement control unit 111 controls the measurement of the subject's electroencephalogram by the measurement unit 17 based on an instruction operation from the subject or evaluator received by the input unit 16 (or instruction information from the subject or evaluator received via the communication unit 14). For example, the measurement control unit 111 controls the timing of the start and end of measurement by the measurement unit 17, and controls the sampling period in the measurement, based on the instruction operation (or instruction information). Then, the measurement control unit 111 outputs the subject's electroencephalogram obtained by measurement by the measurement unit 17 to the preprocessing unit 112.

[0026] Here, the measurement of electroencephalograms may be performed in any situation, but in this embodiment, as an example, it is assumed that the measurement of electroencephalograms is performed in a situation where the assessor and the subject are having a conversation corresponding to the Hamilton Rating Scale for Depression (HAM-D). However, the conversation does not necessarily have to be like this, and for example, a general conversation such as so-called casual conversation may also be used.

[0027] The reason for performing the measurement during conversation is that a depressed patient may fall asleep when resting, and in this case, their brain waves during sleep are measured. Therefore, in this embodiment, by performing the measurement during conversation, it is possible to measure the brain waves of a depressed patient in a state where they are moderately awake (i.e., in a normal state). Furthermore, in this embodiment, noise removal is performed in real time at predetermined time intervals in the pre-processing described below, so that measurements can be performed while removing noise associated with body movements and blinking that occur during conversation. However, this is merely a suitable example, and electroencephalogram measurements may be performed in other situations. The length of time for measurement is also arbitrary, but may be, for example, from 10 minutes to several tens of minutes.

[0028] The preprocessing unit 112 generates measurement data by performing preprocessing on the electroencephalograms input from the measurement control unit 111. Specifically, the preprocessing unit 112 first uses a band-pass filter (not shown) to extract only frequency components in a predetermined frequency band (e.g., 1 to 30 Hz) from the electroencephalograms input from the measurement control unit 111. Next, the preprocessing unit 112 sets a threshold based on the median absolute deviation for each predetermined time unit (e.g., 1 second) for the extracted frequency components of the electroencephalograms. The preprocessing unit 112 then regards outliers exceeding the threshold as mixed noise and removes them. In this way, the preprocessing unit 112 generates measurement data by performing preprocessing, which involves extracting frequency components in a predetermined frequency band and removing mixed noise. The preprocessing unit 112 then outputs the generated measurement data to the measurement data transmitting unit 113.

[0029] The measurement data transmission unit 113 transmits the electroencephalogram data input from the preprocessing unit 112 to the symptom determination device 20. The transmission may be performed in real time each time electroencephalogram data is generated by the measurement control unit 111, or the generated electroencephalogram data may be stored in the storage unit 15, and after the measurement is completed, the electroencephalogram data stored in the storage unit 15 may be transmitted all at once.

[0030] [Configuration of the symptom determination device] Next, the configuration of the symptom determination device 20 will be described with reference to Fig. 3. Fig. 3 is a block diagram showing an example of the configuration of the symptom determination device 20. As shown in Fig. 3, the symptom determination device 20 includes a CPU 21, a ROM 22, a RAM 23, a communication unit 24, a storage unit 25, an input unit 26, an output unit 27, and a drive 28. These units are connected by signal lines and transmit and receive signals to and from each other.

[0031] The CPU 21 executes various processes (for example, a reference data generation process and a symptom determination process, which will be described later) according to a program recorded in the ROM 22 or a program loaded from the storage unit 25 to the RAM 23. The RAM 23 also stores data and the like necessary for the CPU 21 to execute various processes.

[0032] The communication section 24 controls communication so that the CPU 21 can communicate with other devices (for example, the electroencephalogram measuring device 10). The storage unit 25 is configured with a semiconductor memory such as a DRAM (Dynamic Random Access Memory), and stores various data.

[0033] The input unit 26 is composed of various buttons and a touch panel, or an external input device such as a mouse and a keyboard, and inputs various information in response to user instructions. The output unit 27 is composed of a display, a speaker, etc., and outputs images and sounds. Removable media (not shown) such as a magnetic disk, optical disk, magneto-optical disk, or semiconductor memory are appropriately loaded into the drive 28. The program read from the removable media by the drive 28 is installed in the storage unit 25 as needed.

[0034] In the symptom determination device 20, these units cooperate to perform the "reference data generation process" and the "symptom determination process." Here, the reference data generation process is a series of processes in which the symptom determination device 20 generates reference data, which is a determination standard for determining symptoms, based on the measurement data generated by the electroencephalogram measurement device 10. The symptom determination process is a series of processes in which the symptom determination device 20 performs symptom determination based on the measurement data generated by the electroencephalogram measurement device 10 and the reference data. That is, in this embodiment, the symptom determination device 20 first generates reference data, and then uses the generated reference data to achieve objective determination of the symptoms of depression.

[0035] When these reference data generation processes and symptom determination processes are executed, as shown in Figure 3, a measurement data acquisition unit 211, an EEG feature detection unit 212, a reference data generation unit 213, a symptom determination unit 214, and a determination result output unit 215 function in the CPU 21. In addition, a measurement data storage section 251 and a reference data database 252 are provided in one area of ​​the storage section 25. Including cases not specifically mentioned below, data required to realize processing is transmitted and received between these functional blocks at appropriate times.

[0036] The measurement data acquiring unit 211 acquires the measurement data by receiving the measurement data transmitted from the electroencephalogram measuring device 10. Then, the measurement data acquiring unit 211 stores the acquired measurement data in the measurement data storage unit 251. That is, the measurement data storage unit 251 functions as a storage unit that stores the measurement data.

[0037] The electroencephalogram feature detection unit 212 detects electroencephalogram feature data, which is data indicating the features of the measurement data stored in the measurement data storage unit 251 (i.e., the features of the frequency components of the electroencephalograms of the subject). As a premise, there are individual differences in the magnitude of the electroencephalogram amplitude. Therefore, it is not desirable to use this data as is for diagnosing symptoms. Therefore, the electroencephalogram feature detection unit 212 first normalizes the measurement data to absorb these individual differences. For example, the electroencephalogram feature detection unit 212 normalizes the measurement data using amplitude values ​​that indicate a normal distribution. As a result, the amplitude values ​​have an average of 0 and a variance of 1.

[0038] Next, the EEG feature detection unit 212 performs a Fourier transform (for example, a fast Fourier transform (FFT) using a Hamming window) on the measurement data whose amplitude values ​​have been normalized, and then averages the data to calculate a power spectrum indicating the power values ​​of each of a plurality of frequencies (for example, 1 to 30 Hz) as a plurality of frequency components in the measurement data.The EEG feature detection unit 212 then regards this power spectrum as EEG feature data. The electroencephalogram feature detection unit 212 detects electroencephalogram feature data in this manner and outputs the detected electroencephalogram feature data to the reference data generation unit 213 during the reference data generation process and to the symptom determination unit 214 during the symptom determination process.

[0039] The reference data generating unit 213 generates reference data that serves as a criterion for the symptom determination unit 214 (described later) to determine symptoms. Therefore, the reference data generating unit 213 acquires evaluation data of depression-related symptoms for a subject corresponding to the EEG feature data used to create the reference data. This evaluation data of depression-related symptoms is not based on a diagnosis made by a symptom determination process, but is obtained by a conventional method based on a medical interview conducted by a doctor who is the assessor. The conventional method may be, for example, a method based on the Hamilton Depression Rating Scale described above, or another method. For example, a method based on another scale, such as the Montgomery-Asberg Depression Rating Scale (MADRS) or the Beck Depression Inventory (BDI), may also be used.

[0040] As described above, in this embodiment, the depression-related symptom assessment involves determining whether the user U is suffering from depression and, if so, determining the severity of the depressive symptoms. Therefore, the reference data generation unit 213 acquires evaluation data indicating that the user U is a healthy person suffering from depression, or, if so, the level of severity of the depressive symptoms. The severity of the depressive symptoms may be defined using any number of stages, but can be defined using, for example, four stages: mild, moderate, severe, and severe.

[0041] The reference data generating unit 213 acquires such evaluation data of symptoms related to depression, for example, based on an input operation from the assessor accepted by the input unit 26 (or input information from the assessor received via the communication unit 14). Furthermore, the reference data generating unit 213 associates the acquired evaluation data of symptoms related to depression with the electroencephalogram feature data of the corresponding subject to construct a database of reference data. Here, construction includes not only creating a new database but also updating an existing database with new data.

[0042] Then, the reference data generating unit 213 stores the constructed database of reference data in the reference data database 252. That is, the reference data database 252 functions as a storage unit that stores the database of reference data.

[0043] In this way, the reference data generating unit 213 repeatedly stores the electroencephalogram feature data of a plurality of subjects in association with the evaluation data in the reference data database 252, thereby updating the database stored in the reference data database 252. The database created and updated in this way becomes a database that indicates the tendency of the electroencephalogram feature data of subjects corresponding to each stage of depression-related symptoms (i.e., whether they are healthy or at what stage of severity).

[0044] The symptom determination unit 214 determines symptoms related to depression based on each reference data in the database constructed in this way. Specifically, the symptom determination unit 214 determines symptoms related to depression based on the correlation (i.e., the relationship between the intensities of the power spectra) between the electroencephalogram feature data (i.e., the power spectrum indicating the intensities of the frequency components) of the subject to be currently determined and each reference data (i.e., the power spectrum indicating the intensities of the frequency components) in the database constructed in the reference data generation unit 213 and stored in the reference data database 252.

[0045] For example, the symptom determination unit 214 compares the electroencephalogram feature data of the subject to be currently determined with each reference data in the database, identifies the most similar reference data, and determines the stage of depression symptoms (i.e., whether the subject is healthy or at what stage of severity) associated as evaluation data with the most similar reference data as the determination result of the subject to be currently determined.

[0046] Alternatively, for example, the symptom determination unit 214 may make a determination by comparing whether or not the data are different, rather than by determining the closest approximation. For example, the EEG feature data of the subject currently being assessed may be compared with reference data associated with evaluation data indicating a healthy individual. If the difference is smaller than a predetermined standard, the subject may be determined not to be suffering from depression, and if the difference is larger than the predetermined standard, the subject may be determined to be suffering from depression. Similarly, for example, the EEG feature data of the subject currently being assessed may be compared with reference data associated with evaluation data indicating that the subject is suffering from depression. If the difference is smaller than the predetermined standard, the subject may be determined to be suffering from depression, and if the difference is larger than the predetermined standard, the subject may be determined not to be suffering from depression. Furthermore, after a diagnosis of depression has been made, the severity of the depressive symptoms may be further determined by identifying the most similar reference data, as described above. That is, the determination of whether or not a person has depression and the determination of the severity of the depressive symptoms if the person has depression may be treated as separate determinations, and the determination may be made in two stages.

[0047] Furthermore, whether comparing for closest similarity or for discrepancy, the reference data to be compared may be all of the reference data in the database, or may be representative reference data generated from all of the reference data in the database. For example, representative reference data for healthy individuals is generated based on a representative value of all of the reference data associated with evaluation data for healthy individuals. In this case, the representative value may be the average, mode, median, or the like of each of the reference data. Similarly, representative reference data for each severity level is generated based on a representative value of all of the reference data associated with evaluation data of the same severity level. Then, each of these representative reference data for each symptom may be compared with the EEG feature data of the subject to be evaluated.

[0048] Furthermore, the correlation between each piece of data (i.e., whether they are most similar or different) can be determined by any method. For example, this can be determined by comparing the power spectra (i.e., frequency components) of each piece of data using an existing method such as pattern matching. In this case, the power spectra for all frequencies included in each piece of data may be compared, or only the power spectra of predetermined frequencies may be compared. For example, only the power spectra of predetermined frequencies that are particularly different depending on whether or not a person is suffering from depression may be compared. Alternatively, the power spectra for all frequencies may be compared, but the power spectra of the predetermined frequencies may be weighted to be used as a priority for the comparison as a determination criterion.

[0049] Alternatively, for example, the electroencephalogram feature detection section 212 may calculate a power spectrum indicating the power value of any frequency (e.g., any of 1 to 30 [Hz]) as a single frequency component, rather than calculating a power spectrum indicating the power value of each of multiple frequencies (e.g., 1 to 30 [Hz]) as a multiple frequency component. The symptom determination unit 214 may then determine the symptoms of depression based on the correlation between the power spectrum indicating the intensity of this one frequency component as the EEG feature data of the subject to be determined this time and each reference data in the database constructed in the reference data generation unit 213 and stored in the reference data database 252.

[0050] By making a judgment in this manner, the symptom judgment unit 214 judges the stage of depression symptoms (i.e., whether the subject is healthy or at what stage of severity) of the subject to be judged this time. Then, the symptom judgment unit 214 outputs this judgment result to the judgment result output unit 215.

[0051] The determination result output unit 215 outputs to the assessor or the subject the result of the symptom determination made by the symptom determination unit 214. This output may be, for example, a display on a display included in the output unit 27, an audio output from a speaker included in the output unit 27, printing on a paper medium from a printing device via the communication unit 24, or transmission via the communication unit 24 to another device (not shown) used by the assessor or the subject.

[0052] This allows the symptom determination device 20 to determine depressive symptoms in a subject based on an objective index, that is, electroencephalograms in a specific brain region of the subject, and output the determination result to the determiner or the subject.

[0053] [Measurement processing] Next, the flow of the measurement process executed by the EEG measuring device 10 will be described with reference to Fig. 4. Fig. 4 is a flowchart illustrating the flow of the measurement process executed by the EEG measuring device 10. The measurement process is executed in response to an instruction operation to start measurement from the subject or the evaluator.

[0054] In step S11, the measurement control unit 111 controls the measurement of the brain waves of the subject by the measurement unit 17, thereby starting the measurement of the brain waves by the measurement unit 17. Then, the measurement control unit 111 outputs the brain waves of the subject obtained by the measurement by the measurement unit 17 to the preprocessing unit 112.

[0055] In step S12, the preprocessing unit 112 generates measurement data by performing preprocessing on the electroencephalogram input from the measurement control unit 111. Then, the preprocessing unit 112 outputs the generated measurement data to the measurement data transmission unit 113.

[0056] In step S13, the measurement data transmission unit 113 transmits the measurement data input from the preprocessing unit 112 to the symptom determination device 20. Note that, in the figure, it is assumed that the measurement data is generated by the measurement control unit 111 and transmitted in real time, but as described above, it is also possible to store the generated measurement data in the storage unit 15 and transmit all the measurement data stored in the storage unit 15 at once after the measurement is completed.

[0057] In step S14, the measurement control unit 111 determines whether or not to terminate the measurement of electroencephalograms by the measurement unit 17. For example, the measurement control unit 111 determines to terminate the measurement of electroencephalograms when a predetermined time has elapsed since the start of measurement or when the subject or evaluator issues an instruction to terminate the measurement. If the measurement of electroencephalograms is to be terminated, the determination in step S14 is Yes, and the process ends. On the other hand, if the measurement of electroencephalograms is not to be terminated, the determination in step S14 is No, and the process is repeated again from step S11.

[0058] Through the measurement process described above, the EEG measurement device 10 can measure the EEG from the subject and transmit measurement data generated based on the measured EEG to the symptom determination device 20.

[0059] [Reference data generation process] Next, the flow of the reference data generation process executed by the symptom determination device 20 will be described with reference to Fig. 5. Fig. 5 is a flowchart explaining the flow of the reference data generation process executed by the symptom determination device 20. The reference data generation process is executed in response to an instruction operation to start reference data generation from an assessor or an administrator of the symptom determination system S. Note that, as a premise of the process, it is assumed that the measurement data generated by the measurement process has been received by the measurement data acquisition unit 211 and stored in the measurement data storage unit 251.

[0060] In step S21, the electroencephalogram feature detection section 212 detects electroencephalogram feature data from the measurement data stored in the measurement data storage section 251.

[0061] In step S22, the reference data generating section 213 acquires evaluation data of the depression-related symptom assessment for the subject corresponding to the electroencephalogram feature data used to create the reference data.

[0062] In step S23, the reference data generating unit 213 associates the acquired evaluation data with the electroencephalogram feature data of the corresponding subject to construct a database of reference data. As described above, constructing includes not only creating a new database but also updating an existing database with new data.

[0063] In step S24, the reference data generating unit 213 stores the constructed database of reference data in the reference data database 252. This completes the process.

[0064] By the above-described reference data generation process, the symptom determination device 20 can generate reference data that serves as a determination criterion for the symptom determination section 214 to determine the symptom.

[0065] [Symptom determination process] Next, the flow of the symptom determination process executed by the symptom determination device 20 will be described with reference to Fig. 6. Fig. 6 is a flowchart illustrating the flow of the symptom determination process executed by the symptom determination device 20. The symptom determination process is executed in response to an instruction operation to start symptom determination from an evaluator or the like. Note that, as a premise of the process, it is assumed that the measurement data generated by the measurement process has been received by the measurement data acquisition unit 211 and stored in the measurement data storage unit 251. It is also assumed that the database of reference data constructed by the reference data generation process has been stored in the reference data database 252.

[0066] In step S31, the electroencephalogram feature detection section 212 detects electroencephalogram feature data from the measurement data stored in the measurement data storage section 251.

[0067] In step S32, the symptom determination section 214 determines symptoms related to depression based on the electroencephalogram feature data of the subject in step S32 and each reference data in the database constructed by the above-mentioned reference data generation process.

[0068] In step S33, the determination result output section 215 outputs the determination result of the symptom determination section 214 in step S32.

[0069] Through the symptom determination process described above, the symptom determination device 20 determines the depressive symptoms in the subject based on an objective index, that is, electroencephalograms in a specific brain region of the subject. Therefore, according to the symptom determination system S of this embodiment, it is possible to objectively determine symptoms related to mental illness, without relying on the subjectivity of the determiner.

[0070] Furthermore, the symptom assessment process objectively assesses symptoms related to mental illness, thereby resolving common problems associated with conventional techniques, such as the problem that, as mentioned above, when the assessor is the main actor in assessing symptoms, the assessor's subjectivity inevitably ends up being reflected in the assessment results.

[0071] [Example] The above describes an embodiment of the present invention. Next, an example of the embodiment of the present invention will be described with reference to Figs. 7, 8, and 9. Fig. 7 is a graph showing the results of a comparison of electroencephalogram features between healthy subjects and depression patients in this example. Fig. 8 is an enlarged graph of the results of a comparison of electroencephalogram features between healthy subjects and depression patients in this example. Fig. 9 is a graph showing the results of a comparison of electroencephalogram features between healthy subjects and depression patients in this example in terms of relative values.

[0072] First, Fig. 7(a) shows the power spectrum obtained by averaging and normalizing the EEG feature data of multiple healthy subjects. Similarly, Fig. 7(b) shows the power spectrum obtained by averaging and normalizing the EEG feature data of multiple depressed patients.

[0073] In this example, the frequency of healthy subjects was set to 1, and a two-sample t-test was performed on each frequency as a significance test (p<0.05). The asterisks (i.e., star marks) in Fig. 7(b) indicate frequencies that are significantly different between healthy subjects and depression patients in this significance test. The particularly significantly different high-frequency region (the frequency region corresponding to frequencies f1 to f2 in the figure (here, 10 to 30 Hz, as an example)) is shown enlarged in Fig. 8(a) and Fig. 8(b). Thus, the power spectra belonging to the high-frequency region are significantly different from the power spectra belonging to the low-frequency region.

[0074] In order to prove that such differences represent differences between healthy individuals and depressed patients, a comparison between healthy individuals was also performed using a two-sample t-test. However, since there was no significant difference in this case (p<0.05), a search for significant differences was conducted using a higher critical p-value, but the results were the same.

[0075] 7(b), it is clear that the EEG feature data of a healthy subject (i.e., the power spectrum indicating the intensity of frequency components) and the EEG feature data of a depressed patient (i.e., the power spectrum indicating the intensity of frequency components) are significantly different. Therefore, the symptom determination unit 214 can accurately determine the symptoms of depression using the method described above.

[0076] 9 is a diagram showing the relative values ​​of the power spectrum of the depressed patient in FIG. 7(b) when the power spectrum of the healthy subject in FIG. 7(a) is set to 1 (i.e., the value obtained by dividing the power spectrum of the depressed patient by the power spectrum of the healthy subject at each frequency). In FIG. 9, the closer the relative value is to 1, the closer the patient is to the healthy subject. This diagram also shows that the power spectrum belonging to the high frequency range is significantly different from the power spectrum belonging to the low frequency range. In consideration of this, the symptom determination unit 214 may, for example, weight the power spectrum of frequencies belonging to the low frequency range so that it is given priority as a determination criterion for comparison. In the above description with reference to Figures 7, 8, and 9, the values ​​of frequencies f1 and f2, which are the lower and upper limits of the range of the high frequency region, are set to 10 [Hz] and 30 [Hz], respectively. However, this is merely a preferred example and is not intended to limit the values ​​of frequencies f1 and f2.

[0077] [Variations] Although the embodiments of the present invention have been described above, these embodiments are merely illustrative and do not limit the technical scope of the present invention. The present invention can take on various other embodiments and can undergo various modifications such as omissions and substitutions without departing from the spirit of the present invention. In such cases, these embodiments and their modifications are included in the scope and spirit of the invention described in this specification, etc., and are also included in the scope of the invention described in the claims and their equivalents. As an example, the above-described embodiment of the present invention may be modified as follows.

[0078] <First Modification> In the above-described embodiment, the symptom determination unit 214 determines symptoms related to depression based on the correlation (i.e., intensity relationship) between the electroencephalogram feature data (i.e., power spectrum indicating the intensity of frequency components) of the subject to be currently determined and each piece of reference data (i.e., power spectrum indicating the intensity of frequency components) in the database constructed in the reference data generation unit 213 and stored in the reference data database 252. The determination is not limited to this, and other methods may also be used. For example, as described above with reference to the drawings as an example, the power spectrum belonging to the high frequency region is significantly different from the power spectrum belonging to the low frequency region.

[0079] In other words, the power spectrum of depressed patients belonging to the low frequency region is the same as or lower than that of healthy people, but the power spectrum of depressed patients belonging to the high frequency region is higher than that of healthy people. From this, it can be said that the relative relationship between the power spectrum belonging to their own low frequency region and the power spectrum belonging to their own high frequency region is different between depressed patients and healthy people. Based on this viewpoint, by comparing the relative relationship between the power spectrum belonging to the low frequency region and the power spectrum belonging to the high frequency region in the electroencephalogram feature data of a given subject, it is possible to determine whether the subject is a depressed patient or a healthy person. Therefore, according to this modification, it is possible to determine whether the subject is a depressed patient or a healthy person without comparing with reference data as in the above-mentioned embodiment.

[0080] <Second Modification> The above-described embodiment may be modified to take into account the effects of medications taken by a patient with depression. Generally, patients with depression take medications such as benzodiazepines, antidepressants, and anti-anxiety drugs to suppress symptoms of depression. In this regard, since each drug has a different effect, the effect each drug has on the subject's EEG feature data (i.e., the effect that appears on the power spectrum) also differs. Therefore, by comparing the EEG feature data between patients with the same severity of depression who have taken the drug and those who have not (or between the same person before and after taking the drug), we statistically investigate how the effect each drug has on the EEG feature data (i.e., the effect that appears on the power spectrum) differs.

[0081] Then, if the subject to be assessed is taking any medication, the symptom assessment unit 214 corrects the EEG feature data based on the statistical data that has been investigated. That is, the power spectrum is corrected so as to cancel out the influence of the medication on the power spectrum. Then, based on the corrected power spectrum, the symptom assessment unit 214 assesses the symptoms of depression as in the above-described embodiment. This allows for more accurate assessment of the symptoms of depression after canceling out the influence of the medication.

[0082] <Other variations> In the above-described embodiment, the electroencephalogram of a single electrode Fp1 is measured, but electroencephalograms of multiple electrodes may be measured. Then, a diagnosis of depression-related symptoms may be made based on the electroencephalograms of each of the multiple electrodes. In this case, for example, a diagnosis of depression-related symptoms may be made for each of the electroencephalograms measured from each of the multiple electrodes, and the average of the multiple diagnosis results may be used as the diagnosis result for the user U. Furthermore, in the above-described embodiment, the EEG measurement device 10 and the symptom determination device 20 are realized as separate devices, but the EEG measurement device 10 and the symptom determination device 20 may also be realized as an integrated device.

[0083] [Configuration example] As described above, the symptom determination device 20 according to this embodiment includes the electroencephalogram feature detection section 212 and the symptom determination section 214. The electroencephalogram feature detection section 212 detects one or more frequency components of an electroencephalogram in a specific brain region of the subject. The symptom determination section 214 determines whether the subject has a depressive symptom based on the intensity of the frequency components of the electroencephalogram detected by the electroencephalogram feature detection section 212. In this way, the symptom determination device 20 determines the depressive symptoms in the subject based on an objective index, that is, the electroencephalogram in a specific brain region of the subject. Therefore, the symptom determination device 20 can objectively determine symptoms related to mental illness, without relying on the subjectivity of the determiner.

[0084] The symptom determination section 214 determines the depressive symptoms in the subject based on the correlation between the frequency components of the electroencephalogram detected by the electroencephalogram feature detection section 212 and the frequency components of the electroencephalogram that serve as a reference for determining the depressive symptoms. This allows the symptom determination device 20 to more objectively determine symptoms related to mental illness based on predetermined criteria.

[0085] The electroencephalogram characteristic detection unit 212 detects a plurality of frequency components of the electroencephalogram, The symptom determination unit 214 determines whether the patient is in a depressive state by prioritizing the relationship between the intensities of frequency components of a predetermined frequency among the multiple frequency components of the electroencephalogram detected by the electroencephalogram feature detection unit 212 as a determination criterion over the relationship between the intensities of frequency components of other frequencies. This allows the diagnosis of symptoms related to mental illness to be made by prioritizing the relationship between the intensities of frequency components of predetermined frequencies that are considered to be suitable indicators for diagnosing a depressive state as a criterion.

[0086] The electroencephalogram characteristic detection unit 212 detects a plurality of frequency components of the electroencephalogram, The symptom determination unit 214 determines depressive symptoms in the subject based on the results of a comparison of the intensities of frequency components belonging to the low frequency region and frequency components belonging to the high frequency region among the multiple frequency components of the electroencephalogram detected by the electroencephalogram feature detection unit 212. This allows the symptom determination device 20 to objectively determine symptoms related to mental illness without using electroencephalograms of anyone other than the subject.

[0087] The symptom determination section 214 determines the severity of the depressive symptoms in the subject. This makes it possible to determine not only whether or not a subject is suffering from depression, but also the severity of depressive symptoms if the subject is suffering from depression.

[0088] When the subject is taking a drug, the symptom determination section 214 corrects the determination criteria for determining depressive symptoms in the subject based on the effect of the drug being taken. This allows for more accurate determinations to be made, taking into account the effects of medications the subject is taking.

[0089] [Realization of functions through hardware and software] The function of executing the series of processes according to the above-described embodiment can be realized by hardware, software, or a combination of these. In other words, it is sufficient that the function of executing the series of processes described above is realized in any one of the symptom determination systems S, and there is no particular limitation on how this function is realized.

[0090] For example, when the function of executing the above-mentioned series of processes is realized by a processor that executes arithmetic processing, the processor that executes this arithmetic processing includes processors that are composed of various processing devices alone, such as single processors, multiprocessors, and multicore processors, as well as processors that combine these various processing devices with processing circuits such as ASICs (Application Specific Integrated Circuits) or FPGAs (Field-Programmable Gate Arrays).

[0091] Furthermore, for example, when the function of executing the above-described series of processes is realized by software, the program constituting the software is installed on a computer via a network or a recording medium. In this case, the computer may be a computer incorporating dedicated hardware, or may be a general-purpose computer (e.g., a general electronic device such as a general-purpose personal computer) that can execute predetermined functions by installing a program. Furthermore, the steps of writing the program may include only processes that are executed chronologically according to the order, but may also include processes that are executed in parallel or individually. Furthermore, the steps of writing the program may be executed in any order within the scope of the present invention.

[0092] A recording medium having such a program recorded thereon may be provided to a user by being distributed separately from the computer, or may be provided to a user in a state where it is pre-installed in the computer. In this case, the recording medium distributed separately from the computer may be a magnetic disk (including a floppy disk), an optical disk, a magneto-optical disk, or the like. Examples of optical disks include CD-ROMs (Compact Disc-Read Only Memory), DVDs (Digital Versatile Discs), and Blu-ray (registered trademark) discs. Examples of magneto-optical disks include MDs (Mini Discs). These recording media are installed in, for example, drive 28 in FIG. 3 and incorporated into the computer. Also, a recording medium provided to a user in a state where it is pre-installed in the computer may be, for example, ROM 12 in FIG. 2, ROM 22 in FIG. 3, storage unit 15 in FIG. 2, or a hard disk included in storage unit 25 in FIG. 3, on which the program is recorded. [Explanation of symbols]

[0093] 10 EEG measuring device, 20 symptom determination device, 11, 21 CPU, 12, 22 ROM, 13, 23 RAM, 14, 24 communication unit, 15, 25 memory unit, 16, 26 input unit, 17 measurement unit, 27 output unit, 28 drive, 111 measurement control unit, 112 preprocessing unit, 113 measurement data transmission unit, 211 measurement data acquisition unit, 212 EEG feature detection unit, 213 reference data generation unit, 214 symptom determination unit, 215 determination result output unit, 251 measurement data memory unit, 252 reference data database, S symptom determination system, U user

Claims

1. an electroencephalogram (EEG) detection means for detecting a plurality of frequency components of an electroencephalogram in a specific brain region of a subject; a depressive symptom assessment means for assessing depressive symptoms in the subject based on the intensities of a plurality of frequency components of the electroencephalogram detected by the electroencephalogram detection means; Equipped with the depressive symptom assessment means assesses the depressive symptoms of the subject by weighting the intensity of a frequency component of a predetermined frequency among the plurality of frequency components of the electroencephalogram detected by the electroencephalogram detection means, and giving priority to the intensity of frequency components of other frequencies as a assessment criterion. A symptom determination device characterized by:

2. an electroencephalogram (EEG) detection means for detecting a plurality of frequency components of an electroencephalogram in a specific brain region of a subject; a depressive symptom assessment means for assessing depressive symptoms in the subject based on the intensities of a plurality of frequency components of the electroencephalogram detected by the electroencephalogram detection means; Equipped with the depressive symptom assessment means assesses the depressive symptom of the subject based on a comparison result between the intensities of frequency components belonging to a low frequency region and frequency components belonging to a high frequency region among the plurality of frequency components of the electroencephalogram detected by the electroencephalogram detection means, without using frequency components of the electroencephalogram of a person other than the subject; A symptom determination device characterized by:

3. an electroencephalogram (EEG) detection means for detecting a plurality of frequency components of an electroencephalogram in a specific brain region of a subject; a depressive symptom assessment means for assessing depressive symptoms in the subject based on the intensities of a plurality of frequency components of the electroencephalogram detected by the electroencephalogram detection means; Equipped with the depressive symptom assessment means, when the subject is taking a medication, assesses the depressive symptom in the subject after correcting a assessment criterion for assessing the depressive symptom in the subject based on the effect of the medication being taken; A symptom determination device characterized by:

4. 4. The symptom determination device according to claim 1, wherein the depressive symptom determination means determines the severity of the depressive symptoms in the subject.

5. an EEG detection function for detecting multiple frequency components of EEGs in a specific brain region of the subject; a depression symptom determination function that determines depression symptoms in the subject based on the intensities of a plurality of frequency components of the electroencephalogram detected by the electroencephalogram detection function; This is realized by a computer, the depressive symptom assessment function weights the intensity of a frequency component of a predetermined frequency among the plurality of frequency components of the electroencephalogram detected by the electroencephalogram detection function, and assesses the depressive symptom in the subject by prioritizing the intensity of frequency components of other frequencies as a assessment criterion. A symptom determination program characterized by:

6. an EEG detection function for detecting multiple frequency components of EEGs in a specific brain region of the subject; a depression symptom determination function that determines depression symptoms in the subject based on the intensities of a plurality of frequency components of the electroencephalogram detected by the electroencephalogram detection function; This is realized by a computer, the depression symptom assessment function assesses the depression symptom of the subject based on a comparison result of intensities of frequency components belonging to a low frequency region and frequency components belonging to a high frequency region among the plurality of frequency components of the electroencephalogram detected by the electroencephalogram detection function, without using frequency components of the electroencephalogram of a person other than the subject; A symptom determination program characterized by:

7. an EEG detection function for detecting multiple frequency components of EEGs in a specific brain region of the subject; a depression symptom determination function that determines depression symptoms in the subject based on the intensities of a plurality of frequency components of the electroencephalogram detected by the electroencephalogram detection function; This is realized by a computer, the depressive symptom assessment function, when the subject is taking a medication, assesses the depressive symptom in the subject after correcting a assessment criterion for assessing the depressive symptom in the subject based on the effect of the medication being taken; A symptom determination program characterized by:

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