The present application claims priority from Japanese Patent Application JP 2010-104045 filed on Apr. 28, 2010, the content of which is hereby incorporated by reference into this application.
1. Field of the Invention
The present invention relates to a motor function analyzing apparatus that evaluates a motor function of a biological object using a magnetic sensor.
2. Description of the Related Art
Recently, the number of patients with movement disorder increases together with the progression of an aging society. Examples of such movement disorder are diseases that progress a disorder in motor function, such as Parkinson's disease, stroke, cervical myelopathy, dementia, and mental disorder. For example, Parkinson's disease that is a typical disease with movement disorder is an intractable disease which brings about a serious disorder in daily life because of tremor of hands, muscles rigidity, etc. The number of Parkinson's disease patients in Japan reaches 145,000 according to the survey by Japan Ministry of Health, Labor and Welfare in 2005, and it is expected that such number increases thereafter.
Conventionally, it is typical that a doctor checks and sees the motion of a patient and makes an evaluation based on scores representing severity levels in order to diagnose movement disorder. For example, in the case of a diagnosis to Parkinson's disease, a UPDRS (Unified Parkinson's Disease Rating Scale) is widely used as an evaluation index representing the severity level of Parkinson's disease. According to the UPDRS, a motor function is evaluated through plural motions, such as walking, and finger tapping motion (a motion of repeatedly opening/closing the thumb of a hand and the index finger thereof).
According to the UPDRS, however, evaluation is made through the subjective diagnosis by a doctor, so that there is an individual difference among doctors, resulting in insufficient objectivity in some cases. In order to overcome such a problem, apparatuses which measure the finger tapping motion by a patient using a magnetic sensor, and which evaluate a motor function quantitatively have been developed (see, for example, JP 2005-152053 A, JP 2008-246126 A and Kandori et al., “Quantitative magnetic detection of finger movements in patients with Parkinson's disease.”, Neuroscience Research. Vol. 49, No. 2, 2004, pp 253-260).
According to such apparatuses, magnetic sensors are attached to respective nail portions of a thumb and an index finger (hereinafter, referred to as “two fingers”), and a voltage value obtained from the magnetic sensors is converted into a distance value between the two fingers (corresponding to a distance between respective cushion sides of the thumb and the index finger). For example, a Non-patent Literature (Keisuke SHIMA, Eriko KAN, Toshio TSUJI, Tokuo TSUJI, Akihiko KANDORI, Tsuyoshi MIYASHITA, Masaru YOKOE, and Saburo SAKODA, “Magnetic sensor calibration for human finger tap measurement”, Society of Instrument and Control Engineers, Vol. 43, No. 9, 2007, pp 821-828) discloses a technology which measures three calibration points (e.g., data on three distances: 2 cm; 3 cm; and 6 cm) for the two fingers attached with magnetic sensors before measuring a finger tapping motion in order to obtain a correspondence between a voltage value and a distance value, and which substitutes such calibration points into a predetermined formula, thereby deriving a conversion formula of calculating a distance value from a voltage value.
According to the conventional technologies, however, when a calibration measurement includes an error, a calculated distance value may also include a large error in some cases. For example, when the two fingers are widely opened, even if the actual distance value between the two fingers is 15 cm, a value exceeding 30 cm may be falsely output in some cases. Also, according to the conventional technologies, it is necessary to perform three kinds of calibration measurement before a finger tapping motion is measured for every measurement, the management of instruments and the calibration measurement are bothersome.
The present invention has been made in view of the foregoing circumstances, and it is an object of the present invention to provide a motor function analyzing apparatus which simplifies a necessary calibration measurement before measuring a finger tapping motion, and which is capable of evaluating a motor function with high precision.
In order to achieve the above object, a first aspect of the present invention provides a motor function analyzing apparatus that includes: a movement-waveform generating unit which includes a magnetic field generator that generates a magnetic field, the magnetic field generator being attached to predetermined two locations of a biological object, the predetermined two locations changing a distance therebetween due to a motion of the biological object, and a magnetic field detector that detects the magnetic field, the movement-waveform generating unit generating a movement waveform based on magnetic field data detected by the magnetic field detector.
The movement-waveform generating unit includes: a calibration-point measuring unit that measures a calibration point including distance data between the predetermined two locations of the biological object and magnetic field data detected by the magnetic field detector; a conversion-formula generating unit that generates a conversion formula which converts the magnetic field data detected by the magnetic field detector into a movement waveform using the calibration point measured by the calibration-point measuring unit; and a movement-waveform generating unit that converts the magnetic field data detected by the magnetic field detector and generates a movement waveform using the conversion formula generated by the conversion-formula generating unit.
The calibration-point measuring unit includes: an apparatus-unique-voltage measuring unit that measures a voltage unique to each motor function analyzing apparatus with the magnetic field generator and the magnetic field detector being located apart from each other by a predetermined distance; and an subject-unique-voltage measuring unit that measures a voltage unique to each subject with the predetermined two locations of the biological object to which the magnetic field generator and the magnetic field detector are attached being maintaining a predetermined distance between the predetermined two locations.
The other configurations of the present invention will be explained in embodiments of the present invention to be discussed later.
FIG. 31A1 is a diagram showing a change in the conditions of two fingers during a finger tapping motion;
FIG. 31A2 is a diagram showing a change in the conditions of two fingers during a finger tapping motion;
Embodiments for carrying out the present invention (hereinafter, simply referred to as “embodiments”) will be explained in detail with reference to the accompanying drawings.
As shown in
The subject is a measurement target by the motor function measuring apparatus 12. In this embodiment, the subject is, for example, a biological object such as an animal or a human. The motor function measuring system 10 measures a motor function when the subject is caused to do rapid tapping. More specifically, the subject is instructed to perform a finger tapping motion of repeatedly opening/closing the thumb of a hand and the index finger thereof, and motions of the fingers at this time are measured.
The motor function measuring apparatus 12 detects movement information of the subject in time series, and obtains the movement information of the subject relating to at least one of the followings: a distance; a speed; an acceleration; and a jerk, as waveform data.
The motor function measuring apparatus 12 includes motion sensors 22 having a generator coil (a magnetic field generator) that generates a magnetic field and a detector coil (a magnetic field detecting unit) that detects the magnetic field, a motion sensor interface 24, and a motion sensor control unit 26. The motion sensor 22 functions as a sensor for measuring a motor function.
In this case, the motion sensor control unit 26 is arranged on an unillustrated substrate provided inside a housing 28 which is formed in a box shape and serves as a main body. The motion sensors 22 are freely and detachably connected to the housing 28 through first and second connectors 30a and 30b provided at the front face of the housing 28. Also, as will be discussed later, the generator coil is attached to the lower side of the nail portion of the thumb of the subject, and the detector coil is attached to the upper side of the nail portion of the index finger of the subject.
As shown in
In this case, it is preferable that the first to fourth connectors 30a to 30d should be female connectors, respectively. Also, a casing 36 that configures the housing member 20 is mounted on the top face of the housing 28. In the example case shown in
In this embodiment, the explanation will be given of a case in which portions to which a pair of holders 40 are attached are respective nail portions of the thumb and the index finger. The present invention is not limited to this case, and for example, such holders may be attached to finger portions other than the nail portion. Also, the fingers are not limited to the thumb and the index finger, and the holders 40 can be attached to any finger like a pinky finger. Also, portions where the holders 40 are attached are not limited to the nail portion of the subject and the finger thereof, and for example, may be a periphery portion to a finger like the palm of a hand. Hence, the nail portion of the subject, a finger, and a periphery portion to the finger are set as the portions where the holders 40 are attached.
As shown in
As shown in
In the example case shown in
Also, as shown in
When the pair of calibration blocks 106 in a separate configuration are prepared, or when the single calibration block 106a with the multi-step shape 110 is prepared, there is an advantage that both pieces of calibration data for the right hand and the left hand of the subject can be obtained simultaneously. When pieces of calibration data for both hands of the subject are obtained simultaneously, it is possible to suppress the interference of the motion sensor 22 for the right hand and the motion sensor 22 for the left hand by spacing apart respective fingers of the right hand and the left hand by a predetermined distance.
In addition to a case in which the calibration block 106 (106a) is used, calibration data of the subject can be obtained by using, for example, other devices like a calibration data detecting device with a variable resistor.
As shown in
The generated induced electromotive force (that has the same frequency as that of the AC voltage with a certain frequency generated by the AC generator circuit 200) is amplified by a pre-amplifier circuit 204, and a signal having undergone amplification is input into a wave detector circuit 206. The wave detector circuit 206 performs wave detection at the certain frequency generated by the AC generator circuit 200 or at a double frequency. Hence, an output by the AC generator circuit 200 has a phase adjusted by a phase adjuster circuit 208, and a reference signal 210 thereof is input into a reference-signal input terminal of the wave detector circuit 206.
When wave detection is performed at a double frequency of the certain frequency, the phase adjuster circuit 208 is not always requisite. As a simple circuit configuration of performing wave detection at the double frequency, it is appropriate if the certain frequency of the AC generator circuit 200 is set to be twice, the frequency is converted into a half frequency by a frequency divider, and a voltage is input into the current generating amplifier circuit 202, and a signal having a frequency twice as much as the certain frequency of the AC generator circuit 200 may be input as the reference signal 210 into the reference-signal input terminal of the wave detector circuit 206.
An output signal by the wave detector circuit 206 passes through an LPF (Low-Pass Filter) circuit 212, is amplified by an amplifier circuit 214 in order to obtain a desired voltage, and is input into the motor function analyzing apparatus 14. An output signal 216 by the amplifier circuit 214 is a voltage corresponding to a relative distance D between the generator coil and the detector coil attached to the thumb and the index finger, respectively. Note that the wave detector circuit 206, the LPF circuit 212 and the amplifier circuit 214 serve as detected signal processing units, respectively.
The explanation was given of a case in which the magnetic-sensor-type motion sensor 22 is used, but the kind of the motion sensor 22 is not limited to any particular one as long as it can measure a motion through generation of a magnetic field. For example, conventionally well-known strain gauge and acceleration sensor may be used.
As shown in
In this embodiment, a term movement waveform means time-series data of a distance value between the two fingers, and as long as it is mentioned, includes at least one of the followings: a distance waveform; a speed waveform; an acceleration waveform; and a jerk waveform.
The control unit 330 inputs an output signal supplied from the data input unit 320 into the movement waveform generating unit 302, and outputs movement waveform obtained from the movement waveform generating unit 302 and subject information obtained from the subject information processing unit 304 to the display unit 18, i.e., is the unit which inputs/outputs data from various units. The motor function analyzing apparatus 14 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a hard-disk drive, and the like. The process by the control unit 330, etc., is realized by the CPU reading a program from the memory 310 and executing an arithmetic processing.
As shown in
The calibration-point measuring unit 3021 measures three calibration points. The calibration point is a combination (D, V) of a distance value D between the cushion of the thumb and that of the index finger and a voltage value D output by the motor function measuring apparatus 12 when the distance D between the two fingers is maintained. The three calibration points obtained by the calibration-point measuring unit 3021 are used for generating a conversion formula that converts a voltage value into a distance value in the conversion-formula generating unit 3022. Hereinafter, an explanation will be given of how to calculate three calibration points (see a calibration point (0) (D0, V0) in
A voltage value V0 of the calibration point (0) (D0, V0) is a voltage value obtained when the subject slightly touches the thumb to the index finger as shown in
Next, a voltage value V1 of a calibration point (1) (D1, V1) is measured when the subject holds the first block 108a (60 mm) of the calibration block 106 between the thumb and the index finger as shown in
Also, the precision can be improved by setting a limit to the value of D1 as follows. As shown in FIG. 31A1, it is desirable that a distance between respective cushions of the two fingers should be measured (a distance value at this time is set to be D1a) when respective fingertips of the two fingers during a finger tapping operation are in a condition substantially parallel at a maximum, and this distance value should be set to be the value of D1. The reasons why the precision improves when setting D1 in this fashion are the following two reasons.
First, this is because a voltage obtained from the detector coil becomes toughest relative to a varying in the angular direction of the coil when the generator coil and the detector coil are in a positional relationship parallel to each other. The detail of this phenomenon will be explained with reference to
As is indicated by this graph, the magnetic field intensity becomes maximum when θ=0 degree. When θ=60 degrees, the magnetic field intensity decreases to substantially 60 percent of one when θ=0 degree, and the magnetic field intensity becomes zero when θ=90 degrees. Respective layouts of the two coils in respective cases are shown in
Next, the second reason why setting is made so that D1=D1a will be explained. When setting is made so that D1=D1a, respective postures of the two fingers when holding the calibration block 106 become natural postures like the finger tapping motion, so that an error is not likely to be generated during a calibration measurement. A detail of this reason will be explained below.
As shown in FIG. 31A1, a distance between respective cushions of the two fingers is measured when the two fingers become substantially parallel at a maximum during the finger tapping motion, and D1a is obtained. When calibration measurement is made using the portion of the calibration block corresponding to the length D1a, as shown in FIG. 31A2, the calibration block can be held in natural postures like ones during the finger tapping motion. Accordingly, when the calibration block is held in natural postures like ones during the finger tapping motion, a voltage value during the finger tapping motion is not likely to differ largely from a voltage value during a calibration measurement. Hence, the precision of a conversion formula calculated by the movement-waveform converting unit 3023 becomes high.
However, when D1<D1a as shown in
The voltage value V0 of the calibration point (0) and the voltage value V1 of the calibration point (1) depend on the shapes of the fingers of the subject, and how to attach the motion sensors 22 thereto, etc., so that those values are unique to each subject. Accordingly, when the subject changes or when the motion sensors 22 are attached again, it is desirable to measure the voltage values V0 and V1 again for each occasion. When the voltage values V0 and V1 are measured again for each occasion, the precision of a conversion formula obtained from the conversion-formula generating unit 3022 improves.
Eventually, a voltage value V2 of the calibration point (2) (D2, V2) is a voltage value obtained when the detector coil of the motion sensor 22 and the generator coil thereof are located most distant from each other within the restriction of the wire lead 46 (see
D′=α(V−γ)1/3+β (1)
When the detector coil and the generator coil are located most distant from each other, a condition in which the detector coil detects no magnetic field can be approximately produced. This makes it possible to obtain unique offset voltage value to each apparatus.
As explained above, because V2 is a voltage value unique to each apparatus, when such a voltage value is once measured before the apparatus is used, it becomes unnecessary to measure such a voltage value again thereafter. Information on the calibration point (2) is stored in the memory 310 of the control unit 330 or an external memory beforehand.
The method for measuring V2 is not limited to the above-explained method as long as a condition in which no magnetic field is detected can be approximately generated by the method. For example, as shown in
Also, it is preferable if V2 is measured beforehand through an option screen shown in
Next, the conversion-formula generating unit 3022 (see
The conversion formula obtained by the conversion-formula generating unit 3022 is indicated in
The explanation was given of the method of calculating the conversion formula using the three calibration points. That is, the calibration-point measuring unit 3021 includes an apparatus-unique-voltage measuring unit that measures a voltage unique to each apparatus with the magnetic field generator and the magnetic field detector being kept in a condition apart from each other by a predetermined distance, and an subject-unique-voltage measuring unit that measures a voltage unique to each subject with the two predetermined portions of the biological object where the magnetic field generator and the magnetic field detector are attached being kept in a condition apart from each other by the predetermined distance.
In this embodiment, the calibration-point measuring unit 3021 measures the two calibration points (the calibration points (0) and (1)) unique to each subject and the calibration point (the calibration point (2)) unique to each apparatus. However, when both calibration point unique to each apparatus and the calibration points unique to each subject are used, the number of calibration points may be other number than 3.
Next, the movement-waveform converting unit 3023 (see
When a method of causing the conversion-formula generating unit 3022 to calculate the conversion formula using the three calibration points is applied, there are two advantages. The first advantage is that a measurement can be easily carried out with a little number of calibrations. The reason of this advantage will be explained with reference to
According to a conventional scheme, the above-explained formula (1) is used which is an approximate curve representing the relationship between the voltage value V and the distance D between the two fingers, and a calibration point is measured for each subject in order to adjust parameters. In order to obtain the parameters α, β, and γ of this formula, at least three calibration points are requisite, so that three calibration points (a calibration point (3) 1402 (D3, V5), a calibration point (4) 1403 (D4, V4), and a calibration point (5) 1404 (D5, V3)) shown in
As explained above, because three kinds of calibration measurements are requisite for each time before a measurement according to the conventional scheme, it takes a time to start measurement. Also, three blocks are requisite, so that production, management, and storage of the calibration blocks require an effort. According to this embodiment, however, the number of calibration points necessary to measure before a measurement for each time is two (a calibration point (0) 132 and a calibration point (1) 133 shown in
In this fashion, by measuring a calibration point (2) 134 before the apparatus is used, the number of calibration points necessary before a measurement can be reduced. Also, the number of calibration points needing the calibration block is one (the calibration point (1) 133), so that preparation of one kind of calibration block is sufficient. Hence, production, management, and storage of the calibration block become simplified. As is clear from the above explanation, this embodiment can overcome the problem inherent to the conventional scheme.
Next, the second advantage of this embodiment is that a voltage value can be converted into a distance value more precisely than the conventional scheme. According to the conventional scheme, the precision of a distance value calculated from a voltage value largely depends on the precision of the calibration point. This problem of the conventional scheme will be explained with reference to
It is presumed that a conversion curve A1401 is obtained when the calibration point includes no error as shown in
However, according to an actual measurement of a calibration point, an error is often generated in the calibration point because of holding of the calibration block 106 with the two fingers standing up, or holding it strongly, so that it is not always true that a conversion curve A is calculated. For example, when a negative error is generated in the calibration point (3) 1402, and a positive error is generated in the calibration point (5) 1404, a conversion formula B1405 is obtained. In
When a voltage value is converted into a distance value using this conversion curve B1405, the distance value includes a large error. For example, when a voltage value V3 in
On the other hand, according to the method of this embodiment, the precision of the conversion curve is not likely to depend on the error in the calibration point. This is because ends of the conversion curve do not largely vary since the calibration points are located at three points: the left end; the center; and the right end of the conversion curve. According to the conventional scheme, the calibration points (3), (4), and (5) are collectively located around the center of the conversion curve, so that when those calibration points include an error, such an error is amplified in the vicinity of the right and left ends of the conversion curve.
Next, the movement-waveform differentiation unit 3024 (see
The subject information processing unit 304 (see
More specifically, the subject information processing unit 304 performs generally four processes: (1) registers, corrects, deletes, searches, and sorts subject information; (2) associates subject information with measurement data; (3) registers, corrects, and deletes an analysis result of measurement data (adds, corrects, and deletes items); and (4) registers, corrects, and deletes a processed result of a statistical process when such statistical process was executed, together with the subject DB.
Examples of the subject information registered in the subject DB are an subject ID (Identifier), a name, birth date, age, height, weight, the name of disease, and a comment on the subject. Information management by such subject information processing unit 304 can be easily realized by a conventionally well-known program and data structure.
The output processing unit 306 causes the display unit 18 to display the subject information, information on an analysis result, etc., registered in the subject DB in a display form easily understandable visually which uses a graph, a table, etc., as needed. It is not necessary for the output processing unit 306 to display all analysis results simultaneously, and the output processing unit 306 may be configured to display only items selected by a user accordingly.
The display unit 18 displays the subject information obtained from the subject information processing unit 304 and a movement waveform obtained from the movement-waveform generating unit 302, and is realized by, for example, an LCD (Liquid Crystal Display) or a CRT (Cathode Ray Tube) display, and a printer.
The operation input unit 16 is for the user of the motor function measuring apparatus 12 to input subject information, and is realized by, for example, a keyboard and a mouse. When subject information is input, as a user interface that assists the input by the user, an input screen may be displayed on the display.
Next, an explanation will be given of illustrative screens displayed by the motor function measuring system 10 according to this embodiment with reference to
Displayed on the measurement-data-list field 2702 are an “subject ID”, a “name”, a “measurement date”, a “measurement time”, a “measurement period”, a “measurement method”, an “age”, a “sex”, a “first comment”, and a “second comment”. Displayed on the search condition input field 2704 are the “subject ID”, the “name”, the “sex”, the “age”, the “measurement date”, the “measurement method”, the “first comment”, and the “second comment” as items for searching, and those are inputtable or selectable. When the user of the motor function analyzing apparatus 14 (hereinafter, simply referred to as a “user”) inputs or selects any one of those items or a combination thereof, it becomes possible to execute searching. A search result is displayed on the measurement-data-list field 2702.
The service buttons 2706 includes respective buttons (operators) of, as services, new measurement 2720 (first operator) (to create new subject information and to measure a finger tapping), measurement 2722 (first operator) (to measure a finger tapping related to an subject already selected), data analysis 2724 (second operator) (to display analysis information on data selected in the measurement-data-list field 2702), interannual display 2726 (third operator) (to display an interannual graph selected in the measurement-data-list field 2702), “measurement-information delete” (to delete data selected in the measurement-data-list field 2702), and “export” (to output an analysis result of data selected in the measurement-data-list field 2702 in a CSV (Comma Separated Values) format). When such buttons are selected, corresponding functions are activated.
The data analysis button 2724, the interannual display button 2726, the “measurement-information delete” button, and the “export” button are for processes for data selected in the measurement-data-list field 2702. However, when none is selected or when the selected data is already deleted, an error message may be displayed. Also, when the search results exceed 1000 results, a display confirmation message may be displayed.
The service buttons 2706 include, as tools, buttons of “data management” (to edit data selected in the measurement-data-list field 2702) and “option” (to set default values of each screen), and an “end” button (to end this application program) arranged at the lowermost location.
Displayed on the subject-data-list field 2802 are an “subject ID”, a “name”, “birth date”, “sex”, a “dominant hand”, and a “memo”. Displayed on the search condition input field 2804 are the “subject ID”, the “name”, and “sex” as items for searching, and those are inputtable or selectable. When the user inputs or selects any one of such items or a combination thereof, it becomes possible to execute searching. When a button of “start searching” is operated, searching starts and when a button of “clear condition” is operated, searching conditions set are collectively cleared.
The service buttons 2806 include buttons of, as services, new measurement 2720 (first operator) and measurement 2722 (first operator). Those functions are same as those of the measurement-data-list screen (see
The subject-information setting screen has, at the bottom portion thereof, buttons of “obtain information based on an subject ID” (to obtain subject information registered in the subject DB based on an ID input in the field of “subject ID”), “save” (to save the setting and display a setting screen for a measurement (see FIG. 19)), and “close” (to close the subject-information setting screen and to return to the main screen (see
When the button of subject information setting 3012 is operated, the subject-information setting screen (see
As shown in
The screen for executing measurement also includes buttons of “display metronome” and “close” (to close this screen), and a measurement time display bar (displays a measurement time in a progress bar form) which is located at the lowermost location. A message for confirming saving of measurement information may be displayed when measurement is executed.
As shown in
The voltage value V2 measured by the calibration-point measuring unit 3021 shown in
By using the above-explained screens shown in
Next, a detailed explanation will be given of a second embodiment with reference to the accompanying drawings as needed. The structural elements shown in
As explained above, the conversion-formula generating unit 3022 generates a conversion formula that converts voltage data supplied from the motor function measuring apparatus 12 into a movement waveform. In this embodiment, finger tapping motions of plural subjects are measured in practice, and a conversion formula (hereinafter, referred to as an individual conversion formula) unique to each subject is generated. Next, those individual conversion formulae are averaged, and a single conversion formula (hereinafter, referred to as a master curve) is calculated. Explanations will be given of the above-explained two processes.
In order to generate individual conversion formulae, finger tapping motions of subjects are measured in practice. As shown in
Voltage data and distance data obtained thus way are plotted on a scatter diagram as shown in
Next, in order to generate a master curve, n number of individual conversion formulae are generated (where k=1 to n) with plural subjects (the number thereof is n) being as test targets. The n number of individual conversion formulae are taken as a conversion formula group F 271. As shown in
Next, as shown in
The master curve is calculated through an averaging in the distance direction in this embodiment, but may be calculated through an averaging in the voltage direction. Also, without using the obtained master curve as it is, the master curve may be corrected with a calibration point (8) 282 (Dx, Vx) (see
As explained above, the master curve is limited within the range of Vc, so that it is necessary to generate a conversion curve through another method for ranges other than the range of Vc. As shown in
Likewise, regarding portions where the voltage is equal to or smaller than VcN, such portions between a right end 292 of the master curve and a calibration point (7) 294 (Dmax, Vmax) are compensated by quadratic polynomial equation. Vmax at the calibration point (7) is a voltage obtained when the detector coil of the motion sensor 22 and the generator coil thereof are apart from each other at a maximum, and is a value that is recorded in the apparatus beforehand. The distance value Dmax is a preset value, and is 300 mm in this embodiment. In addition, Dmax may not be 300 mm if Dmax is large enough compared to a distance between the cushions of the two fingers when the subject opens the two fingers at a maximum. Also, the value of Dmax may be an actual measured value Dm (see
The movement-waveform converting unit 3023 (see
In order to obtain the individual conversion formula in this embodiment, the finger tapping motion of the subject is actually measured, but the individual conversion formula may be calculated by building a model that simulates the skeleton of the thumb, that of the index finger, and the motions thereof. More specifically, as shown in
The individual conversion formula fk is obtained based on the voltage value and the distance value obtained in this fashion. Likewise, regarding plural subjects, parameters, such as the length of each joint and the angle between the joints, are extracted, and respective finger tapping motions are simulated, thereby obtaining the conversion formula group F. The calculation thereafter is same as the above-explained method. In addition, as the parameters of the skeleton model, an average value of the parameters extracted from the image of the actual finger of the subject or a dispersion value thereof may be used, or a value presumed from literatures may be used, without using the parameters extracted from the image of the actual finger of the subject.
As explained above, according to the motor function measuring apparatus 12 according to the first and second embodiments, it is needless to say that the measurement result by the apparatus can assist not only diagnosis of the severity level of Parkinson's disease but also diagnosis of other movement disorders, such as a neural disease like rheumatism.
Also, through the calibration method explained in the first and second embodiments, a motor function inspection is enabled which is more precise and simpler than the conventional scheme.
That is, according to the above-explained embodiments, a calibration point unique to each apparatus and measured before the apparatus is used and a calibration point unique to each subject and measured every time the subject changes are both used. According to the above-explained embodiments, a voltage value can be converted into a distance value highly precisely by using the calibration point unique to each subject and the number of calibration measurements can be reduced and the measurement is simplified by using the calibration point unique to each apparatus. Accordingly, by using the calibration point unique to each apparatus and the calibration point unique to each subject as needed, a motor function inspection is enabled which is simpler and more precise than the conventional scheme.
As explained above, the conversion-formula generating unit 3022 includes an individual-conversion-formula generating unit, an averaged-conversion-formula generating unit, and a conversion-formula compensating unit.
The individual-conversion-formula generating unit generates a conversion formula based on distance data obtained by causing a predetermined measuring apparatus to measure a distance between predetermined two portions of a biological object to which a magnetic field generator and a magnetic field detector are attached, and magnetic field data detected by the magnetic field detector.
The averaged-conversion-formula generating unit generates an averaged-conversion-formula of plural conversion formulae obtained for plural biological objects by the individual-conversion-formula generating unit.
The conversion-formula compensating unit compensates a range where no distance data is present corresponding to magnetic field data in the averaged-conversion-formula obtained by the averaged-conversion-formula generating unit with an averaged-conversion-formula using a calibration point obtained by the calibration-point measuring unit.
The embodiments of the present invention were explained above, but the present invention is not limited to the above-explained embodiments, and can be changed and modified in various forms within the scope and spirit of the present invention.
For example, when the holder 40 (see
The above-explained specific configurations can be changed and modified in various forms appropriately without departing from the scope and spirit of the present invention.
Number | Date | Country | Kind |
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2010-104045 | Apr 2010 | JP | national |