JPS61162932A - Brain wave measuring apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a pulse wave measuring device, and particularly to a volume pulse wave measuring device used for clinical diagnosis of the circulatory system.

[Background of the invention]

Photoelectric fingertip plethysmometers have conventionally been used to use the measurement results of pulse waves at fingertips for clinical diagnosis of the circulatory system. This method electrically detects changes in the volume of capillaries at the fingertips as changes in the amount of absorbed light.The principle is simple, pulse waves can be measured relatively easily, and it is non-invasive. Because of this, it is used to diagnose the circulatory system of patients. However, this photoelectric fingertip plethysmometer uses a tungsten lamp with a tungsten filament as the light source, and uses a solar cell or other device for the receiver that receives the light that passes through the fingertip, so the light from the light source spreads out and is weak. Therefore, the S/N is poor, resulting in low reliability, and it cannot be used for diagnosis of patients with slight peripheral circulatory system disorders, and the heat radiation from the tungsten lamp as the light source is a burden on the patient. It could not be widely used for diagnosis because of problems such as .

[Purpose of the invention]

It is an object of the present invention to provide a pulse wave measuring device that eliminates such problems and enables qualitative and quantitative evaluation of peripheral circulatory system disorders.

[Summary of the invention]

The present invention comprises a transducer including a light emitting diode that irradiates light onto a measurement site consisting of the tip of a finger or a finger, a phototransistor that measures the amount of light from the light emitting diode that has passed through the measurement site, and a pulse wave meter main body. a first pulse wave meter; a second pulse wave meter that has the same configuration as the first pulse waveform and measures pulse waves at a standard site such as the ear at the same time as the first pulse wave meter; From the measurement results of the first and second sphygmographs, the pulse wave period, notch time, rise time, and arrival time of the pulse wave measured by the first sphygmograph are measured by the second sphygmograph. The present invention is characterized by having calculation means for calculating a delay time with respect to the arrival time of the pulse wave.

[Embodiments of the invention]

Examples will be described below.

FIG. 1 shows the configuration of a pulse wave measuring device according to an embodiment, and FIG. 2 shows a part of the configuration of its main parts, and shows the state during pulse wave measurement. In this diagram, 1 is the finger.

2 represents an ear, and 3 and 4 each represent a light emitting diode (L
ED), 5 and 6 each indicate a phototransistor, 7 a pulse wave meter body, 8 an A/D converter, 9 a microcomputer, 10 a printer, 11 a floppy desk, 12 a color display, 13 is LE
D power supply, 14 is an I/V converter, 15, 16, and 17 are signal pie-pass filters and variable gain amplifiers, DC offsets, 18 and 19, respectively.
shows a variable pull gain amplifier and low pass filter for calibration.

That is, the pulse wave measuring device of this embodiment consists of a transducer consisting of an LED and a phototransistor, and a pulse wave meter main body, and has two sets of pulse wave meters having the configuration shown in FIG. 2, and has two input channels. Simultaneous measurement of two locations is possible. The LED used for the transducer has a center wavelength of 940 nm, an output of 1.8 mW, a beam diameter of φ1.5 mm on the irradiation surface, and a phototransistor's light reception half-power angle of 10°. The input voltage of the A/D converter is O
~5V, data is 8 bits, conversion time is about 120μS
It is.

Next, the effects of this pulse wave measuring device will be explained based on quantitative evaluation of peripheral circulatory system disorders performed using this pulse wave measuring device.

The subject was kept at rest in a supine position for about 10 minutes on a bed in a constant temperature room kept at 23.2°C, and transducers were attached to the measurement site (tips of fingers and toes) and the ear shell as a control. is shaded by black cloth. The pulse wave displayed on the CRT is monitored, and data is sampled when a stable state is detected. Change the measurement site and repeat one or more operations.

Then, a polynomial adaptive smoothing method was applied to remove noise superimposed on the signal, a smoothing differential method was applied to waveform analysis, and a maximum Endby method (MEM) was applied, and calculation processing was performed by a computer. Arithmetic processing such as waveform analysis was performed all at once after measurement.

The measurement target is asymptomatic healthy person 1 whose main artery is patent.
A total of 20 patients: 0 patients and 10 patients with various occlusions of the main arteries.
This is an example.

Figures 3, 4, and 5 show toe pulse waves obtained using the pulse wave measuring device of this embodiment, and show the original waveform, the smoothed waveform, and the differential waveform, respectively. The horizontal axis represents time (sec,), and the vertical axis represents input voltage (Vo).
it), input voltage (Volt), differential coefficient (V/s
ee,) is taken, T, To.

Tu indicates the periodic notch time and rise time, respectively.

Figures 6 and 7 show the waveforms of the finger and ear superimposed, and show the waveform after smoothing processing and the −th order differential waveform, respectively, with the horizontal axis representing time (see, ) and the vertical axis representing The input voltage (Vo it) and the differential coefficient (V/see, ) are taken respectively, T indicates the pulse wave at the toe, E indicates the pulse wave at the ear, and T
, To, and Tu, a delay time Td with respect to the arrival time of the ear pulse wave is shown. The figure shows a case where there is a failure. In these figures, the horizontal and vertical axes represent frequency (H
z), the relative spectrum is taken, and f,, f are the frequencies at which the relative spectrum is 110 dB, -2
It shows the frequency at which it is 0 dB. In Figure 8, which shows the normal case, the maximum value of the spectrum is 71938.1 and the noise difference is , 784879, fl and f are 2.37 (Hz) and 4.41 (Hz), respectively. In Figure 9, which shows the case where there is a disturbance, the maximum value of the spectrum is 38389.6, and the noise difference is 1.69489.
and f are 2.32 (Hz) and 3.11 (H
z).

Figures 10 and 11 show the measured values obtained as described above classified according to the patency status of the anterior and posterior tibial arteries, and the relationship between Tu and Td and the relationship between fl and fl. It shows. Figure 10 shows T on the horizontal and vertical axes, respectively.
u (sec,), T e (see,) are the 11th
In the figure, the horizontal axis is f t (Hz), the vertical axis is f2 (Hz), and ta, tp. indicate the anterior tibial artery and the posterior tibial artery, respectively, + indicates patency of the main artery, and - indicates occlusion.

Tables 1 and 2 show actual measured values in the cases of FIGS. 10 and 11, respectively.

The average value (Av) and standard deviation (σ
), the number of samples (N) is indicated.

These figures and tables show that in most cases of total blockage of ta, tp, the Tu waiting time is 0.3 seconds or more, or the Td waiting time is 0.3 seconds or more.
2 seconds or more, and fitf2 is 2 seconds or more.
, 5 Hz, 3, in the range below 5 Hz, the number of samples N = 21, T u = 0.203 ± 0.034 se
c,, f, = 5.28 ± 1.40 Hz were obtained, and in both the occluded group (marked 0 in the figure), N = 40 and T u = 0.
338±0.064sec, f, ==3.82±
A value of 1.32 Hz was obtained, and a clear difference was seen between these two groups. In the other two groups (marked ・ and Δ in the figure) whose arterial conditions are between the two, Tu is between the two.

It was also found that both f8 values were comparable to those in the occlusion group.

As described above, the pulse wave measuring device of this embodiment analyzes the waveform of a pulse wave, and when there is a disorder in the peripheral circulatory system, the S
/N ratio.

In addition, since it has a two-channel pulse wave meter, one of them measures the fingertip pulse wave, and the other one measures the ear pulse wave, for example, and the time when the ear pulse wave arrives. It has become possible to measure the delay time of the pulse wave at the fingertip, making quantitative evaluation and diagnosis of circulatory disorders more effective. For example, as a result of waveform analysis using a microcomputer, it has become possible to clearly differentiate between a normal group and an abnormal group. This makes it possible to provide useful information.

Also, this pulse wave measuring device uses an LED and a phototransistor for the transducer.

It does not impose a heat load on the patient, unlike when using a tungsten lamp, and as a result, high pulse waves can be recorded continuously for a long period of time, making it possible to judge the effectiveness of drug administration, etc., and to evaluate and treat circulatory system disorders. It can also be an effective means.

〔Effect of the invention〕

The present invention makes it possible to provide a pulse wave measuring device capable of qualitatively and quantitatively evaluating peripheral circulatory system disorders, and has great industrial effects.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the pulse wave measuring device of the present invention, FIG. 2 is a block diagram of the main parts of FIG. 1, and FIG. 4 and 5 are explanatory diagrams of the original waveform, the waveform after smoothing processing, and the differential waveform of the pulse wave obtained using the embodiment of FIG. 1, and FIGS. 6 and 7 are illustrations of the finger and ear. 8 and 9 are explanatory diagrams showing the pulse wave spectrum obtained by MEM, and FIG. and FIG. 11 is a diagram showing the measurement results of pulse waves obtained using the embodiment of FIG. 1, classified according to the patency status of the anterior tibial artery and the posterior tibial artery. DESCRIPTION OF SYMBOLS 1... Finger, 2... Ear, 3, 4... Light emitting diode, 5° 6... Phototransistor, 7... Pulse waveform body part, 8... A/D converter, 9... ... Microcomputer, 10... Printer, 11... Floppy desk, 12... Color display.

Claims (1)

[Claims] 1. A transducer consisting of a light-emitting diode that irradiates light onto a measurement site such as the tip of a finger or a finger, and a phototransistor that measures the amount of light from the light-emitting diode that has passed through the measurement site; and a pulse wave meter main body. a second pulse wave meter that has the same configuration as the first pulse waveform and measures pulse waves at a standard site such as the ear at the same time as the first pulse wave meter; Based on the measurement results of the first and second pulse wave meters, the pulse wave period, notch time, rise time, and arrival time of the measured pulse wave of the first pulse wave meter are measured by the second pulse wave meter. A pulse wave measuring device characterized by having a calculation means for calculating a delay time with respect to a wave arrival time.