WO2010035600A1

WO2010035600A1 - Pain relief device

Info

Publication number: WO2010035600A1
Application number: PCT/JP2009/064701
Authority: WO
Inventors: 美仁福井
Original assignee: テルモ株式会社
Priority date: 2008-09-25
Filing date: 2009-08-24
Publication date: 2010-04-01

Abstract

The object of the invention is to stimulate a nerve at the timing most effective for relief of a pulsating pain, while consuming less energy so that the life of the battery is extended. Circulatory dynamics, such as the electrocardiac wave, the pressure pulse wave, and the cardiac sound are measured in the treatment of the pulsating pain, such as a migraine headache or cluster headache. On the basis of the measurement values, the generation of a stimulation signal to stimulate a peripheral nerve and the strength of the stimulation signal are controlled. The strength of an electric stimulation signal is controlled by changing the frequency or the level of amplitude of the electric stimulation signal at the timing of the stimulation. Frequency, pulse width, pulse current, pulse voltage, and so forth are considered as parameters of the electric stimulation signal.

Description

Pain relief device

The present invention relates to a pain relieving apparatus that relieves pain by stimulating nerves, and particularly relates to a pain relieving apparatus that can adjust stimulation based on circulatory dynamics for pulsatile pain.

In pain treatment, electrical stimulation therapy that relieves pain by electrically stimulating nerves is effective. This method is effective when a predetermined effect cannot be obtained by conventional drug therapy, nerve block therapy, or surgical therapy, or when the treatment cannot be continued due to side effects or the like. This electrical stimulation therapy includes spinal cord electrical stimulation therapy and peripheral nerve electrical stimulation therapy. Spinal cord electrostimulation therapy is a method of performing electrical stimulation by placing an electrode lead outside the spinal dura mater that covers the spinal cord. In addition, the peripheral nerve electrical stimulation therapy is a therapy for performing electrical stimulation by placing an electrode lead directly on the peripheral nerve or subcutaneously near the peripheral nerve. In these spinal cord electrical stimulation therapy and peripheral nerve electrical stimulation therapy, pain can be alleviated by interfering with pain transmission through the spinal cord or peripheral nerve using electrical stimulation.

Migraine is a chronic headache that occurs on one side (sometimes both sides) of the head, and may be accompanied by nausea, vomiting, photosensitivity, and hypersensitivity. In general, there are many women in their 20s and 50s, and the number of patients is said to be about four times that of men. Cluster headache is more common in men and is the most painful of all chronic headaches. Headache occurs on one side of the head and is once or twice a year, but daily headaches occur every day for a certain period (often 1-2 months). Migraine and cluster headache are characterized by painful pulsation, and it is known that the heartbeat pulsates with the heartbeat like a pulse. In recent years, trials of peripheral nerve electrical stimulation therapy for migraine and cluster headache have been made. This is intended to relieve the pain by electrically stimulating the occipital nerve, which is a peripheral nerve that exits from the cervical vertebrae Nos. 2 and 3 and travels toward the parietal region of the occipital region. In this trial, electrical stimulation is usually performed by placing electrodes under the neck of the neck where the occipital nerve is running, and the stimulation parameters such as voltage and frequency at the time of stimulation depend on the intensity of pain. Had to be changed manually.

The technique described in Patent Document 1 intends to relieve a headache with a leadless stimulation device implanted near the occipital nerve. This Patent Document 1 particularly discloses a method for adjusting stimulation parameters using a sensor. Is disclosed.

US Pat. No. 6,735,475

However, it is difficult to manually change the intensity of stimulation according to the pulsatility of pain, and in the technique described in Patent Document 1, the pulsation of pain characteristic of migraine or cluster headache Because it is not a specialized stimulation method, pulsatile discomfort remains or in order to remove this discomfort, the stimulation intensity must be set according to the peak of painful pulsation, and always The stimulation intensity must be kept high. Therefore, a high voltage is required and there is a problem of shortening the battery life.

The present invention has been made in view of the above points, and measures whether circulatory dynamics such as electrocardiogram, pressure pulse wave or heart sound are measured, and is stimulation performed for a certain period in synchronization with detection of ventricular contraction or blood output? Another object of the present invention is to provide a pain relieving device that can relieve pain by increasing the intensity of stimulation over normal time for a certain period.

The present invention for solving the above problems includes a stimulation signal generation unit that generates a stimulation signal for electrically stimulating a nerve, a circulation dynamics measurement sensor that measures circulation dynamics, a stimulation signal generation unit, and circulation dynamics measurement A control unit connected to the sensor, and the control unit generates a stimulation signal from the stimulation signal generation unit in response to an output from the hemodynamic measurement sensor in order to treat pulsatile pain. I try to control it.

Here, it is preferable that the electrically stimulated nerve is a spinal cord or a peripheral nerve such as a occipital nerve. The pulsatile pain is a migraine or cluster headache, and the circulatory dynamics measured by the circulatory dynamics measuring unit is any one of electrocardiogram, pressure pulse wave, and heart sound.

As a preferred embodiment of the present invention, when the control unit detects ventricular contraction or blood output, generation of an electrical stimulation signal may be started, or the control unit may start ventricular contraction or blood. When the output is detected, the intensity of the electrical stimulation signal may be increased. Here, it is desirable that the parameters of the electrical stimulation signal depend on at least one of frequency, pulse width, pulse current, and pulse voltage, or a plurality of combinations selected from these.

According to the above-described configuration of the present invention, the nerve can be stimulated at the timing of the heart ventricle contraction or the blood pumping out of the heart in synchronization with the pulsatile pain cycle.

According to the present invention, the nerve can be stimulated for a predetermined stimulation period in synchronization with the pulsation of pain, so that pain having a pulsating surname can be relieved accurately and discomfort given to the patient can be reduced. it can. Since the intensity of the electrical stimulation signal for stimulating the nerve is increased only during the stimulation period, there is also an effect that the battery life can be extended.

It is a functional block diagram which shows the pain alleviation apparatus which concerns on 1st embodiment of this invention. It is a wave form diagram which shows the electrical signal of a circulatory dynamics. It is a wave form diagram which shows the example of an electrical stimulation signal. It is a flowchart which shows the flow of operation | movement of the pain alleviation apparatus which concerns on 1st embodiment of this invention. It is a functional block diagram which shows the pain alleviation apparatus which concerns on 2nd embodiment of this invention. It is a wave form diagram which shows the example of an electrical stimulation signal. It is a flowchart which shows the flow of operation | movement of the pain alleviation apparatus which concerns on 2nd embodiment of this invention. It is a functional block diagram which shows the pain alleviation apparatus which concerns on 3rd embodiment of this invention. It is a flowchart which shows the flow of operation | movement of the pain alleviation apparatus which concerns on 3rd embodiment of this invention. It is a functional block diagram which shows the pain alleviation apparatus which concerns on 4th embodiment of this invention. It is a wave form diagram which shows the example of an electrical stimulation signal. It is a flowchart which shows the flow of operation | movement of the pain alleviation apparatus which concerns on 4th embodiment of this invention. It is a functional block diagram which shows the pain alleviation apparatus which concerns on 5th embodiment of this invention. It is a wave form diagram which shows the example of an electrical stimulation signal.

Hereinafter, the best mode for carrying out the invention (hereinafter referred to as “embodiment”) will be described. The description will be given in the following order.
1. 1. First embodiment Second embodiment 3. 3. Third embodiment 4. Fourth embodiment 5. Fifth embodiment Modified example

<1. First Embodiment>
An example of the first embodiment of the present invention will be described with reference to FIGS.

[Configuration of Pain Relief Device]
The pain relieving device is generally sealed in a biocompatible container and implanted in the body. This container is provided with a connector for exchanging signals with the outside, and is connected to a sensor and an electrode lead. The electrode lead is guided to a nerve site to be stimulated through a subcutaneous tunnel, and nerve stimulation is performed by a stimulation electrode provided on the electrode lead. As a site for implanting the pain relieving device, the chest, abdomen, or neck is generally subcutaneous.
FIG. 1 is a functional block diagram showing a pain alleviating apparatus according to the first embodiment of the present invention.
The pain relieving apparatus 101 according to the first embodiment detects heart ventricular contraction or blood output from the heart, and performs electrical stimulation on peripheral nerves at a timing synchronized with the detected ventricular contraction. . Here, the contraction of the ventricle is detected by detecting the pumping of blood from the ventricle. Therefore, “ventricular contraction” and “blood output” mean the same thing.

The pain relieving apparatus 101 includes a circulatory dynamic measurement sensor 102, a control unit 103, and a stimulation signal generation unit 104 that applies an electrical stimulation signal to a peripheral nerve via an electrode lead (not shown).

The circulatory dynamic measurement sensor 102 is for obtaining the heartbeat timing of the patient in which the pain relieving apparatus 101 is implanted, and is mainly composed of a sensor, an amplifier, and a filter for noise removal. It is connected to the control unit 103 so that it can be output to the control unit 103 as an electrical signal. Typical examples of circulatory dynamics include electrocardiograms, pressure pulse waves, or heart sounds. In addition, the sensor part of the circulatory dynamic measurement sensor 102 is disposed at a place (in vivo) corresponding to the type of circulatory dynamics to be measured.

The control unit 103 controls the stimulation signal generation unit 104 based on the electrical signal indicating the circulation dynamics input from the circulation dynamic measurement sensor 102.

The stimulation signal generation unit 104 generates an electrical stimulation signal based on an instruction from the control unit 103, and this electrical stimulation signal is applied to the peripheral nerve via an electrode lead (not shown).

More specifically, the control unit 103 includes a first detection unit 105, a timer 106, a stimulation period setting value storage unit 107, and a comparison unit 108.

The first detection unit 105 is electrically connected to the circulatory dynamic measurement sensor 102 and the stimulus signal generation unit 104. The first detection unit 105 detects the contraction of the ventricle based on the electrical signal indicating the circulation dynamics input from the circulation dynamic measurement sensor 102. Then, at the timing when the contraction of the ventricle is detected, the stimulation signal generation unit 104 generates an electrical stimulation signal. Specifically, a signal indicating the detection (hereinafter referred to as “blood output detection signal”) is output to the stimulation signal generation unit 104 at the timing when the ventricular contraction is detected (hereinafter referred to as “heartbeat timing”). Further, the first detection unit 105 operates the timer 106 at the timing when the contraction of the ventricle is detected. Details of detection of ventricular contraction will be described later with reference to FIG.

The timer 106 measures the elapsed time from the contraction of the ventricle detected by the first detection unit 105 and inputs the elapsed time to the comparison unit 108. The stimulation period setting value storage unit 107 stores stimulation period setting values in advance. This stimulation period set value is preferably shorter than the interval between successive heartbeats, and ideally about 0.3 seconds.

The comparison unit 108 is a so-called comparator that compares two inputs and switches the output depending on which is larger. That is, the comparison unit 108 compares the elapsed time from the timer 106 with the stimulation period setting value stored in the stimulation period setting value storage unit 107. Then, when the elapsed time becomes larger than the stimulation period setting value, a signal indicating that the elapsed time becomes larger than the stimulation period setting value is generated and output to the stimulation signal generation unit 104. The stimulation signal generation unit 104 stops the generation of the electrical stimulation signal with the input of the signal as a trigger.

[Circulation dynamics]
FIG. 2 is a diagram showing various circulatory dynamic electrical signals measured by the circulatory dynamic measurement sensor 102.
FIG. 2A is an electrocardiogram showing a time-series change of an electric signal of the electrocardiogram. The vertical axis represents the signal level of an electrical signal indicating electrocardiogram. The horizontal axis is the time axis.
When the pain relieving device is implanted under the chest, the electrocardiogram can be measured by arranging an electrocardiographic electrode on a container in which the pain relieving device is sealed. When the pain relief device is implanted in a place away from the chest, connect the ECG lead to the connector of the container and place the ECG electrode at the tip of the ECG lead at a position where the ECG signal level increases. It is also possible to measure by implanting. Alternatively, it is possible to insert an electrocardiogram lead into the heart intravenously and measure the electrocardiogram from within the heart.

An electrical signal indicating electrocardiogram is a signal having a predetermined period. The electric signal indicating the electrocardiogram is composed of five waves, P wave, Q wave, R wave, S wave, and T wave, and conspicuous Q wave, R wave, and S wave are collectively called QRS wave. . The ventricular contraction of the heart occurs at the timing when this QRS wave is generated. It is known that this substantially coincides with the timing of blood discharge from the heart.

That is, when the measurement target of the circulatory dynamic measurement sensor 102 is an electrocardiogram, the first detection unit 105 detects the timing of ventricular contraction of the heart by detecting the QRS wave. In order to detect the QRS wave, for example, a circuit including a filter that passes a frequency range of the QRS wave and a comparator in which a predetermined threshold is set can be used.

FIG. 2B is a diagram illustrating a time-series change in the electrical signal of the pressure pulse wave. The vertical axis represents the signal level of the electrical signal indicating the pressure pulse wave. The horizontal axis is a time axis common to the electrocardiogram of FIG. 2A.
When the pain relief device is implanted under the neck of the neck, the pressure pulse wave can be measured on the carotid artery by placing an acceleration sensor on a container in which the pain relief device is sealed. When the pain relieving device is implanted in a place away from the neck, an acceleration sensor is placed subcutaneously near the carotid artery, and the lead connected to the acceleration sensor is connected to the connector of the pain relieving device container through the subcutaneous tunnel. It is also possible to connect to and measure.

The electrical signal indicating the pressure pulse wave is a signal representing a change in blood pressure in the blood vessel. The position where the signal level of the electric signal indicating the pressure pulse wave increases rapidly indicates the timing at which blood is pumped from the heart.

That is, when the measurement target of the circulatory dynamic measurement sensor 102 is a pressure pulse wave, the first detection unit 105 detects the position where the signal level of the electrical signal indicating the pressure pulse wave increases rapidly, thereby blood from the heart. Detect the timing of the beat. The position where the signal level of the electric signal indicating the pressure pulse wave increases abruptly can also be detected by a circuit comprising a filter and a comparator in which a predetermined threshold is set, as in the case of an electrocardiogram.

FIG. 2C is a heart sound diagram showing an electrical signal of a heart sound. The vertical axis represents the signal level of an electrical signal indicating heart sound, and the horizontal axis represents a time axis common to the electrocardiogram in FIG. 2A.
When the pain relieving device is implanted under the chest, the heart sound can be measured by placing an acceleration sensor on a container in which the pain relieving device is sealed. When the pain relief device is implanted in a place away from the chest, an acceleration sensor is placed under the chest, and the lead connected to the acceleration sensor is connected to the connector of the pain relief device container through the subcutaneous tunnel. It is also possible to measure.

The electrical signal indicating the heart sound is also a signal having a predetermined cycle. The electrical signal indicating the heart sound is composed of three waves, a heart sound I sound, a heart sound II sound, and a heart sound III sound.

Heart sound I is a sound generated when the tricuspid valve between the right and right ventricles and the mitral valve between the left and left ventricles close at the beginning of the ventricular systole. It has the feature that it can be heard in line with the QRS wave. In other words, ventricular contraction occurs at the timing when the heart sound I sound is generated, which substantially coincides with the timing of blood discharge from the heart.

Heart sound II sound is generated when the pulmonary valve and aortic valve close at the beginning of the ventricular diastole. The heart sound II sound is characterized by being generated after the T wave of the electrocardiogram. The heart sound III sound is a sound that fills the ventricle with blood when the ventricle expands. The heart sound III sound is a weak signal compared to the heart sound I sound and the heart sound II sound.

When the measurement target of the circulatory dynamic measurement sensor 102 is a heart sound, the first detection unit 105 detects the timing of the ventricular contraction of the heart by detecting the heart sound I sound. Since the heart sound III sound is weaker than the heart sound I sound and the heart sound II sound, only the heart sound I sound and the heart sound II sound can be extracted by a filter and a comparator in which a predetermined threshold is set. Further, since the period from the heart sound I to the heart sound II sound is short compared to the heartbeat cycle, after detecting the heart sound I sound, during a predetermined period corresponding to the period from the heart sound I to the heart sound II sound By ignoring the signal from the circulatory dynamic measurement sensor 102, it is possible to prevent erroneous detection of the heart sound II sound as the heart sound I sound.

Hereinafter, description will be made on the assumption that the circulatory dynamic measurement sensor 102 measures an electrocardiogram.

[Electric stimulation signal]
Next, the electrical stimulus signal generated by the stimulus signal generator 104 will be described.
The electrical stimulation signal used for stimulation of the peripheral nerve is generally a burst wave by a rectangular pulse train. FIG. 3 is a waveform diagram showing a time-series change when a burst wave is used as the electrical stimulation signal. The vertical axis represents the signal level of the electrical stimulation signal, that is, the voltage. The horizontal axis is a time axis common to FIGS. 2A to 2C. In the electrical stimulation signal shown in FIG. 3, each vertical line represents an individual rectangular pulse, and the reciprocal of the interval between adjacent vertical lines represents the frequency. In the present embodiment, a period during which the stimulation signal generation unit 104 generates an electrical stimulation signal is referred to as a “stimulation period”.

The timing at which the stimulation period starts, that is, the timing at which the stimulation signal generator 104 starts generating the electrical stimulation signal coincides with the detection of the QRS wave in the electrocardiogram shown in FIG. 2A. The timing at which the stimulation period ends, that is, the timing at which the stimulation signal generation unit 104 stops generating the electrical stimulation signal is stored in the stimulation period setting value storage unit 107 for about 0.3 seconds from the start of the stimulation period. Equal to the stimulation period setting value.

The strength with which the electrical stimulation signal stimulates the peripheral nerve is preferably changed according to the degree of pain of the patient according to the electrical stimulation parameter of the electrical stimulation signal. Actually, the pulse width and pulse voltage (pulse current when using a constant current pulse) or the interval (frequency) of each rectangular pulse of the burst wave used for the electrical stimulation signal is changed. By adjusting the strength to stimulate the peripheral nerve.

[Operation of pain relief device]
Next, the operation of the pain alleviating apparatus 101 will be described.
FIG. 4 is a flowchart showing an operation flow of the pain alleviating apparatus 101 according to the first embodiment of the present invention.

First, when the sensor portion of the circulatory dynamic measurement sensor 102 is implanted at a predetermined position in the living body and the pain alleviating apparatus 101 becomes available (step S11), the electrical stimulation parameter of the stimulation signal generation unit 104 is changed. Initialization is performed (step S12). That is, the electrical stimulation parameters such as frequency, pulse width, pulse current, and pulse voltage are set to initial values. This initialized state is a state in which the stimulus signal generation unit 104 does not operate.

Next, the circulatory dynamics measurement sensor 102 measures an electrical signal indicating the circulatory dynamics via a sensor installed at a predetermined location of the living body (step S13), and the electrical signal indicating the circulatory dynamics is measured by the control unit 103. One detection unit 105 outputs the result.

Then, the first detection unit 105 checks whether or not ventricular contraction is detected based on the electrical signal indicating the circulatory dynamics input from the circulatory dynamic measuring sensor 102 (step S14). If ventricular contraction is not detected (NO in step S14), the first detection unit 105 waits until ventricular contraction is detected.

When ventricular contraction is detected (YES in step S14), the first detection unit 105 stops the measurement of the circulatory dynamics by the circulatory dynamic measurement sensor 102 (step S15). Then, the first detection unit 105 generates a blood output detection signal and outputs this blood output detection signal to the stimulation signal generation unit 104. The stimulation signal generation unit 104 generates an electrical stimulation signal with the input of the blood output detection signal as a trigger, and starts stimulation of the peripheral nerve by the electrical stimulation signal (step S16). Further, the first detection unit 105 starts the timer 106 simultaneously with the start of stimulation of the peripheral nerve, that is, detection of ventricular contraction, and starts counting time from detection of ventricular contraction (step S17). Then, the counted time is input to the comparison unit 108.

Here, the comparison unit 108 compares the time from the detection of ventricular contraction input from the timer 106 with the stimulation period setting value stored in advance in the stimulation period setting value storage unit 107, and which value is It is confirmed whether it is larger (step S18). If the time from the detection of the contraction of the ventricle is smaller than the stimulation period setting value (NO in step S18), the nerve stimulation from the stimulation signal generation unit 104 is continued until this time reaches the stimulation period setting value.

When the time from the detection of the contraction of the ventricle has reached the stimulation period set value (YES in step S18), the comparison unit 108 stops the operation of the stimulation signal generation unit 104. That is, the stimulation signal generation unit 104 stops the stimulation by the electrical stimulation signal for the peripheral nerve (step S19).

After the above processing is completed, the processing returns to step S13 and the processing from step S13 to step S19 is repeated.

As described above, in the first embodiment of the present invention, nerves are stimulated by an electrical stimulation signal in synchronism with the contraction of the heart's ventricle (the pumping of blood from the heart). Pain occurs in synchronization with the pumping of blood, so stimulating nerves in synchronization with the pulsation of pain can alleviate pain with pulsation and reduce discomfort for the patient. It becomes possible to reduce.

In the first embodiment of the present invention, the electrical stimulation signal is generated only for a predetermined stimulation period from the time when the heart ventricle contracts (blood from the heart). In other words, the stimulus signal is not generated during a period of low necessity. This has the effect of extending the life of the battery compared to the conventional one and reducing the risk of side effects.

<2. Second Embodiment>
Next, an example of the second embodiment of the present invention will be described with reference to FIGS. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted or simplified.

[Configuration of Pain Relief Device]
FIG. 5 is a functional block diagram showing a pain alleviating apparatus according to the second embodiment of the present invention.
The pain alleviating apparatus 501 of the present embodiment always stimulates the peripheral nerve at a predetermined frequency f1, and when there is contraction of the heart ventricle (blood from the heart), the frequency f2 higher than the frequency f1. To stimulate the peripheral nerves. That is, the pain alleviating apparatus 501 sets the electrical stimulus signal generated by the stimulus signal generation unit 104 to a stimulus having a frequency f1 that is a relatively weak electrical stimulus or a stimulus having a frequency f2 that is a stronger electrical stimulus. In addition, a parameter adjustment unit 502 is added to the pain alleviating apparatus 101 shown in FIG.

The parameter adjustment unit 502 is electrically connected to the first detection unit 105 and the comparison unit 108. The parameter adjustment unit 502 changes the frequency of the electrical stimulation signal generated by the stimulation signal generation unit 104 based on the outputs from the first detection unit 105 and the comparison unit 108. In other words, it is said that the parameter adjustment unit 502 functions to provide the stimulation signal generation unit 104 with a signal for changing the frequency (parameter) of the electrical stimulation signal (hereinafter referred to as “stimulation intensity change signal”). It will be.

Specifically, the parameter adjustment unit 502 sets the frequency of the electrical stimulation signal to be higher than the normal frequency f1 at the timing when the first detection unit 105 detects the contraction of the ventricle of the heart (the pumping of blood from the heart). A stimulus intensity change signal for setting the frequency f2 is given to the stimulus signal generator 104. Conversely, the parameter adjustment unit 502 increases the frequency of the electrical stimulation signal approximately 0.3 seconds after the first detection unit 105 detects the contraction of the ventricle of the heart (the output from the heart). A stimulus intensity change signal for returning from the frequency f2 to the lower frequency f1 is provided to the stimulus signal generator 104. This time of 0.3 seconds is a time corresponding to the stimulation period setting value stored in the stimulation period setting value storage unit 107.

[Electric stimulation signal]
Next, the electrical stimulus signal generated by the stimulus signal generator 104 will be described.
FIG. 6 is a waveform diagram showing a time-series change when a burst wave is used as the electrical stimulation signal.
The vertical axis represents the signal level of the electrical stimulation signal, that is, the voltage. The horizontal axis is a time axis. In the electrical stimulation signal, each vertical line represents an individual rectangular pulse, and the reciprocal of the interval between the adjacent vertical lines represents the frequency of the electrical stimulation signal. In each of the embodiments described later (third to fifth embodiments and modifications) including the second embodiment, unlike the first embodiment, the stimulation intensity of the electrical stimulation signal is increased. In this way, a period in which parameters such as frequency and voltage are changed is referred to as a “stimulation period”.

The timing at which the stimulation period starts, that is, the timing at which the stimulation signal generator 104 starts generating an electrical stimulation signal having a high frequency f2 coincides with the timing at which the QRS wave in the electrocardiogram shown in FIG. 2A is detected. The timing at which the stimulation period ends, that is, the timing at which the stimulation signal generation unit 104 returns to the electrical stimulation signal having the low frequency f1 is stored in the stimulation period setting value storage unit 107 for about 0.3 seconds from the start of the stimulation period. Set to the stimulation period setting value.

Generally, the degree of strength with which the electrical stimulation signal stimulates the peripheral nerve depends on the stimulation frequency, and the stimulation intensity increases as the frequency increases. In the present embodiment example, it is possible to preset the level of the stimulation frequency according to the degree of pain of the patient, for example, the level and depth of the pulsation of pain, which is appropriate for each individual patient. It is possible to perform various treatments.

[Operation of pain relief device]
Next, the operation of the pain alleviating apparatus 501 will be described.
FIG. 7 is a flowchart showing a flow of operations of the pain alleviating apparatus 501 in the second embodiment of the present invention.

First, when the sensor portion of the circulatory dynamic measurement sensor 102 is implanted at a predetermined position in the living body and the pain relieving device 501 becomes available (step S21), the stimulation signal generation unit 104 uses an electrical stimulation parameter. A certain pulse width, pulse current, and pulse voltage are set to initial values, and the parameter adjusting unit 502 supplies a signal for setting the frequency of the electrical stimulation signal to f1 to the stimulation signal generating unit 104 so that the frequency of the electrical stimulation parameter is initialized. It becomes. This is the initialization of the electrical stimulation parameters (step S22). Then, the stimulation signal generation unit 104 generates an electrical stimulation signal with the frequency f1, and stimulates the peripheral nerve with the electrical stimulation signal with the frequency f1 (step S23).

Next, the circulatory dynamics measurement sensor 102 measures an electrical signal indicating the circulatory dynamics via a sensor installed at a predetermined location of the living body (step S24), and the electrical signal indicating the circulatory dynamics is sent to the control unit 103. One detection unit 105 outputs the result.

Then, the first detection unit 105 checks whether or not ventricular contraction is detected based on the electrical signal indicating the circulatory dynamics input from the circulatory dynamic measuring sensor 102 (step S25). When ventricular contraction is not detected, the first detection unit 105 waits for detection of ventricular contraction (NO in step S25). Until then, the stimulation signal generation unit 104 continues the stimulation of the peripheral nerve by the electrical stimulation signal of the low frequency f1.

When ventricular contraction is detected (YES in step S25), the first detection unit 105 stops the measurement of the circulatory dynamics by the circulatory dynamic measurement sensor 102 (step S26). At the same time, the first detection unit 105 generates a blood output detection signal and gives this blood output detection signal to the parameter adjustment unit 502. Then, the parameter adjustment unit 502 generates a stimulation intensity change signal for changing the frequency of the electrical stimulation signal generated by the stimulation signal generation unit 104 to the frequency f2, and uses this stimulation intensity change signal as the stimulation signal generation unit 104. Output to. As a result, the stimulation signal generation unit 104 generates an electrical stimulation signal having a frequency f2 higher than the frequency f1, and starts stimulation of the peripheral nerve by the electrical stimulation signal having the frequency f2 (step S27).

Further, the first detection unit 105 starts the timer 106 simultaneously with the start of stimulation of the peripheral nerve by the electrical stimulation signal of the frequency f2, that is, the detection of the ventricular contraction, and starts counting the time from the detection of the contraction of the ventricle (Step). S28). Then, the counted time is input to the comparison unit 108.

Here, the comparison unit 108 compares the time from the detection of ventricular contraction input from the timer 106 with the stimulation period setting value stored in advance in the stimulation period setting value storage unit 107, and which value is It is confirmed whether it is larger (step S29). While the time since the detection of the contraction of the ventricle is smaller than the stimulation period setting value (NO in step S29), stimulation at a high frequency f2 is continuously performed.

When the time from the detection of ventricular contraction reaches the stimulation period setting value (YES in step S29), the comparison unit 108 sets the frequency of the electrical stimulation signal generated by the stimulation signal generation unit 104 to the parameter adjustment unit 502 to f1. A stimulus intensity change signal is generated, and this stimulus intensity change signal is given to the stimulus signal generator 104. As a result, the stimulation signal generation unit 104 generates an electrical stimulation signal having a frequency f1 lower than the frequency f2, and returns to a state in which the peripheral nerve is stimulated by the electrical stimulation signal having the lower frequency f1 (step S30).

After the above processing is completed, the processing returns to step S24, and the processing from step S24 to step S30 is repeated.

As described above, in the second embodiment of the present invention, peripheral nerves are always stimulated at a predetermined frequency f1, and nerves are detected at a frequency f2 higher than the frequency f1 for a predetermined stimulation period from detection of cardiac ventricular contraction. To stimulate. By adopting such a configuration, it is effective for a patient who always feels a relatively strong pain other than pulsation after a predetermined period of time has elapsed since detection of ventricular contraction. That is, for normal pain, the pain is relieved by a stimulus having a frequency f1, which is a relatively weak electrical stimulus, and a frequency f2 which is a stronger electrical stimulus than the stimulus having the frequency f1 is added to the pain caused by pulsation. Deal with the stimulus. This has the effect of extending the life of the battery compared to the conventional one and reducing the risk of side effects.

<3. Third Embodiment>
Next, an example of the third embodiment of the present invention will be described with reference to FIGS. In the following description, components similar to those in the first and second embodiments are denoted by the same reference numerals, and description thereof is omitted or simplified.

[Configuration of Pain Relief Device]
FIG. 8 is a functional block diagram showing a pain alleviating apparatus according to the third embodiment of the present invention.
The pain relieving apparatus 601 of the third embodiment determines a stimulation period in which the electrical stimulation signal is set to the high frequency f2 based on the heart rate or the heartbeat interval. Therefore, the pain relieving apparatus 601 includes a heart rate / heart rate interval measuring unit 603 and a stimulation period setting value selecting unit 604 as an alternative to the stimulation period setting value storage unit 107 of the pain relieving apparatus 501 of the second embodiment. It has become.

The heart rate / beat interval measuring unit 603 is electrically connected to the stimulation period setting value selecting unit 604. Then, the heart rate or heart rate measured by the heart rate / heart rate interval measurement unit 603 is output to the stimulation period setting value selection unit 604.

The stimulation period setting value selection unit 604 calculates a stimulation period setting value for the heart rate interval input from the heart rate / heart rate interval measurement unit 603, for example, according to the following equation.
(Stimulation period set value) = 0.5 x (Heart rate interval)
The stimulation period setting value selection unit 604 can store a table representing the relationship between the heartbeat interval and the stimulation period in advance, and can select the stimulation period setting value based on the measured heartbeat interval from this correspondence. It is.

The stimulation period setting value selection unit 604 is electrically connected to the comparison unit 108 so as to output the stimulation period setting value calculated from the above formula or selected from the table to the comparison unit 108. The heart rate / heart rate interval measurement unit 603 may measure a heart rate. However, in that case, the stimulation period setting value selection unit 604 calculates or selects the stimulation period setting value based on the heart rate. The heartbeat interval is calculated by 60 ÷ heart rate.

[Operation of pain relief device]
Next, the operation of the pain alleviating apparatus 601 will be described.
FIG. 9 is a flowchart showing an operation flow of the pain alleviating apparatus 601 according to the third embodiment of the present invention. In FIG. 9, the process from step S31 to step S36 is completely the same as the process from step S21 to step S26 shown in FIG. 7, so the description up to the process from step S31 to step S36 is omitted here. Then, the processing after step S37 will be described.

After the circulatory dynamics measurement sensor 102 stops measuring the circulatory dynamics in step S36, the heart rate / heart beat interval measuring unit 603 measures the immediately preceding heart rate or heart beat interval (step S37), and the measured heart rate or heart beat interval. Is output to the stimulation period setting value selection unit 604. Then, the stimulation period setting value selection unit 604 derives the stimulation period setting value using the above-described formula or table (step S38), and the derived stimulation period setting value is input to the comparison unit 108. At the same time, the first detection unit 105 generates, in the parameter adjustment unit 502, a stimulation intensity change signal that sets the frequency of the electrical stimulation signal generated by the stimulation signal generation unit 104 to f2. Then, this stimulation intensity change signal is given to the stimulation signal generator 104. As a result, the stimulation signal generation unit 104 generates an electrical stimulation signal having a frequency f2 higher than the frequency f1, and starts stimulation of the peripheral nerve by the electrical stimulation signal having the frequency f2 (step S39). Further, the first detection unit 105 starts the timer 106 simultaneously with the start of stimulation of the peripheral nerve by the electrical stimulation signal of the frequency f2, that is, the detection of the ventricular contraction, and starts counting time from the detection of the ventricular contraction ( Step S40). Then, the counted time is input to the comparison unit 108.

Here, the comparison unit 108 compares the time from the detection of ventricular contraction input from the timer 106 with the stimulation period setting value derived by the stimulation period setting value selection unit 604, and which value is greater. (Step S41). As long as the time since the detection of the contraction of the ventricle is smaller than the stimulation period setting value (NO in step S41), stimulation at a high frequency f2 is continuously performed.

When the time from the detection of contraction of the ventricle reaches the stimulation period setting value (YES in step S41), the comparison unit 108 sets the frequency of the electrical stimulation signal generated by the stimulation signal generation unit 104 to the parameter adjustment unit 502 to the high frequency f2. The stimulus intensity change signal having a low frequency f1 is generated, and the stimulus intensity change signal is supplied to the stimulus signal generation unit 104. Based on this stimulation intensity change signal, the stimulation signal generator 104 returns to stimulation of the peripheral nerve by the electrical stimulation signal of the low frequency f1 (step S42).

After the above processing is completed, the processing returns to step S34, and the processing from step S34 to step S42 is repeated.

As described above, in the third embodiment of the present invention, the stimulation period in which the electrical stimulation signal is set to the high frequency f2 is determined based on the heart rate or the heartbeat interval. The time required for pulsation changes depending on the patient's metabolism and mental stress, and becomes shorter as the heart rate increases (beat interval decreases). Along with this, the pulsation of pain felt by the patient also changes. Therefore, by determining the stimulation period based on the heart rate or the heartbeat interval, the optimal stimulation period for the patient can be set. As a result, pain having pulsation can be alleviated more accurately and the battery life can be extended.

<4. Fourth Embodiment>

An example of the fourth embodiment of the present invention will be described with reference to FIGS. In the following description, the same components as those in the first to third embodiments are denoted by the same reference numerals, and the description thereof is omitted or simplified.

[Configuration of Pain Relief Device]
FIG. 10 is a functional block diagram showing a pain alleviating apparatus according to the fourth embodiment of the present invention.
The pain alleviating apparatus 701 of this embodiment always stimulates the peripheral nerve at a predetermined frequency f1, and when there is contraction of the ventricle of the heart, the nerve is stimulated at a frequency f2 higher than the frequency f1. Further, when there is physical activity in this state, the nerve is stimulated at a frequency f3 higher than the frequency f2. In order to realize this function, the pain relieving device 701 replaces the parameter adjusting unit 502 of the pain relieving device 501 shown in FIG. 5 with a parameter adjusting unit 703 and replaces the control unit 103 with the second detecting unit. The control part 702 further provided with is provided.

The control unit 702 controls the parameter adjustment unit 703 based on an electrical signal indicating the circulation dynamics input from the circulation dynamic measurement sensor 102.

The parameter adjustment unit 703 outputs a stimulus intensity change signal to the stimulus signal generation unit 104 based on an instruction from the control unit 702.

In other words, when electrical stimulation is normally performed on the nerve with the first stimulation intensity and only ventricular contraction is detected, the nerve is synchronized with the detected ventricular contraction (heartbeat timing) for a predetermined period for the nerve. In the meantime, a stimulation intensity change signal is generated for electrical stimulation with a second stimulation intensity that is higher than the first stimulation intensity. Further, in addition to ventricular contraction, when a metabolic request or physical activity is detected by a second detection unit 704 described later, a third stimulation intensity that is stronger than the second stimulation intensity for a predetermined period with respect to the nerve at the timing. A stimulus intensity change signal for performing electrical stimulation is output to the stimulus signal generation unit 104.

More specifically, the control unit 702 includes a first detection unit 105, a timer 106, a stimulation period set value storage unit 107, a comparison unit 108, and a second detection unit 704. Since the first detection unit 105, the timer 106, the stimulation period set value storage unit 107, and the comparison unit 108 are as described above, the description thereof is omitted.

The second detection unit 704 includes an acceleration sensor and a vibration sensor that detect physical activity, that is, that the body has moved, or a temperature sensor that detects increase in metabolic demand, that is, a patient's metabolism, an oxygen saturation sensor, and the like. And is placed in the body corresponding to these sensors. When detecting the metabolic request or physical activity, the second detection unit 704 sends a signal indicating this detection (hereinafter referred to as “physical activity detection signal”) to the parameter adjustment unit 703 while detecting the metabolic request or physical activity. Output. The physical activity detected by the second detection unit includes both an active activity such as walking and a passive activity received by riding a vehicle.

Accelerometer and vibration sensor are installed in the pain relief container and detect acceleration and vibration caused by active or passive activities. A temperature sensor and an oxygen saturation sensor are generally placed in a central vein where peripheral venous blood that carries heat and carbon dioxide produced by muscles and organs joins, Connected. The temperature sensor detects metabolic demands such as fever and exercise by measuring central venous blood temperature. The oxygen saturation sensor includes a light emitting unit and a light receiving unit, and detects metabolic demands such as fever and exercise by measuring oxygen saturation by capturing transmission and reflection of emitted light in blood.

[Electric stimulation signal]
Next, the electrical stimulus signal generated by the stimulus signal generator 104 will be described.
The electrical stimulation signal used for nerve stimulation is generally a burst wave by a rectangular pulse train. FIG. 11 is a waveform diagram showing a time-series change when a burst wave is used as the electrical stimulation signal. The vertical axis represents the signal level of the electrical stimulation signal, that is, the voltage. The horizontal axis is a time axis common to FIGS. 2A to 2C. In each electrical stimulation signal shown in FIG. 11, each vertical line represents an individual rectangular pulse (pulse width is not shown), and the reciprocal of the interval between adjacent vertical lines indicates the frequency. Yes.

FIG. 11A shows a stimulation signal generation unit when the second detection unit 704 has not detected a metabolic request or physical activity, that is, when no physical activity detection signal is output from the second detection unit 704 to the parameter adjustment unit 703. It is the figure which showed the electrical stimulation signal which 104 produces | generates.

FIG. 11B shows that when the second detection unit 704 detects a metabolic request or physical activity, that is, when a physical activity detection signal is output from the second detection unit 704 to the parameter adjustment unit 703, the stimulation signal generation unit 104 It is the figure which showed the electrical stimulation signal to produce | generate.

Regardless of whether metabolic demand or physical activity is detected, the timing at which the frequency of the electrical stimulation signal is changed, that is, the timing at which the stimulation intensity changing signal is output from the parameter adjustment unit 703 to the stimulation signal generation unit 104 is shown in FIG. This corresponds to the detection of the QRS wave of the electrocardiogram shown in FIG. The timing at which the predetermined period with high stimulation intensity ends, that is, the timing at which the stimulation signal generator 104 returns the frequency of the electrical stimulation signal before the change is about 0.3 seconds from the start of the predetermined period with high stimulation intensity, that is, It is equal to the stimulation period setting value stored in the stimulation period setting value storage unit 107.

When no metabolic demand or physical activity is detected, the frequency of the electrical stimulation signal is changed from f1 to f2 (f2> f1) with the detection of the QRS wave as a trigger, as shown in FIG. 11A. Here, the case where no metabolic request or physical activity is detected refers to the case where the parameter adjustment unit 703 has received a blood output detection signal. The stimulation intensity of the electrical stimulation signal at frequency f1 corresponds to the first stimulation intensity described above, and the stimulation intensity of the electrical stimulation signal at frequency f2 corresponds to the second stimulation intensity described above.

When a metabolic request or physical activity is detected, as shown in FIG. 11B, the frequency of the electrical stimulation signal is changed from f1 to f3 (f3> f2) triggered by the detection of the QRS wave. The case where a metabolic request or physical activity is detected here refers to a case where the parameter adjustment unit 703 receives a blood output detection signal and a physical activity detection signal. Note that the stimulation intensity of the electrical stimulation signal at the frequency f3 corresponds to the third stimulation intensity described above.

Here, the voltage of the electrical stimulation signal, the pulse width, the frequency f1 at the first stimulation intensity, the frequency f2 at the second stimulation intensity, and the frequency f3 at the third stimulation intensity are determined according to the nature of the patient's pain. And are set by the patient.

[Operation of pain relief device]
Next, the operation of the pain alleviating apparatus 701 will be described.
FIG. 12 is a flowchart showing an operation flow of the pain alleviating apparatus 701 according to the fourth embodiment of the present invention.

First, the sensor portion of the circulatory dynamic measurement sensor 102 is implanted at a predetermined position in the living body, and the pain relieving device 701 is made available (step S51). In the state of step S51, the stimulation signal generation unit 104 sets electrical stimulation parameters such as pulse width, pulse current, and pulse voltage to initial values, and the parameter adjustment unit 703 sets the frequency of the electrical stimulation signal. A stimulus intensity change signal for f1 is given to the stimulus signal generator 104. Thereby, the frequency of the electrical stimulation parameter is also initialized, and the initialization of the electrical stimulation parameter is completed (step S52). Then, the stimulation signal generation unit 104 generates an electrical stimulation signal having the first stimulation intensity, that is, the frequency f1, and stimulates the nerve with the electrical stimulation signal having the frequency f1 (step S53).

Next, the circulatory dynamics measurement sensor 102 measures an electrical signal indicating the circulatory dynamics via a sensor installed at a predetermined location of the living body (step S54), and the electrical signal indicating the circulatory dynamics is sent to the control unit 702. One detection unit 105 outputs the result. In parallel with the processing in step S54, the second detection unit 704 starts measuring metabolic demand or physical activity.

Then, the first detection unit 105 checks whether or not ventricular contraction is detected based on the electrical signal indicating the circulatory dynamics input from the circulatory dynamic measuring sensor 102 (step S55). When ventricular contraction is not detected, the first detection unit 105 waits for detection of ventricular contraction (NO in step S55). Until then, the stimulation signal generation unit 104 continues nerve stimulation by the electrical stimulation signal of the low frequency f1.

If it is determined that ventricular contraction is detected (YES in step S55), the second detection unit 704 checks whether a metabolic request or physical activity is detected (step S56).

If a metabolic request or physical activity is not detected (NO in step S56), the first detection unit 105 stops the measurement of the circulatory dynamics by the circulatory dynamic measurement sensor 102, and the second detection unit detects the metabolic request or physical activity. Activity measurement is stopped (step S57). At the same time, the first detection unit 105 outputs a blood output detection signal to the parameter adjustment unit 703. Then, the parameter adjustment unit 703 generates a stimulation intensity change signal that changes the frequency of the electrical stimulation signal generated by the stimulation signal generation unit 104 to f2. Then, this stimulation intensity change signal is given to the stimulation signal generator 104. As a result, the stimulation signal generation unit 104 generates an electrical stimulation signal (see FIG. 11A) having a frequency f2 higher than the frequency f1, and starts nerve stimulation using the electrical stimulation signal having the frequency f2 (step S58). Then, the process proceeds to step S61.

On the other hand, when a metabolic request or physical activity is detected in step S56 (YES in step S56), the second detection unit 704 stops measuring the metabolic request or physical activity (step S59) and physical activity. The detection signal is output to the parameter adjustment unit 703. At this time, in the first detection unit 105, the measurement of the circulatory dynamics by the circulatory dynamics measurement sensor 102 is stopped, and a blood output detection signal is output to the parameter adjustment unit 703.

When receiving the blood output detection signal and the physical activity detection signal, the parameter adjustment unit 703 generates a stimulation intensity change signal for changing the frequency of the electrical stimulation signal generated by the stimulation signal generation unit 104 to f3. Then, this stimulation intensity change signal is given to the stimulation signal generator 104. As a result, the stimulation signal generation unit 104 generates an electrical stimulation signal (see FIG. 11B) having a frequency f3 higher than the frequency f2, and starts nerve stimulation using the electrical stimulation signal having the frequency f3 (step S60). ), The process proceeds to step S61.

Subsequently, the first detection unit 105 starts the timer 106 simultaneously with the detection of the ventricular contraction, and starts counting the time from the ventricular contraction (step S61). Then, the counted time is input to the comparison unit 108.

Here, the comparison unit 108 compares the time from the contraction of the ventricle input from the timer 106 with the stimulation period setting value stored in advance in the stimulation period setting value storage unit 107, and which value is greater (Step S62). While the time from the contraction of the ventricle is smaller than the stimulation period set value (NO in step S62), the nerves by the electrical stimulation signal of the frequency f2 changed by the process of step S58 or the frequency f3 changed by the process of step S60 are used. Stimulation is performed continuously.

In step S62, when the time from the contraction of the ventricle reaches the stimulation period setting value (YES in step S62), the comparison unit 108 supplies a signal to the parameter adjustment unit 703, and the stimulation signal generation unit 104 generates it. A stimulus intensity change signal for changing the frequency of the electrical stimulus signal to f1 is generated. Then, the stimulation intensity change signal is given to the stimulation signal generation unit 104 from the parameter adjustment unit 703. As a result, the stimulation signal generation unit 104 generates an electrical stimulation signal having the frequency f1, and returns to a state in which nerve stimulation is performed using the electrical stimulation signal having the frequency f1 (step S63).
After the above processing is completed, the processing returns to step S54 and the processing from step S54 to step S63 is repeated.

As described above, in the fourth embodiment of the present invention, the nerve is stimulated by the electrical stimulation signal in synchronization with the contraction of the ventricle of the heart (the pumping of blood from the heart). Pain increases in synchrony with blood pumping, and stimulating nerves in synchrony with the pulsation of pain can alleviate pain with pulsatile and reduce discomfort for the patient. It becomes possible to reduce.

In the fourth embodiment of the present invention, a strong electrical stimulation signal is generated for a predetermined stimulation period from the time when the heart ventricle contracts. That is, the nerve is stimulated with an electrical stimulation signal with a strong stimulation intensity during a predetermined period when the pain is strong, and the nerve is stimulated with an electrical stimulation signal with a weak stimulation intensity during a period when the pain is weak. Thereby, the lifetime of the battery can be made longer than that of the conventional one, and the side effect risk can be reduced.

Furthermore, in the fourth embodiment of the present invention, nerves are stimulated with an electrical stimulation signal having a stronger stimulation intensity when a metabolic demand or physical activity is detected. This can also relieve pain that increases with metabolic demand or physical activity.
<5. Fifth embodiment>

Next, an example of the fifth embodiment of the present invention will be described with reference to FIG. In the following description, the same components as those in the first to fourth embodiments are denoted by the same reference numerals, and the description thereof is omitted or simplified.

[Configuration of Pain Relief Device]
FIG. 13 is a functional block diagram showing the pain alleviating apparatus in the fifth embodiment of the present invention.
The pain relieving apparatus 801 as the fifth embodiment of the present invention is a metabolic request or physical activity (for example, heart rate increase) that is a trigger for changing the stimulation intensity of the electrical stimulation signal to the third stimulation intensity. The detection is performed using the measurement of the circulation dynamics in the circulation dynamic measurement sensor 102. Therefore, the second detection unit 803 of the control unit 802 is electrically connected to the circulatory dynamic measurement sensor 102, and detects, for example, an increase in heart rate based on the circulatory dynamics measured by the circulatory dynamic measurement sensor 102. . That is, the normal heart rate is stored in advance in a memory provided in the second detection unit 803 and compared with the heart rate obtained from the detected circulatory dynamics. Assume that metabolic demand has been detected. When the second detection unit 803 detects a metabolic request (heart rate increase), the second detection unit 803 generates a physical activity detection signal and outputs it to the parameter adjustment unit 703.

As described above, in the fifth embodiment of the present invention, the second detection unit detects the metabolic demand or physical activity (for example, heart rate increase) using the circulatory dynamics measured by the circulatory dynamic measuring sensor. To do so. Therefore, it is not necessary to provide an acceleration sensor, a temperature sensor, a vibration sensor, an oxygen saturation sensor, or the like in the second detection unit, the configuration of the entire device can be simplified, and the cost for manufacturing the device can be reduced. There is an effect that can be done.

<6. Modification>
As described above, the pain alleviating devices of the first to fifth embodiments change the intensity of the electrical stimulation signal by changing the stimulation frequency. As described above, generally, the intensity of the electrical stimulation signal is generally adjusted by changing a predetermined pulse interval (or frequency). On the other hand, as shown in FIG. 14A, the frequency is changed. Instead, the voltage strength during the stimulation period may be changed. In other words, electrical stimulation is normally performed with the voltage V1, and when only one of the ventricular contractions is detected, the electrical stimulation is performed with the voltage V2 (> V1) at a timing synchronized with the detected ventricular contraction, In addition to ventricular contraction, when metabolic demand or physical activity is detected, electrical stimulation is performed at voltage V3 (> V2) at this timing, so that the intensity of the stimulation can be increased or decreased in the same manner as changing the level of the frequency. The effect of changing is obtained. Further, in order to adjust the intensity of the electrical stimulation signal, it is also possible to adjust the electrical stimulation parameters by a plurality of combinations selected from the frequency, pulse width, pulse current, and pulse voltage.

Furthermore, as shown in FIGS. 14B and 14C, the voltage or frequency of the electrical stimulation signal during the stimulation period may be gradually changed. As a result, the stimulus is gradually increased when the patient is given a stimulus, and the magnitude of the stimulus is gradually reduced when the stimulus is weakened. Can be relieved. The vertical axis and horizontal axis in FIG. 14 are the same as those in FIGS.

Also, in each of the above-described embodiments, the target for stimulation with the electrical stimulation signal is the peripheral nerve. Although the occipital nerve is generally used as the peripheral nerve for stimulation, it is also possible to stimulate at least one of the large occipital nerve, the small occipital nerve, and the third occipital nerve, which are branches of the occipital nerve. It is also possible to place an electrode outside the spinal dura to stimulate the spinal cord in the region where the occipital nerve originates. In this case, the spinal cord in the region from the first cervical vertebra to the third cervical vertebra is preferred. Furthermore, it can be applied to stimulation of the vagus nerve, which is known to relieve the pain of migraine or cluster headache by stimulation, or stimulation of the brain region related to migraine or cluster headache.

In each of the above-described embodiments, the pain relief device and the sensor have been described as being implanted in the body. Generally, the pain relieving device is implanted with only an electrode lead for a few days to a week, and this is connected to an external pain relieving device to confirm the effect of stimulation. Even in such a case, the same effect can be obtained by placing the sensor on the body surface, measuring electrocardiogram, pressure pulse wave, heart sound, etc., and controlling the electrical stimulation signal with an external pain relief device. Needless to say.

Further, in the fourth and fifth embodiments described above, when a metabolic demand or physical activity is detected, a fixed value (f3, V3) is used as the third stimulus intensity, but this is detected. It is also possible to control the third stimulus intensity according to the metabolic demand or the degree of physical activity. That is, when the detected metabolic demand or physical activity is small, the third stimulus intensity is weak (but stronger than f2 or V2), and when the detected metabolic demand or physical activity is large, the third stimulus intensity is increased. It is also possible to do.

In addition, the present invention is not limited to the embodiments described above, and various modifications and changes can be made without departing from the scope of the present invention.

101, 501, 601, 701, 801 ... Pain alleviation device, 102 ... Circulation dynamic measurement sensor, 103, 602, 702, 802 ... Control unit, 104 ... Stimulus signal generation unit, 105 ... First detection unit, 106 ... Timer, 107: stimulation period set value storage unit, 108: comparison unit, 502, 703 ... parameter adjustment unit, 603 ... heart rate / beat interval measurement unit, 604 ... stimulation period set value selection unit, 704, 803 ... second detection unit,

Claims

A stimulation signal generator for generating a stimulation signal for electrically stimulating the nerve;
A circulatory dynamic measurement sensor for measuring the circulatory dynamic
A control unit connected to the stimulation signal generation unit and the circulatory dynamics measurement sensor,
The control unit controls the generation of the stimulation signal from the stimulation signal generation unit in response to an output from the circulatory dynamic measurement sensor in order to treat pulsating pain.
Pain relief device.
The controller is
Based on the circulatory dynamics measured by the circulatory dynamic measurement sensor, comprising a first detector for detecting the timing of the heartbeat,
The stimulation signal generation unit controls generation of the stimulation signal in response to the timing of the heartbeat detected by the first detection unit.
The pain relieving apparatus according to claim 1.
In response to detection of the timing of the heartbeat detected by the first detection unit, the first detection unit causes the stimulation signal generation unit to start generating the stimulation signal.
The pain relieving apparatus according to claim 2.
A parameter adjustment unit that changes the intensity of the stimulation signal to be generated by the stimulation signal generation unit;
The parameter adjustment unit increases the intensity of the stimulation signal generated by the stimulation signal generation unit in response to detection of the timing of the heartbeat detected by the first detection unit;
The pain relieving apparatus according to claim 2.
The controller is
A second detector for detecting metabolic demand or physical activity;
The parameter adjustment unit responds to the detection of the heartbeat timing detected by the first detection unit in response to the metabolic demand or physical activity detected by the second detection unit in order to treat pain having pulsation. Based on the intensity of the stimulus signal generated by the stimulus signal generator,
The pain relieving apparatus according to claim 4.
The parameter adjustment unit adjusts the intensity of the stimulation signal generated from the stimulation signal generation unit according to the degree of the metabolic demand or physical activity,
The pain relieving apparatus according to claim 5.
The parameter adjustment unit includes:
In response to the detection of the heartbeat timing detected by the first detection unit, the intensity of the stimulus signal of the first intensity that is normally generated by the stimulus generation unit is set to a second value that is higher than the first intensity. Change to strength,
In response to detection of heartbeat timing detected by the first detection unit when the metabolic demand or physical activity is detected by the second detection unit, the intensity of the stimulation signal generated by the stimulation signal generation unit To a third strength that is even stronger than the second strength,
The pain relieving apparatus according to claim 6.
The adjustment of the intensity of the stimulation signal is made by adjusting at least one of a frequency, a pulse width, a pulse current, and a pulse voltage, which are parameters of the stimulation signal, or a plurality of combinations selected from these.
The pain alleviating device according to any one of claims 4 to 7.
The circulatory dynamics measurement sensor is a sensor that measures the circulatory dynamics of any one of an electrocardiogram, a pressure pulse wave, and a heart sound,
The pain according to any one of claims 2 to 8, wherein the first detection unit detects the timing of the heartbeat based on any one of the electrocardiogram, pressure pulse wave, and heart sound detected by the hemodynamic measurement sensor. Mitigation device.
Detection of the timing of the heartbeat is detection of the start of ventricular contraction;
The pain relieving apparatus according to claim 9.
The second detection unit calculates a heart rate using the timing of the heart beat detected by the first detection unit, and detects the metabolic demand or the physical activity based on the calculated fluctuation of the heart rate.
The pain alleviating device according to any one of claims 5 to 10.
The second detection unit is an acceleration sensor or a vibration sensor.
The pain alleviating device according to any one of claims 5 to 10.
The nerve stimulated by the stimulation signal generator is a spinal cord in a region between the first cervical vertebra and the third cervical vertebra.
The pain alleviating device according to any one of claims 1 to 12.
The nerve stimulated by the stimulation signal generator is a peripheral nerve,
The pain alleviating device according to any one of claims 1 to 12.
The peripheral nerve is the occipital nerve;
The pain relieving apparatus according to claim 14.
The pulsatile pain is migraine or cluster headache,
The pain alleviating device according to any one of claims 1 to 15.
The generation of the stimulation signal is performed for a predetermined period from the detection of the timing of the heartbeat, or the increase of the intensity of the stimulation signal is performed for a predetermined period of time from the detection of the timing of the heartbeat.
The pain relieving apparatus according to claim 3 or 4.
The predetermined period is a fixed period.
The pain relieving apparatus according to claim 17.
The predetermined period is adjusted based on a heart rate or a heart beat interval calculated by detecting the contraction of the ventricle.
The pain relieving apparatus according to claim 17.