DE102010052710A1 - Transcutaneous electrical nerve stimulation or electrical muscle stimulation device for use by e.g. human, has signaling equipment that compares measured value for resistor with reference value - Google Patents

Abstract

The device has electronic controller (1) and electric surge generator (2). The cables (3) are connected by electrodes (4), spaced apart from each other, and mounted on skin (5) of human or animal. The electric surge generator measures signal current flowing through cables and pair of electrodes. The electronic controller derives contact resistance between electrodes and skin based on signal current. The signaling equipment (6) compares measured value for resistor with reference value.

Description

The invention relates to a TENS or EMS device for transcutaneous electrical nerve stimulation or electrical muscle stimulation, comprising an electronic control and an electrical pulse generator to which at least two pairs of electrodes are connected via two cables each, which are spaced apart on the skin of a Humans or other living things is attachable.

On the current state of the art electrostimulation devices for humans and animals are known and proven. An interesting variant is the TENS devices for "transcutaneous electrical nerve stimulation" in which electrical impulses are transmitted through the skin to the nerves in the uppermost skin layer.

It is assumed that the stimuli of pain receptors - the nociceptors - are absorbed into the skin, muscles and joints and connected in the posterior horn of the spinal cord to the second neuron of the pain path. Here, many neurons from the periphery are converged on a single neuron, which is why the process is referred to as "wide-dynamic-range neuron (WDR neuron)".

Descending, ie descending pathways inhibit transmission to the WDR neuron with a transmitter or they innervate an inhibitory interneuron within the spinal cord. This then releases endogenous opioid peptides, such as endorphins and the like, and inhibits signal transduction to the WDR neuron via micro-receptors. In this way, an efficient pain relief can be achieved.

Another application for electrostimulation devices is electronic muscle stimulation (EMS). Here, the muscles are stimulated by electrical impulses to contractions, which is useful in rehabilitation and / or training to build muscle.

In both applications, the electrical impulses from the device are routed via cables to electrodes that must be attached to the skin. In the current state of the art, the electrodes are attached or glued to the skin by means of clamping devices or suction cups.

A very simple and cost-effective attachment is a strap which is passed around a human body part or the human body and closed into a ring, on the inside of which the electrodes are arranged, which are pressed by the tension of the belt on the skin. Although this type of attachment is safe, it is especially uncomfortable when the patient is moving or when exercising.

An alternative is vacuum sucked electrodes, from which either air is sucked through a central vacuum device or a vacuum is generated at the electrode itself. The limitation of this type of fixation is that while a very high negative pressure, a tight fit is achieved, but the strain on the skin can be so high that it is reddened or even form hematomas.

Therefore, it is currently common practice for electrostimulation devices to use self-adhesive electrodes. This principle is z. B. of the disclosure DE 1 466 783 presented: The metallic contact surface is surrounded by another surface, which is coated with an adhesive that adheres to the skin. Most is between electrode and skin nor a contact agent, such. B. a gel spread.

All electrodes which are not permanently fixed in a specific position by a holding device embracing the body will gradually become loose, especially during muscle stimulation due to perspiration of the skin and / or the action of body hair, before they completely fall off.

In this case, a "loose" seat, in which only a portion of the conductive surface is in contact with the skin, is very disadvantageous, because it can come between the skin-spaced, electrically conductive surface and the skin to rollovers, which are unpleasant shocks be felt.

Against this background, the invention has the task of creating a device in electrostimulation devices, which checks the contact of the electrodes with the skin and warns in time of "loose" sitting electrodes and at least reduces the risk of such flashovers, ideally but even eliminated.

As a solution, the invention presents that from the electrical pulse generator a measuring current is abgebar, which flows over two cables and a pair of electrodes and the skin and which is measurable in the electronic control and from the measuring current in the electronic control, the electrical resistance can be derived consisting essentially of the contact resistance between the electrodes and the skin and the resistance reading being comparable to a reference value storable in the electronic control and as a result of the test Comparison result is perceptible by a reporting device by the user.

An essential feature of the invention is thus the idea to use the contact resistance between skin and electrodes as a test criterion for a proper fit of the electrode on the skin.

It is a further, essential realization of the invention that this contact resistance between skin and electrodes is always much greater than the electrical resistance of the connector and the resistance of the cable, so that with a fully sufficient for this test accuracy of the sum of the resistance Of the plug and the cable and the contact resistance skin to electrode the values for plugs and cables in the simplest case can be neglected. The measured electrical resistance is thus equated in the simplest case with the contact resistance between skin and electrodes.

This finding makes it possible to further, critically important feature of the invention, namely the actuator itself - ie the electrode on the skin - to transiently transform to a sensor. Two major advantages of this idea are that it saves the effort of an additional sensor and certainly also the route to be tested is detected.

Therefore, in this application, the measured electrical resistance is equated with the contact resistance between skin and electrode.

In the simplest variant, the result of this test is limited to the digital statement as to whether the actual contact resistance has exceeded the reference value or is even lower. This can in the simplest case by a reporting device such. B. a light emitting diode are displayed. A green LED indicates that a test has taken place and that the value determined for the contact resistance is still below the reference value. If the contact resistance is above the reference value, this would be indicated by a red LED. The light-emitting diodes thus not only signal the exceeding or undershooting of the reference value, but also confirm the actual performance of a test.

It makes sense to choose the reference value for the contact resistance in such a way that the monitoring does not respond even in the case of a marginal impairment of the electrode by the smallest welding droplets or a few hairs. On the other hand, the contact resistance should not rise so high that even small flashovers take place.

In the optimal case, the reference value is set to be a small amount below the value at which first flashovers occur. When this has been achieved, it makes sense to turn off the stimulation with an increase in the contact resistance above the reference value and to inform the user about it, so z. For example, by the flashing of the red LED or by the activation of a plain text display with the instruction: "Check electrodes!".

In a further refined variant, in order to take into account the electrical resistance of plug and cable in the control, a corresponding correction value can still be stored, which is taken into account in the calculation of the contact resistance between the skin and the electrodes. In practice, however, this is unlikely to be necessary in most applications.

Of course, there are also all other common methods of information output, such. As a speaker or a vibration alarm by a so-called "unbalance" possible.

Such an examination may, for. B. be started automatically by the device at the beginning of each stimulation and the result can be signaled by a speaker or by a plain text display with the message "electrode seat in order".

Alternatively or additionally, such a test procedure can also be triggered by the user, for. B. by a corresponding button. In another variant, the device automatically triggers a check of the contact resistance between the skin and the electrodes at regular intervals. It is understood that electrical stimulation must be avoided during the duration of this test. However, since a single test is so short that its duration by the user is not even approachable, and because the actual stimulation pulses are always interrupted by the current-free breaks principle, such a regular test without any disadvantage to the actual function of the device.

As mentioned, the monitoring according to the invention of a proper function of the electrodes is based on a meaningful reference value being stored in the device, which is possible in different ways. The least expense requires the storage of a fixed value in the manufacture of the devices.

Alternatives or additions to this are subsequent changes to an already completed device by an authorized person. In order to reserve for this access only to a limited group of people or even a single person, the invention proposes to enter a code number or activate another key or act with a mechanical key, whereupon then the reference value is changeable. Another alternative is the connection to an electronic data carrier, such. As a memory card or a USB stick or the connection to another electronic control module.

Another option for setting the reference value is an automatic fine adjustment at the beginning of a stimulation. Since a conductive attachment of the electrodes to the skin is essential for this purpose, the user should be prompted before checking the contact resistance to check the proper fit of the electrodes and confirm. For a "dialogue" between the device and the user is conceivable, such. For example, after a certain amount of time and / or after pressing a confirmation button, the message "Measurement" lights up and after the completion of the report: "Reference value stored for the electrodes!" Or - at Too high value of the measurement the renewed request "check the seat of the electrons".

It is the goal of the monitoring, that in too high a contact resistance between the skin and electrodes - so in case of too much attack of sweat or loosening too many hairs - the stimulation is switched off in time so that there are no flashovers between the electrode and Skin is coming.

As a further refinement of the device, it makes sense to prevent this shutdown as possible by already warning the user before reaching the threshold value, so it is informed that the actual contact resistance is already significantly different from the initial value, but not yet the reference value has exceeded, but has risen only in the vicinity. For this purpose, the user a warning message such. For example: "Check electrodes!" But the stimulation will continue anyway.

Numerous options for a signaling device on the TENS device itself have already been described as a signaling device for the contact resistance of the electrodes. It is also useful, however, to arrange a message device directly to the electrode, such. B. a light emitting diode. Thus, the user is even without the "detour" over the interpretation of a display on the device directly to the location of the cause of the problem, namely led to the electrode. The supply line to this signaling device would then run parallel to or within the cable to the contact surfaces of the electrodes.

All test methods described so far each use a pair of electrodes, because the electrodes for the intended use of the electrostimulation device are always required in pairs.

As an alternative embodiment, it is proposed that each electrode has at least two mutually electrically insulated contact surfaces, each of which is connected to the device via its own electrical conductor. In operation, these two conductors are connected in parallel and acted upon together with the electrical pulses, so that both contact surfaces also transmit an electrical impulse. For checking the contact resistance, however, these two conductors are used separately, so that the circuit of the measuring current via the two parallel conductors and the two, isolated from each other contact surfaces in the electrode and the skin in between is closed. If the two partial surfaces have a significant distance from each other, a certain contact resistance will be measured despite the relatively short distance of the measuring current on the skin.

As already described above for the measurement by means of two clearly spaced-apart electrodes, a reference value can also be stored in the electronic control for this case. It is clear that this reference value is smaller than the one mentioned above, since the two partial surfaces within an electrode always have a very small distance from each other.

The automatic examination of the fit of the electrodes is particularly advantageous for veterinary use, as an animal to be treated may panic in an electric shock, which can quickly destroy the benefits of the treatment. Therefore, a timely, automatic shutdown for looser electrodes even more important than in human medicine.

In the following, further details and features of the invention will be explained in more detail with reference to an example. However, this is not intended to limit the invention, but only to explain. It shows in a schematic representation:

1 TENS device with person to be treated

In 1 is incongruently a TENS device drawn that over two cables 3 with one each electrode 4 connected to the skin 5 of a person is upset. In 1 the TENS device is very much enlarged and the human being is very much reduced in size.

This clarifies the 1 very nice, that from the TENS device over a first cable 3 and a first electrode 4 and continue over a stretch in the skin 5 and back to a second electrode 4 and a second cable 3 a circuit is closed again in the TENS device. This circuit has two functions in a stimulation device according to the invention:
To explain this, the lower part of the TENS device is cut diagrammatically and thus gives the view of the electronic control 1 and the electric pulse generator disposed thereon 2 free. On the outside of the device are above the serving buttons and above the display for the mode two reporting devices 6 arranged here z. B. two LEDs.

In 1 The two operating modes of a TENS device according to the invention can be understood as follows:
The electronic control 1 starts the electric pulse generator regularly 2 , which is connected via - not shown here - connections to the two plugs on the top right of the TENS device. From there, the circuit is via two cables 3 with one electrode each 4 on the skin 5 closed. As a result, a pulse-like current flows, which has such a high energy density that it has the desired function in humans, so z. B. the desired muscle contraction or the desired pain relief.

Looking at 1 it is immediately clear that this circuit is interrupted when the contact between the electrodes 4 and the skin 5 no longer exists. If the contact resistance is so great that no appreciable current can flow, the TENS device is also ineffective.

That is why in 1 also the second, inventive operating mode of one in the breaks of the pulse generator 2 TENS device according to the invention comprehensible. In this mode, the circuit is made up of the two cables 3 , the two electrodes 4 and the skin 5 not within the TENS device via the pulse generator 2 closed, but via the electronic control 1 , The Electronic 1 triggers a - very small - measuring current, which flows in the aforementioned circuit. Since the contact resistances of the plug connection and within the cable are relatively very low, it is quite possible to derive the contact resistance between the two electrodes on the skin.

In 1 This becomes clear when a bad fit of the electrodes 4 or in secretion of sweat from the pores of the skin 5 or with multiple hairs between skin 5 and electrode 4 the contact resistance increases. Out 1 is derivable that the surfaces of an electrode 4 that are no longer in direct contact with the skin 5 but spaced therefrom, act like an air capacitor discharging above a certain minimum voltage. This discharge is an unpleasant electrical shock that interferes with the use of a TENS device for pain relief as well as the stimulation of a muscle in EMS operation.

Before such a shock, the message device 6 warn in time, here z. B. with two LEDs, one of which can be a red and the other green. These two light-emitting diodes serve to transmit the result of checking the contact resistance between the two electrodes 4 and the skin 5 of the user.

For this purpose, the TENS device is switched internally, so that the two electrodes 4 and the two cables 3 no longer be operated as an actuator that emits electrical impulses, but a sensor for determining the contact resistance between the electrodes 4 and the skin 5 are. A measuring current flows internally in the controller 1 is compared with a reference value stored there. If, as a result of the test, the contact resistance is less than the reference value, the green LED lights up, indicating that a check has taken place and that the result is positive, ie the contact resistance between the electrode 4 and skin 5 is below the respective upper limit.

If, however, the measurement shows that the contact resistance is greater than or equal to the limit value, the red LED lights up, confirming that a check has taken place and that the result is negative, ie further operation of the electrical stimulation no longer makes sense. Therefore, the stimulation is turned off and the user needs the seat of the electrodes 4 to verify. In order to not only tell him what has happened - via the LED - but also to point out to him what he should do now, that can be done in 1 drawn display for a message "electrodes check!" be used.

Out 1 is also deducible that by means of the control buttons on the front of the device, the user can start by himself a check of the electrode seat.

Also vividly in 1 that for entering the reference value in the controller 1 A key code can be activated via the keypad so that only authorized persons can use the key code Change of such an important reference is possible.

LIST OF REFERENCE NUMBERS

1

electronic control

2

electrical pulse generator, from control 1 controlled

3

Cable, connects pulse generator 2 with electrode 4

4

Electrodes for transmitting the pulses into the skin 5

5

Skin, with electrodes 4 connected

6

Signaling device for contact resistance between electrodes 4 and skin 5

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 1466783A [0009]

Claims (11)

TENS or EMS device for transcutaneous electrical nerve stimulation or electrical muscle stimulation, comprising - an electronic controller ( 1 ) and - an electrical pulse generator ( 2 ), to the above - two cables ( 3 ) - at least one pair of electrodes ( 4 ), which are spaced apart on the skin ( 5 ) Of a human or other living being attachable, characterized in that - (from the electrical pulse generator 2 ) a measuring current can be delivered, - via two cables ( 3 ) and a pair of electrodes ( 4 ) and the skin ( 5 ) flows and - in the electronic control ( 1 ) is measurable and - from the measuring current in the electronic control ( 1 ) the electrical resistance can be derived, which essentially consists of the contact resistance between the electrodes ( 4 ) and skin ( 5 ) and - the resistance reading is comparable to a reference value used in the electronic control system ( 1 ) and - as a result of the test, the result of the comparison by a reporting device ( 6 ) is perceptible by the user. TENS or EMS device according to claim 1, characterized in that with an increase in the contact resistance over the reference value, the stimulation is switched off and information about it is perceived by the user. TENS or EMS device according to one of the preceding claims, characterized in that a test is started automatically at the beginning of each stimulation. TENS or EMS device according to one of the preceding claims, characterized in that an examination can be started by the user. TENS or EMS device according to one of the preceding claims, characterized in that a test at regular intervals by the electronic control 1 is triggered and the stimulation is interrupted for the duration of the test. TENS or EMS device according to one of the preceding claims, characterized in that the reference value - Is firmly entered in the manufacture of the device and / or - after entering a code number or activating another key is entered or changed and / or - Is changeable by connection to a data carrier or another electronic control device. TENS or EMS device according to one of the preceding claims, characterized in that the reference value of the electronic control 1 can be specified at the beginning of a stimulation depending on the measurement result of the transition resistance. TENS or EMS device according to claim 7, characterized in that prior to the determination of the transition resistance of the user is prompted by the device to check the proper fit of the electrodes and confirm. TENS or EMS device according to one of the preceding claims, characterized in that with an increase in the transition resistance beyond a certain part of the reference value, a corresponding information as a warning to the user is recognizable and the stimulation is still weitertensbar. TENS or EMS device according to one of the preceding claims, characterized in that a signaling device 6 on an electrode 4 is arranged, the electrical supply line parallel or inside the cable 3 runs. TENS or EMS device according to one of the preceding claims, characterized in that - at least one electrode 4 has two mutually electrically isolated contact surfaces, which are each supplied with its own power conductor and - for the contact resistance between these two contact surfaces a special reference value in the electronic control 1 can be stored and - after the application of such an electrode to the human skin, the contact resistance between the two contact surfaces measurable comparable to the reference value and the comparison result by a reporting device 6 the user can be displayed.

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