WO1986001733A1

WO1986001733A1 - Installation for muscular stimulation

Info

Publication number: WO1986001733A1
Application number: PCT/FR1985/000256
Authority: WO
Inventors: Francis Berthelin
Original assignee: Francis Berthelin
Priority date: 1984-09-20
Filing date: 1985-09-20
Publication date: 1986-03-27
Also published as: FR2570529A1; FR2570529B1; EP0194298A1

Abstract

An analogue unit (120) delivering a pulse voltage or current to electrodes A1?-A2? is servo-controlled by a control unit (110) to generate at least one of the following parameters of the pulse current (130): shape, amplitude, period and duration of the pulses, pulse evolution in frequency, time duration and time amplitude, instants of changes of pulse shape. Application to electrotherapy.

Description

"MUSCLE STIMULATION FACILITY"

The invention relates to a muscular stimulation installation.

Muscle stimulation installations are already known which produce alternating currents intended to stimulate or produce motor or respiratory functions of a patient and this for the purpose of rehabilitation, assistance or research.

For these stimulations, we know that the physiological efficiency of a current depends on amplitude and its frequency. Experience shows that above a KHz, the currents have practically no more motor effect and beyond a few KHz, they are completely painless, but on the other hand, they penetrate very deeply into the body. This property is used to produce within a muscle mass, the excitement of a quota of fibers.

To this end, these known installations produce two alternating currents between two pairs of electrodes, the frequency of these currents (of the order of a few KHz) being chosen to obtain the desired penetration, while being painless and ineffective, to the point of physiological view. To obtain good efficiency, the frequency of one of these currents is slightly offset from the other (for example 300 Hz), so that in the area where the two currents coexist, the beat phenomena give birth to two other currents, one which is equal to the sum of the frequencies of the two initial currents and which is therefore too high to have any efficiency, the other which is equal to the difference of the frequencies of these two currents (for example 300 Hz) and which has a physiological action. In this case, the amplitude of this beat current by difference is equal to the lower of the amplitudes of the two initial currents.

However, the known installations are inconvenient, impractical and their possibilities are extremely limited. Thus, the beat or the offset between the initial frequencies is poorly controlled and its value is never known with precision and above all cannot change over time. Also, the amplitude of these currents is statically regulated by stud rheostats and no precise indication is given.

The main drawback of these known installations however lies in the weakness of the management of the dynamics of this amplitude of the currents. In fact, the evolution of the amplitude over time is produced by an electromechanical system, which makes it possible to obtain current programming in simple sequences, but in this case it is a command by any or nothing. However, the brutal excitement of a muscle is not without danger. Installations are also known which have the possibility of establishing progressive excitation by means of a cam which acts on a potentiometer, but due to their construction, the possibilities of these installations are very limited. In general, there is also the problem, in electrotherapy, of delivering a variable voltage whose characteristics are adapted to the treatment of the patient. Thus, in particular, it is desirable to be able to vary, over time and in an appropriate manner, the form of the order transmitting electrical energy to the patient.

The object of the present invention is in particular to remedy the drawbacks, by solving the technical problems raised. To this end, it relates to a muscular stimulation installation comprising at least one pair of electrodes intended to be placed on the patient's body at the height of the muscles to be stimulated, this pair of electrodes being supplied from at least one signal generator, installation characterized in that the generator comprises an analog assembly assigned to the production and the sending, on the pair of electrodes, of a pulse current to para variable meters, and in that this analog assembly is slaved to a control member adapted to manage at least one of the following parameters of the pulse current: shape, amplitude and duration of the pulses, evolution of the pulses, frequency in duration and in amplitude in time, moments of change in pulse shape.

Thanks to these provisions, the present invention overcomes the drawbacks mentioned above since the installation control member makes it possible to determine and vary, on demand, or in a predetermined manner the shape of the pulses, their amplitude, their duration. and their period. Note also that for the purposes of the present invention, a "pulse" can have any duration.

It is therefore possible to create an impulse tension whose characteristics are exactly in accordance with those desired or determined for therapeutic treatment.

In a family of embodiments of the installation according to the invention, said control member is a computer.

Thanks to this arrangement, particularly flexible installations are made, making it possible to create, possibly on demand, by means of suitable software, any type of pulse current or voltage. According to another characteristic of the invention, said analog assembly is assigned to the production and the sending, on the pair of electrodes, of a pulse current with adjustable frequency.

According to another characteristic of the invention, the installation comprises at least two pairs of electrodes and the generator comprises at least two channels each assigned to the production and the sending to the pairs of electrodes of an alternating current to adjustable frequency, the frequencies of these currents being slightly offset, the computer managing the amplitudes and frequencies of these currents and therefore of their resulting beat. According to another characteristic of the invention, the analog assembly comprises in each of the channels, an adjustable frequency oscillator each supplying a pair of electrodes via a multiplier and a power amplifier, the multipliers of the two channels also receiving the same voltage from a digital analog converter controlled by the computer.

According to another characteristic of the invention, the oscillators are constituted by voltage-controlled oscillators to determine the frequency of the alternating currents of frequency slightly offset, the frequency of the oscillator of one of the channels being controlled by the voltage from '' an adjustable voltage means while the frequency of the oscillator of the other channel is controlled by means of an adder receiving the same voltage from the adjustable voltage means as well as a voltage from a digital analog converter controlled by the computer, these two oscillators thus producing two alternating currents of adjustable frequencies and slightly offset with respect to each other.

In another family of embodiments of the installation according to the invention, said control member is adapted to manage at least one of said parameters randomly. It is possible to choose an appropriately programmed computer or calculator for the control unit. However, according to a characteristic advantageously implemented in one of the preferred embodiments of the invention, said control member comprises a generator of random signals.

According to another characteristic, said generator comprises a noise generator.

As a variant, which can advantageously be combined with the above characteristic, said generator comprises a pulse generator with variable and random width and / or amplitude. According to another characteristic of the invention, advantageously implemented in this variant, said pulse generator is adapted to produce pulses of random width and of amplitude inversely proportional to the width. Thanks to these provisions, it is possible to produce stimulation installations of which at least some of the parameters of the voltage or of the pulse current vary continuously, which makes it possible to avoid a habituation of the patient as occurs when the characteristics of the current are predetermined and / or relatively constant or repetitive. In addition, the use of analog devices such as the generator of random signals makes it possible to produce installations according to the invention in a simple, inexpensive manner and the consumption of electrical energy is low.

The invention is shown by way of non-limiting example in the accompanying drawings, in which:

- Figure 1 is a perspective view of the assembly of an installation according to the invention; - Figure 2 is the block diagram of the analog assembly of the installation of Figure 1;

- Figure 3 is an example of the shape of a signal supplied to one of the pairs of electrodes of the installation; - Figure 4 is a block diagram showing another embodiment according to the invention;

- Figure 5 is a block diagram showing yet another embodiment according to the invention.

The object of the present invention is therefore to provide a muscular stimulation installation which makes it possible to appropriately control all the parameters of the stimulation currents on the static and dynamic plane.

In general, this object is achieved by slaving an analog assembly supplying a pulse current with variable parameters to a control member adapted to manage at least one of these parameters. We will now describe an embodiment belonging to a family of embodiments of the invention, characterized, in general, by the use, as a control member, of a processor, calculator or computer.

In a preferred embodiment of this aspect of the invention, the analog electronic assembly produces the impulse and alternating currents and has all the static adjustments, frequency, gain of the amplifiers as well as of the frequency meters and the galvanometers. The computer system is, on the contrary, intended to manage the evolution over time of these parameters, that is to say, the evolution of the amplitudes and therefore the sequencing of the excitations, as well as the variation of the frequency shift. . "The installation shown in FIG. 1 attached ^{^} consists of a power supply unit 1, a microcomputer 2 and an analog assembly 3 connected to two groups of electrodes 4 and 5 each comprising two pairs of electrodes "A ^" , A_, B., B _2. Since in the example shown, 1 "installation ^" comprises two groups of electrodes 4 and 5, the analog assembly 3 comprises two parts identical 3., 3 ₂ , the computer 2 managing these two parts 3 .., 3 ~ according to two independent or synchronized sequences as required. The electrodes A ₁ , A ₃ , B ₁ , B_ are preferably made up of plates moldable conductors which are applied to the patient's body so that for each group of electrodes, the electrodes of the two pairs are arranged on either side of a muscle to be stimulated and so that the straight line connecting the electrodes of a pair crosses with the right connecting the electrodes of the other pair of the same group. Thus, by supplying the pairs of electrodes * A ₁ , A ₂ on the one hand, and- B ₁ , B_ on the other hand, using alternating currents of neighboring frequencies, one will obtain at high- " tor of this muscle, an alternating current resulting from the lower beat of the initial currents supplying these two pairs of electrodes, this alternating beat current being able to stimulate the muscle considered. The power supply unit 1 is intended to supply the microcomputer 2 and this supply has been carried out separately for reasons of security and noise immunity. This box is connected to the mains by the cord 6 and comprises an on-off switch 7, an indicator light 8 showing the power-up and a fuse 9.

The microcomputer 2, known in itself, receives its energy via the cable 10 and is provided with a keyboard 11, a display 12 and a printer 13. The push-button 14 is a reset and the switch 15 determines whether the microcomputer is in program loading mode from a cassette, the reader of which connects to connector 16 or whether the program is running, that is to say, first input of the parameters and, secondly, actual operation. The switch 17 is intended to immediately stop operation with reset of the currents. According to one embodiment, this microcomputer may be constituted by memories of the EPROM type. The analog assembly 3 receives the commands from the microcomputer 2 by a flat cable 18, it has its own power supply and is connected to the sector by the cable 19,

This analog assembly 3 has a switch 19 for starting up and an indicator 20 for highlighting the power supply. This switch and this indicator are located in the middle of the front face on either side of the sets of command and control means 3, 3_ each assigned to one of the groups of electrodes 4, 5.

These two sets 3 .., 3 ~ being identical, only one of them will be described in connection with FIG. 2.

The galvanometers 21, 22 indicate what are the amplitudes of the initial alternating currents applied to the pairs of electrodes A ₁ , A- and B ₁ , B_. Potentiometers 23, 24 allow the gain adjustment of the amplifiers delivering these initial currents to be adjusted. The frequency of these currents is set by potentiometer 25 and the basic value of this frequency is indicated by frequency meter 26.

Each assembly 3 .., 3 ₂ comprises (see FIG. 2), an interface circuit 27 using which the microcomputer '5 -2 controls two digital-analog converters 28, 29.

The digital-analog converter 28 is intended to control ^* the dynamic amplitude of the currents and therefore the envelope curve and the rhythm of the signals, while the digital-converter. analog is intended to determine the offset between the

-TO quences "of the initial currents brought to the pairs of electrodes Rγ, A_ and B .., B ₂ and therefore to determine the frequency of the lower beat, of these two alternating currents, ensuring muscle stimulation.

The generation of the currents assigned each to

15 one of the pairs of electrodes A ₁ , A ₂ , B ₁ , B ₂ is obtained by two channels each comprising an oscillator controlled in tension ~ 30, respectively 3.Î, and a multiplier, 32 respectively 33.

The operating frequency of the oscillator

20 tor 30 is determined by the voltage from potentiometer 25 and the sinusoidal, rectangular or triangular alternating current of constant amplitude which results therefrom is supplied on the one hand to the frequency meter 26, which therefore indicates the frequency of the initial basic current and , on the other hand, on one

25 of the inputs of the multiplier 32.

This multiplier 32 receives on its second input and through the adaptation circuit 4, the voltage from the digital-analog converter 28, so that at the output of the multiplier 32 the alternating current from

30 the oscillator 30 is amplitude modulated by the voltage from the analog converter 28, the value of this voltage being determined by the program 2 of the microcomputer 2.

The signal from the multiplier 32 (see Figure 3) is therefore an alternating current signal 35 whose

35 frequency is determined by the oscillator 30 and whose envelope curve 36 is determined from the microcomputer 2 so that this microcomputer determines the shape and the rise time T. of the signal, the duration of the plateau T ₃ , the shape and the fall time T_ of this signal as well as the spacing T. between the various signals.

Due to the construction of the installation according to the invention, the operator will therefore be able to modify all the amplitude parameters of these signals by modifying the program recorded on the cassette 2 of the microcomputer 2 while the basic frequency will be determined on the potentiometer 25. The signal from the multiplier 32 is brought to a power amplifier 37 whose grain is adjustable by the operator using the potentiometer 23, according to each patient, and is then brought to the pair of electrodes A ₁ , A_ by means of an isolation transformer 38, the voltage of this initial basic current being indicated by the galvanometer 21.

The voltage-controlled oscillator 31 of the second channel receives its control input voltage from the adder 39 which receives, on the one hand, the voltage from the potentiometer 25, on the other hand, the voltage from the digital analog converter 29 via the adaptation circuit 40.

As indicated above, the voltage from the digital analog converter 29 is determined by the program recorded on the microcomputer 2 and this voltage is added, in the adder 39, to the voltage from the potentiometer 25 so that the output voltage of this adder 39 determines an operating frequency of the oscillator 31 which corresponds to the operating frequency of the oscillator 30 increased by a value determined by the voltage from the digital analog converter 29. The alternating current from the oscillator 31 is therefore slightly different from the operating frequency of the oscillator 30 (for example 300 Hz), this frequency difference being variable as a function of the program information recorded in the microcomputer 2. The alternating current coming from the oscillator 31 is brought to one of the inputs of the multiplier 33 which also receives on its second input a voltage, of modulation identical to that brought to the multiplier 32 and coming from the digital analog converter 28.

Thus, the envelope curves of the signals is above the multipliers 32 and 33 are identical, the alternating currents of these signals however being of a slightly different frequency. The signals from the multiplier 33 are then brought to a power amplifier 41, the gain of which is adjustable by the potentiometer 24 and, finally, to the pair of electrodes B ₁ , B ₂ via the isolation transformer 42 , the amplitude of the current supplied to these electrodes being indicated by the galvanometer 22. It will be noted that in this installation, the powers of the signals supplied to the electrodes A ₁ , A ₂ and B ₁ , B ₂ are adjustable independently of one of the other by potentiometers 23, 24 so that by adjusting the amplitude of one of the signals with respect to the other one can move the zone of maximum muscular excitation towards such or such pair of electrodes.

Also, the isolation transformers 38 and 42 ensure the galvanic isolation of the patient from the installation as well as the independence adaptation, but also they make it possible to have two currents without common reference.

This installation therefore makes it possible to excite any quota of muscle fibers by a judicious arrangement of the electrodes and to move the area of maximum rapid activity between these electrodes, thanks to the adjustment of the amplitude of one of the signals. compared to each other. The muscular excitation which results from the beating of the frequencies of the signals brought to the two pairs of electrodes is also adjustable according to the control provided by the microcomputer by the adjustment, in amplitude, of these signals via the digital analog converter 28 and pa the frequency setting of this beat through the digital analog converter 29. It will be noted that the computer provided according to the invention can also be used to determine operating programs each frozen on a memory (EPROM or microprocessor), these programs then being used to manage the functions of the various signal generators.

We will now describe, using FIG. 4, another preferred embodiment of a muscular stimulation installation according to the invention.

In the embodiment chosen and shown in this figure, a computer or computer 110 is connected to an interface circuit 111 itself connected to an analog assembly 120, adapted to produce on a pair of electrodes A ₁ and A ₂ a pulse voltage or current with variable parameters. To this end, this analog assembly 120 comprises on the one hand, a current generator 125, connected to parametric members 121, 122, 123, 124, adapted to vary here the shape of the pulses (member 121), the duration of these impulses (organ 122), the period of the impulses (organ 123) and the amplitude of the impulses (organ 124).

The generator 125 thus produces a current, an example of which is illustrated in FIG. 4 under the reference 130.

It is observed that the current 130 is constituted by a series of pulses 131 of variable shapes (square, rectangular, triangular, partially sinusoidal, etc.).

In operation, the computer 110, which may optionally include a programming keyboard and / or read-only or read-only memories, on which a program is prerecorded (members not shown in FIG. 4) controls, via the circuit of interface 111 and parametric members 121-124 the shape of the current or voltage 130 delivered on the electrodes A ₁ -A ₂ .

It can be seen that the computer 110 does indeed constitute a control member controlling the analog assembly 120 via the interface 111, this control member being adapted to manage at least one of the following parameters of the impulse current, delivered by the analog unit: shape, amplitude, period and duration of the pulses, instants of change of shape of the pulses. According to another characteristic of the invention, the computer 110 can be responsible for a control program adapted to deliver a current 130 of which at least one of the following parameters: shape, duration, period and amplitude, is random.

The computer can also randomly control the timing of the pulse shape change over time.

According to a particularly advantageous characteristic which is not shown, the computer 110 notably comprises a microprocessor with which said control program is pre-recorded. The assembly 120 is qualified as "analog" within the meaning of the invention in that it delivers at its output on the electrodes A ₁ and A ₂ a voltage or a current of variable shape. Those skilled in the art know how to make such analog assemblies which therefore do not need to be described in detail in the present application.

It will be noted, however, that the "analog" assembly 120 can advantageously be produced using digital elements which are particularly well suited to cooperation with a computer assembly such as the computer or computer 110.

We will now describe, with the support of FIG. 5, an embodiment belonging to another family of embodiments of the invention in which the control member does not include a computer.

A preferred embodiment of an installation according to the invention belonging to this family is generally characterized in that said control member notably includes a generator of random signals. Referring to the diagram in FIG. 5, the apparatus, which is referenced at 500, comprises: on the one hand, a control member or generator of random signals 200 which comprises the following members:. a noise generator 210 which supplies a random or pseudo-random voltage,. an adjustable threshold detector 211 which doses the quantity of selected pulses,. a re-triggerable variable width pulse generator 212 which supplies the pulses of random duration and frequency,. an oscillator 213 which serves as a clock for the device,. a logic switch 214 which switches the signals,. interrupt logic 215 which suppresses the arrival of signals,

. a prepositionable 8-bit up-down counter

220 which evaluates signals,. a maximum logical value detector 216 for detecting the maximum authorized in a count,. a. digital / analog converter 216 which stores ("latch") the value provided by the assembly 215 and transforms it into positive direct voltage,. a Bistable 217 rocker which manages the authorizations,. a pulse detector 218 which announces the end of a conversion,

. an analog switch 219 which cadences the passage of the voltage,. a start-up logic 221 provided with a switch 222 on the other hand, an analog assembly 300 comprising the following members:

. a current amplifier 310,

. a DC / DC converter 311 to obtain, by drawing from a general supply not shown, a high voltage source adjustable here 120 volts,

. a high voltage stabilizer and regulator 312,

. a command for the high voltage passage 313,

. two electrodes A ₁ , A ₂ . In operation, the variable width trigger pulse generator 212 provides a random voltage fluctuating around an average voltage. This generator comprises a monostable rocker, not shown, the period of which is made variable thanks to a partial integration of the output pulses of the detector with adjustable threshold 211.

This partial integration can be modified by adjusting a capacity and / or d.a resistance that conventionally comprises the rocker. At the output, in the illustrated example there are pulses of approximately 20 μs to 200 μs. The pulses are then calibrated by logic elements 215, 220. They are stored in digital form according to their durations, converted into voltage, inversely proportional to their digital magnitudes and re-emitted when the two parameters

(duration and amplitude) are known. This shifts, in real time, their emission but does not harm in any way their initial values (duration and hazards). These pulses are amplified in current by the amplifier 310, then in voltage by the control 313.

The converter 311 coupled with the regulator stabilizer 312 provides a stable and reliable high voltage source. This high voltage is chopped to the rhythm of the random pulses supplied by the analogy switch 219 and amplified by the amplifier 310.

There are thus available on the electrodes A ₁ -A ₂ of the apparatus of FIG. 5, pulses of random width and distribution and of amplitude inversely proportional to their width. The electrical energy thus delivered to the patien by each pulse is advantageously constant. In addition, this "constant" energy, which can be different for each patient, is regulated by a setpoint value imposed by the user by means of an element 314.

Of course, the present invention is in no way limited to the various embodiments chosen and shown in the drawings, but on the contrary covers any variant. In particular, it will be noted that the "muscular" stimulation installation according to the invention can very well be used to treat other organs of the human or animal body, and, in particular, the skin, without going beyond the ambit of the invention.

Claims

1. Muscle stimulation installation comprising at least one pair of electrodes (A ₁ , A ₂ , B ₁ , B ₂ ) intended to be placed on the patient's body at the level of the muscles to be stimulated, this pair of electrodes being supplied from at least one signal generator, installation characterized in that the generator comprises an analog assembly (3 ₁ ) assigned to the production and the sending, on the pair of electrodes, of a pulse current with parameters variables and in that this analog assembly (3) is slaved to a control member adapted to manage at least one of the following parameters of the pulse current: shape, amplitude, period and duration of the pulses, evolution of the pulses in frequency, in duration, and in amplitude over time, instants of change of pulse shape.

2. Installation according to claim 1

/ characterized in that said control member is a computer (110) (2).

3. Installation according to claim 2, characterized in that said analog assembly (3 ₁ ) is assigned to the production and sending, on the pair of electrodes (A ₁ , A ₂ ), of a current pulse with adjustable frequency.

4. Installation according to claim 3, characterized in that it comprises at least two pairs of electrodes and in that the generator comprises at least two channels (30, 32 and 31, 33) each assigned to production and to sending on the pairs of electrodes an alternating current with adjustable frequency, the frequencies of these currents being slightly offset, the computer managing the amplitudes and frequencies of these currents and, therefore, their resulting beat

5. Installation according to claim 4, characterized in that the analog assembly comprises in each of the channels, an adjustable frequency oscillator (30, 31) each supplying a pair of electrodes (A ₁ , A ₁ ; B ₁ , B ₂ ) via a multiplier (32, 33) and a power amplifier (37, 41) the multipliers (32, 33) of the two channels also receiving the same voltage from a digital converter analog (28) controlled by the computer (2).

6. Installation according to claim 4, characterized in that the oscillators (30, 31) are constituted by voltage controlled oscillators to determine the frequency of alternating currents of slightly offset frequencies, the frequency of the oscillator (30) of one of the channels being controlled by the voltage from an adjustable voltage means (25), while the frequency of the oscillator (31) of the other channel is controlled by means of an adder (39 ) "receiving the same voltage from the adjustable voltage means (25) as well as a voltage from a digital analog converter (29) controlled by the computer, these two oscillators thus producing two alternating currents of adjustable frequencies and slightly offset from each other.

7. Installation according to any one of claims 1 to 6, characterized in that the gain of the power amplifier (23, 24) of each channel, is adjustable and is connected to its pair of electrodes (A ₁ , A ₂ , B ₁ , B-) by an isolation transformer.

8. Installation according to claim 1, characterized in that said control member (200) comprises a generator of random signals.

9. Installation according to any one of claims 1 or 8, characterized in that said control member comprises a generator (200) of pulses of variable and random width and / or amplitude.

10. Installation according to claim 9, characterized in that said pulse generator (200) is adapted to produce pulses of random width and distribution and amplitude inversely proportional to the width.