Electrophysiological analysis system

(54) Title: ANALYSIS SYSTEM (57) Summary:

ELECTROPHYSIOLOGICAL AND PROCESS OF

DIAGNOSIS (30) Unionist Priority: 23/02/2007 fr 0753461 (66) Internal Priority: 860446 (73) Holder (s): medical impetus (72) Inventor (s): nicolas bocquet, philippe Brunswick (74) Attorney (es) ): Alexandre Fukuda Yamashita (86) International Order: pct EP2008052211 of

22/02/2008 (87) International Publication: wo 2008 / i07324de 12/09/2008

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^ε3 “ELECTROPHYSIOLOGICAL ANALYSIS SYSTEM AND DIAGNOSTIC PROCESS”

Field of the Invention

The present invention relates generally to medical diagnostic apparatus and processes in the field of human or animal health.

Fundamentals of the Invention

Considering the cost of blood tests and the invasive nature of previous blood collections, doctors are increasingly reluctant to prescribe too frequent check-ups to their patients.

This results in an evident under-detection of certain diseases whose detection is carried out mainly by blood test, such as diabetes, hypertension, hyperthyroidism, coronary diseases, ...

In addition, when these diseases are detected, it is usually very difficult or costly to evaluate the effectiveness of the prescribed treatment, as it is impossible, in practice, to perform daily blood tests.

On the other hand, different electrophysiological measurement systems are known, such as electrocardiography and electroencephalography devices. These systems are passive in the sense that they measure electrical phenomena naturally generated by the human body, which have the advantages of being non-invasive, but whose possibilities in terms of diagnosis are limited.

Electrophysiological measurement systems called active, based on impedanciometry, are also known. The working principle of these devices is to circulate currents between different electrodes applied to the body and to examine the way in which certain regions of the body attenuate this current. In fact, these very high frequency techniques have the disadvantage of being highly dependent. degree of skin - electrode interface and in particular its capacitive effect. The reproducibility of measurements between patients and even in the same patient is not reliable for these measures at high frequency. Measurements at very low frequencies can, in turn, be harmful to cells.

On the other hand, diagnostic systems are known, in which they are applied on electrodes, applied on the fingers of the same hand, impulses of rectangular tension of certain frequency, necessarily high to be able to detect the capacitive phenomena at the level of the skin, and it is studied the current that circulates in that part of the body in response to this rectangular tension. This system has evolved to integrate, in connection with the high frequency of the pulses, a Fourier analysis that provides the spectral distribution of the verified current. However, this known system has limited applications in very localized detections (in the vicinity of the fingers and toes), and only allows diagnostics within the limits of conventional acupuncture techniques.

The Depositor has already managed to expand the diagnostic possibilities of electrophysiological-type systems, allowing it to detect a number of diseases, pathologies, pathological regions or other disorders that are usually detectable by blood tests or other body fluids.

It thus developed a non-invasive, simple-to-use diagnostic system that has a specificity and some sensitivities equivalent to laboratory tests, allowing it to detect with improved reliability and with a wider range of possibilities for certain pathologies, certain pathological predispositions or certain dysfunctions of organs.

This analysis system is described in document FR-A-2 887 427.

Brief Description of the Invention

The present invention aims to propose an improved system, which allows, in particular, to consider the evolution of electrochemical phenomena that occur in the body depending on the voltage level that the electrodes are subjected to.

The present invention also aims to propose a data processing process with a view to elaborating a diagnosis, which is capable of considering measures that reveal these electrochemical phenomena.

For this purpose, according to a first aspect, an electrophysiological analysis system is proposed, in particular, for the detection of pathological conditions, characterized by the fact that it comprises:

a series of electrodes suitable to be applied in different regions away from the human body, a source of adjustable continuous voltage and capable of generating, in response to the command circuit, successive pulses of a continuous voltage that varies from one pulse to another, and the pulse duration is greater than or equal to approximately 0.2 seconds, a switching circuit capable of selectively connecting a pair of electrodes called active to the voltage source, and to connect at least one other electrode in high impedance, a measuring circuit capable of collecting data representative of the current in the active electrodes, and potentials in at least some electrodes connected in high impedance in response to the application of said impulses, and characterized by the fact that the range of voltages covered by the impulses is proper to provoke, from one impulse to another, the appearance or disappearance of phenomena and letroochemicals in the vicinity of the active electrodes.

Certain preferred, but not limiting, aspects of this system are as follows:

* the system also includes a processing device capable of analyzing the reciprocal evolution of said current and said potentials in relation to the voltage of the pulses, and comparing that evolution with at least one reference evolution.

* the switching circuit is capable of successively connecting different pairs of active electrodes to the referred voltage source.

* the switching circuit is suitable, when a pair of electrodes is connected to the voltage source, to connect all other electrodes in high impedance.

* the measuring circuit comprises a resistor capable of being connected between one of the electrodes of an active pair and a reference voltage.

* the system also comprises a calibration circuit capable, for a pair of given active electrodes, to adjust the value of the measurement resistance so that it is of the same order of magnitude as the resistance present between the two active electrodes in the presence of continuous tension.

* the calibration circuit is able to adjust the measurement resistance value so that it is close to the resistance of the human body.

* the data representative of the current in the active electrodes is derived from the potential difference measured at the terminals of the measurement resistor.

* the measuring circuit is capable of measuring the potentials in all electrodes.

* voltage pulses have a voltage value between approximately 1 and 4 volts, and a duration between approximately 0.5 and 5 seconds.

* the voltage of successive impulses varies in one direction and then in another.

* the voltage of the successive pulses varies with a first step and then with a second step less than the first.

* the voltage of the successive pulses varies per step between approximately 0.05 and 1 volt.

* successive pulses are separated by a duration between approximately 0.5 and 5 seconds.

* the switching circuit is able to connect the same pair of electrodes to the voltage source according to two inverted polarities.

* the system comprises two electrodes for the left and right front lobes, two electrodes for the left and right hands and two electrodes for the left and right feet.

* the switching circuit is capable of connecting pairs of electrodes to the voltage source consisting of the left front electrode and the right front electrode, the right front electrode and the left front electrode, the left hand electrode and the right hand electrode, the the right hand electrode and the left hand electrode, the left foot electrode and the right foot electrode, and the right foot electrode and the left foot electrode.

* after a certain pair of electrodes is connected to the voltage source with a certain polarity, the switching circuit is able to connect that same pair of electrodes to the voltage source with an inverted polarity, only after another pair of electrodes, distant in the body, it was connected to a voltage source.

It is proposed, according to a second aspect of the present invention, a process for diagnosing a patient in order to detect a pathology, pathological predisposition or other disorder, characterized by the fact that it comprises the following steps:

- receive a data set comprising measures that reveal electrochemical phenomena in the vicinity of electrodes applied on the patient's skin at predetermined body locations,

- access at least one memorized reference data set that comprises measures that reveal electrochemical phenomena obtained under the same conditions in patients identified as affected, or not affected, by this pathology, and

- compare the said data set received with the reference data sets and, according to the criteria of proximity between the received data set and the reference data sets , identify the patient as affected or not affected.

Preferred, but not limiting, aspects of this process are as follows:

* the data sets also comprise physiological and / or behavioral and / or environmental data.

* the data sets comprise measurements taken on a patient after a predetermined effort by the patient.

* the measured data are obtained from current values ​​in active electrodes and potential values ​​in high impedance electrodes in response to the application of voltage pulses between active electrodes, whose voltage level varies from one pulse to another to cause the appearance or disappearance of electrochemical phenomena in the vicinity of the active electrodes.

* these measurements are provided by a system, as defined above.

* the process is performed on a computer equipment remote to the system, and connected to it by a data communication channel.

Brief Description of the Figures

More aspects, objectives and advantages of the present invention will appear better with the detailed description given below of preferred embodiments of the present invention, given by way of non-limiting example, and made with reference to the accompanying drawings, in which:

Figure 1 is a block diagram that illustrates the different functional elements of an acquisition system, according to the present invention,

Figure 2 illustrates the equivalent electrical scheme of the system in Figure 1, when the electrodes are connected to different locations in the human body,

Figures 3A, 3B and 3C are schematic images of the screen and generated by a data processing system associated with the acquisition system in Figure 1, and

Figures 4A and 4B are tables of reference data sets carried out in a data processing process to obtain a diagnosis, according to the present invention.

Detailed Description of the Invention

A system for diagnosing electrophysiological measurements will now be described in accordance with the present invention. This system is based on an active operating principle, in direct current mode as opposed, in particular, to state-of-the-art impedance systems whose drawbacks were mentioned above

After a determined number of tests, the Depositors observed that the application of a low continuous voltage to the terminals of a pair of spaced electrodes (anode and cathode) promotes different electrochemical behaviors to the anode and the cathode.

In particular, it is observed that the Cl- chloride ions react to the anode, whereas, with the cathode, the reaction of H + ions is observed. An object of the present invention is to allow the distinction between the behavior of the anode on one side and the cathode on the other side.

On this principle, the Depositors discovered that it was possible to use the electrodes in two ways, one in the presence of a current and under a potential difference that can vary in order to observe the evolution of electrochemical phenomena with anode and cathode, and the other , in the presence of a minimum current (at high impedance) in at least one other electrode, in order to observe the evolution of the potential intermediates in the body. This makes it possible to evaluate the drops in anodic and cathodic voltages separately and, therefore, to separately assess the levels of Cl- and H +.

Tests on patients affected by certain pathologies have shown that, in this respect, different behaviors, in terms of static resistance and electrochemical tension, may reveal these pathologies. For example, certain changes in the pH of the cathode detected by changes in resistance can reveal disturbances of the acidosis and alkalosis type, while certain variations in the concentration of chloride ions in the anode can make it possible to diagnose diseases, such as mucoviscidosis.

These measurements of chloride concentrations and acid-base balance reactivity are likely to indicate homeostatic, hormonal, vascular, metabolic dysfunctions, etc. These dysfunctions can, in turn, correspond to physiological states that reveal pathologies or varied pathological predispositions, in particular:

- vascular (hypertension and extensive atheroma);

- hormonal (hypo- and hyperthyroidism, etc.)

- metabolic (diabetes, etc.),

- chronic (renal failure, etc.), but also revealing the effect of certain drug treatments or others.

The system of the present invention that will be described in detail now aims to explore the preceding phenomena or analogous phenomena.

In Figure 1, a diagnostic system by electrophysiological measures capable of exploring the principles set out, which comprises, in an appropriate cabinet (not shown), a central processing unit 10 comprising, for example, a microprocessor associated with appropriate memories, as well as inputs and outputs, for example, for a control keyboard and a display device.

This central unit controls an electrical voltage generator 21 capable of producing, in response to appropriate command signals, pulses of constant but adjustable voltage for each of the pulses. The pulse duration, at least 0.2 seconds and typically between 0.5 and 5 seconds, is also possibly adjustable.

The central unit 10 also applies control signals to a circuit that forms the measurement resistance 22 susceptible, as it will be exposed, to be connected between an electrode and a reference voltage, such as the mass (0 volt), and to present in its terminals a voltage to be measured which is directly proportional to the current flowing through it. The adjustment of the ohmic value of this resistance allows to optimize the voltage measurement as a function of the observed current level, as will be seen later.

This circuit that forms resistance of variable measure is typically a potentiometer with digital command.

The system also comprises an electronic switching circuit susceptible, in each one between N terminals, both to apply voltage pulses generated by circuit 21, as well as to connect the measurement resistor 22, or even to place that terminal in high impedance, so classic in itself it can be seen as connected to the ground by a resistance of very high ohmic value.

The switching circuit 30 reacts to control signals provided by the central unit to modify the connections of the N terminals according to different sequences, as will be seen in detail below.

The system further comprises a measuring circuit 40 sensitive to instructions from the central unit for sequential or simultaneous measurement of the voltages present at a given time in each of the N terminals of the switching circuit. Advantageously, this circuit uses conventional techniques of analog / digital conversion in several inputs and multiplexing.

The N terminals of the switching circuit are also connected to N connectors that allow the electrical connection of N surface electrodes En.

In the present embodiment, the number N is equal to 6, and the 10 6 connected electrodes are intended to be placed in the region of the two frontal lobes, the two hands or wrists, and the two feet or ankles of a patient.

Thus, a certain number of measurement possibilities are obtained, as will be seen in more detail below.

The central unit is also capable of processing the set of information and data used in the system, data that mainly comprise, depending on time, the voltage level generated at the level of the generator 21, the value of the measurement resistance 22, and the voltage levels found, simultaneously or almost simultaneously, at the level of the six terminals of the switch and, therefore, at the level of the six electrodes E1 to E6. This processing, as will be detailed, aims to detect and signal, in particular, visually the existence of a physiological state linked to a pathological predisposition, to the use or not of a treatment, to a pathology or other disorder.

Alternatively, this detection processing can be carried out on a deported equipment, after having loaded (through physical support or wired or wired network communication) all the data collected by the central unit 10 and stored in it.

The electronic switching circuit 30 allows to select sequentially two electrodes such as anode Ea and cathode Ec, the first being connected to the voltage generator 21 and the second being connected to the measuring resistance Rmes of the unit 22. During this time, the other electrodes (in this if four others, indicated by Eb1 to Eb4) are connected in high impedance.

The equivalent electrical circuit is illustrated in Figure 2. Measurement circuit 40 is capable of measuring, with an appropriate sampling frequency, for example, from 100 to 10000 Hz, the voltages present in each of the 6 electrodes, and the voltage of anode Va is equal to the voltage supplied by the voltage generator 21, whereas the cathode voltage Vc determines, by knowing the ohmic value of the resistance Rmes, the value of the current I circulating in the electrodes Ea and Ec. Here, the extremely weak current that can circulate in the electrodes Eb1 to Eb4, whose connection at high impedance is illustrated by resistors Rb1 to Rb4, is typically set at a value greater than 10 ΜΩ.

The potentials on the Eb1 to Eb4 electrodes are referred to as Vb1 to Vb4 respectively.

It should be noted that, in practice, the central unit 10 can examine, in addition to the evolution over time of voltages Va and Vc, check the evolution of the four voltages Vb1 to Vb4 individually, the evolution of an average of these values, indicated here by Vb.

The device, as described above, is controlled by the central unit 10, in order to perform a number of operations.

The first operation is an automatic calibration, performed after the electrodes have been applied to the patient.

Thus, for each pair of electrodes that is used in pairs (anode, cathode), and, for example, the pair of forehead electrodes, the pair of hand electrodes and the pair of foot electrodes, device 10 causes the application , at the anode, of a continuous voltage, for example, on the order of 2 volts, and adjust the value of the resistance Rmes in order to obtain a cathode voltage stabilized at approximately half (or a determined fraction, preferably between 0, 1 and 0.9) of the anode voltage. This corresponds to adjusting the Rmes so that it is close (at least in the same order of magnitude) to the resistance present between these two electrodes, which accumulates the electrode / skin contact resistances and the resistance of the body between the two distant regions of the body. The optimal values ​​of Rmes for each pair (anode, cathode) that will then be used for the measurements themselves, as described below, are memorized one by one, in the form of their command signals, and will be remembered by central unit depending on the pair (anode, cathode) that is used.

This automatic calibration step allows to have, for each pair (anode, cathode), the Rmes value that offers the best dynamics and the best resolution to measure the evolution of the current that passes through the pair of electrodes considered during the actual measurements, and must it is clear that the resistance present between the electrodes can vary widely depending, in particular, on the surface of the electrodes, the quality of the electrode-skin contact and the aging of the electrode material.

Naturally, if necessary, it is possible to duplicate these automatic calibration operations in the event that an anode / cathode pair of electrodes becomes a cathode / anode pair, which is achieved by exchanging the level of the switching circuit 30 the connections of the two electrodes .

The actual measurements are made by first selecting a pair of active electrodes (anode, cathode), and adjusting Rmes to their appropriate value as described above.

A series of continuous voltage pulses is then applied over the anode in a sufficient duration (in the order of 0.5 to 5 seconds) to achieve a certain stabilization of current I, starting from a high voltage level (typically in the order of 4 volts) , approximately half in the electrode terminals for the reasons explained above), up to a low voltage level (typically on the order of 1 to 2 volts), with a step of the order of 0.05 to 0.5 volts between two successive pulses . An increasing evolution is of course also possible.

During each voltage pulse commanded by the central unit 10, it simultaneously controls the measuring circuit 40 in order to reveal, with the determined sampling frequency (preferably between 100 and 10000 Hz as indicated above), the potentials present in each of the six electrodes.

Among these potentials, the potential Va is representative of the voltage generated by the generator 21, while the potential Vc is directly proportional to the current I circulating at anode Ea and at cathode Ec, allowing it to be calculated if necessary.

The other potentials are those observed elsewhere in the body to which the other electrodes are applied, but crossed by an essentially zero current (high impedance).

The measurements above are made for several pairs of active electrodes.

Typically, in a system with six electrodes as described above, measurements are made with the following pairs of electrodes (abbreviated designation in parentheses):

Anode Cathode left forehead (FG) right forehead (FD) left hand (MG) right forehead (FD) left forehead (FG) right hand (MD) right hand (MD) left foot (PG) right foot (PD) left hand ( MG) right foot (PD) left foot (PG)

For each pair of electrodes, the evolution of the current during each of the impulses is mainly linked to the dynamics of establishment of the electrochemical phenomena at the anode and cathode level, under an increasingly different potential difference.

The potential levels and their evolution over time during the impulse not only at the cathode (Vc), but also at passive electrodes Eb1 to Eb4 (Vb1 to Vb4) as a function of the voltage level Va of the considered pulse, determine a number of raw data that can be processed in several ways.

According to an advantageous variant, voltage pulses can be provided whose voltage level varies in one direction and then in the other. More particularly, it can be predicted that the voltage level starts to increase with a relatively coarse step, for example, from 0.2 to 1.0 volts, and continues to decrease, with a reduced step, for example, from 0.1 The

0.05 volts after the detection of the appearance of an electrochemical phenomenon has been carried out, as will be described below ,.

Currently, a process particularly useful for the detection of pathological predispositions, or pathologies, linked in particular to the concentration of chloride anions or to the pH value (concentration of hydrogen cations), consists of examining the evolution of curves that reflect the evolution of the voltages Vc and Vbi (or its average) at the end of the pulse, as a function of the value of the voltage Va of the pulse, for each of the six pairs of electrodes.

More precisely, it was observed that this curve was at first practically linear, and that after a certain potential difference between the electrodes, the linearity disappeared, and the curve increased with an increasing inclination due to the appearance of electrochemical phenomena.

It was also observed that the anode voltage level Va from which the curve flexes, as well as the cathode voltage level Vc and the voltage levels of inactive electrodes Vb1 to Vb4 (or its average Vb), were also revealing of these or those types of disorders.

Thus, Figures 3A and 3B of the drawings illustrate images of the screens emitted by a data processing system (either based on the central unit 10, or extracted on the basis of the collected data.

Figure 3A illustrates the evolution of the voltage levels reported in each of the six electrodes, voltages designated respectively by V_Fg, V_Fd, Fmg, Vmd, Vpg, Vp_D, during the application of a pulse (in this case with a duration of one second) in the example where the anode and cathode Ea and Ec are respectively the electrodes PD and PG. It is observed in these curves that the voltage V_PD, which is the anode voltage generated by the generator 21, is quite constant throughout the duration of the pulse, whereas the other measured voltages vary initially quite intensely (increasing or decreasing), to begin to stabilize and stay finally stable at the end of the momentum. It is the values ​​of the end-of-pulse voltages, for a plurality of pulses of different voltage levels, that are used to establish the curves shown in Figure 3B.

These curves illustrate the mutual evolution of the cathode voltage (that is, of the current I), indicated in the ordinate, and of the potential differences respectively Va-Vb, Vb-Vc and Va-Vc, respectively, and the voltage is indicated in the abscissa. These curves are constituted by the data processing system as a function of the voltage values ​​obtained at the end of each pulse of the applied pulse series as described above.

It is observed that for each one of these curves, there is a threshold voltage value (respectively VSa, VSc and VSe) for which this curve leaves its linear aspect to flex, which is an indicator of the appearance (or disappearance, in the direction of decreasing voltages) of an electrochemical phenomenon at the anode or cathode.

From these values, which each correspond to a given value of current I and therefore to a given value of voltage Vc, it is possible to obtain the three values ​​VSa, VSc and VSe that correspond to these thresholds.

As these processes are performed for each of the six pairs of electrodes chosen, three sextuplets of VSa, VSc and VSe values ​​are obtained for a given patient that correspond to these thresholds.

In Figure 3C, which will now be described, it is possible from each of these three sextuplets to build graphs, such as radar-type curves, which allow you to easily visually compare the characteristics obtained for a given patient with model or reference curves, which correspond healthy patients or certain pathologies or pathological dispositions. They also facilitate comparison with characteristics previously obtained with the same patient, in particular for monitoring the effect of a treatment.

Of course, the person skilled in the art will be able to imagine several other processes with the data collected pulse by pulse as described above, and even between pulses, without departing from the scope of the present invention whose specificity lies in the way of acquiring the data.

In addition, and as will be described in detail below, the different types of measurements can be combined in very different ways as part of a data processing process in order to diagnose this or that pathology, pathological evolution or pathological predisposition.

A standardization functionality optionally provided for in the system of the present invention will now be described, which allows to avoid certain voltage measurement lags (offset in Anglo-Saxon terminology) due in particular to the use of different electrode materials or materials whose aging has an impact on behavior in contact with the skin. In fact, it was observed that according to the nature of the electrode materials and their degree of wear or aging, the electrode / skin interfaces constituted electrochemical cells that generate variable voltages (more or less) from a few tens to a few hundred millivolts, likely to distort measurements. This functionality consists, after the electrodes have been applied to the patient, of connecting one of the electrodes to the voltage source, which emits, for example, a continuous value of 2 volts, of connecting the five other electrodes in high impedance, and measuring by means of of the measurement circuit the static potentials in these five other electrodes. These operations are repeated by applying continuous voltage to each of the five other electrodes successively.

It is carried out in this way, for a quick operation since it requires a few seconds to configure the electrodes, a mapping that allows calculating the lag voltages that will be used to correct the measurements made when the voltage pulses are applied during the acquisition process written above. More precisely, whenever a given electrode is selected as an anode, the lag voltages found when that same electrode was connected to the voltage source will be used to correct the voltages found in the other electrodes by the measurement circuit.

In order to minimize the need to make corrections, all electrodes are preferably made of the same material. It is preferable to choose a material with a high nickel content, which material was considered after conducting in vitro experiments as the most appropriate for making measurements using chlorides. This is probably explained by a phenomenon of activation of the surface of the nickel substrate by chloride ions. Alternatively, silver electrodes or silver-rich alloy can be used, giving rise to electrochemical pairs (Ag / AgCI) that can contribute to obtain interesting measurements.

The surface of the electrodes is chosen as large as practically possible, taking into account the fact that the electrodes are relatively rigid and must be in contact with the skin throughout its length. A surface of 2 to 100 cm² will generally be chosen depending on the location of the body where the electrode is to be placed.

Of course, the numerous variants of the system are possible. In particular, you can vary the number of electrodes, and use, for example, eight electrodes (four for the extremities of the limbs, two for the forehead and two for the chest).

In addition, the system architecture of the present invention may be a wireless architecture of the type illustrated in Figure 3 of document FR-A-2 887 427 which can be consulted for further details.

Likewise, a real-time or near real-time local or remote processing system can be associated with the present invention in accordance with the principles described in particular in the document mentioned.

An example of a data processing process for diagnostic purposes will now be described which explores the measurements of electrochemical phenomena carried out in particular with an apparatus, as described above, and which can be carried out locally or remotely.

In general, the process consists primarily of acquiring multidimensional data sets measured in a population of patients whose or whose pathologies are known, and if necessary in patients already identified as healthy, through a system, in particular, such as described above. These multidimensional measurements are completed with patients' physiological, behavioral and / or environmental values, such as age, sex, weight, tobacco consumption, profession, lifestyle, etc.

It is also possible to take into account the evolution of these values ​​over time, with adequate spacing (from a few hours to several years).

The process can also take into account multidimensional data sets before and after a predetermined effort (stress test).

This creates a combination of reference data sets for a number of pathologies, by known techniques for extracting significant data ("data mining" in Anglo-Saxon terminology).

These data typically comprise ranges of reference values ​​according to different dimensions, for different pathologies.

Advantageously, these reference data sets can be progressively enriched and / or improved based on new acquisitions about affected patients, by iterating the process of extracting significant data.

In addition, through known learning techniques, reference data sets can be improved over time, for example, based on state of the art instruments, such as decision trees, neuron networks or machines with support vectors.

Each set of multidimensional data obtained with the system described above in patients to be diagnosed or whose previous diagnosis requires confirmation or follow-up, and completed by the additional data available (typed or memorized elsewhere) such as gender and age of the patient. patient's habits and lifestyle (and more generally any other physiological, behavioral, environmental, etc.) can then be compared with the reference data sets memorized in association with the data processing unit in charge of carrying out the process, by any appropriate comparison technique (weighted sum or not, score, overlap or similarity) reference data, etc.).

Prior to this comparison, and again in a classic way in itself, the input data is normalized, if necessary.

The table in Figure 4A illustrates a set of reference data obtained for a pathology of chronic renal failure.

In this example and the following, this data set comprises a set of N multiplets of ranges of significant values ​​obtained with a series of affected patients (Class = 1) and with a series of unaffected patients (Class = 0), and these multiplets they are designated by their names R002 to R008 and form a cloud of multidimensional volumes in the corresponding N-dimensional space.

In this example, the different dimensions are as follows:

- the patient's age (AGE),

- MM: the average of the electrochemical conductances MD-MG and MG-MD,

- FF: the average of the electrochemical conductances FD-FG and FG-FD,

- FM: the average of the conductances of the anodes FD and FG,

- MP: the average of the electrochemical conductances PD-PG and PG-PD,

- the patient's weight (POIDS),

- the patient's gender (SEX).

It should be noted here that the data purity index ("Purity" in the table in Figure 4A) indicates a probability that the rule used corresponds to the indicated class.

Another example of a reference data set for an autonomic neuropathy type pathology is illustrated in Figure 4B.

In a particular embodiment, data processing for diagnostic purposes is carried out at the level of a remote server connected to the acquisition system, as described above by a wireless communication channel (local or extended network such as the Internet or GSM, with appropriate data security).

Diagnostic information can then be returned to any media, paper or screen.