WO2017187043A1

WO2017187043A1 - Assessment of a heart coherence factor

Info

Publication number: WO2017187043A1
Application number: PCT/FR2017/050916
Authority: WO
Inventors: Johann ARIAS; Olivier Fournier; Pierre GILFRICHE; Edouard COUDERC
Original assignee: Urgotech
Priority date: 2016-04-28
Filing date: 2017-04-18
Publication date: 2017-11-02
Also published as: FR3050633B1; FR3050633A1

Abstract

Method for assessing a heart coherence factor of an individual, method during which: - time intervals (I(n)) between heart beats are determined from an individual's cardiac activity signal (SAC) representing heart beats; and - the heart coherence factor (S_I(n) is determined on the basis of the time intervals between said heart beats. Use of a device for carrying out said method.

Description

EVALUATION OF A CARDIAC COHERENCE FACTOR

The present invention relates to a method for evaluating a cardiac coherence factor of an individual. The concept of cardiac coherence refers to a state of "cardiac coherence", which is a particular state of the heart rate, in which the cardiovascular system has a form of resonance with respiration.

It has thus been observed that in this state of cardiac coherence, the nervous, cardiovascular, hormonal and immune systems work in a harmonious and efficient manner. In certain fields of activity, particularly in the military sector, in the medical sector and for top athletes, this state of cardiac coherence is used for the improvement of the performance, for the treatment of trauma, for the training personnel likely to be confronted with critical situations, for increasing resistance to emotional shocks, etc. In order to determine whether an individual is in a state of cardiac coherence or not, it is commonly used to compare the cardiac data and respiratory data of the individual.

This procedure has disadvantages. Indeed, this determination is based on an acquisition of physiological data implementing expensive and bulky equipment, which results in strong constraints weighing on the circumstances in which the acquisition and processing of the acquired data can be achieved, as well as over the time range during which the individual's cardiac activity can be analyzed.

Also, the invention aims to improve the situation.

For this purpose, the invention relates to a method for evaluating a cardiac coherence factor of an individual, wherein:

determining, from a cardiac activity signal of the individual representative of cardiac pulsations, time intervals between said cardiac pulsations, and the cardiac coherence factor is determined as a function of the time intervals between said cardiac pulsations.

According to one aspect of the invention, for the determination of the cardiac coherence factor, for each time interval of all or part of the time intervals between said cardiac pulsations, a heart rate is determined for the time interval considered from the inverse of said time interval considered.

According to one aspect of the invention, the heart rate of a time interval considered is determined from the relation:

,, 1000 * 60

where I (n) is the time interval considered, n indexes the time intervals between the heartbeats, and BPM (n) is the heart rate of the interval I (n).

According to one aspect of the invention, for determining the cardiac coherence factor, for at least one time interval associated with a heart rate, a smoothed heart rate is determined from said heart rate and the heart rate associated with the heart rate. a time interval following or preceding the time interval considered.

According to one aspect of the invention, for the determination of the cardiac coherence factor, for at least one time interval associated with a heart rate, a variation of the heart rate is determined from the heart rate associated with said time interval and the heart rate associated with a time interval preceding the time interval considered.

According to one aspect of the invention, the variation of the heart rate is determined from the relation:

1 if BPM _t (n) - BPM _t (n - 1)> 1

-1 if BPM ^ ri - BPM ^ n - 1) <1,

V n- 1) else where BPM ₁ is the smoothed heart rate associated with the time interval considered, n indexes the time intervals between heartbeats, and V is the change in heart rate.

According to one aspect of the invention, for the determination of the cardiac coherence factor, for at least one time interval associated with a variation of the heart rate, a change in heart rate variation is determined from the variation of the heart rate. cardiac frequency.

According to one aspect of the invention, the change in heart rate variation is determined from the relation:

where CgtV is the change in heart rate variation, V is the change in heart rate, and n indexes the time intervals between heartbeats.

According to one aspect of the invention, for the determination of the cardiac coherence factor, for at least one time interval associated with a change in heart rate variation, a duration since a last change of variation is determined from the change in heart rate. variation.

According to one aspect of the invention, the duration since a last variation change is determined from the relation: - l) if CgtVÇn) = 1

t (n) - t (n-1) else where Te is the duration since a last variation change, n indexes the time intervals between the heartbeats, CgtV is the change of variation, t (n) is the moment end of the interval considered and t (n-1) designates the start time of the time interval considered.

According to one aspect of the invention, for the determination of the cardiac coherence factor, for at least one time interval associated with a duration since a last change of variation, determining a value of a cardiac coherence point parameter from said duration since a change of variation.

According to one aspect of the invention, the value of the cardiac coherence point parameter is determined from the relation:

P (n) = \ n CgtVW - the _[P2 otherwise

Where P is the cardiac coherence point parameter, CgtV is the variation change, Tc is the duration since a change of variation, n indexes the time intervals, Tc1 and Tc2 are predetermined threshold values, and PI, P2 and P3 are predetermined number of points.

According to one aspect of the invention, for the determination of the cardiac coherence factor, for at least one time interval associated with a cardiac coherence point parameter, a cardiac coherence score is determined according to said cardiac coherence point parameter. .

According to one aspect of the invention, the cardiac coherence score is determined from the relation:

where S is the cardiac coherence score, P is the point parameter, CgtV is the change of variation, j is a nonzero number of intervals, and n indexes the time intervals with n greater than or equal to j.

According to one aspect of the invention, for at least one time interval associated with a cardiac coherence score, the cardiac coherence factor is determined from said cardiac coherence score and at least one cardiac coherence score of one interval of time preceding the time interval considered.

According to one aspect of the invention, for at least one time interval with which a cardiac coherence factor is associated, an indicator representative of a proportion of low cardiac coherence scores is also determined, an indicator representative of a proportion of mean cardiac coherence scores, and an indicator representative of a proportion of high cardiac coherence scores from the smoothed cardiac coherence score.

According to one aspect of the invention, the individual is encouraged to perform a breathing exercise configured to increase the cardiac coherence of the individual based on the value of a magnitude determined from the cardiac coherence factor relative to a value. threshold.

The invention further relates to a computer program comprising instructions for implementing the method as defined above, when this program is executed by a processor. The invention further relates to a module for evaluating an individual's cardiac coherence factor, said evaluation module being configured to:

determining, from a cardiac activity signal of the individual representative of cardiac pulsations, time intervals between said cardiac pulsations, and

determining the individual's cardiac coherence factor as a function of the time intervals between said heartbeats.

The invention further relates to a device for evaluating a cardiac coherence factor of an individual, the device comprising: a device for acquiring a cardiac activity signal of the individual representative of heartbeats, and

an evaluation module, said evaluation module being configured to:

determining, from the cardiac activity signal of the individual, the time intervals between said cardiac pulsations, and

According to one aspect of the invention, the evaluation device comprises a bracelet intended to be worn by the individual on the wrist, the acquisition device being fixed or integrated into said bracelet.

According to one aspect of the invention, the evaluation device comprises an atrium intended to be coupled to an ear of the individual, the acquisition device being fixed or integrated in said atrium. The invention will be better understood on reading the detailed description which follows, given solely by way of example and with reference to the appended figures, in which:

- Figure 1 is a schematic illustration of an evaluation device according to the invention;

FIG. 2 illustrates an atrium of an evaluation device according to a variant of the invention;

Figure 3 illustrates a signal acquired by the evaluation device according to the invention;

Figure 4 is a block diagram illustrating an evaluation method according to the invention;

Figure 5 illustrates time intervals of the signal of Figure 4;

FIG. 6 illustrates a curve of variation of a smoothed heart rate determined during the method according to the invention;

Figure 7 illustrates a variation curve of a time since the last change of variation;

FIG. 8 illustrates a curve of variation of a cardiac coherence score and of indicators determined during the method according to the invention; and

FIG. 9 illustrates elements displayed on a display of the evaluation device during the method according to the invention. Figure 1 illustrates an EVAL evaluation device according to the invention, hereinafter EVAL device.

The EVAL device is adapted for acquiring signals of cardiac activity of an individual, as well as for determining, from acquired signals, at least one cardiac coherence factor of the individual. The cardiac coherence factor is representative of a degree of cardiac coherence of the individual, i.e., the extent to which the individual is in the cardiac coherence state described above.

The EVAL device comprises a TERM terminal configured to perform all or part of a cardiac activity signal processing of an individual adapted to provide at least the cardiac coherence factor, the cardiac activity signals being representative of cardiac heartbeats. the individual. The terminal TERM is for example an electronic equipment, such as for example a "smart" mobile phone, a portable tablet, a computer, etc. The term "smart mobile phone" refers to a smartphone (which translates to "smart phone"), also known as a smartphone. In particular, the terminal TERM is for example a smartphone whose operation is based on the execution of an operating system such as Symbian OS marketed by the company Symbian, BlackBerry OS marketed by the company BlackBerry, Android marketed by the Google company , iOS marketed by Apple, Windows Mobile marketed by Microsoft or Linux. The EVAL device further comprises an ACQ acquisition device for acquiring SAC cardiac activity signals, in particular representative of the individual's cardiac pulsations, the storage of the acquired signals and their transmission to the TERM terminal.

In the example of Figure 1, the ACQ acquisition device is integrated or attached to a bracelet BRAC. In other words, in the example of FIG. 1, the EVAL device comprises a BRAC bracelet to which the ACQ acquisition device is integrated or fixed.

Alternatively, with reference to Figure 2, the ACQ acquisition device is integrated or attached to a headset OREIL. In other words, in a variant, the EVAL device comprises an OREIL headset to which the ACQ acquisition device is integrated or fixed.

In some embodiments, the EVAL device simultaneously comprises the BRAC bracelet and the OREIL headset, and comprises two ACQ acquisition devices respectively integrated or attached to the bracelet and the atrium. The acquisition devices are then for example substantially identical.

The ACQ acquisition device comprises a cardiac activity CAP sensor for acquiring the SAC signals, a MEM1 memory adapted for storing the SAC signals, a CPU1 processing module, an ER transmission / reception device for the communication. with the TERM terminal and a BATT battery for power supply.

Advantageously, the CAP sensor is configured to acquire a cardiac activity signal by plethysmography. In the corresponding embodiments, the CAP sensor is located at a suitable location of the bracelet or atrium so that the wearing of the bracelet by the individual or the atrium respectively results in a configuration of the sensor in which this last is next to a blood vessel of the individual. Preferably, the arrangement of the ACQ acquisition device on the BRAC bracelet or the OREIL earpiece and the shape of the BRAC or OREIL are configured so that the CAP sensor is substantially in contact with the skin of the user during the wearing of the BRAC bracelet or ORIIL headset by the latter.

The sensor CAP comprises for example at least one light-emitting diode for emitting a light beam towards the area of the individual opposite which the sensor is intended to be arranged (wrist or ear depending on the equipment to which it is attached or integrated).

In addition, the CAP sensor comprises a photodiode configured to receive the beam backscattered by the corresponding area of the individual and form a representative SAC cardiac activity signal including heartbeats of the individual. An example of a signal SAC obtained is illustrated in FIG. 3. This figure illustrates a signal SAC obtained for a measurement made over approximately 400 seconds. The signal has four portions A, B, C, D corresponding to different situations. Portion A corresponds to the signal obtained in a situation where the individual is in a calm state and is substantially immobile, portion B corresponds to a stress situation while the individual is immobile, portion C corresponds to a situation without stress in which the individual is in motion, and the portion D corresponds to a situation analogous to that of the portion A.

The memory MEM1 is adapted for storing the signals acquired by the sensor CAP.

The processing module CPU1 is configured to carry out the control of the organs of the acquisition device, in particular to trigger the acquisition of cardiac signals SAC by the sensor CAP, or else the sending of the signals SAC contained in the memory MEM1 to the terminal TERM via the transmission / reception device ER. The CPU1 processing module is for example a processor, or a microcontroller.

In particular, the processing module CPU1 is configured to trigger the transmission of all or part of the acquired signals SAC contained in the memory MEM1 on receipt of a request received from the terminal TERM. Advantageously, in some embodiments, the CPU1 processing module is further configured to preprocess the SAC signals. For example, during this pretreatment, the processing module extracts signals all or part of the time intervals between two heartbeats. This is described in more detail below. The transmission / reception device ER is configured to allow communications between the acquisition device ACQ and the terminal TERM.

For example, the transmission / reception device ER is adapted for wireless communication with the terminal. For example, this wireless communication is a radio frequency communication. For example, the ER device is adapted to perform Bluetooth type communications.

Advantageously, in these embodiments, the CPU1 processing module is specifically configured to perform the preprocessing via which the time intervals between the pulses are extracted from the SAC signals, for example so that only these intervals are sent to the TERM terminal, as opposed to the signals. Full bags. Alternatively or in parallel, the transmission / reception device ER is adapted to perform a wired communication with the terminal TERM. In the wired communication embodiments, the acquisition device is for example configured to send to the terminal all of the SAC signals.

The terminal TERM comprises a display device AFF, a communication interface I for communication with the acquisition device ACQ, a processing module CPU2 and a memory MEM2. In addition, the TERM terminal also includes an electric power source (not shown) and / or is connected to such a source.

The AFF display device is adapted to perform the display of signals or data constructed from the heart activity signals acquired by the acquisition device, as will be seen later.

The memory MEM2 is adapted to store the SAC cardiac activity signals received from the acquisition device ACQ and the data resulting from the possible pretreatment of the signal SAC by the acquisition device. In addition, it is configured to contain software whose execution by the processor module CPU2 allows the operation of the terminal TERM. In particular, the memory MEM2 comprises an evaluation module MOD according to the invention detailed below.

The processor module CPU2 is adapted to control the terminals of the terminal TERM, in particular the interface I, in order to obtain the signals contained in the memory MEM1 of the acquisition device ACQ. Specifically, the processing module CPU2 is advantageously configured to trigger the sending by the interface I of requests to the acquisition device ACQ, the reception of which results in the transmission of all or part of the cardiac activity signals SAC contained in FIG. the memory MEM1 and / or data originating from the pretreatment of the signals SAC by the acquisition device. In addition, the processor module CPU2 TERM terminal is configured to implement the evaluation module MOD.

The evaluation module MOD is for example a software module contained in the memory MEM2 of the terminal TERM.

The evaluation module MOD is configured to determine at least one cardiac coherence factor of an individual from a cardiac activity signal SAC acquired by the acquisition device ACQ.

More specifically, the evaluation module MOD is configured to determine the cardiac coherence factor from at least a portion of the time intervals between the heartbeats of the signal SAC. Preferably, the time intervals each correspond to a time interval separating two consecutive heartbeats.

To do this, the evaluation module MOD is configured, together with the acquisition device ACQ, to implement the evaluation method described hereinafter with reference to the figures, in particular FIG. 4, when it is executed by the CPU2 processing module TERM terminal.

During an acquisition step S1, a cardiac activity signal SAC is acquired via the acquisition device ACQ. With reference to Figures 3 and 5, the signal is representative of cardiac activity, including heartbeats of the individual. The signal covers a given period of time, for example of the order of several tens of seconds. Once acquired, the signal SAC is stored in the memory MEM1 of the acquisition device. During a step S2, the signal SAC is sent to the terminal TERM. For example, this step is performed in response to the receipt of a request sent by the terminal TERM requesting the sending of the acquired signal.

Once transferred to the terminal TERM via the transmission / reception device ER, the signal is stored in the memory MEM2 of the terminal TERM.

Once stored in the memory MEM2, the signal is processed by the evaluation module MOD, which results in the following steps. Note that the preceding and / or subsequent steps are implemented on the entire received signal, or on successive windows of the signal, for example windows of the order of a few seconds. For example, after a few seconds of acquisition, the data acquired during a given time window are sent to the terminal even though the acquisition of the signal on the following window is in progress.

This makes it possible to obtain the coherence factor in real time, rather than afterwards.

In a step S3, from the acquired signal SAC, the time intervals noted I (n) between the heartbeats are evaluated, where n indexes the time intervals.

For example, with reference to Figure 5, the time intervals I (n) are determined from local extrema of the SAC signal. For example, the time intervals determined from maximum local maxima and / or mini local minima.

Advantageously, they are determined from only local maxima, or only local minima. Alternatively, they are determined from local maxima and local minima.

For example, for the determination of the interval I (n), an instant t (n-1) corresponding to the start-of-interval heartbeat is determined, and an instant t (n) corresponding to the next heartbeat is determined. The duration of the interval I (n), hereinafter also called time interval, corresponds to the difference between these instants t (n) and t (n-1).

The time intervals are for example in milliseconds.

As indicated above, optionally, once the signal SAC acquired by the acquisition module, and before sending to the TERM terminal, the processing module CPU1 performs a preprocessing of the signal SAC. As indicated above, this pretreatment optionally includes an extraction of the time intervals noted I (n) between two heartbeats.

In other words, alternatively, this step of determining the intervals is performed by the acquisition module. In step S2, the data provided by this preprocessing step is then sent to the TERM terminal rather than the entire SAC signal.

In a step S4, for at least one time interval I (n), a heart rate denoted BPM (n) is determined from the time interval. BPM is the English acronym for "Beats per Minute" which means pulsation per minute. This determination is for example made from the formula:

Thus, for index n, there is an interval I (n) in milliseconds, a heart rate BPM (n) and times t (n-1) and t (n) in seconds. Moments check the relationship:

t {n) = tin - 1) +

1000

Advantageously, for n = 1, one chooses (1) = / (1) / 1000, with t (0) taken equal to 0.

In a step S5, for at least one time interval associated with a heart rate BPM (n), a smoothed heart rate BPMi (n) is determined from the heart rate.

This determination is for example implemented via the relation:

BPMin - 1) + BPM (n)

BPMiiri) =

Advantageously, for n = 1, one chooses IP (l) = BP (1). Figure 6 provides an illustrative curve of the smoothed heart rates obtained for a SAC signal acquired over approximately 110 seconds. In a step S6, for at least one interval I (n) with which a smoothed heart rate BPM (n) is associated, a variation V (n) of the smoothed heart rate from said smoothed heart rate is determined. For example, via this variation, we look for the index n if the BPM are increasing or decreasing.

For example, this determination is implemented via the following relation:

'1 if BPM _t (n) - BPMi (n - 1)> 1

V n) = -1 if BPMiin) - BPM. (N - 1) <-1

V (n-1) otherwise

Where V (n) is the variation of the smoothed heart rate. For example, we choose 7 (1) = 1

During a step S7, for at least one interval associated with a variation of heart rate, a change of variation denoted CgtV (n) is determined from the variation of the heart rate.

The variation of variations CgtV (n) is for example determined from the relation:

For example, we choose CgtVÇl) = 0.

The change of variation parameter provides information on changes in the SAC signal relating to a change in monotonic heart rate.

During a step S 8, for at least one time interval with which a change of variation CgtV (n) is associated, a time is determined since the last change of variation from the change of variation.

For example, this determination is made from the relation: t (n) - t n - 1) if CgtV (n) = 1

Tc (n) =

Jc n - 1) + t (n) - t (n - 1) else where Te is the time since the last variation change.

For example, we choose Tc (l) = 0. Figure 7 provides an illustrative curve of the times since the last change in variation obtained for the SAC signal from which the curve of Figure 4 was obtained.

During a step S9, for at least one time interval associated with a time since the last variation change Tc (n), a cardiac coherence point parameter is determined from said time since the last variation change.

For example, if this time is between 3 and 7 seconds, it is assumed that the person is in cardiac coherence, so that his cardiac coherence point parameter increases.

For example, the parameter is determined from the relation: Tc (n - 1)> Tel and Tc (n - 1) <Tc2

P2 otherwise

P3 else If CgtV (n) is zero, that is to say that no change of variation has occurred for index n, we give 1 point. This is to have a parameter whose value is based does not present an "all or nothing" configuration.

Tel and Tc2 are predetermined threshold values. They are for example expressed in seconds. Tel values are preferably between 0 and 10, preferably between 2 and 5. In addition, the values of Tc2 are preferably between 5 and 10.

PI, P2 and P3 are predetermined number of points.

Advantageously, PI, P2 and P3 observe one and / or the other of the relations P1> P3> P2 and

P1 <100 * P3.

In a step S 10, for at least one interval with which a cardiac coherence point parameter is associated, a cardiac coherence score of S (n) is determined from said cardiac coherence point parameter.

For example, this determination is implemented from the relation:

, P (.Q

5 (n) = 100 *

i = nj _j CgtV (i) where S is the cardiac coherence score, P is the point parameter, CgtV is the change of variation, j is a nonzero number of intervals, and n indexes the time intervals with n greater than or equal to j.

In other words, the score is determined from a weighted average over a number j of successive intervals. Advantageously, j is greater than or equal to 5. For example, it is equal to 9. However, more generally, j is advantageously greater than or equal to 1, and is advantageously between 1 and 20.

Note that the cardiac coherence score is expressed as a percentage.

During a step SU, for at least one interval associated with a cardiac coherence score, a cardiac coherence score smoothed Si is determined from the cardiac coherence score.

For example, this determination is made from the relation:

where k denotes the number of intervals on which the smoothing is performed, and Si denotes the smoothed score. For example, k is taken greater than or equal to 2. For example, it is taken equal to 4. The smoothed cardiac coherence score corresponds to the cardiac coherence factor described above. It is also expressed as a percentage.

In a step S 12, for at least one time interval with which a cardiac coherence factor is associated, a PSI indicator representative of a proportion of low cardiac coherence scores is also determined, a PS2 indicator representative of a proportion of mean cardiac coherence scores, and a PS3 indicator representative of a proportion of high cardiac coherence scores from the smoothed cardiac coherence score.

These indicators are for example determined from the following relationships:

PS3 n) = 100% - PSl (n) - PS2 n)

As previously, j is for example equal to 9. However, more generally, j is advantageously greater than or equal to 1, and is advantageously between 1 and 20.

Figure 8 illustrates together a curve of variation of the cardiac coherence factor and the variations of the above indicators for the SAC signal from which the curve of Figure 4 was obtained.

In a step S13, a signal representative of the cardiac coherence factor determined from the signal SAC is generated. This signal is for example generated by the MOD module.

Advantageously, the signal is also representative of at least a portion of the quantities determined during the previous steps. This signal is for example used during step S 13 for displaying, via the display AFF TERM terminal, all or some of the quantities determined in the previous steps and / or one or more quantities determined from the quantities thus determined.

For example, with reference to FIG. 9, a curve of variation of the heart rate or of the smoothed heart rate over the entire period of time of the ACQ signal (BPM curve in the upper right part) is displayed. Alternatively or in parallel, a curve of variation of the consistency score or of the smoothed score, ie of the coherence factor, is displayed over this lapse of time (curve S in the lower right part), or on the set of past time windows while the acquisition is still in progress. In addition, alternatively or in parallel, a mean cardiac coherence score SM determined as a mean of the cardiac coherence score or the cardiac coherence factor over this period of time (upper left), or on the whole time windows passed while the acquisition is still in progress. Alternatively or in parallel, for each indicator PSI to PS 3, an average of the value of the indicator is also displayed over this lapse of time, or of all the time windows passed while the acquisition is still in progress. These averages are for example displayed in the form of a joint histogram having three portions respectively associated with one of the indicators (middle of Figure 9 in the left-hand part).

Advantageously, during a step S 14, a breathing exercise is constructed for the user and the breathing exercise is submitted to the user, for example via the display of the terminal TERM.

The proposed exercise is configured to increase the individual's cardiac coherence. For example, the exercise proposed to the user includes instructions for implementing a sequence including inspirations and expirations. Optionally, it comprises one or more full-lung apnea phases, and / or one or more apnea phases with empty lungs, intervening for example between inspiration and expiration (or vice versa). The instructions corresponding to these elements are configured to intervene at times planned to increase the cardiac coherence of the individual.

This step S 14 takes place for example parallel to the acquisition step, so that the acquired signal accounts for the breathing exercise and its effect on the cardiac coherence factor.

Advantageously, the method further comprises a step S 15 during which the user is invited to perform a breathing exercise configured to increase the coherence factor of the individual according to the signal generated during step S 13. The exercise is for example as described above.

More specifically, when the signal is representative of the fact that at least a quantity determined from the cardiac coherence factor has a value greater (or less) than a predetermined threshold value, the user is invited to carry out the exercise in question. .

The magnitude in question is for example the cardiac coherence factor. Alternatively, consider the mean S _M of the coherence factor on all or part of the signal SAC. In some embodiments, the quantity in question is for example a combination of the values of a part of the quantities determined during the above steps, in particular the cardiac coherence factor.

The invitation takes for example the form of a message displayed on the display AFF calling the user to confirm whether or not he wishes to perform a breathing exercise.

The invention has several advantages.

Indeed, it makes it possible to evaluate the cardiac coherence of an individual in a simple manner, on the basis of data that can be acquired by means of inexpensive and compact equipment, so that the acquisition and processing of the required data are less constrained.

In addition, the treatment itself is relatively uncomplicated, in particular because it does not rely on a Fourier analysis that can mobilize significant processing resources.

Moreover, the factor obtained makes it possible to improve the individual's cardiac coherence in a simplified manner, particularly from the point of view of the acquisition of the data and of their processing.

Variations are conceivable.

For example, certain quantities are determined from quantities relative to intervals preceding the time interval considered. Alternatively, these quantities are determined from quantities relating to subsequent time intervals.

Claims

claims

A method for evaluating a cardiac coherence factor of an individual, wherein:

determining, from a cardiac activity signal (SAC) of the individual representative of cardiac pulsations, time intervals (I (n)) between said cardiac pulsations, and

the cardiac coherence factor (S n) is determined as a function of the time intervals between said cardiac pulsations.

The method according to claim 1, wherein, for determining the cardiac coherence factor, for each time interval (I (n)) of all or part of the time intervals between said cardiac pulsations, determining a heart rate ( BPM (n)) for the time interval considered from the inverse of said time interval considered.

The method of claim 2, wherein the heart rate of a time interval considered is determined from the relation:

, _N 1000 * 60

BPM (n) =

/(not)

The method of claim 2 or 3, wherein, for determining the cardiac coherence factor, for at least one time interval (I (n)) with which a heart rate is associated, a smoothed heart rate is determined (BPM ^ n)) from said heart rate and the heart rate associated with a time interval following or preceding the time interval considered.

The method according to any one of claims 2 to 4, wherein, for determining the cardiac coherence factor, for at least one time interval (I (n)) associated with a heart rate, a variation of the heart rate (V (n)) from the heart rate associated with said time interval and the heart rate associated with a time interval preceding the time interval considered.

The method of claims 4 and 5, wherein the variation of the heart rate is determined from the relation:

1 if BPM _l (n) - BPM _t (n - 1)> 1

-1 if BPM _t (n) - BPM _t (n - 1) <1,

V (n-1) otherwise

where BPMj is the smoothed heart rate associated with the time interval considered, n indexes the time intervals between the heartbeats, and V is the variation of the heart rate.

The method of claim 5 or 6, wherein, for determining the cardiac coherence factor, for at least one time interval (I (n)) associated with a change in heart rate, a change in variation is determined. (CgtV (n)) of the heart rate from the variation of the heart rate

(V (n)).

The method of claim 7, wherein the change in heart rate variation is determined from the relation:

The method of claim 7 or 8, wherein, for determining the cardiac coherence factor, for at least one time interval associated with a change in heart rate variation, determining a duration (Tc (n)). since a last change of variation from the change of variation (CgtV (n)).

The method of claim 9, wherein the duration since a last change of variation is determined from the relation:

not where Te is the duration since a last variation change, n indexes the time intervals between the heartbeats, CgtV is the change of variation, t (n) is the end time of the interval considered and t (n- l) designates the start time of the considered time interval.

The method of claim 9 or 10, wherein, for determining the cardiac coherence factor, for at least one time interval associated with a duration since a last change of variation, determining a value of a parameter of cardiac coherence points (P (n)) from said duration since a change of variation (Tc (n)).

The method of claim 11, wherein the value of the cardiac coherence point parameter is determined from the relation:

P (n) = j *> l P2 otherwise

P3 otherwise

where P is the cardiac coherence point parameter, CgtV is the change of variation, Tc is the duration since a change of variation, n indexes the time intervals, Tel and Tc2 are predetermined threshold values, and PI, P2 and P3 are predetermined number of points.

The method of claim 11 or 12, wherein, for determining the cardiac coherence factor, for at least one time interval associated with a cardiac coherence point parameter, determining a cardiac coherence score (S (n )) according to said cardiac coherence point parameter (P (n)).

The method of claim 13, wherein the cardiac coherence score is determined from the relation:

The method of claim 13 or 14, wherein for at least one time interval associated with a cardiac coherence score, the cardiac coherence factor is determined from said cardiac coherence score (S (n)) and at least one cardiac coherence score of a time interval preceding the time interval considered.

The method of claim 15, wherein for at least one time interval with which a cardiac coherence factor is associated, an indicator (PS1 (n)) representative of a proportion of low cardiac coherence scores is further determined. an indicator (PS2 (n)) representative of a proportion of mean cardiac coherence scores, and an indicator (PS3 (n)) representative of a proportion of high cardiac coherence scores from the smoothed cardiac coherence score.

A method according to any one of the preceding claims, wherein the individual is urged to perform a breathing exercise configured to increase the individual's cardiac coherence as a function of the value of a magnitude determined from the cardiac coherence relative to a threshold value.

18. Computer program comprising instructions for implementing the method according to one of claims 1 to 17, when the program (MOD) is executed by a processor.

19. Module for evaluating an individual's cardiac coherence factor, said evaluation module being configured to:

determining, from a heart activity signal (SAC) of the individual representative of heartbeats, time intervals between said heartbeats, and

determining the cardiac coherence factor (S n) of the individual as a function of the time intervals between said heartbeats.

20. A device for evaluating a cardiac coherence factor of an individual, the device comprising:

an acquisition device (ACQ) for a cardiac activity signal (SAC) of the individual representative of heartbeats, and an evaluation module (MOD), said evaluation module (MOD) being configured to:

determining, from the cardiac activity signal (SAC) of the individual, time intervals between said cardiac pulsations and determining the cardiac coherence factor of the individual as a function of the time intervals between said cardiac pulsations.

21. Evaluation device according to claim 20, characterized in that the evaluation device comprises a bracelet (BRAC) intended to be worn by the individual on the wrist, the acquisition device (ACQ) being fixed or integrated with said bracelet (BRAC).

22. Evaluation device according to claim 20, characterized in that the evaluation device comprises an atrium (ORE) intended to be coupled to an ear of the individual, the acquisition device (ACQ) being fixed or integrated to said atrium.