WO2008017246A1

WO2008017246A1 - Physiological signal acquiring device

Info

Publication number: WO2008017246A1
Application number: PCT/CN2007/002315
Authority: WO
Inventors: Chang-An Chou
Original assignee: Chang-An Chou
Priority date: 2006-08-02
Filing date: 2007-08-01
Publication date: 2008-02-14

Abstract

A piezoelectric sensing element disposed on the nose or a region surrounding the nose for detecting snoring signals includes a conducting layer (20) and a piezoelectric layer (22), wherein the piezoelectric layer (22) is carried by the conducting layer (20), and the piezoelectric layer (22) is used to sense the snoring vibration of nasal cavity, two electric connecting contacts (24), respectively connected to the conducting layer (20) and the piezoelectric layer (22), and a sealing protection used for compressing and coating the conducting layer (20). Moreover, a respiratory event sensor for detecting respiratory signals is further disclosed which includes at least a piezoelectric snore sensing element (S), which has a multi-layered structure, at least an airflow sensing element (R), and at least an attaching component (100) for simultaneously attaching the piezoelectric snore sensing element (S) and the airflow sensing element (R) on a user's face.

Description

PHYSIOLOGICAL SIGNAL ACQUIRING DEVICE

FIELD OF THE INVENTION

The present invention is related to physiological signal acquiring devices and methods for employing thereof, and more particularly, to physiological devices having piezoelectric sensing element for sensing snore signal and method for employing thereof.

BACKGROUND OF THE INVENTION

Recently, discussions related to sleep problems become more and more popular, and sleep apnea is namely one of the important issues thereof.

Traditionally, the detailed sleep apnea monitoring has to employ numerous sensors/electrodes, such as, ECG, EEG, EMG, EOG, SP02, respiration etc., so that, as known, this monitoring is disadvantageous of complicated and uncomfortable sensors/electrodes installation.

Accordingly, many improvements related to simplification are developed, especially applications which intend to utilize fewer sensors/electrodes to judge the sleep apnea syndrome or other sleep physiological conditions. For example, US 6,485,432 Bl disclosed a sensor for simultaneously detecting temperature and sound by PVDF. However, this is disadvantageous of high cost and complicated manufacturing procedures because the PVDF is a thin film requiring the dedicated and difficult processing process, which is different from the common used material, and further, the two signals have to be separated by particular technology for analysis. Therefore, it is hard to be popularized.

For examining sleep apnea/hypopnea syndrome, no matter in detail or simple, airflow is the physiological signal absolutely to be detected for revealing the actual respiration condition since respiration is the most direct index for sleep apnea. Except airflow itself, in respiration monitoring, snore is also an important index. When the breathing passage is blocked, people naturally will breathe harder for obtaining oxygen, so the snore happens. Besides, more advantageously, the snore index also can help to judge if the user has an obstructive sleep apnea/hypopnea, and after confirming, the user may directly receive the relative treatments without further detailed examination. Therefore, it is also important to monitor the snore during sleep. Generally, the snore sensor can be divided into two types: sound-detecting type, which employs a sound receiving element, and vibration-detecting type, which employs a piezoelectric sensing element.

The commonly used sound receiving element is microphone, which decides the arisen time and quantity of snore directly depending on the sound difference. This manner is advantageous of easy installation and sound obtaining, but also disadvantageous of non-easy eliminated external interference, namely, during sound receiving, the sound around the user will also be recorded at the same time, so as to cause the analysis more difficult. And, for solving this problem, the installing position and inner composition of the microphone should be cooperated.

As to the piezoelectric sensing element, it is advantageous of easy signal decision based on a proper installation and of great transformation efficiency and high accuracy. But, it is disadvantageous of inconvenient setting procedure because the sensing element should contact the user's skin. For example, the piezoelectric snoring sensing element is always disposed on the neck (throat), but it always happens that the sensing element comes off or becomes unfitted to the skin surface owing to the head movement, so as to cause measurement error. Therefore, if this problem can be solved, then the snoring measurement via the piezoelectric element can become more convenient and more accurate.

Consequently, there are many improved snoring sensors developed, such as, US 6,254,545 Bl and US 6,894,427 B2 disclosed of utilizing PVDF to sense the snoring vibration through the flexibility thereof so that it can fit to the skin surface better. However, it is a difficulty to process the PVDF film, and the cost thereof is high since PVDF is a rare material and the manufacturing process thereof is also complicated.

So, the object of the present invention is to provide an improved piezoelectric snoring sensing element for affording a better sensing effect, a more convenient installation procedure, and also a further reduced cost, so that it can cooperate with the airflow sensor to provide a more convenient respiration event sensor, thereby facilitating the methods employing thereof.

SUMMARY OF THE INVENTION

The present invention provides a piezoelectric sensing element disposed on the nose or a region surrounding the nose for detecting snoring signals includes a conducting material and a piezoelectric material, wherein the piezoelectric material is carried by the conducting material, and the piezoelectric material is used to sense the snoring vibration of nasal cavity, two electric connecting contacts, respectively connected to the conducting material and the piezoelectric material, and a sealing protection used for compressing and coating the conducting material, the piezoelectric material and the electric connecting contacts, so as to form the piezoelectric sensing element.

According to above description, the present invention also provides a method for detecting snoring signal. The method includes steps of a) providing a piezoelectric sensing element with a multi-layered structure, which at least comprises a conducting layer, a piezoelectric layer and two electric connecting contacts, which are connected to an external device via connecting wires, b) attaching the piezoelectric sensing element on the nose or a region surrounding the nose by an attaching element so as to contact the piezoelectric sensing element with the skin surface, and c) transforming a snoring vibration generated from the nasal cavity into an electric signal by the piezoelectric sensing element and transmitting thereof to the external device through the electric connecting contacts and the connecting wires.

In another aspect, the present invention provides a respiratory event sensor for detecting respiratory signals includes at least a piezoelectric snore sensing element, which has a multi-layered structure, at least an airflow sensing element, and at least an attaching component, for simultaneously attaching the piezoelectric snore sensing element and the airflow sensing element on a user's face so as to position the piezoelectric snore sensing element on the nose or around nose and the airflow sensing element between the mouth and nostril, thereby simultaneously acquiring the airflow and the snore signals.

According to above description, the present invention also provides a method for judging the type of sleep apnea/hypopnea events through a respiratory event sensor including at least a snore sensing element and at least an airflow sensing element. The method includes steps of a) installing the respiratory event sensor on a user, b) acquiring snore signal and airflow signal simultaneously by the respiratory event sensor from the user during sleep, c) counting A/H events (Apnea/Hypopnea events) and snore events during a certain period and recording the timing information for each event, d) generating a correlation factor between the A/H events and the snore events based on the counting and the timing information, e) judging if the correlation factor is higher than a predetermined threshold, and f) if the correlation factor is higher than the predetermined threshold, classifying the A/H events contain obstructive conditions.

BRIEF DESCRIPTION OF THE DRAWINGS

A more detailed understanding of the invention may be had from the following description of a preferred embodiment, given by way of example, and to be understood in conjunction with the accompanying drawings, wherein:

Fig. 1 is a schematic view showing the appearance of a conventional piezoelectric snore sensor;

Fig. 2 A and 2B are respectively a vertical view and a sectional drawing of the internal structure of the conventional piezoelectric snore sensor;

Figs. 3A~3C are schematic views showing the internal structure of a piezoelectric sensing element in a preferred embodiment according to the present invention;

Figs. 4A-4C are schematic view showing the internal structure of a piezoelectric sensing element in another preferred embodiment according to the present invention;

Fig. 5 is a schematic view showing the connection between the piezoelectric sensing element and an external device according to the present invention;

Figs. 6A~6B are schematic views showing the additional bulge(s) installed in the piezoelectric sensing element according to the present invention;

Fig. 7 is a schematic view showing the region surrounding the nose for positioning the piezoelectric sensing element according to the present invention;

Figs. 8A-8B are schematic views showing the examples of attaching elements for fixing the piezoelectric sensing element on the face;

Fig. 9 is a schematic view showing an example that the piezoelectric sensing element is adhered to the nose through the attaching element;

Fig. 10 is a flow chart showing the method for judging the type of sleep apnea/hypopnea by utilizing a respiratory event sensor according to the present invention;

Figs. 11 A-IlD are schematic views showing the different outer structures of the respiratory event sensors according to the present invention;

Figs. 12A-12B are schematic views showing the possible circuit arrangements of the respiratory event sensor according to the present invention;

Figs. 13A~13B are schematic views showing an example of the respiratory event sensor according to the present invention; and

Fig. 13C is schematic view showing another example of the respiratory event sensor according to the present invention

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Different from the conventional piezoelectric snoring sensing element disposed on the neck, the piezoelectric snoring sensing element according to the present invention is disposed on the nose or the region surrounding the nose, that is, the present invention provides a novel snoring sensing method, which is characteristic of, except better detecting effect, low cost and convenient usage.

Generally, the snoring sensor disposed around the nose is a microphone and the piezoelectric element is located on the neck whose appearance is similar to a thicker coin, such as Piezo Sensor 1250 produced by SleepMate^®, as shown in Fig. 1. However, since the neck might have lots of turning movements which might rise and fall the skin surface frequently, the hard plate is difficult to completely attach to the neck surface, or even been attached well, it still might depart from the attachment owing to some body movement, such as body turn over or body turn aside. Obviously, the accuracy thereof might be doubted.

Based on this defect, the applicant develops an improved snore sensing manner.

Since the neck rises and falls too often and the reason why the piezoelectric element is disposed on the neck is the throat is where the snoring sound comes from, if there is a place where also can draw the snoring signal with identical or even better effect, then it of course is a great choice to replace the neck.

The applicant discovers that not only the snoring vibration is occurred at throat, but also the whole sound tract will have resonance, so that, theoretically, the vibration can be sensed all over the sound tract. Accordingly, the applicant selects the nose and the region surrounding the nose for disposing the piezoelectric snoring sensing element since the surface change thereof is less than the neck and the vibration can be enhanced by the resonance of the nasal cavity.

But, the applicant found that the conventional hard plate-type snoring sensor is not suitable for being positioned on the nose since the diameter and thickness thereof are both too large for the nose and may also cause an uncompleted attachment. Therefore, it is believed that if the size of the piezoelectric element is reduced, it might positively improve the snore signal drawing effect from the nose and the region souring the nose. And, after experimenting, this theory is confirmed.

Because the nose is a cavity which can enhance the snoring vibration and the size-reduced piezoelectric element can sense the vibration through the whole body thereof (not only the partial surface thereof, like the conventional hard plate-type snoring sensor), the snoring signal drawn by this size-reduced on-nose piezoelectric sensing element is not only very clear but also much more distinct than the conventional one.

Accordingly, for reducing the size, the structure and the manufacturing procedures of the snoring sensing element in the present invention is developed to have differences from the conventional one.

As known, the piezoelectric sensing element is formed by a conducting material and a piezoelectric material, in which the piezoelectric material senses the skin vibration and transmits to the conducting material, so as to form the electric signal. In the conventional piezoelectric snoring sensor, as shown in Fig. 2, a conducting material 10 is used as the bottom layer and a piezoelectric material 12, such as ceramic, is partially covered thereon, with an electric element 14, such as a resistor, bridges therebetween, and a connection to the external device is performed for forming a measuring loop. Then, the whole structure is coated by an outer plastic or rubber, so as to complete the conventional snoring sensor.

As to the snoring sensing element according to the present invention, it also adopts the conducting material to carry the piezoelectric material, so that there is no need to employ any particular material and processing technology, thereby the cost will not be increased. But, for reducing the width and thickness, the present invention utilizes a different structure and manufacturing procedures from the conventional technology.

In structure, the present invention adopts a multi-layered structure, as shown in Fig. 3, a conducting layer 20, a piezoelectric layer 22 and two electric connecting contacts 24, wherein the piezoelectric layer 22 is carried by the conducting layer 20, in which the piezoelectric material 22 is covered on one side of the conducting layer 20 so as to form a combination with one conducting surface and one piezoelectric surface, and two electric connecting contacts 24 are respectively disposed on each surface thereof.

Here, the electric connecting contacts 24 can be implemented as different types. For example, for reducing the welding process, they can be implemented as flat layers, as shown in Fig. 3, so that they can be respectively placed on the conducting layer and the piezoelectric layer without welding. However, it should be noticed that in this embodiment, the conducting layer and the piezoelectric layer should have an identical area, which means that the conducting layer should be totally covered by the piezoelectric material, so that the electric connecting layers 24 can be randomly placed thereon without short circuit. Therefore, this embodiment is advantageous of the decreased processing steps and also the reduced cost.

Alternatively, the electric connecting contacts 24 also can be respectively welded on the conducting layer and piezoelectric layer for better fixation. In this embodiment, the conducting layer does not need to be totally covered by the piezoelectric material because the short circuit possibility is eliminated by the welding. Since the electric connecting contacts are welded on the surfaces, the flat form structure, as described above, is no more needed, so that it can be implemented as the connecting wires being directly welded thereon without further structuring the contacts, as shown in Fig. 4.

After completing the multi-layered structure, the whole structure can be easily coated/sealed by a sealing protection, for example, heat shrinkable tube or silicone, rubber or sponge, and, except providing protection, this sealing protection also can make the electric connecting contacts to be more tightly contact the conducting layer and the piezoelectric layer, even without welding. Besides, the sealing protection also plays a medium for transmitting the vibrations from the skin surface to the piezoelectric material, so that it is important to select a material that can reliably transmit the vibration and/or act as a filter to remove certain unwanted frequencies.

Here, it should be noticed that, as compared with the conventional technology, in the piezoelectric sensing element according to the present invention, the resistor is not included.

The applicant, after evaluation, believes that it is not necessary to dispose the resistor on the sensing element, and the sensing also can be achieved if the resistor is located at any location of the measuring loop, for example, the external device 26, as shown in Fig. 5, or even the connecting wires. And, through this design, the steps for forming the sensing element are further decreased, so that the manufacturing complexity caused from the degraded size can be reduced and also the cost since the welding might be executed by manpower.

Furthermore, for achieving a better contact between the sensing element and the (nasal) skin, before sealing, a bulge 28 can be additionally placed above the multi-layered structure, so as to form a protruding surface. Here, the bulge can be position at one side (as shown in Fig, 6A) or both sides (as shown in Fig. 6B), without limitation, and the bulge can be made of silicone, rubber or plastic.

After experimenting, the result is that the signal drawn by the snoring sensing element formed according to the above description is clear, and the sensitivity of the sensing element is not reduced owing to the size degradation or structure simplification. Oppositely, the reduced size makes the whole snoring sensing element can sense the vibration without being limited to partial region thereof.

Most importantly, the installation position is no more restricted.

Since the nose has less movement during sleep and is less influenced by body turn over or turn aside, it will be easier to position this novel snoring sensing element. Besides, the vibration of the nasal cavity is quite obvious, so that the signal can have sufficient strength for being sensed by the sensing element. Therefore, the user no longer need to waste effort to fix the sensing element, for example, by adhering many tapes, and the uncomfortable feel owing to the considerable fixing tapes is also eliminated.

Besides, as detecting sleep physiological condition, this on-nose sensing element can be further combined with the on-face sensor, such as, airflow sensor, so as to reduce wiring. It is especially benefit as executing a completed sleep physiological condition monitoring, which monitors many physiological signals, such as, EKG, EEQ snoring, airflow, SP02, EOG and EMG etc. Because, during the completed monitoring, so many sensors/electrodes will need many wires to connect to the external device, the reduction of wiring is a grateful improvement, especially for the user.

Moreover, since the volume of the snore sensing element is small, it is possible to install two on the nose or the region surrounding the nose at one side or two sides, so that the redundancy detection for correction becomes executable.

The region for positioning the sensing element is a quadrilateral region demarcated by the cheekbones, the mouth and the nasal between the eyes, as shown in Fig. 7. Therefore, the sensing element is not limited to be positioned on the nose, and it is also practicable to be positioned in the region surrounding the nose, so that the installing position is flexible and can be adjusted according to user habit or the cooperation with other sensors.

The snoring sensing element according to the present invention can be attached to the nose or the region surrounding the nose through an attaching element 32, as shown in Fig. 8, wherein the attaching element 32 can be a designed patch having a shape conforming to the nose (as shown in Figs. 8A and 8B), or simply the medical tape, namely, the attaching element is focused on adhering the snoring element onto the nose or the region surrounding the nose, as shown in Fig. 9, and not the shape or material thereof.

In addition, the piezoelectric material used in the present invention, as described above, is the common piezoelectric material, for example, single crystal, such as quartz, tourmaline, LiNbO3 or LiTaO3, thin film, such as ZnO, polymer, such as polyvinylidene fluoride, ceramic, such as BaTiO3 or PZT, and composite material, such as PVDF-PZT.

According to another embodiment of the present invention, the piezoelectric sensing element can be applied to other kinds of skin vibration detection. The piezoelectric sensing element can be embedded in a rigid housing for being located on a flat skin surface and/or for sensing a slighter vibration. Through the rigid housing, the sensed vibration can be magnified, so that the signal intensity can be increased, and thus, the slighter vibration signal, for example, the heart beating or the pulse, also can be detected, and further, the setting position of the sensing element becomes less critical. Therefore, the rigid housing provides the piezoelectric sensing element different kinds of applications. Here, the rigid material can be made of plastic or acrylic, not limited, and has no shape limitation.

Following, some applications related to utilize the piezoelectric snore sensing element according to the present invention are described.

Firstly, the piezoelectric snore sensing element is used to cooperate with the airflow sensing element for achieving a simplified sleep apnea/hypopnea pre-screening method.

As know, sleep apnea and sleep hypopnea are two common kinds of sleep respiratory disturbance and can be separated into obstructive type and central type. The obstructive sleep apnea/hypopnea is caused from the respiratory tract being blocked, and the central sleep apnea/hypopnea is caused by central nervous system abnormality which might need further diagnosis and treatment. The airflow sensor can easily detect the respiration reduction or stop, but it can not be sure which kind of sleep apnea/hypopnea happens. Therefore, except airflow, one more physiological signal is needed for differentiation. Since most sleep apnea/hypopnea events belong to obstructive type, here, in the present invention, snoring signal is selected to help this judgment. Besides, if the sleep apnea/hypopnea can be screened and identified as obstructive, the user can directly receive the treatment without further detailed examination in the sleep laboratory, for example, the user might be suggested to receive a surgery or use the CPAP (continuous positive airway pressure) devices etc.

The basis for choosing the snoring signal as an assistance in judging obstructive sleep apnea/hyupopnea is that when the respiratory tract is increasingly blocked owing to the gradually relaxed muscle, the snore sound starts to occur, and when the user is awaked by the blocked tract, the respiration returns back to normal, so that the snoring signal can be utilized to recognize the obstructive sleep apnea/hypopnea. Therefore, the combination of simultaneously sensing airflow and snore is a positive way to decide if the user has the obstructive sleep apnea/hypopnea.

Usually, for recognition, the number of sleep apnea/hypopnea events (A/H events) and the number of snore events in a specific period of time will both be counted, and then, a correlation factor therebetween can be calculated.

Please refer to Fig.10, which is a flow chart for judging the type of sleep apnea/hypopnea. As shown, after obtaining both airflow and snore signals, the A/H events and the snore events during a certain period are both counted, and also, the timing information of each event is recorded. Then, a correlation factor between A/H and snore events based on the counts and the timing information is generated. Here, the correlation factor can be generated, for example, by calculating a rate of the sum fo time occupied by A/H events each of which occurs accompanying with the snore event to the sum of time occupied by whole A/H events. Following, according to the correlation factor, the type of the sleep apnea/hypopnea can be identified. At first, the correlation factor is compared with a predetermined threshold, and if the correlation factor is higher than the threshold, it can classify that the sleep apnea/hypopnea contains obstructive conditions, and if the correlation factor is lower than the threshold, a further judging procedure continues. Then, it will decide that if the number of the A/H events is higher than normal average, for example, 15 times per hour. If yes, it will suggest the user to receive advanced sleep examination, and if not, another further judging procedure continues. Following, it will decide that if the number of the snore events is higher than normal average. If yes, it represents that the user is a potential patient for obstructive sleep apnea/hypopnea, and if not, the no apnea judgment can be made. Therefore, without complex sensor/electrode installation or difficult analysis technology, the obstructive sleep apnea/hypopnea can be easily and roughly identified, and except of this, this design also can indicate the user that he/she needs advanced sleep examination, has the potential of obstructive apnea or not.

Through this simple design, the sleep apnea/hypopnea can be pre-screened in a very simple manner with a very low cost, so that the user can even implement this examine at home without difficulty, and thus, the completed sleep physiological monitoring executed in the sleep laboratory can be left to people who need the more advanced and detailed examination.

Consequently, to develop a respiratory event sensor including an airflow sensing element and a snore sensing element is meaningful, no matter in theory or in real application.

For achieving this combined sensor design which simultaneously locates the airflow sensing element and the snore sensing element on the face, a unique structure for attaching both is developed, and Figs. 11 A- 1 ID show some possibilities, but not limited.

In the present invention, at least an attaching component is employed for locating the airflow sensing element between the mouth and the nostril and the snoring sensing element on the nose or around the nose.

Here, the quantity of attaching component can be implemented as one or more, depending on different sensor types and/or usage demands. For example, when the number is implemented to be one, the attaching component can be designed as shown in Figs. HA and HB (not limited). In Fig. 11 A, except the attaching component 100, a substrate 120 is further included to carry three airflow sensing element R at the right positions. In Fig. HB, the attaching component 140 directly attaches the snore sensing element S and the airflow sensing elements R at the same time.

When the quantity of the attaching component is implemented as plural, the face area attached by the attaching components might even be reduced. For example, if two attaching components are employed, as shown in Fig. 11C, which is one of the possible examples, the attaching components 160 may respectively attach two ends of the substrate 120 and further extend to have an arm to attach the snoring sensing elements S. In this embodiment, through the arm, the position for attaching the snoring sensing element S can be more flexible, and further, this design will be more suitable for male user who wears moustache. Alternatively, Fig. HD discloses another possibility of plural attaching components. Here, the nasal airflow sensing elements R are respectively combined with a snoring sensing element through an attaching component 180, the oral airflow sensing element R is alone attached by the attaching component 200 and the attaching components 180 and 200 are connected through connecting wires.

Therefore, the principle for designing the attaching component is that the sensing elements can be attached at the proper positions for increasing sensing accuracy and the attaching component itself can fit to the skin surface for preventing from coming-off, and most importantly, it should provide the user the least uncomfortable feeling during signal acquiring, so as to increase the possibility of the user to use this respiratory event sensor. It should be noticed that these shape designs are only shown for illustration, not for limitation.

As to the material of the attaching component, it only needs to be a material which has a flexible property for conforming to the skin surface, has an adhering capability for attaching the sensing elements on the face and is suitable for contacting with human skin for a long period of monitoring time, for example, medical tape or patch might be the suitable material.

Moreover, the airflow sensing element can also have different choices. For example, it can be thermistor, thermal coupler or airflow pressure sensing element, namely, any sensing element which can sense heat and/or airflow on the respiratory tract can be used in the present invention for airflow detection.

Regarding the circuit arrangement inside the respiratory sensor, it also can have many choices. For example, the airflow sensing elements and the snore sensing element can be located in one single loop in parallel (as shown in Fig. 12A) or serial (as shown in Fig. 12B) connection, so that two kinds of signals can be outputted in one loop and then be separated in the external device by hardware, for example, filter, conversion circuit or by software, such as, digital signal processing. Alternatively, the airflow sensing elements and the snore sensing element also can separately employ different connecting loops, as shown in Fig. 13 A, but integrated together for better organization.

Furthermore, the connection manners of the respiration sensor with external device also can be different, as shown in Fig. 13A-13C. Here, the substrate 220 is used as a connecting medium. That is, the snore sensing element(s) is connected to the substrate 220 at the connecting points 240, which together with the connecting points 260 are integrated to connect to an external device. Through this design, the connecting wires from the sensing elements (the snore and the airflow) are all gathered up, so that there is only one bundle 300 of wires connecting from the respiration sensor to the external device, thereby the wiring complexity is minimized. Moreover, the connection with the external device can be implemented as direct soldering, as shown in Fig. 13 C, in which the substrate 220 is implemented as a flexible PCB, or using a connector 280, as shown in Figs. 13 A and 13B.

Preferably, the connection is further hidden under the attaching component 320, no matter the welding points 240, 260 or the connector 280, so that the connection can be more stable and also more beautiful.

More particularly, through utilizing the connector 280, the wires 300 and the connector 280 of the respiratory event sensor can be implemented as reusable, so that every time executing the detection, only the sensor portion needs to be changed. Therefore, the cost can be even more reduced.

In another preferred embodiment, the respiratory event sensor of the present invention can be further connected with respiration effort belts, so that if the A/H events do not have a high correlation with the snore events, then the movements of the thorax and the abdomen can help to judge if central sleep apnea events occur.

Therefore, the respiratory event sensor according to the present invention is a simple structured sensor which has the pre-screen function for sleep apnea, and people who do not want to spend their time and money to sleep in the sleep laboratory for whole night can execute the monitoring at home with uncomplicated operation and low price.

In the aforesaid, the present invention provides a novel piezoelectric snoring signal sensing element and a method for detecting the snoring signal via thereof, wherein although the conventional conducting and piezoelectric materials are employed, through utilizing different structure and manufacturing procedures, the present invention successfully reduces the element volume, facilitates the adhering process and also improves the sensing ability, so that the manufacturing cost is also reduced. Moreover, since the novel snoring sensing element is positioned on the nose or the region surrounding the nose, the measurement might not be easily influenced by body turn over, and more importantly, it can combine with other on-face sensors for further reducing the wire complexity during physiological monitoring, especially the airflow sensor. As the piezoelectric snore sensor is combined with the airflow sensor, a novel respiratory event sensor is formed which also can provide a method for judging the type of sleep apnea events, wherein, through employing the snoring signal and the airflow signal simultaneously, the obstructive sleep apnea can be easily and roughly identified and other opinions for the user also can be provided. Since only two kinds of sensing elements are needed, the measuring method is quite simple and the cost is also very low. Therefore, the respiratory event sensor according to the present invention is suitable for user to operate at home for pre-screening the sleep apnea.

The above examples and disclosure are intended to be illustrative and not exhaustive. These examples and description will suggest many variations and alternatives to one of ordinary skill in this art. All these alternatives and variations are intended to be included within the scope of the attached claims. Those familiar with the art may recognize other equivalents to the specific embodiments described herein which equivalents are also intended to be encompassed by the claims attached hereto.

Claims

What is claimed is:

1. A piezoelectric sensing element disposed on the nose or a region surrounding the nose for detecting snoring signals, comprising: a conducting material and a piezoelectric material, wherein the piezoelectric material is carried by the conducting material, and the piezoelectric material is used to sense the snoring vibration of nasal cavity; two electric connecting contacts, respectively connected to the conducting material and the piezoelectric material; and a sealing protection used for compressing and coating the conducting material, the piezoelectric material and the electric connecting contacts, so as to form the piezoelectric sensing element.

2. The piezoelectric sensing element as claimed in claim 1, further comprising at least a bulge, located above the electric connecting contact for forming the piezoelectric sensing element a protruded appearance after sealing, so as to increase the sensitivity to the vibration.

3. The piezoelectric sensing element as claimed in claim 2, wherein the bulge is made of silicone, rubber or plastic.

4. The piezoelectric sensing element as claimed in claim 1, wherein the electric connecting contacts are connected with an external device through connecting wires to form a measuring loop.

5. The piezoelectric sensing element as claimed in claim 4, wherein the measuring loop further comprises a resistor.

6. The piezoelectric sensing element as claimed in claim 5, wherein the resistor is disposed in the external device and/or in the connecting wires.

7. The piezoelectric sensing element as claimed in claim 1, wherein the conducting material is completely covered by the piezoelectric material.

8. The piezoelectric sensing element as claimed in claim 1, wherein the conducting material is partially covered by the piezoelectric material.

9. The piezoelectric sensing element as claimed in claim 1, wherein the sealing protection is formed by heat shrinkable tube, silicone, rubber or sponge.

10. The piezoelectric sensing element as claimed in claim 1, wherein the sealing protection is a medium for transmitting vibrations from the skin surface to the piezoelectric material.

11. A method for detecting snoring signal, comprising steps of: a) providing a piezoelectric sensing element with a multi-layered structure, which at least comprises a conducting layer, a piezoelectric layer and two electric connecting contacts, which are connected to an external device via connecting wires; b) attaching the piezoelectric sensing element on the nose or a region surrounding the nose by an attaching element so as to contact the piezoelectric sensing element with the skin surface; and c) transforming a snoring vibration generated from the nasal cavity into an electric signal by the piezoelectric sensing element and transmitting thereof to the external device through the electric connecting contacts and the connecting wires.

12. The method as claimed in claim 11, wherein the piezoelectric layer is made of a ceramic or a polyvinylidene fluoride.

13. The method as claimed in claim 11, wherein the conducting layer is made of metal.

14. The method as claimed in claim 11, wherein the region surrounding the nose is a quadrilateral region demarcated by the cheekbones, the mouth and the nasal between the eyes.

15. The method as claimed in claim 11, wherein when the quantity of the piezoelectric sensing element is plural, the piezoelectric sensing elements are disposed on the nose or the region surrounding the nose at one or two sides thereof.

16. The method as claimed in claim 11, wherein the piezoelectric sensing element is contacted with the skin through any portion thereof.

17. A respiratory event sensor for detecting respiratory signals, comprising: at least a piezoelectric snore sensing element, which has a multi-layered structure; at least an airflow sensing element; and at least an attaching component, for simultaneously attaching the piezoelectric snore sensing element and the airflow sensing element on a user's face so as to position the piezoelectric snore sensing element on the nose or around nose and the airflow sensing element between the mouth and nostril, thereby simultaneously acquiring the airflow and the snore signals.

18. The respiratory event sensor as claimed in claim 17, wherein the airflow sensing element further comprises a substrate for carrying thereof.

19. The respiratory event sensor as claimed in claim 17, wherein the attaching component attaches the airflow sensing element through attaching the substrate.

20. The respiratory event sensor as claimed in claim 17, wherein when the quantity of the attaching component is plural, the attaching components are located at different positions of the respiratory event sensor.

21. The respiratory event sensor as claimed in claim 20, wherein each attaching component is used to attach the piezoelectric snore sensing element and/or the airflow sensing element.

22. The respiratory event sensor as claimed in claim 17, wherein the attaching component has an adhesive surface for adhering to skin surface.

23. The respiratory event sensor as claimed in claim 17, wherein the piezoelectric snore sensing element and the airflow sensing element are electrically connected through at least a connecting wire.

24. The respiratory event sensor as claimed in claim 23, wherein the connecting wire is carried by the attaching component.

25. The respiratory event sensor as claimed in claim 17, wherein the number of the piezoelectric snore sensing element is capable of being two.

26. The respiratory event sensor as claimed in claim 25, wherein the two piezoelectric snore sensing elements are located at one side or two sides of the nose.

27. A method for judging the type of sleep apnea/hypopnea events through a respiratory event sensor including at least a snore sensing element and at least an airflow sensing element, comprising steps of: a) installing the respiratory event sensor on a user; b) acquiring snore signal and airflow signal simultaneously by the respiratory event sensor from the user during sleep; c) counting A/H events (Apnea/Hypopnea events) and snore events during a certain period and recording the timing information for each event; d) generating a correlation factor between the A/H events and the snore events based on the counting and the timing information; e) judging if the correlation factor is higher than a predetermined threshold; and f) if the correlation factor is higher than the predetermined threshold, classifying the A/H events contain obstructive conditions.

28. The method as claimed in claim 27, wherein the respiratory event sensor further comprises respiratory effort belts for sensing thoracic and abdominal movement of the user during sleep.

29. The method as claimed in claim 28, further comprising steps of: g) judging if the user occurs central sleep apnea/hypopnea events through comparing the A/H events with the thoracic and abdominal movements sensed by the respiratory effort belts.

30. The method as claimed in claim 27, wherein the correlation factor is generated by calculating a rate of the sum of time occupied by A/H events, which accompany with the snore event, to the sum of time occupied by whole A/H events.

31. The method as claimed in claim 27, wherein the correlation factor is generated by calculating a ratio of the sum of time occupied by A/H events, which occur accompanying with snore event, to the sum of time occupied by whole A/H events.