A DEVICE FOR MEASURING PAIN

Scope of the invention

[001] The present invention relates to the technical field of devices for medical use.

[002] In particular, the invention relates to an innovative device capable both of quantifying the pain of a patient precisely and objectively and of enabling a more objective assessment of the therapeutic effectiveness.

Brief outline of prior art

[003] The need to measure or anyway to classify the level of individual pain more objectively is of relevant importance not only for pain therapists but also for all clinicians who must control pain, such as in all surgical disciplines for post-operative pain.

[004] The availability of logical levels to determine pain more objectively becomes important to formulate adequate therapies and assess their results.

[005] The widespread method to date is the use of a pain scale proposed in several graphical versions. However, despite the efforts to make it sensitive, specific and objective, it remains an intrinsically subjective method, limited by the scarce repetitiveness, also because it is clearly subject to variations in mood of the patient under examination and it is also influenced by the health worker administering it.

[006] An example of pain scale is shown in figure 1 of known art. It shows colors and emoticon images that influence the patient under examination psychologically, thus losing the necessary objectiveness.

[007] A further example with a better result is a non- graduated scale (fig. 2) of known length (for example 10 cm) which is digitalized by the operator afterwards by measuring the level in millimeters wherein the pain sign is marked by the patient under examination. This enables to avoid influencing his judgement with misleading images and symbols but it remains anyway a subjective test. This structure of pain scale is less immediate for many patients and it can be administered more hardly to elderly patients and to patients in the postoperative period.

[008] In order to overcome these limitations, skin rubbing systems with flexible filaments of variable sections are known to assess the thresholds of sensitivity and hyperalgesia .

[009] These flexible filaments, known as "Von Frey filaments" are based in their action mechanism on surface mechanical stimulations of Pacinian corpuscles. However, this method is not precise given that the skin of each person has its own sensitivity that is highly variable and independent from the intrinsic thresholds of the corpuscles and the methodology is operator-dependent. In addition, this methodology is less used in hospital setting, in case that one aims to assess the pain level more than once in the same day; still this methodology is not suitable for assessing the pain level in case that one feels it in deep areas of the human body and in joints.

Summary of the invention

[0010] Therefore, it is felt the need for a precise and objective assembly enabling to assess the threshold value of pain and enabling the objective monitoring of pain over time.

[0011] In particular, it is felt the need for a precise and objective assembly enabling to assess the threshold value of pain with applied digital feed-back systems to objectify the stimulation thresholds of different nature and from which obtaining individual perception thresholds of the stimulus.

[0012] Therefore, the aim of the present invention is to provide an assembly for measuring pain which resolves the above-mentioned technical disadvantages.

[0013] In particular, the aim of the present invention is to provide an assembly for measuring pain which is not only objective but also repeatable with precision and simplicity in use, thus reducing the limitation due to the experience and manual skill of the operator carrying out the analysis.

[0014] These and other aims are achieved with the subject assembly for measuring pain, according to claim 1.

[0015] This measuring assembly for measuring the pain threshold of a subject comprises:

A generator of electrical impulses for electrostimulation;

A device for generating a vibration;

A device for generating a jet of a gaseous flow.

[0016] In this manner, all said technical disadvantages are readily resolved.

[0017] In particular, it is now possible to generate (preferably in succession) thanks to the above-mentioned assembly, an electrical stimulation, a mechanical stimulation (through a vibrating device) and a stimulation through the supply of a gas flow, generally air, at a certain pressure and/or temperature impacting onto a point of the subject's body.

[0018] The perception of these stimuli enables to determine a threshold value of pain for each patient and enables to assess its modification over time with regard to the possible applied therapy.

[0019] The execution order can be any, for example a first electrical stimulation and then the mechanical vibrating one and lastly the one through the air jet.

[0020] Thanks to these stimulations, one can create a perception scale of the pain threshold that is objective and thus resolves all technical drawbacks due to the current solutions.

[0021] Preferably, advantageously, the air jet can be at variable temperature so as to better stimulate the patient's perception.

[0022] Preferably, advantageously and in combination with the description above or independently from the description above, the mechanical vibration can be at variable intensity and/or frequency.

[0023] If necessary, the vibrating body can also be adjusted at a predetermined temperature.

[0024] Advantageously, the generator of impulses can be programmed for generating one or more trains of impulses. [0025] Advantageously, each train can be formed by at least two impulses, preferably four.

[0026] Advantageously, each impulse can be in the shape of a square or triangular or sinusoidal wave, therefore without excluding the possibility that each train is made up by a succession of impulses of shapes different from each other or having all the same shape.

[0027] Advantageously, the width of each impulse can be comprised for example in a range between OV and 70V and even more preferably between OV and 50V (V = Volt).

[0028] Advantageously, each impulse can have an adjustable duration.

[0029] For example, advantageously, the duration of each impulse can be comprised in a range between 50 microseconds and 1 millisecond.

[0030] Advantageously, the time interval between one impulse and the subsequent one in a train of impulses can be adjustable and/or advantageously the time interval between one train and the subsequent one can be adjustable.

[0031]Advantageously, the assembly for generating vibrations includes a vibrating end to which a vibration is transmitted by means of a vibrating mass that can be activated in such a way as to generate a vibration at a predetermined frequency.

[0032]Advantageously, the intensity and/or frequency of the vibration can be adjustable.

[0033]Advantageously, as already mentioned above, the device for generating vibrations can also comprise first temperature control means programmed for bringing the vibrating end to a predetermined desired temperature.

[0034]Advantageously, the said device for generating a gas flow can be programmed for generating impulses of gas flow, such as air, adjustable according to a duration of each impulse comprised in a range between 0.5 sec and 2 sec.

[0035]Advantageously, as mentioned above, second temperature control means can be further comprised, preferably in the form of a thermocouple with Peltier effect 43 and its function is enabling an adjustment of temperature of the gas jet, such as air as mentioned, to a predetermined desired temperature.

[0036] Advantageously, the pressure can be adjustable in a range between 2 and 4 atmospheres.

[0037] It is also described here a method for determining the pain threshold of a subject and comprising the following phases that can be executed according to any sequential order:

- The stimulation of the subject through the supply of one or more trains of electrical impulses for generating an electrostimulation; The stimulation of the subject through a vibration generated with a vibrating device;

- The stimulation of the subject through jets of a gaseous flow, such as air jets, at a predetermined pressure and/or temperature.

[0038] It is also described here the combined use of a generator of electrical impulses for electrostimulation, of a device for generating a vibration and of a device for generating a jet of a gaseous flow to generate in sequence, according to any order, one or more trains of electrical impulses, a mechanical vibration and a gaseous flow at a predetermined pressure for measuring a pain threshold of a subject.

[0039]As mentioned, the execution order can be any, for example, firstly a vibration then a gaseous flow and electrical impulses only lastly.

Brief description of the drawings [0040]Additional features and advantages of the present device, according to the invention, will become apparent from the following description of some preferred embodiments thereof, given only by way of non-limitative examples, with reference to the attached drawings, wherein:

Both figure 1 and figure 2 show two examples of solution according to prior art;

Figure 3 is a schematization of a part of the assembly subject of the invention and specifically of the central control panel to which electrodes are connected for electrical stimulation and handpieces for the air jet and the generation of vibrations;

Figure 4 is a graphic concerning a generation of trains of impulse whereas figure 4A shows some examples of trains of impulses; Figure 5 schematizes the device generating the vibration;

Figure 6 schematizes the device determining the jet of gaseous flow, such as air, under pressure;

Figure 7 schematizes a radar - graph;

Description of some preferred embodiments [0041] The invention mainly consists of the combination of three components as a whole generating the assembly to determine a measurement of the threshold pain.

[0042] These three components will be described in detail below and comprise:

A generator of impulses for electrostimulation;

A device (such as a handpiece) for generating mechanical solicitations, preferably vibrations at a certain frequency;

A device (such as a handpiece) for generating a gas flow (for example air jets) at a certain pressure, preferably at adjustable pressure values;

Then it may be provided a possible system for adjusting the temperature of the gaseous flow (for example air) and/or of the vibrating part of the device for generating vibrations.

[0043] The whole can be integrated into a single object integrating these components, each one adapted to its specific function.

[ 0044 ]Alternatively, these above-mentioned components could be separated parts and therefore define disjointed devices that work and are controlled together synergically .

[0045] The above-described components are therefore described below both in structural and functional detail. [0046] The preferred embodiment provides a single controller 1 (or equally controlling device) to which the three above-described components are connected and with the controller adapted to control their functionality .

[0047] Therefore, preferably, the assembly is controlled by said main controller, schematized in figure 3, to which all the various parts described in detail below are connected.

THE CENTRAL CONTROLLER:

[0048] Figure 3 shows the controller 1 to which the components forming the generator of impulses, the generator of vibrations and the air jet generator are connected in a removable way.

[0049] Therefore, the said controller 1 provides inside itself the control electronics (for example one or more suitably programmed processors) to control the operation of the various components that can be connected to it. [0050] It is formed by a frame in the form of box-shaped element 2 containing the electronics for the operation inside it.

[0051]As shown in figure 3, the box-shaped element 2 comprises a front side 3 thereof provided with the control panel 4 through which the operation is controlled and/or the data are read.

[0052] The control panel can have different layouts and therefore the depiction of figure 3 is not to be considered as limiting.

[0053] Obviously, the technology of digital screen can be used, possibly of the touch screen type.

[0054] In particular, a 5" touch screen display can be provided to set the operative parameters of the device. [0055] The box-shaped element 2 contains the electronics suitable for generating the trains of synthetized electrical impulses, controlled by a microprocessor, that are therefore sent through a cable 5. [0056] The same occurs for the generation of vibrations and air jets given that, through it, vibrations and air jets at desired values may be activated.

[0057] Figure 3 shows indeed the connections (in particular, three connections 50, 51, 52) and to each one of the connections, the cable 5 for the electrodes (6a, 6b), the cable going to the device for generating the vibration and the cable for the device generating the air jet under pressure can be connected, preferably in a removable manner.

[0058] Therefore, each cable can end with a "Jack connector" suitable for being inserted into the suitable connection (50, 51, 52).

[0059] Therefore, the control panel enables to adjust the desired values for the generation of electrical impulses of electrostimulation, vibrations and air jets.

THE DEVICE FOR GENERATING IMPULSES :

[0060] Therefore, still with reference to figure 3, the cable 5 is connected on one side thereof to the box-shaped element 2, in particular to the connection 50, whereas on the opposite part, it ends with at least one couple of electrodes (6a, 6b).

[0061] Accordingly, it is possible to generate a difference of potential between the electrodes (stimulating) that causes a passage of current into the body moving along the segment comprised between one electrode and the other one.

[0062] Therefore, substantially, an electrical impulse generator with digital control is generated to control all intensity parameters (duration and width) and their delivery frequencies. [0063] The introduced difference of potential is in the form of a train of impulses, each impulse is constituted by a difference of potential.

[0064] Therefore, this current will be adjustable and modulable since it is adjustable and modulable in width, duration, frequency and repetitiveness of emission, both the single impulse and the whole train of impulses.

[0065] In particular, sequences of trains of impulses are supplied with stimulating electrical charges variable in the parameters of width, duration and frequency that cause trains of stimulation currents of the different nervous fibers and corpuscles used for pain transmission in the body.

[0066] The current passes through the body in the form of single impulses or trains of impulses penetrating by the transcutaneous way, stimulating nerves with the well-known TENS technique (transcutaneous electrical nerve stimulation) .

[0067] Therefore, according to the invention, the generator of impulses for electrostimulation 1, subject of the invention, must be programmed so as to be able to generate:

[0068] - Wave shape: a specific wave shape programmable in shape and intensity to constitute a single impulse or a programmable train of impulses. Therefore, the wave can be for example square-shaped and/or triangular and/or sinusoidal .

[0069] For example, it is possible to deliver four alternated impulses of a second TOF (train of four) which is a method well-known by the anesthetists.

[0070] Preferably, the time can be also programmable, both the one between the impulses constituting the train and the one delivered between the different trains.

[0071] Therefore, figure 4 shows an example wherein two trains of square-shaped wave (train 1, train 2) are sent according to a time interval T between a train and the subsequent one which must be preferably greater or equal to 500ms (milliseconds). Each train is preferably formed by a block of at least two or more impulses, typically four.

[0072] - Width of impulses: This width must be adjustable between 0V and 70V, even more preferably between 0V and 50V. This width can be preferably adjusted through a multiple potentiometer equipped with a knob with a graduated precision scale or through an encoder equipped with a knob with a graduated precision scale.

[0073] Figure 4 shows an example of two trains at a value lower than 25V but greater than 0V.

[0074] - Time duration of each impulse: each impulse can have an adjustable duration between 50 microseconds and 1 millisecond .

[0075] There is also a possibility of generating a continuous stimulation at 50Hz.

[0076] The above-mentioned operation values are believed to be optimal for the operation and the purposes of the invention and therefore to stimulate the user so as to be able to measure the pain sensation, obviously without causing any physical damage.

[0077] Figure 4A shows, by way of example, some trains of impulses with triangular or square-shaped wave.

HANDIPIECE FOR GENERATING MECHANICAL SOLICITATIONS:

[0078] Figure 5 describes the device for generating mechanical solicitations that is still connected, through cable, to the box-shaped element of figure 3 (for example through the connector 51 or 52) and therefore it can be controlled through this box-shaped element, specifically through the control screen 4. [0079] The device of figure 5 (also named handpiece) is preferably a generator of vibrations.

[0080] It is preferably equipped with an eccentric motor (such as a micromotor). The rotation of the eccentric is such that it generates the desired vibration, at a predetermined frequency.

[0081] In particular, figure 5 shows the vibrating mass with number 30.

[0082] An electric small motor, such as a stepper motor, activates into rotation an eccentric which forms the vibrating mass as a whole.

[0083] The rotation of the eccentric causes the vibration. [0084] It may preferably be made through 3D printing with a shape that can be held and a conical tip for the transmission of vibrations to the skin.

[0085] Still as shown in figure 5, the device is equipped with the stimulating tip 31 that vibrates after the activation of the small motor, thanks to the eccentric which is made to rotate.

[0086] The tip 31 may have various shapes and stiffness. [0087] Also in this case, the frequency and intensity of vibration is controlled by a control panel through the microprocessor that controls the rotation speed of the electric stepper motor.

[0088] The microprocessor is obviously installed inside the box-shaped element 2 that shapes the above-described central controller.

[0089] The frequency and intensity of vibration that are most suitable for the purposes may vary and anyway can be modulated and therefore better defined on the basis of experimental data depending on specific needs.

[0090] A solution with more than one motor with different selectable eccentric masses and also positioned in the same handpiece is possible. [0091] Possibly, the handpiece can be equipped with first temperature control means, such as a thermocouple, that can heat and/or cool the vibrating tip at a predetermined temperature.

[0092] Different temperature thresholds could be set.

[0093] Preferably, the reachable temperature delta with respect to the room temperature of operation, is approximately more or less than 20°C with respect to the room temperature.

[0094] Preferably, the PELTIER effect can be used for reaching this temperature difference.

[0095] Therefore, if one operates in an environment with a temperature of approximately 24°C, temperatures up to a maximum of approximately 44°C or down to a minimum of approximately 0°C can be generated.

[0096] In this way, it will be possible to make someone feel a vibration through a cold or hot tip.

HANDPIECE FOR THE GENERATION OF AIR JETS AT CONSTANT PRESSURE

[0097] Figure 6 shows the device (also named handpiece) for generating jets of gas (generally air) under adjustable pressure.

[0098] Pressure remains constant at the set value, once it has been adjusted.

[0099] As indicated in figure 6, an air compressor generating the required send pressure is comprised.

[00100] In this way, the air contained in suitable tanks can be sent to a nozzle 45 under the said operative pressure.

[00101] Therefore, two tanks are provided, one of them (41) with hot air and one (42) with cold air.

[00102] Second temperature control means, preferably in the form of a thermocouple with Peltier effect 43 are then comprised and the function of these means is heating to a certain temperature the gas contained inside a tank and cooling the gas inside the other container with a temperature delta, for example of 20°C, between each other.

[ 00103 ] In this way, a tank will contain a hot gas (such as hot air) and the other tank will contain a cold gas (such as cold air).

[ 00104 ] A solenoid valve 44 is then provided for each tank for generating trains of air jets.

[ 00105 ] The solenoid valve is controlled by the microprocessor, still integrated into the box-shaped element of figure 3, while opening/closing, thereby determining the passage of hot or cold compressed air or a mix thereof through the nozzle 45.

[ 00106 ] The nozzle can for example contain inside it an electromechanical actuator controlling a needle obturator movable between an opening and a closing position.

[ 00107 ] Therefore, the microcontroller controls the opening of the electromechanical valves (one of them or both) and controls the activation of the electromechanical actuator that can open the obturator for the release of the gaseous flow under pressure, generally air as mentioned.

[ 00108 ] Also in this case, the handpiece can be made through 3D printing with a shape that can be held and a conical tip for the emission of air jets at a fixed distance from the skin.

[ 00109 ] The shape of the handpiece 45 can be similar to the one for the mechanical stimulation with the various nozzles of various sections, for example from 0,5 mm to 2 mm of diameter and also of the interchangeable type.

[ 00110 ] The compressed air that will be emitted under an adjustable pressure (controlled by a pressure regulator) can be taken from the different two tanks of compressed air with different temperatures (hot/cold) controlled by thermocouples with Peltier effect interposed between each other.

[00111] The whole can be powered by an external rechargeable battery through a suitable battery charger. [00112] Preferably but not necessarily, air impulses can be provided and the duration of each one may vary from a minimum of 0,5 sec to 2 sec with a pressure value adjustable between 2 and 4 atmospheres with manual trains (activated manually) or automatically preset.

[00113] The above-indicated values are believed to be preferred for the purposes but they do not exclude other possible values that could prove to be useful from trials.

USE OF THE ASSEMBLY :

[00114] The operator (doctor or algologist) decides the sequence of use of the various stimuli.

[00115] For example, starting from air stimulations with progressive intensity and variable temperatures to set sensitive thresholds equivalent to the Von Frey filaments with jets of hot air, cold air or air at room temperature. [00116] Subsequently, one may proceed with the vibratory mechanical stimulation still with the same purpose, thereby varying the mechanical vibratory stimulations at increasing intensity.

[00117] Lastly, one proceeds with electrical stimulations which will be combined in trains of impulses of various shape, intensity and frequency increased in intensity until reaching the nociceptive threshold with a digital system of signal objectivation.

[00118] A processor can acquire the intensity thresholds of air flows, vibratory stimulation and current that are felt by the user to determine a threshold value of objective pain according to a predetermined algorithm, assessing the possible modification over time also in relation with the ongoing therapy.

[00119]The interpretation of all applied stimuli can be generated under strict microprocessor control and can be measured quantitatively in terms of numerical applied energy to reflecting the pain level of each individual. The synthetized energy of each stimulation applied to the skin is also individually or multiplexed vectorized in a radar graph. In this manner is possible to show the differences between normal colour coded patterns of a pre set reference radar graph and the actually measured pain levels of the tested patient.

[00120]In this manner is possible to summarize and quantify visually in one single nomogram the deviation -if any- of each vector having altered length compared to reference value. The different pattern induced by the pain provides easy and intuitive characterization for objective follow up reports.

TENS = Vector Length equivalent to the parameter of a transcutaneous electrical stimulation;

VIBRATION = Vector Length equivalent to the parameter of the intensity of mechanical vibration;

COLD = Vector Length equivalent to the parameter of cold temperature applied with the Peltier Thermocouple

HEAT = Vector Length equivalent to the parameter heat temperature applied with the Peltier thermocouple

Heat - Cold = Vector Length equivalent to the parameter of time lag detection of temperature changes;

Tens&COLD = Vector attenuation of cold or tens induced sensitivity;

T.o.F.: Train of Four (or more) electrical pulses detected on hyper-algetic skin segments;