Transcutaneous auricular vagus nerve stimulation

Abstract

A TENS device (100) comprises connection port(s) (110, 112, 115) configured to be electrically connected to cymba concha and cavum concha electrodes (220, 230) of a taVNS device (200) The TENS device (100) comprises a pulse generator (140) connected to the connection port(s) (110, 112, 115) and arranged to generate adjustable electrical stimulations pulses to be applied over the cymba concha and cavum concha electrodes (220, 230). A controller (150) of the TENS device (100) is configured to adjust, in response to activation of a user input (120), a stimulation parameter of the adjustable electrical stimulation pulses generated by the pulse generator (140) during a treatment session, store, in a memory (160), treatment information comprising settings of the stimulation parameter, retrieve, in response to activation of the user input (120), the treatment information from the memory (160) and control the pulse generator (140) to generate, during a subsequent treatment session, adjustable electrical stimulation pulses according to the settings of the stimulation parameter comprised in the retrieved treatment information.

Description

[0001] TRANSCUTANEOUS AURICULAR VAGUS NERVE STIMULATION

[0002] TECHNICAL FIELD

[0003] The present invention generally relates to transcutaneous auricular vagus nerve stimulation (taVNS), and in particular to a transcutaneous electrical nerve stimulation (TENS) device for such taVNS.

[0004] BACKGROUND

[0005] The vagus nerves play a major role in maintaining autonomic tone throughout the brain, thorax and abdomen. Electrical vagus nerve stimulation (VNS) is currently authorized for drug-resistant epilepsy, major depression and morbid obesity. Such VNS is conducted in the form of a cervical implantable device. VNS implantation requires a surgical procedure that positions the lead wire at the cervical portion of the trunk of the left vagus nerve while the pulse generator is inserted subcutaneously in a pocket created in the upper chest. The most common adverse effects of implanted VNS devices are related to the surgical intervention at implantation. Laryngo-tracheal dysfunction, which is related to the stimulation of the inferior recurrent laryngeal nerve, occurs in approximately two thirds of cohorts treated for epilepsy and is usually transient. But there are also other surgical challenges including electrode fracture, dislocation, generator malfunction, wound infection, recurrent laryngeal nerve palsy and cardiac arrhythmias under test stimulation.

[0006] An attractive and promising approach to circumvent the caveats of invasive VNS in humans is to use VNS engendered by an external pulse generator. Two types of transcutaneous VNS have been developed: transcutaneous cervical VNS (tcVNS) and transcutaneous auricular VNS (taVNS). tcVNS can be accomplished by delivering an electrical signal to the cervical vagus nerve, situated within the carotid sheath posterolateral to the internal and common carotid arteries and medial to the internal jugular vein, with electrodes placed on the skin covering the sternocleidomastoid muscle. Although implanted electrodes for VNS are positioned at a similar location, the position of the vagus nerve beneath the skin, superficial fascia and sternocleidomastoid muscle makes the transcutaneous electrical stimulation of the vagus fibers difficult to access with current bioelectronic devices most likely stimulating both afferent and efferent fibers in the vagus nerve bundle.

[0007] The auricular branch of the vagus nerve projects sensory input to the brain stem nucleus tractus solitarius (NTS), which receives approximately 95% of all vagal afferents. The NTS projects to numerous areas in forebrain, amygdala, hippocampal, limbic and brainstem structures including the nucleus ambiguus, the locus coeruleus and the dorsal motor nucleus, which promotes motor outflow of the vagus nerve. Functional magnetic resonance imaging (fMRI) studies in humans verify that the central projections of the auricular branch of the vagus nerve are consistent with the vagal projections activated after invasive VNS and can be accessed non-invasively via the external ear in taVNS. taVNS, generally performed at home, is accomplished using a small battery-powered hand-held stimulating device generating pulsed electrical currents, which are delivered via skin electrodes in the auricle.

[0008] Shortcomings of these handheld taVNS devices is to accurately deliver the stimulation pulses at correct positions in the auricle, and provide sufficient electrical contact between the stimulation electrodes and the skin during the complete stimulation session.

[0009] US 2022 / 0143390 discloses a multi-electrode ear shell including an inner surface and an outer surface. The inner surface corresponds to a surface of an ear and is configured to overlap a cymba and a cavum of the ear. The multi-electrode ear shell further includes multiple sockets configured to receive stimulation electrodes that can be in contact to various locations including the cymba, cavum, crus of helix, antihelix, tragus, auricular acupuncture points, and the like. A conductive gel is applied on the skin of the ear to provide sufficient electrical contact between the stimulation electrodes and the skin.

[0010] WO 2024 / 093757 discloses a neurostimulation device that is wearable by a user to stimulate the auricular branch of vagus nerve (ABVN) of the user’s ear. The device is wireless and comprises at least one electrode designed to be located in the cymba conchae for stimulation of the ramus auricularis nervi vagi (RANV) when an electrical voltage difference is applied. A neurostimulation system comprising the neurostimulation device and a controller unit is disclosed. The neurostimulation system has at least one detector configured to detect one or more parameter values. The controller unit can then set one or more parameters of the stimulation pulse delivered by the neurostimulation device based on the detected one or more parameter values.

[0011] There is still a need for a TENS device that can be used together with a taVNS device to achieve taVNS. There is, in particular, a need for such a TENS device that can deliver stimulation pulses in accordance with the user’s preferences.

[0012] SUMMARY

[0013] It is a general objective to provide a TENS device that can deliver stimulation pulses in accordance with the user’s preferences. This and other objectives are met by embodiments disclosed herein.

[0014] The present invention is defined in the independent claim. Further embodiments of the invention are defined in the dependent claims.

[0015] An aspect of the invention relates to a TENS device comprising a cymba concha connection port configured to be electrically connected to a cymba concha electrode of a taVNS device and a cavum concha connection port configured to be electrically connected to a cavum concha electrode of the taVNS device, or a common cymba concha and cavum concha connection port configured to be electrically connected to the cymba concha electrode and the cavum concha electrode of the taVNS device. The TENS device also comprises a pulse generator connected to the cymba concha connection port and the cavum concha connection port, or the common cymba concha and cavum concha connection port and arranged to generate adjustable electrical stimulations pulses to be applied over the cymba concha electrode and the cavum concha electrode. The TENS device further comprises a user input, a memory and a controller configured to adjust, in response to activation of the user input, a stimulation parameter of the adjustable electrical stimulation pulses generated by the pulse generator during a treatment session. The controller is also configured to store, in the memory, treatment information comprising settings of the stimulation parameter of the adjustable electrical stimulation pulses generated by the pulse generator during the treatment session. The controller is further configured to retrieve, in response to activation of the user input, the treatment information from the memory, and control the pulse generator to generate, during a subsequent treatment session, adjustable electrical stimulation pulses according to the settings of the stimulation parameter comprised in the retrieved treatment information.

[0016] The TENS device records and stores adjustments of stimulation parameter(s) of the electrical stimulation pulses made by a user during a treatment session. The TENS device can then perform a subsequent treatment session with the same adjusted stimulation parameter(s) of the electrical stimulation pulses as previously selected by the user and recorded and stored for a past treatment session. The TENS device thereby facilitates repeating previously performed treatment sessions with previously user-adjusted stimulation parameter settings for the electrical stimulation pulses. The TENS device can thereby deliver stimulation pulses in accordance with the user’s preferences.

[0017] BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The embodiments, together with further objects and advantages thereof, may best be understood by making reference to the following description taken together with the accompanying drawings, in which: Fig. 1 illustrates a TENS device according to an embodiment;

[0019] Fig. 2 illustrates a TENS device according to another embodiment;

[0020] Fig. 3 illustrates a TENS device according to a further embodiment;

[0021] Fig. 4 illustrates a TENS device according yet another embodiment;

[0022] Fig. 5 schematically illustrates components of a TENS device according to an embodiment;

[0023] Fig. 6 illustrates a taVNS device 200 according to an embodiment;

[0024] Fig. 7 illustrates a taVNS device 200 according to another embodiment; and

[0025] Fig. 8 is a diagram illustrating adjustment of current settings of a TENS device during a treatment session.

[0026] DETAILED DESCRIPTION

[0027] The present invention generally relates to transcutaneous auricular vagus nerve stimulation (taVNS), and in particular to a transcutaneous electrical nerve stimulation (TENS) device for such taVNS.

[0028] A taVNS device can be used to provide transcutaneous auricular vagus nerve stimulation of a user, for instance, at home. This is achieved by placement of the stimulation electrodes at the correct stimulation sites in the external ear of the user. Electrical stimulations pulses are then generated by a TENS device connected to the taVNS device and delivered to the stimulation sites by the stimulation electrodes of the taVNS device to thereby stimulate the auricular branch of the vagus nerve.

[0029] TENS devices used for such taVNS could be static or adjustable. The former generates non-adjustable electrical stimulation pulses, such as electrical stimulation pulses having a preset current, pulse width, frequency and the number of electrical stimulation pulses per pulse burst. Such static TENS devices, however, suffer from the shortcoming of not being able to adjust the electrical stimulation pulses and thereby the treatment session to the particular user, i.e., human subject. Generally, the settings of the electrical stimulation pulses that are preferred to achieve an efficient stimulation of the auricular branch of the vagus nerve may differ from user to user. Furthermore, the preferred settings of the electrical stimulation pulses may also change over time for a given user, i.e., from one treatment session to another subsequent treatment session. Accordingly, it is generally preferred to use adjustable TENS devices, in which at least one stimulation parameter of the generated electrical stimulation pulses can be adjusted by the user.

[0030] A problem with adjustable TENS devices of the prior art is that it is hard and very cumbersome for the user to replicate a previously performed treatment session, during which the user has adjusted one or more stimulation parameters of the electrical stimulation pulses once or several times during the previous treatment session. In most cases, the adjustable TENS device starts a subsequent treatment session with default settings of the stimulation parameters or with the last settings of the stimulation parameters as adjusted by the user during the last treatment session. It is then up to the user to recall or recollect how he or she adjusted the stimulation parameters during the last treatment session. The prior art adjustable TENS devices are thereby not user friendly in terms of generating stimulation pulses in accordance with the user’s preferences.

[0031] The TENS device of the invention solves the above-mentioned shortcomings of prior art TENS devices, including adjustable TENS devices, by recording and storing the adjustments of stimulation parameter(s) of the electrical stimulation pulses made by a user during a treatment session. The TENS device of the invention can then perform a subsequent treatment session with the same adjusted stimulation parameter(s) of the electrical stimulation pulses as previously selected by the user and recorded and stored for a past treatment session. The TENS device thereby facilitates repeating previously performed treatment sessions with previously user-adjusted stimulation parameter settings for the electrical stimulation pulses.

[0032] The present invention relates to a TENS device 100, see Figs. 1-5, also referred to as stimulation device in the art. The TENS device 100 comprises, see Figs. 1 and 3, a cymba concha connection port 110 configured to be electrically connected to a cymba concha electrode 220 of a taVNS device 200, see Figs. 6-7, and a cavum concha connection port 112 configured to be electrically connected to a cavum concha electrode 230 of the taVNS device 200. Alternatively, the TENS device 100 comprises, see Figs. 2 and 4, a common cymba concha and cavum concha connection port 115 configured to be electrically connected to the cymba concha electrode 220 and the cavum concha electrode 230 of the taVNS device 200. The TENS device 100 also comprises a pulse generator 140 connected to the cymba concha connection port 110 and the cavum concha connection port 112 or the common cymba concha and cavum concha connection port 115 and arranged to generate adjustable electrical stimulations pulses to be applied over the cymba concha electrode 220 and the cavum concha electrode 230. The TENS device 100 further comprises a user input 120, a memory 160, and a controller 150 connected to the pulse generator 140, the user input 120 and the memory 160. The controller 150 is configured to adjust, in response to activation of the user input 120, a stimulation parameter of the adjustable electrical stimulation pulses generated by the pulse generator 140 during a treatment session. The controller 150 is also configured to store, in the memory 160, treatment information comprising settings of the stimulation parameter of the adjustable electrical stimulation pulses generated by the pulse generator 140 during the treatment session. The controller 150 is further configured to retrieve, in response to activation of the user input 120, the treatment information from the memory 160 and control the pulse generator 140 to generate, during a subsequent treatment session, adjustable electrical stimulation pulses according to the settings of the stimulation parameter comprised in the retrieved treatment information.

[0033] The TENS device 100, thus, comprises a user input 120, which the user can use to adjust a stimulation parameter of the adjustable electrical stimulation pulses generated by the pulse generator 140. The user input 120 could be in the form of one or more keys 122, 124 as shown in Figs. 1-4. Other examples of user input 120 include a touch-sensitive screen or display 130 or indeed any input that can be activated by the user to adjust the stimulation parameter.

[0034] As an illustrative, but non-limiting, example the user input 120 could include a first key 122, or a first area of a touch-sensitive screen or display 130, that can be activated by the user to increase a value of the stimulation parameter of the adjustable electrical stimulation pulses and a second key 124, or a second area of the touch-sensitive screen or display 130, that can be activated by the user to decrease a value of the stimulation parameter.

[0035] The controller 150 thereby adjusts, in real-time during an ongoing stimulation or treatment session, the stimulation parameter of the adjustable electrical stimulation pulses generated by the pulse generator 140 in response to activation of the user input 120. The controller 150 further stores treatment information comprising settings of the stimulation parameter in the memory 160 to thereby be available therein after the end of the treatment session. This means that the user can select, for a subsequent treatment session, to repeat a previously performed treatment session including any adjustments of the stimulation parameter of the adjustable electrical stimulation pulses since the treatment information generated for the previously performed treatment session is stored in the memory 160. The controller 150 thereby retrieves the stored treatment information from the memory 160 in response to activation of the user input 120 and control the pulse generator 140 to generate, during the subsequent treatment session, adjustable electrical stimulation pulses according to the settings of the stimulation parameter used during the previously performed treatment session and comprised in the retrieved treatment information.

[0036] In an embodiment, the user of the TENS device 100 preferably has the option to perform a subsequent treatment session using the same settings of the stimulation parameter as were used during a previously performed treatment session or perform the subsequent treatment session with default settings of the TENS device 100, which may be adjusted during the subsequent treatment session by the user by activating the user input 120.

[0037] Thus, in an embodiment, the controller 150 is configured to retrieve, in response to a first activation of the user input 120, the treatment information from the memory160 and control the pulse generator 140 to generate, during the subsequent treatment session, adjustable electrical stimulation pulses according to the settings of the stimulation parameter comprised in the retrieved treatment information. In this embodiment, the controller 150 is also configured to, in response to a second activation of the user input 120, control the pulse generator 140 to generate, during the subsequent treatment session, adjustable electrical stimulation pulses according to default settings of the stimulation parameter.

[0038] The user then has the option for a subsequent treatment session to thereby repeat a previously performed treatment session or perform the subsequent treatment session using default settings of the stimulation parameter by either doing a first or second activation of the user input 120. First and second activation of the user input 120 as used herein could be in the form of activating different keys 126, 128 of the user input 120 or activating different areas of a touch-sensitive screen 130.

[0039] If the user decides not to repeat the previously performed treatment session, then the controller 150 preferably records the subsequent treatment session by storing, in the memory 160, treatment information comprising settings of the stimulation parameter of the adjustable electrical stimulation pulses generated by the pulse generator 140 during the subsequent treatment session.

[0040] The memory 160 could be configured to store treatment information comprising settings of the stimulation parameter during one treatment session or treatment information for multiple treatment sessions. In the former case, the treatment information could be the settings used in the most recent treatment session. In the latter case, the memory 160 could store treatment information for all or at least a subset of previously performed treatment sessions. In such a case, the user can use the user input 120 to select which treatment information to retrieve from the memory 160 and to use during the subsequent treatment session. In other words, the user can select among previously performed treatment sessions and the settings of the stimulation parameters used during these treatment sessions and then select one of them to be repeated during a subsequent treatment session.

[0041] In an embodiment, the controller 150 is configured to determine, at each sampling occasion of a plurality of sampling occasions during the treatment session, a current setting of the stimulation parameter. The controller 150 is also, in this embodiment, configured to generate the treatment information based on the determined current setting of the simulation parameter.

[0042] In this embodiment, a treatment session is divided into a number of sampling intervals and thereby a number of sampling occasions, at which the controller 150 reads or determines a current setting of the stimulation parameter. As an example, the controller 150 could be configured to sample the setting of the stimulation parameter at a pre-defined sampling frequency, such as every Xthsecond for some positive value of X, such as 0.25, 0.5, 0.75, 1 , 1.5, 2, 2.5, 3, 4, 5, 6, 7, 8, 9, 10, 12.5, 15, 17.5, 20, 25, 30, 45, 60, or indeed some other value larger than zero. In such a case, a number of such current settings of the stimulation parameter are determined during a treatment session. For instance, assume that the treatment session has a duration of Y minutes, for some positive value of Y, such as 1 , 2, 3, 4, 5, 6, 7, 8, 9, 10, or indeed some other positive value, then Yx60 / X settings of the stimulation parameters are determined by the controller 150 during the treatment session. The treatment information can then be generated based on these Yx60 / X settings of the stimulation parameters, such as in the form of an array or vector of Yx60 / X stimulation parameter values. As an example, assume that a current setting or value of the stimulation parameter is Pk for some value k=1...Yx60 / X, then the treatment information could comprise the settings or values Pi, P2, ..., PYX6O / X.

[0043] In another embodiment, the controller 150 is configured to pairwise compare successively determined or sampled values or settings of the stimulation parameter, i.e., compare Pk with Pk+1. In such an embodiment, the controller 150 merely needs to store a setting of the stimulation parameter Pk+1 if it is different from the previous setting of the stimulation parameter Pk. As an example, assume the following five values of the stimulation parameter at sampling occasions 1 to 5: Pi = 1 mA, P2 = 1 mA, P3 = 1 .5 mA, P4 = 1 .5 mA, P5 = 1.5 mA. In such an example, Pi=P2, P2^Ps, Ps=P , and P =Ps. In such an example, it is sufficient to store the settings Pi and P3 in the memory 160 as long as the treatment information then comprises information enabling determination of the time point of change from setting Pi to setting P3 during the treatment session. Such information could, for instance, be the sampling occasion or number for P3, i.e., 3 in this illustrative example.

[0044] In a further embodiment, the controller 150 is configured to determine, in response to activation of the user input 120, a time interval from a start of the treatment session to a time point of adjusting a setting of the stimulation parameter. The controller 150, is in this embodiment, also configured to determine the treatment information based on the determined time interval(s) and the adjusted setting(s) of the stimulation parameter. Such an embodiment is schematically illustrated in Fig. 8.

[0045] Fig. 8 is a diagram illustrating adjustment of current settings of a TENS device during a treatment session. The treatment session starts at time point tO and ends at time point tE. During the treatment session, the user changes the setting of a stimulation parameter as represented by current of the adjustable electrical stimulation pulses at time points t1 , between time points t2 and t3 and at a time point t4. Thus, the treatment session starts with a default current 11 at tO. At time point t1 , the user uses the user input 120 to increase the current from 11 to I2. The user then gradually increases the current of the adjustable electrical stimulation pulses from I2 to I3 during the time interval from t2 up to t3. Finally, the user reduces the current down to IO at time point t4 and then ends the treatment session at tE.

[0046] In such an example, the controller 150 could be configured to determine the treatment information to define that the current 11 is used during the time interval t1-tO, the current is increased to I2 at t1 and maintained at I2 during the time interval t2-t1 , the current is increased to I3 during the time interval t3-t2, the current is maintained at I3 during the time interval t4-t3, and the current is reduced to IO at t4 and maintained at IO during the time interval tE-t4.

[0047] In an embodiment, the stimulation parameter is selected from the group consisting of current of the adjustable electrical stimulation pulses, pulse width of the adjustable electrical stimulation pulses, frequency of the adjustable electrical stimulation pulses, and number of adjustable electrical stimulation pulses per pulse burst.

[0048] In an embodiment, only one of the above-mentioned stimulation parameters is adjustable for the electrical stimulation pulses, such as the current of the adjustable electrical stimulation pulses. In another embodiment, multiple, i.e., at least two, of the stimulation parameters are adjustable. In such an embodiment, the user can use the user input 120 to adjust one or more stimulation parameters of the adjustable electrical stimulation pulses generated by the pulser generator 140 during the treatment session. The controller 150 then stores, in the memory 160, treatment information comprising settings of the one or more stimulation parameters of the adjustable electrical stimulation pulses generated by the pulse generator 140 during the treatment session. Thus, in such an embodiment, the treatment information could comprise settings of more than one stimulation parameter. In a preferred embodiment, the treatment information comprises settings of all stimulation parameters that are adjustable by the user by activation of the user input 120. Thus, in an embodiment, the adjustable stimulation parameters are two of, three of or indeed all four of current of the adjustable electrical stimulation pulses, pulse width of the adjustable electrical stimulation pulses, frequency of the adjustable electrical stimulation pulses, and number of adjustable electrical stimulation pulses per pulse burst.

[0049] In a preferred embodiment, the stimulation parameter is current of the adjustable electrical stimulation pulses.

[0050] In an embodiment, the controller 150 is configured to determine a duration of the treatment session. In this embodiment, the controller 150 is also configured to determine the treatment information based on the determined duration of the treatment session. As an example and with reference to Fig. 8, the controller 150 could be configured determine the duration based on the start time point tO and the end time point tE, i.e., the duration being tE-tO.

[0051] In an embodiment, the TENS device 100 comprises the cymba concha connection port 110 and the cavum concha connection port 112 as shown in Fig. 1 .

[0052] In another embodiment, the TENS device comprises the common cymba concha and cavum concha connection port 115 as shown in Fig. 2.

[0053] The embodiments of the TENS device 100 shown in Figs. 1 and 2 are configured to be used in connection with a taVNS device 200 as shown in Fig. 6 comprising an electrode support 210 with a cymba concha electrode 220 and a cavum concha electrode 230. Fig. 7 illustrates another taVNS device 200 comprising a first electrode support 210A with a first cymba concha electrode 220A and a first cavum concha electrode 230A and a second electrode support 210B with a second cymba concha electrode 220B and a second cavum concha electrode 230B. A TENS device 100 configured to be used in connection with the taVNS device 200 as shown in Fig. 7 is illustrated in Figs. 3 and 4. In such an embodiment, the cymba concha connection port 110 of the TENS device 100 as shown in Fig. 3 is a first cymba concha connection port 110 configured to be electrically connected to a first cymba concha electrode 220A of the taVNS device 200 and the cavum concha connection port 112 is a first cavum concha connection port 112 configured to be electrically connected to a first cavum concha electrode 230A of the taVNS device 200. The TENS device 100 in Fig. 3 further comprises a second cymba concha connection port 114 configured to be electrically connected to a second cymba concha electrode 220B of the taVNS device 200 and a second cavum concha connection port 116 configured to be electrically connected to a second cavum concha electrode 230B of the taVNS device 200.

[0054] Correspondingly, the common cymba concha and cavum concha connection port 115 of the TENS device 100 as shown in Fig. 4 is a first common cymba concha and cavum concha connection port 115 configured to be electrically connected to the first cymba concha electrode 220A and the first cavum concha electrode 230A of the taVNS device 200. The TENS device 100 in Fig. 4 further comprises a second common cymba concha and cavum concha connection port 117 configured to be electrically connected to the second cymba concha electrode 220B and the second cavum concha electrode 230B of the taVNS device 200.

[0055] The TENS device 100 as shown in Figs. 1 and 2 and configured to be used with a taVNS device 200 as shown in Fig. 6 enables transcutaneous auricular vagus nerve stimulation atone ear of the user, whereas the TENS device 100 as shown in Figs. 3 and 4 and configured to be used with a taVNS device 200 as shown in Fig. 7 enables simultaneous transcutaneous auricular vagus nerve stimulation at both ears of the user.

[0056] The embodiments of the invention therefore also relate to a TENS system comprising a taVNS device 200 and a TENS device 100 according to any of the embodiments. The taVNS device 200 comprises an electrode support 210, a cymba concha electrode 220 attached to and protruding from the electrode support 210 and configured to be in contact with skin in cymba concha of an ear of a human subject, and a cavum concha electrode 230 attached to and protruding from the electrode support 210 and configured to be in contact with skin in cavum concha of the ear of the human subject. The taVNS device 200 also comprises an elastic headband 240 attached to the electrode support 210 and configured, when attached to a head of the human subject, to exert a pressure onto the electrode support 210 to press the cymba concha electrode 220 towards the skin in cymba concha of the ear of the human subject, and the cavum concha electrode 230 onto the skin in cavum concha of the ear of the human subject. A taVNS device 200 as shown in Fig. 6 is disclosed in WO 2024 / 228655.

[0057] The electrode support 210 of the taVNS system 200 shown in Fig. 6 does not comprise any other electrodes than the cymba concha electrode 220 and the cavum concha electrode 230.

[0058] The electrode support 210 of the taVNS device 200 thereby only contains two electrodes, i.e., the cymba concha electrode 220 and the cavum concha electrode 230. The design of the taVNS device 200 enables a correct positioning of these electrodes 220, 230 in contact with the skin at the cymba concha and cavum concha, respectively, of the ear. Furthermore, the positions of the two electrodes 220, 230 at the electrode support 210 is preferably fixed in terms of not being adjustable along the length or width of the electrode support 210. However, the protrusion of one or both electrodes 220, 230 from the electrode support 210 is preferably adjustable as will be further described herein.

[0059] The cymba concha electrode 220 and the cavum concha electrode 230 are made of an electrically conducting material, preferably an electrically conducting metal or metal alloy. The electrically conducting material, preferably electrically conducting metal or metal alloy, should not only have good electrical conductivity but should also preferably be biologically acceptable. Electrically conducting metals and metal alloys generally have a resistivity at 20°C in the order of 10’8Qm and thereby an electrical conductivity at 20°C in the order of 106-107S / m. In a particular embodiment, the electrically conducting material, preferably electrically conducting metal or metal alloy, of the electrodes 220, 230 has an electrical conductivity of at least 106S / m, preferably at least 0.5x107S / m, and more preferably at least 107S / m at 20°C. More preferably, the electrically conducting material, preferably electrically conducting metal or metal alloy, has an electrical conductivity at 20°C of at least 3x 107S / m.

[0060] Biologically acceptable or biologically tolerant as used herein indicates that the electrically conducting material, preferably electrically conducting metal or metal alloy, does not cause any significant deleterious effects to the skin in the ear when the electrodes 220, 230 are in contact with the skin in cymba concha and cavum concha during the duration of a treatment session. In particular, the electrically conducting material, preferably electrically conducting metal or metal alloy, should not cause any significant skin irritation during such normal use of the taVNS device 200.

[0061] Currently preferred electrically conducting materials include aluminum and aluminum alloys. Aluminum has a resistivity of 2.65x1 O’8Qm and an electrical conductivity of 3.77x107S / m at 20°C. In an embodiment, the cymba concha electrode 220 is made of aluminum or an aluminum alloy or comprises an electrode surface 221 made of aluminum or the aluminum alloy. Alternatively, or preferably in addition, the cavum concha electrode 230 is made of aluminum or an aluminum alloy or comprises an electrode surface 231 made of aluminum of the aluminum alloy. In a preferred embodiment, the cymba concha electrode 220 and the cavum concha electrode 230 are made of aluminum or comprise a respective electrode surface 221 , 231 made of aluminum.

[0062] Other metals and metal alloys that could be used for the electrodes 220, 230 or at least the electrode surfaces 221 , 231 include gold and silver and alloys thereof.

[0063] The electrodes 220, 230 may be made of a single metal or metal alloy, preferably aluminum or an aluminum alloy. For instance, the electrodes 220, 230 could be solid electrodes consisting of the single metal or metal alloy. Alternatively, the electrodes 220, 230 could comprise an electrically conducting core material, preferably an electrically conducting metal or metal alloy, and then comprising an electrode surface 221 , 231 made of another electrically conducting material, preferably another electrically conducting metal or metal alloy. The electrode surface 221 , 231 could then be in the form an electrically conducting coating or surface layer on the electrode core. As an example, the electrode core could be made of copper or an alloy thereof.

[0064] The electrically conducting material of the electrode core does then not necessarily have to be biologically acceptable since it will not be in direct contact with the skin of the human subject. Thus, electrically conducting material, preferably electrically conducting metals or metal alloys, having a high electrically conductivity but not necessary biologically acceptable could be used as electrode core material.

[0065] In a preferred embodiment, the cymba concha electrode 220 and the cavum concha electrode 230 are made of the same electrically conducting material or materials. Hence, both electrodes 220, 230 are preferably solid electrodes made of a single electrically conducting material, preferably a single electrically conducting metal or metal alloy, or both electrodes 220, 230 comprise an electrically conducting core material, preferably an electrically conducting metal or metal alloy, and an electrode surface 221 , 231 made of another electrically conducting material, preferably another electrically conducting metal or metal alloy. In an embodiment, the cymba concha electrode 220 is configured to be in direct physical contact with the skin in the cymba concha of the ear of the human subject and the cavum concha electrode 230 is configured to be in direct physical contact with the skin in the cavum concha of the ear of the human subject.

[0066] Hence, the two electrodes 220, 230 of the electrode support 210 are configured to be not only in electrical contact with but also direct physical contact with the skin in the cymba concha and cavum concha, respectively. In particular, the respective electrode surface 221 , 231 of the electrodes 220, 230 is configured to be in direct physical contact and electrical contact with the skin in these regions (cymba concha and cavum concha, respectively) of the ear of the human subject.

[0067] Direct physical contact as used herein means that the electrodes 220, 230, or rather the electrode surface 221 , 231 , directly contacts and touches the skin in cymba concha and cavum concha, respectively. Accordingly, no intermediate medium, including an electrically conducting gel, is used to mediate the electrical contact between the electrodes 220, 230 and the skin.

[0068] In an embodiment, the cymba concha electrode 220 comprises an electrode body 223 in electrical contact with a power cord 250 and a hemispherical electrode head 222 comprising an electrode surface 221 configured to be in contact with the skin the cymba concha of the ear of the human subject.

[0069] In an embodiment, the electrode body 223 could be in the form of a cylinder having the hemispherical electrode head 222 at one of its ends and the other, opposite end facing the electrode support 210. Such a design of the cymba concha electrode 220 provides a smooth hemispherical electrode surface 221 touching the skin at cymba concha while the electrode body 223 enables the hemispherical electrode head 222 to protrude into cymba concha while avoiding surrounding structures or regions in the ear that should not be electrically stimulated, such as the crus of helix, antihelix and inferior crus of antihelix.

[0070] In an embodiment, the cavum concha electrode 230 comprises an electrode body 233 in electrical contact with a power cord 252 and a hemispherical electrode head 232 comprising an electrode surface 231 configured to be in contact with the skin the cavum concha of the ear of the human subject.

[0071] In an embodiment, the electrode body 233 could be in the form of a cylinder having the hemispherical electrode head 232 at one of its ends and the other, opposite end facing the electrode support 210. Such a design of the cymba concha electrode 230 provides a smooth hemispherical electrode surface 231 touching the skin at cavum concha while the electrode body 233 enables the hemispherical electrode head 232 to protrude into cavum concha while avoiding surrounding structures or regions in the ear that should not be electrically stimulated, such as the crus of helix, tragus, and antitragus.

[0072] In an embodiment, the electrode body 233 of the cavum concha electrode 230 is attached to an adjustable electrode shaft. In such an embodiment, the adjustable electrode shaft is arranged to adjust a protrusion of the hemispherical electrode head 232 of the cavum concha electrode 230 relative the electrode support 110.

[0073] In this embodiment, the protrusion of the cymba concha electrode 230 relative the electrode support 210 is adjustable. This means that the distance between the end of the hemispherical electrode head 232 and thereby of the electrode surface 231 and the electrode support 210 could be adjusted so that electrode surface 231 correctly touches the skin in cavum concha when the elastic headband 240 is attached to the head of the human subject.

[0074] In a particular embodiment, the taVNS device 200 also comprises an adjustment screw 212 arranged at the electrode support 210 in contact with the adjustable electrode shaft 234. The adjustment screw 212 is then configured to attach the adjustable electrode shaft 234 at a selected position relative the electrode support 210.

[0075] In a preferred embodiment, the adjustment screw 212 can be screwed clockwise or counter-clockwise relative the electrode support 210. Turning the adjustment screw 212 one way, preferably clockwise, causes movement of the cavum concha electrode 230 further away from the electrode support 210, whereas turning the adjustment screw 212 the other way, preferably counter-clockwise, causes movement of the cavum concha electrode 230 towards the electrode support 210. Accordingly, the adjustment screw 212 can thereby be used to adjust the amount or level of protrusion of the cavum concha electrode 230, and in particular of the hemispherical electrode head 232, from the electrode support 210.

[0076] The embodiment shown in Fig. 6 enables adjustment of the protrusion of the cavum concha electrode 230. In another embodiment, the protrusion of the cymba concha electrode 220 from the electrode support 210 can be adjusted, for instance by an adjustment screw. In a further embodiment, the protrusions of both the cymba concha electrode 220 and cavum concha electrode 230 can be adjusted, preferably individually adjusted. In such an embodiment, the TENS device 200 preferably comprises two adjustment screws 212.

[0077] In Fig. 6, the power cord 250 interconnects the cymba concha electrode 220 and the TENS device 100, whereas the power cord 252 interconnects the cavum concha electrode 230 and the TENS device 100. In such a case, the power cord 250 is connectable to the cymba concha connection port 110 and the power cord 252 is connectable to the cavum concha connection port 112 of the TENS device 100 in Fig. 1.

[0078] I n another embodiment, the taVNS device 200 has a common power cord for the cymba concha electrode 220 and the cavum concha electrode 230. In such an embodiment, this common power cord is connectable to the common cymba concha and cavum concha connection port 115 of the TENS device 100 in Fig. 2.

[0079] The electrode support 210 of the taVNS device 200 is designed to be positioned external of the outer ear of the human subject when the electrodes 220, 230 are in contact with the skin of the cymba concha and cavum concha, respectively. In a typical embodiment, the electrode support 210 is configured to be aligned with at least a portion of the external ear of the human subject when the elastic headband 240 is attached to the head of the human subject. However, the electrode support 210 is preferably present outside of the external ear, i.e. , not in the form of an ear shell to be attached inside the external ear.

[0080] In an embodiment, the electrodes 220, 230 are attached to and protrude from an inner surface of the electrode support 210. This inner surface of the electrode support 210 is thereby facing the external ear of the human subject when the elastic headband 240 is attached to the head of the human subject. The inner surface is preferably a flat surface, i.e., does not correspond to a surface of the ear.

[0081] The taVNS device 200 comprises an elastic headband 240 attached to the electrode support 210. The elastic headband 240 is designed to be attached to the head of the human subject. At such a position on the head, the electrode support 210 will be aligned with one external or outer ear of the human subject, i.e., the right ear or the left ear, preferably the left ear. Furthermore, at such a position the cymba concha electrode 220 will be aligned with the cymba concha and the cavum concha electrode 230 will be aligned with cavum concha of the ear. The headband 240 is elastic to enable it to be attached to the head of the human subject but is preferably made of or comprises a rigid material that is capable of exerting an inward pressure or force on the electrode support 210 against the ear of the human subject. The headband 240 comprises an over-head band or piece 242 designed to run over and on top of a least a portion of the head of the human subject. The headband 240 may optionally be held in position against the head of the human subject by a retention device 244. In such a case, the retention device 244 is preferably arranged at one end of the over-head band 242 with the electrode support 210 arranged at the other end of the over-head band 242. The retention device 244 will not only provide a comfortable contact with the side of the head preferably at a position above the non-stimulated ear but may also help balance the headband 240 on the head of the human subject. Hence, the retention device 244 could provide a counterweight to at least partly balance the weight of the electrode support 210.

[0082] The elastic headband 240 may be attached to the electrode support 210 or may be integrally formed with the electrode support 210. In the latter case, the elastic headband 240, or at least the over-head band 242 thereof, and the electrode support 210 form a monolithic unit.

[0083] The headband 240 may optionally include an adjustment mechanism for fitting the headband 240 to the head of the human subject. Such an adjustment mechanism can then be used to adjust the size of the headband 240 to different head sizes. Furthermore, the adjustment mechanism could be used to adjust the pressure exerted by the headband 240 onto the electrode support 210 to press the electrodes 220, 230 attached to and protruding from the electrode support 210 in physical contact with the skin in the cymba concha and cavum concha of the ear. An illustrative, but non-limiting, example of such an adjustment mechanism is to include telescoping sections to extend or retract the ends of the elastic headband 240. Such telescoping sections could then be lockable using well-known solutions, such as friction or rachet brakes.

[0084] In an embodiment, the TENS system comprises a taVNS device 200 as shown in Fig. 7. In such an embodiment, the taVNS device 200 comprises a first electrode support 210A, a first cymba concha electrode 220A attached to and protruding from the first electrode support 210A and configured to be in contact with skin in cymba concha of a first ear of the human subject, and a first cavum concha electrode 230 attached to and protruding from the first electrode support 210A and configured to be in contact with skin in cavum concha of the first ear of the human subject. The taVNS device 200 also comprises a second electrode support 210B, a second cymba concha electrode 220B attached to and protruding from the second electrode support 210B and configured to be in contact with skin in cymba concha of a second ear of the human subject and a second cavum concha electrode 230B attached to and protruding from the second electrode support 210B and configured to be in contact with skin in cavum concha of the second ear of the human subject. The elastic headband 240 is then attached to the first electrode support 21 OA and the second electrode support 21 OB and configured, when attached to a head of the human subject, to exert a pressure onto the first electrode support 21 OA and the second electrode support 21 OB to press the first cymba concha electrode 220A towards the skin in cymba concha of the first ear of the human subject, the first cavum concha electrode 230A onto the skin in cavum concha of the first ear of the human subject, the second cymba concha electrode 220B towards the skin in cymba concha of the second ear of the human subject, and the second cavum concha electrode 230B onto the skin in cavum concha of the second ear of the human subject.

[0085] In an embodiment, the taVNS device 200 comprises a first cymba concha power cord 250A connectable to the first cymba concha connection port 110 of the TENS device 100 shown in Fig. 3, a first cavum concha power cord 252A connectable to the first cavum concha connection port 112 of the TENS device 100, a second cymba concha power cord 250B connectable to the second cymba concha connection port 114 of the TENS device 100 shown in Fig. 3, and a second cavum concha power cord 252B connectable to the second cavum concha connection port 116 of the TENS device 100.

[0086] In another embodiment, the taVNS device 200 has a first common power cord for the first cymba concha electrode 220A and the first cavum concha electrode 230A and a second common power cord for the second cymba concha electrode 220B and the second cavum concha electrode 230B. In such an embodiment, this first common power cord is connectable to the first common cymba concha and cavum concha connection port 115 of the TENS device 100 in Fig. 4 and the second common power cord is connectable to the second common cymba concha and cavum concha connection port 117 of the TENS device 100.

[0087] The various embodiments described in the foregoing in connection to Fig. 6 also apply for the taVNS device 200 as shown in Fig. 7.

[0088] The TENS system of the invention could be applied to treat various medical conditions, which would benefit from taVNS. Illustrative, but non-limiting, examples of such medical conditions include epilepsy, depression, obesity, migraine, cluster headaches, insomnia, neuropathic pain, back pain, chronic pain, cognitive decline, inflammatory diseases, such as rheumatoid arthritis, Crohn’s disease, ulcerative colitis, systemic lupus erythematosus (SLE), multiple sclerosis and Alzheimer’s disease. The embodiments described above are to be understood as a few illustrative examples of the present invention. It will be understood by those skilled in the art that various modifications, combinations and changes may be made to the embodiments without departing from the scope of the present invention. In particular, different part solutions in the different embodiments can be combined in other configurations, where technically possible.

Claims

CLAIMS1 . A transcutaneous electrical nerve stimulation, TENS, device (100) comprising: ia) a cymba concha connection port (110) configured to be electrically connected to a cymba concha electrode (220) of a transcutaneous auricular vagus nerve stimulation, taVNS, device (200); and ib) a cavum concha connection port (112) configured to be electrically connected to a cavum concha electrode (230) of the taVNS device (200); or ii) a common cymba concha and cavum concha connection port (115) configured to be electrically connected to the cymba concha electrode (220) and the cavum concha electrode (230) of the taVNS device (200); a pulse generator (140) connected to the cymba concha connection port (110) and the cavum concha connection port (112) or the common cymba concha and cavum concha connection port (115) and arranged to generate adjustable electrical stimulations pulses to be applied over the cymba concha electrode (220) and the cavum concha electrode (230); a user input (120); a memory (160); and a controller (150) connected to the pulse generator (140), the user input (120) and the memory (160) and configured to: adjust, in response to activation of the user input (120), a stimulation parameter of the adjustable electrical stimulation pulses generated by the pulse generator (140) during a treatment session; store, in the memory (160), treatment information comprising settings of the stimulation parameter of the adjustable electrical stimulation pulses generated by the pulse generator (140) during the treatment session; retrieve, in response to activation of the user input (120), the treatment information from the memory (160); and control the pulse generator (140) to generate, during a subsequent treatment session, adjustable electrical stimulation pulses according to the settings of the stimulation parameter comprised in the retrieved treatment information.

2. The TENS device according to claim 1 , wherein the controller (150) is configured to: determine, at each sampling occasion of a plurality of sampling occasions during the treatment session, a current setting of the stimulation parameter; and generate the treatment information based on the determined current settings of the stimulation parameter.

3. The TENS device according to claim 1 , wherein the controller (150) is configured to: determine, in response to activation of the user input (120), a time interval from a start of the treatment session to a time point of adjusting a setting of the stimulation parameter; and determine the treatment information based on the determined time interval(s) and the adjusted setting(s) of the stimulation parameter.

4. The TENS device according to any one of claims 1 to 3, wherein the stimulation parameter is selected from the group consisting of current of the adjustable electrical stimulation pulses, pulse width of the adjustable electrical stimulation pulses, frequency of the adjustable electrical stimulation pulses, and number of adjustable electrical stimulation pulses per pulse burst.

5. The TENS device according to claim 4, wherein the stimulation parameter is current of the adjustable electrical stimulation pulses.

6. The TENS device according to any one of claims 1 to 6, wherein the controller (150) is configured to: determine a duration of the treatment session; and determine the treatment information based on the determined duration of the treatment session.

7. The TENS device according to any one of claims 1 to 6, wherein the TENS device (100) comprises: the cymba concha connection port (110); and the cavum concha connection port (112).

8. The TENS device according to any one of claims 1 to 6, wherein the TENS device (100) comprises the common cymba concha and cavum concha connection port (115).

9. The TENS device according to any one of claims 1 to 6, wherein ia) the cymba concha connection port (110) is a first cymba concha connection port (110) configured to be electrically connected to a first cymba concha electrode (220A) of the taVNS device (200); and ib) the cavum concha connection port (112) is a first cavum concha connection port (112) configured to be electrically connected to a first cavum concha electrode (230A) of the taVNS device (200); orii) the common cymba concha and cavum concha connection port (115) is a first common cymba concha and cavum concha connection port (115) configured to be electrically connected to the first cymba concha electrode (220A) and the first cavum concha electrode (230A) of the taVNS device (200); the TENS devices (100) further comprises: iiia) a second cymba concha connection port (114) configured to be electrically connected to a second cymba concha electrode (220B) of the taVNS device (200); and iiib) a second cavum concha connection port (116) configured to be electrically connected to a second cavum concha electrode (230B) of the taVNS device (200); or iv) a second common cymba concha and cavum concha connection port (117) configured to be electrically connected to the second cymba concha electrode (220B) and the second cavum concha electrode (230B) of the taVNS device (200).

10. A transcutaneous electrical nerve stimulation (TENS) system comprising: a transcutaneous auricular vagus nerve stimulation (taVNS) device (200) comprising: an electrode support (210); a cymba concha electrode (220) attached to and protruding from the electrode support (210) and configured to be in contact with skin in cymba concha of an ear of a human subject; a cavum concha electrode (230) attached to and protruding from the electrode support (210) and configured to be in contact with skin in cavum concha of the ear of the human subject; and an elastic headband (240) attached to the electrode support (210) and configured, when attached to a head of the human subject, to exert a pressure onto the electrode support (210) to press the cymba concha electrode (220) towards the skin in cymba concha of the ear of the human subject, and the cavum concha electrode (230) onto the skin in cavum concha of the ear of the human subject; and a transcutaneous electrical nerve stimulation (TENS) device (100) according to any one of claims 1 to 9.

11. The TENS system according to claim 10, wherein the electrode support (210) is a first electrode support (210A); the cymba concha electrode (220) is a first cymba concha electrode (220A) attached to and protruding from the first electrode support (210A) and configured to be in contact with skin in cymba concha of a first ear of the human subject;the cavum concha electrode (230) is a first cavum concha electrode (230) attached to and protruding from the first electrode support (21 OA) and configured to be in contact with skin in cavum concha of the first ear of the human subject; the taVNS device (200) further comprises: a second electrode support (21 OB); a second cymba concha electrode (220B) attached to and protruding from the second electrode support (21 OB) and configured to be in contact with skin in cymba concha of a second ear of the human subject; and a second cavum concha electrode (230B) attached to and protruding from the second electrode support (21 OB) and configured to be in contact with skin in cavum concha of the second ear of the human subject; the elastic headband (240) is attached to the first electrode support (210A) and the second electrode support (210B) and configured, when attached to a head of the human subject, to exert a pressure onto the first electrode support (210A) and the second electrode support (210B) to press the first cymba concha electrode (220A) towards the skin in cymba concha of the first ear of the human subject, the first cavum concha electrode (230A) onto the skin in cavum concha of the first ear of the human subject, the second cymba concha electrode (220B) towards the skin in cymba concha of the second ear of the human subject, and the second cavum concha electrode (230B) onto the skin in cavum concha of the second ear of the human subject; and the TENS device (100) is according to claim 9.

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