Stimulation unit for targeted application of a vibro-tactile stimulus

Abstract

In general, the present invention relates to neuromodulation. More particularly, the present invention relates to a stimulation unit for applying a vibro-tactile stimulus to a part of a body of a user. Such stimulation unit comprises a contactor for contacting the part of the body of the user and an oscillation assembly for guiding and accelerating the contactor along an oscillation direction, wherein the oscillation assembly is adapted to accelerate the contactor essentially along the oscillation direction only. The present invention also relates to devices comprising, and methods using, such stimulation units.

Description

[0001] August 26, 2025 curetec GmbH C175393WO KAU / Fim

[0002] Stimulation unit for targeted application of a vibro-tactile stimulus

[0003] 1. Technical Field

[0004] In general, the present invention relates to neuromodulation. More particularly, the present invention relates to a stimulation unit for applying a vibro-tactile stimulus to a part of a body of a user and devices comprising such stimulation units. Stimulation units and devices according to the present invention enable a particularly targeted application of vibro-tactile stimuli. Furthermore, the present invention relates to a method for providing vibro-tactile stimulation to a user, including a method using such stimulation units.

[0005] 2. Background

[0006] Numerous neurological and psychiatric diseases are characterized by abnormal neuronal activity. The aim of therapeutic neuromodulation procedures is to reduce this abnormal neuronal activity in a targeted manner with few side effects. In the case of pathologically increased synchronization between neurons, as can be observed in patients suffering from Parkinson’s disease, for example, a neuromodulation procedure is required that causes desynchronization of the affected area of the brain. For example, one may employ neuromodulation procedures which may disrupt synchronous activity by temporally staggered stimulation of different subpopulations of the affected area. These procedures are known under the name of Coordinated Reset, among others. In most cases, several stimulation sites are stimulated at different times and the stimulation pattern is repeated several times over several hours a day.

[0007] Coordinated Reset has been successfully deployed as direct invasive electrical stimulation of a patient’s brain - known as deep brain stimulation - in Parkinson’s patients (Adamchic et al. 2014 Movement Disorders). It has also been investigated in detail in animal studies (Tass et al. 2012 Annals in Neurology; Wang et al. 2016 Brain Stimulation). In these studies, rod-shaped electrodes of small diameter were used, which comprise several (usually 4-8) stimulation contacts that are positioned a few millimeters (e.g., o.5-1.5 mm) apart along the rod-shaped electrode. Said animal studies (Tass et al. 2012 Annals in Neurology) revealed that the effect of the stimulation may be significantly enhanced if neighboring stimulation contacts stimulate areas of the brain that are as different as possible and if there is only a small or even virtually no spatial overlap of the stimulated areas. This may be jeopardized, though, if the applied stimuli are too intense, since a more intense stimulus generally yields a stimulation of a larger area (activation range, e.g., a spherical or circular area with an activation radius of 5 mm). With a distance of 1.5 mm between the stimulation contacts, this in turn results in a stimulation of largely the same neuronal structures by the different stimulation contacts. Only a reduction of the stimulation intensity, i.e., a reduction of the stimulation intensity at each stimulation contact, yields a smaller activation range, which is in the order of magnitude of the distance between the stimulation contacts and in turn exhibits a good therapeutic effect. Precisely this effect was observed in the independent studies cited, with less intense stimulation having a significantly better effect (Tass et al. 2012 Annals in Neurology; Wang et al. 2016 Brain Stimulation).

[0008] The present invention seeks to exploit these findings for non-invasive therapeutic neuromodulation, in particular for non-invasive therapeutic neuromodulation employing vibro-tactile stimulation, which has thus far - if at all - only been possible with restrictions in the state of the art.

[0009] A particular example for this is the apparatus shown in Fig. 1A which was developed at For- schungszentrum Jiilich and is currently being clinically tested in the United States on behalf of Synergic Medical Technologies Inc. and Stanford University. The clinical tests appear promising (Syrkin-Nikolau et al. 2018, Pfeifer et al. 2021).

[0010] As can be seen, the apparatus comprises two devices for applying vibro-tactile stimulation to hands of a user, each of the two devices comprising a (mutually mirror-symmetric) glove-like shape (for a left and a right hand of the user, respectively). Each of the devices comprises four stimulation units for applying vibro-tactile stimuli to a respective finger of a hand of a user. As can be seen, in total, the devices shown in Fig. 1A are adapted to apply vibro-tactile stimuli to all fingers except the thumb of the hand of the user. (Hereinafter, the expression finger also refers to a thumb.) For ease of understanding, Fig. 1B shows a device similar to those shown in Fig. 1A, but as applied to a hand of a user and comprising only a single stimulation unit for applying vibro-tactile stimuli to an index finger of the hand of the user.

[0011] The stimulation units of this apparatus and its devices for applying vibro-tactile stimulation tend to couple mechanically during use. For example, when the user holds his / her fingers in a relaxed position, the (housings of the) stimulation units are in contact with each other. This may cause a vibro-tactile stimulus originating from one of the stimulation units to not only reach the respective finger to which that stimulation unit is applied, but also a neighboring finger to which another one of the stimulation units is applied, due to the mechanical coupling through contact between the housing of these two stimulation units. Such mechanical coupling may also arise, or may at least be reinforced, when the user places his / her hand, and with it the stimulation units, on an object such as a table or an armrest. As a result, there is (non-negligible) spatial overlap of the parts of the body (hand) of the user - and hence of the areas of the brain associated with these parts of the body (hand) of the user - that are stimulated by different stimulation units. Taking the findings from the above-discussed animal studies seriously, this overlap must be detrimental to stimulation results.

[0012] The present invention aims to address these and other shortcomings of the prior art.

[0013] 3. Summary

[0014] The present invention does so, inter alia, by providing a stimulation unit for applying a vibro- tactile stimulus to a part of a body of a user according to independent claim i. Such a stimulation unit comprises a contactor for contacting the part of the body of the user and an oscillation assembly for guiding and accelerating the contactor along an oscillation direction. In particular, the oscillation assembly is adapted to accelerate the contactor essentially along the oscillation direction only.

[0015] In particular, the oscillation assembly may be adapted to accelerate the contactor back and forth along the oscillation direction, such that the contactor oscillates along the oscillation direction. This may in turn apply a vibro-tactile stimulus to the part of the body of the user.

[0016] In the context of the present invention, accelerating the contactor essentially along the oscillation direction only means that the contactor is not accelerated and / or moved, or only accelerated and / or moved to a negligible extent, in any direction other than the oscillation direction. That is, the oscillation assembly may be adapted to accelerate the contactor such as to provide kinetic energy to the contactor, wherein less than io%, preferably less than 5%, more preferably less than 2%, most preferably less than 1% of the kinetic energy is associated with an acceleration and / or movement of the contactor perpendicular to the oscillation direction. Additionally or alternatively, the oscillation assembly may be adapted to accelerate the contactor such that a ratio between a maximum displacement of the contactor along the oscillation direction and a maximum displacement of the contactor perpendicular to the oscillation direction is at least io:i, more preferably at least 20:1, most preferably at least 50:1. In the context of the present invention, two directions may be considered perpendicular or essentially perpendicular if they comprise an angle between 750and 105 °, preferably between 850and 95 °, more preferably between 890and 91 °, most preferably between 89.90and 90.1 °.

[0017] Accelerating the contactor essentially along the oscillation direction only allows a very precise targeting of the contactor, and hence of the respective vibro-tactile stimulus the contactor is adapted to apply, onto the respective part of the body of the user. A spread and / or smearing of the vibro-tactile stimulus across the portion of the body of the user is avoided or at least minimized. This is already beneficial for stimulation results on its own, but particularly so when considering applications in which multiple stimulation units are applied to different parts of a body of a user. Since it allows the contactor, and hence the respective vibro-tactile stimulus the contactor is adapted to apply, to be targeted very precisely onto the respective part of the body of the user, the present invention in turn also allows to clearly separate, i.e., to minimize or even avoid any overlap of, different parts of the body of the user that receive vibro-tactile stimuli from respective different stimulation units. That is, using the present invention, it becomes possible to arrange stimulation units in a way that ensures that there is (virtually) no part of a body of a user that receives vibro-tactile stimuli from more than one stimulation unit, however without arranging the stimulation units at disadvantageously large mutual (anatomical) distances that would otherwise be necessary to provide tolerances for any spread and / or smearing of the vibro- tactile stimuli applied by the stimulation units. This translates to a more precise stimulation of areas of the brain that are, though neighboring, as different as possible, and / or to virtually no spatial overlap of the stimulated areas of the brain. As explained earlier, this provides for enhanced stimulation results.

[0018] In some embodiments, the stimulation unit may be adapted such that the oscillation direction is essentially perpendicular to the part of the body of the user (e.g., to a surface of the part of the body of the user) when the stimulation unit is applied to the user. This further enhances the targeting of the contactor, and hence of the respective vibro-tactile stimulus the contactor is adapted to apply, onto the respective part of the body of the user as the risk of a lateral slipping of the contactor is avoided. In this context, the expression lateral may refer to any direction other than the oscillation direction, in particular to any direction perpendicular to the oscillation direction. Thus, a spread and / or smearing of the vibro-tactile stimulus across the portion of the body of the user, if any, is further minimized. This in turn yields a targeted, non-diffuse stimulation sensation.

[0019] In some embodiments of the stimulation unit according to the present invention, the contactor may not be attached to the oscillation assembly and / or a housing of the stimulation unit. In some embodiments, the contactor may at least not be attached to the oscillation assembly and / or a housing of the stimulation unit via any elastic element. In particular, or alternatively, the oscillation assembly may not comprise any spring. Herein, a spring, or mechanical spring, is to be understood as an elastic element that stores mechanical energy when an opposing force is applied to it and that releases this mechanical energy when the opposing force is removed.

[0020] Would the contactor be attached (e.g., affixed) to the oscillation assembly and / or a housing of the stimulation unit, especially via an elastic element such as one or more springs of the oscillation assembly, an acceleration - and hence an oscillation and / or vibration - of the contactor, as well as of the oscillation assembly and / or of the housing, along a direction different than the oscillation direction, in particular perpendicular thereto, could hardly be avoided. In reality no attachment is perfectly symmetrical. Every attachment, every elastic element and every spring is subject to mechanical and / or assembly tolerances. For example, a (leaf) spring maybe made from sheet metal, which sheet metal however generally has different moduli of elasticity along its rolling direction as opposed to perpendicular thereto, which in turn yields asymmetrical properties of the (leaf) spring. The present invention addresses these issues, yielding stimulation units superior to those known in the prior art that prescribe the use of a spring. Measurements performed by one of the inventors have confirmed that, in terms of peak-to-peak deflection (of the contactor and / or of the housing of the stimulation unit), spring-based stimulation units from the prior art vibrate (oscillate) three to ten times as much perpendicular to the oscillation direction during use as compared to stimulation units according to the present invention.

[0021] In particular, the present invention provides stimulation units superior to those disclosed in US 7798 982 B2, which is the type of stimulation unit that the prior-art apparatus of Fig. 1A (and Fig. 1B) employs. Curiously, US 7798 982 B2 describes the use of a spring in a stimulation unit as advantageous precisely because it causes vibrations of the respective housing of the stimulation unit - which on the flipside however causes the disadvantageous mechanical coupling in the prior-art apparatus of Fig. 1A (and Fig. 1B) that was described further above. Theoretically, the vibrations of the housing caused by the use of a spring, as (exemplarily) described in US 7798 982 B2, could be countered by a high ratio between a mass of the housing and / or the oscillation assembly on the one hand and a mass of the contactor on the other. However, depending on the application, this may be undesirable, as it may render the stimulation unit less comfortable to wear. By (instead, optionally) dispensing with a spring and / or any other attachment of the contactor to the oscillation assembly and / or the housing, in particular via an elastic element, the present invention allows to keep a mass of the housing and / or the oscillation assembly and / or the contactor low. In a preferred embodiment, a housing and the oscillation assembly of the stimulation unit may comprise a mass between 5 g and 50 g, preferably between 10 g and 20 g, most preferably between 12.5 g and 15 g.

[0022] Dispensing with a spring and / or any other attachment of the contactor to the oscillation assembly and / or the housing, in particular via an elastic element, also reduces losses, in particular deformation losses that would otherwise occur in the spring and / or attachment (usually up to 30%).

[0023] Furthermore, dispensing with a spring and / or any other attachment of the contactor to the oscillation assembly and / or the housing, in particular via an elastic element, may avoid or at least minimize any post-pulse oscillation of the contactor that could adversely affect control and / or predictability of the stimulation. Although the (tissue of the) part of the body of the user to which the stimulation unit is to apply vibro-tactile stimuli serves as a damping element to some extent, the associated damping factor depends, inter alia, on the age of the user and on the daily mechanical load on the respective part of the body (consider the effect of muscles below and / or within the part of the body, callus formation, etc.) and therefore cannot reliably be taken into account.

[0024] In some embodiments, the oscillation assembly may be adapted to generate a magnetic field to guide and / or accelerate the contactor. To this end, the contactor may comprise one or more, preferably at least four, magnets, e.g., static magnets. This may allow to guide and / or accelerate the contactor along the oscillation direction without the need for any mechanical connection and / or attachment of the contactor to a housing of the stimulation unit and / or to the oscillation assembly. The contactor positions (centers) itself in the magnetic field and hence - a suitable arrangement of the oscillation assembly provided - along the oscillation direction. In a sense, the magnetic field functions as a magnetic (as opposed to a mechanical) spring. Besides, using a magnetic field to guide and / or accelerate the contactor increases controllability of the stimulation unit and the contactor, respectively. Especially as compared to, e.g., springbased stimulation units, a magnetic-field-based stimulation unit may react virtually immediately to control inputs. In particular, it may trigger and / or terminate any oscillation of the contactor without delay, i.e., with a virtually zero settling time and / or without any post-pulse oscillations.

[0025] To generate a magnetic field to guide and / or accelerate the contactor, the oscillation assembly may comprise one or more, preferably at least two or at least four, magnets, e.g., electromagnetic coils. Preferably, the oscillation assembly comprises an even number of magnets that are arranged symmetrically with respect to the contactor, e.g., mirror-symmetric with respect to at least one plane in which the contactor lies. Such symmetric architecture may help ensure that the contactor is accelerated essentially along the oscillation direction only.

[0026] Where the one or more magnets of the oscillation assembly comprise (or consist of) one or more electromagnetic coils, the one or more electromagnetic coils may comprise at least one core (e.g., a single core or a core each). Where there is an even number of electromagnetic coils, the electromagnetic coils may pairwise share a common core, e.g., a U-shaped common core whose ends extend through one of the electromagnetic coils each and point towards a plane in which the contactor lies.

[0027] In an embodiment, the oscillation assembly may comprise at least one rail oriented along the oscillation direction, wherein the contactor is arranged to slide along the at least one rail. Preferably, the at least one rail may be attached to a housing of the stimulation unit. Arranging the contactor in this manner (e.g., relative to the oscillation assembly and / or the housing of the stimulation unit) ensures that the contactor is free to move along the oscillation direction, while movements perpendicular to the oscillation direction are impeded, however without the need to attach the contactor to, or suspend it in, the oscillation assembly and / or the housing.

[0028] In some embodiments, a stimulation unit according to the present invention may be adapted to be applied to a finger of the user, specifically in that a housing of the stimulation unit comprises a concave surface for receiving the finger of the user. Therein, the oscillation assembly may then be arranged to accelerate the contactor through an aperture in the concave surface. The aperture may ensure that a primaiy tension is applied to the target surface of the finger when the finger is forced against the concave surface. Preferably, the concave surface may receive a palmar surface of the finger of the user, such that the contactor contacts the palmar surface of the finger (during use). Therein, the oscillation direction may then be essentially perpendicular to the palmar surface of the (tip of the) finger. Adapting the stimulation unit to be applied to a finger of the user may result in enhanced stimulation results and increased user comfort as well as usability when endeavoring to apply vibro- tactile stimulation to a hand and / or fingers of a user.

[0029] Studies surveyed by one of the inventors have found that it is preferable if the concave surface is characterized by a radius between io mm and 17 mm, preferably between 11.5 mm and 15.5 mm, most preferably between 13 mm and 14 mm. Meanwhile, the aperture may have a diameter between 5 mm and 10 mm, preferably between 6 mm and 9 mm, most preferably between 7 mm and 8 mm, whereas the contactor may comprise a diameter (perpendicular to the oscillation direction) between 2.5 mm and 7.5 mm, preferably between 3.5 mm and 6.5 mm, most preferably between 4.5 mm and 5.5 mm, as suitable with respect to the diameter of the aperture. Herein, the diameter of a given object is to be understood as the maximum distance between any two points on a perimeter of the object.

[0030] Similarly, studies surveyed by one of the inventors have found that it is preferable, additionally or alternatively, if the stimulation unit and / or the concave surface is adapted to receive the finger of the user such that the aperture is located within 3 mm, preferably within 1 mm from a midline of the finger of the user and / or between 5 mm and 15 mm, preferably between 7 mm and 13 mm, most preferably between 9.5 mm and 10.5 mm from a tip of the finger of the user.

[0031] Details on the studies mentioned here will be discussed in the detailed description below.

[0032] In some embodiments, a stimulation unit according to the present invention may comprise one or more sensors. For example, a stimulation unit according to the present invention may comprise a kinematic sensor for determining a position and / or an orientation of the stimulation unit, e.g., in three-dimensional space and / or relative to another stimulation unit. Inherently, the kinematic sensor is also for determining a position and / or an orientation of the part of the body of the user to which the stimulation unit is to be applied. The kinematic sensor may preferably be configured to provide, regularly, continuously or on demand, data on the position and / or the orientation, respectively, of the stimulation unit to a control unit. Additionally or alternatively, a stimulation unit according to the present invention may comprise an electrostatic sensor for interfacing with the part of the body of the user. Such electrostatic sensor may preferably be configured to provide, regularly, continuously or on demand, data on a state of at least the part of the body of the user to a control unit.

[0033] Such kinematic sensor and such electrostatic sensor may also be integrated, e.g., into a single sensor. An example of a sensor providing all of the above is sensor LSM6DS3TR-C manufactured by ST Micro.

[0034] The described sensors may facilitate the acquisition of data pertaining to symptoms, e.g., in patients with movement disorders, such as tremor, bradykinesia, rigidity and / or other symptoms. For example, the described sensors may be employed to evaluate the quality of gait and to monitor gait irregularities such as freezing of gait. The acquired data may be utilized in various ways.

[0035] For example, the acquired data maybe used to monitor an intensity of symptoms, in turn allowing to evaluate an effectiveness of the vibro-tactile stimulation applied. For example, the acquired data may be provided to (e.g., visualized for) the user or a health care professional to this end.

[0036] Additionally or alternatively, the acquired data may also enable enhanced stimulation protocol selection and / or adjustment. Such selection and / or adjustment maybe manual, e.g., by the user or a health care professional, or it maybe automatic. For instance, if complications related to bradykinesia are identified, a stimulation protocol designed to address these complications may be selected. Additionally or alternatively, if tremor-related issues are identified, a stimulation protocol designed to address these issues may be selected. Additionally or alternatively, if it is identified that the user is experiencing issues with gait, such as freezing of gait, a stimulation protocol may be selected that assists the user in overcoming these issues with gait. Generally, a stimulation protocol selected in such a way may be applied until another stimulation protocol is selected (e.g., because another complication and / or issue is identified) or for a pre-defined time.

[0037] Additionally or alternatively, the acquired data may also be used to control one or more stimulation parameters in a closed-loop fashion. For instance, a level of tremor, bradykinesia, rigidity and / or other symptoms maybe used to (e.g., continuously) control stimulation parameters, e.g., stimulation intensity or stimulation frequency. This may allow to provide demand-controlled stimulation. The kinematic sensor and / or the electrostatic sensor, or a sensor integrating both, may incorporate in-sensor artificial intelligence computing, enabling the identification of complex and diverse symptom aspects in-sensor, in turn reducing the workload at the control unit. Additionally or alternatively, the kinematic sensor and / or the electrostatic sensor, or a sensor integrating both, may incorporate rapid data logging, sensor-fusion capabilities, and / or analog input processing from further, external sensors. An example of a sensor providing all of the above is sensor ISM330BX manufactured by ST Micro.

[0038] Using stimulation units as just described, an enhanced version of the apparatus of Fig. 1A (and Fig. 1B) may be provided. Accordingly, to address the above-discussed shortcomings of this and similar prior-art apparatuses and / or prior-art devices for applying vibro-tactile stimulation, the present invention provides a device for applying vibro-tactile stimulation, comprising a glovelike shape and at least two stimulation units as described above, wherein each of the at least two stimulation units is arranged to receive a different finger, preferably a different fingertip, of the user. Preferably, the stimulation units are arranged to receive the respective finger and / or fingertip of the user such that the oscillation direction is essentially perpendicular to a palmar surface of the finger, in particular to a palmar surface of a tip of the finger. Therein, the stimulation units may be arranged such that the contactors contact the palmar surface of the finger and / or of the tip of the finger (during use). Preferred placement of a contactor of a stimulation unit with respect to a finger and / or fingertip of a user has been discussed above already.

[0039] As has been outlined elsewhere herein already, using stimulation units according to the present invention may minimize or even entirely avoid vibrations of a housing of the stimulation unit. At least, using stimulation units according to the present invention may minimize or even entirely avoid lateral vibrations, i.e., vibrations in a direction other than the oscillation direction, in particular perpendicular thereto. Thus, when using stimulation units according to the present invention in a device for applying vibro-tactile stimulation as just described, a mechanical coupling between the different stimulation units may be minimized or even entirely avoided, irrespective of how the user holds his / her hand and / or whether the user places his / her hand on an object. As a result, a vibro-tactile stimulus originating from one of the stimulation units only reaches the respective finger to which that stimulation unit is applied, but not also, e.g., any neighboring fingers. That is, there is no (or at most negligible) spatial overlap of the parts of the body (hand) of the user - and hence of the areas of the brain associated with these parts of the body (hand) of the user - that are stimulated by different stimulation units. This greatly enhances stimulation effects as well as user comfort and usability, as the device may be used in arbitrary positions of the user and / or his / her hand.

[0040] The above-discussed aspects of the present invention mainly aim at leveraging a more precise targeting of vibro-tactile stimuli, which, inter alia, allows to minimize or even avoid any spatial overlap of parts of the body of the user - and hence of the areas of the brain associated with these parts of the body of the user - that are stimulated by different stimulation units. The approach of these aspects may also be summarized as mechanical decoupling.

[0041] In further aspects, the present invention aims at arranging multiple (at least two) stimulation units at suitable mutual (anatomical) distances such as to (further) minimize or even avoid any spatial overlap of parts of the body of the user - and hence of the areas of the brain associated with these parts of the body of the user - that are stimulated by different ones of the multiple (at least two) stimulation units. The approach of these aspects may also be summarized as anatomical decoupling.

[0042] In a sense, mechanical decoupling and anatomical decoupling may be thought to be interrelated. The more targeted the application of vibro-tactile stimuli by a set of stimulation units is, the closer together the stimulation units of the set may be arranged. As outlined elsewhere herein, if there is less spread and / or smearing of the vibro-tactile stimuli applied by the stimulation units, the stimulation units may be arranged closer together since it becomes increasingly unnecessary to provide tolerances for said spread and / or smearing, and vice versa. As a result, more stimulation units may be placed on a target stimulation area while allowing different and more effective stimulation algorithms to be applied. Generally, particularly enhanced stimulation effects may be expected when combining different aspects of the present invention, e.g., when combining aspects of mechanical decoupling with aspects of anatomical decoupling.

[0043] As a possible realization of anatomical decoupling, the present invention provides a method for providing vibro-tactile stimulation to a user, which method comprises applying at least two, preferably four to eight, stimulation units for applying a vibro-tactile stimulus to a part of a body of the user within an activation radius dact from a contactor of the respective stimulation unit, such that contactors of the at least two stimulation units comprise a mutual (anatomical) distance of at least i.6-dact, more preferably of at least i.8-dact, most preferably of at least 2-dact. Preferably, the at least two stimulation units for applying a vibro-tactile stimulus maybe such as described above, e.g., the stimulation units may (additionally) realize mechanical decoupling.

[0044] When a stimulation unit is used to apply vibro-tactile stimulation to a part of a body of a user, each vibro-tactile stimulus will not only be felt by the user in a (virtually) point-like area where the contactor contacts the part of the body. Rather, each vibro-tactile stimulus will be felt in a generally circular area centered around the contactor and / or the (virtually) point-like area where the contactor contacts the part of the body, respectively. Accordingly, the area in which a vibro-tactile stimulus applied by a stimulation unit is felt by a user may be described and / or characterized by an activation radius dact-

[0045] Generally, the activation radius dact maybe different (e.g., have a different value), e.g., at different frequencies of vibro-tactile stimuli to be applied and at different locations on a body of a user to which vibro-tactile stimuli are to be applied. That is, the activation radius dact generally depends on one or more of: a frequency and / or an intensity of the vibro-tactile stimulus to be applied as well as a part of a body of a user to which the vibro-tactile stimulus is to be applied.

[0046] To put it the other way around, a user’s two-point discrimination, i.e., the user’s ability to discern that two nearby objects touching a part of a body are truly touching two distinct points, not one point on the part of the body, differs across different parts of the body of the user and depends on a frequency associated with the objects touching the part of the body of the user.

[0047] Taking this into account, the inventors have found that enhanced stimulation results can be expected if stimulation units are applied to a part of a body of a user such that contactors of the at least two stimulation units comprise a mutual (anatomical) distance of at least i.6-dact, more preferably of at least i.8-dact, most preferably of at least 2,-dact- This may minimize or even avoid any spatial overlap of parts of the body of the user - and hence of the areas of the brain associated with these parts of the body of the user - that are stimulated by different ones of the at least two stimulation units.

[0048] Herein, an anatomical distance may be understood to mean the shortest distance between two points on a body of a user as measured along the body of the user. For example, while two fingertips of the user may comprise a mutual physical distance of a few mm, or none at all, when pressed together, irrespectively, they may comprise an anatomical distance of (at least) the total length of the respective fingers. Specifically with a view to fingers of a user, one of the inventors found that vibro-tactile stimuli of high frequencies, e.g., of 250 Hz, activate cells, in particular mechanoreceptors / Pacinian corpuscles (details will be discussed in the detailed description below), within a radius between 20 mm and 25 mm of where the respective stimulus (and / or contactor of the stimulation unit) is applied / centered. That is, for fingers of a user, the activation radius was found to be between 20 mm and 25 mm. Note that the activation radius maybe different (e.g., smaller) for vibro-tactile stimuli of different (e.g., lower) frequencies and / or if vibro-tactile stimuli of the same (or different) frequencies would be applied to a different part of a body (e.g., a forearm) of a user.

[0049] Accordingly, applying at least two stimulation units for applying a vibro-tactile stimulus to a part of a body of a user, in particular to a hand and / or fingers of a user, such that contactors of the at least two stimulation units comprise a mutual (anatomical) distance of at least 40 mm, more preferably of at least 45 mm, most preferably of at least 50 mm may minimize or even avoid any spatial overlap of parts of the body of the user - and hence of the areas of the brain associated with these parts of the body of the user - that are stimulated by different ones of the at least two stimulation units. This (further) enhances stimulation effects, as discussed in various instances before.

[0050] Furthermore, stimulation units according to the present invention may accordingly be adapted to apply a vibro-tactile stimulus to an area between 250 mm2and 8000 mm2, preferably between 1000 mm2and 4000 mm2, most preferably between 1500 mm2and 2000 mm2.

[0051] As mentioned already, this particular application and / or arrangement of stimulation units may generally be provided for when applying vibro-tactile stimulation to different fingers, in particular fingertips, of a user. Anatomically, fingers and in particular fingertips of a user are sufficiently separated (decoupled), such as to exclude that activation of cells in one finger or fingertip leads to activation of cells in another finger or fingertip. That is, vibro-tactile stimulation of fingers and / or fingertips generally implements / respects the anatomical decoupling advanced by the present invention. But it is important to note that devices known in the prior art for vibro- tactile stimulation of fingers and / or fingertips, such as those of Fig. 1A (and Fig. 1B) do not provide for mechanical decoupling, which jeopardizes stimulation results despite the anatomical decoupling present between different fingers and / or fingertips. Yet, as laid out above, the present invention also provides a solution to this problem. The application of stimulation units to a body of a user at the above-mentioned mutual (anatomical) distances (between contactors) may, in an aspect of the present invention, also be predefined by (and / or inherent in) a design of a device for applying vibro-tactile stimulation. That is, the present invention furthermore provides a device for applying vibro-tactile stimulation to a user, which device comprises at least two stimulation units for applying a vibro-tactile stimulus to a part of a body of the user within an activation radius dact from a contactor of the respective stimulation unit, wherein the at least two stimulation units are arranged such that contactors of the at least two stimulation units comprise a mutual (anatomical) distance of at least i.6-dact, more preferably of at least i.8-dact, most preferably of at least 2-dact(when the device and / or the at least two stimulation units is / are applied to the user). Such device inherently ensures suitable placement of stimulation units on a body of a user that minimizes or even avoids any spatial overlap of parts of the body of the user - and hence of the areas of the brain associated with these parts of the body of the user - that are stimulated by different ones of the at least two stimulation units.

[0052] In an embodiment, the at least two stimulation units may be attached to a cuff and / or a sleeve of the device. Such cuff and / or sleeve may allow for particularly easy and comfortable application of the device and its stimulation units - at preferable mutual (anatomical) distances (between contactors) -, e.g., to an arm (e.g., a forearm), a leg or a foot of a user.

[0053] Preferably, the at least two stimulation units for applying a vibro-tactile stimulus of the device maybe such as described above, e.g., the stimulation units may (additionally) realize mechanical decoupling.

[0054] Stimulation units according to the present invention, and devices comprising such, may generally be controlled by separate, but also by a common control unit. Control units for controlling stimulation units and / or devices according to the present invention maybe adapted to activate the stimulation units, in particular in a coordinated manner. That is, stimulation units and / or devices according to the present invention maybe controlled implement Coordinated Reset approaches, or Dynamic Coordinated Reset approaches as disclosed, and in particular as claimed, in DE io 2020208431 Al. In controlling the stimulation units, a frequency and / or an intensity of the resulting vibro-tactile stimuli needs to be considered. It has been found that a frequency of a vibro-tactile stimulus between 200 Hz and 300 Hz, preferably between 230 Hz and 270 Hz, most preferably of 250 Hz maybe optimal for stimulation effectiveness.

[0055] The present invention also encompasses embodiments in which multiple devices for applying vibro-tactile stimulation are used, potentially in a (wirelessly) coordinated and / or synchronized manner, on different parts of a body of a user.

[0056] 4. Brief Description of the Figures

[0057] Figs. 1A and 1B: Prior-art apparatus comprising two devices for applying vibro-tactile stimulation to hands of a user;

[0058] Fig. 2B: Embodiment of an oscillation assembly and contactor according to the present invention;

[0059] Fig. 2B: Cross-section of the embodiment of an oscillation assembly and contactor shown in Fig. 2A;

[0060] Fig. 2B: Embodiment of a further oscillation assembly and contactor according to the present invention;

[0061] Fig. 3B: Cross-section of the further embodiment of an oscillation assembly and contactor shown in Fig. 3A;

[0062] Fig. 4: Prior-art diagram illustrating the response of Pacinian corpuscles to vibro- tactile stimuli of different frequencies;

[0063] Fig. 5: Prior-art illustration showing the distribution of Pacinian corpuscles in a hand of a user;

[0064] Fig. 6: Prior-art illustration showing the response threshold to vibro-tactile stimulation of different areas of a palm of a hand of a user; Fig. 7: Illustration of preferred placement of a contactor of a stimulation unit with respect to a finger of a user;

[0065] Fig. 8: Illustration of a radius of a tip of a finger of a user;

[0066] Figs. 9A-9C: Embodiment of a device for applying vibro-tactile stimulation according to the present invention, comprising four stimulation units and (optionally) a glove-like shape;

[0067] Figs. 10A-10D: Exemplary application of stimulation units to different parts of a body of a user according to the present invention.

[0068] 5. Detailed Description of Some Embodiments

[0069] For the sake of brevity only a few embodiments will be described in the following. The skilled person will recognize that the specific features described with reference to these embodiments may be modified and combined differently and that individual features may also be omitted if they are not essential. The general explanations in the sections above will also be valid for the following more detailed explanations.

[0070] Figs. 2A and 2B show a stimulation unit 200 according to the present invention. Stimulation unit 200 comprises a housing 210 (only shown in Fig. 2B, not in Fig. 2A). Stimulation unit 200 and / or housing 210 comprise(s) a surface 211 for receiving a part of a body of a user (not shown). Surface 211 comprises an aperture 212.

[0071] Stimulation unit 200 furthermore comprises a contactor 220 for contacting a part of a body of a user, e.g., the part of the body of the user that surface 211 is to receive and to which stimulation unit 200 is to apply a vibro-tactile stimulus using contactor 220 as will be described below. Towards its bottom end, i.e., towards the end that is opposite the end that is to be in contact with a part of a body of a user, contactor 220 comprises a generally cuboid base 221. Atop base 221, i.e., towards the end that is to be in contact with a part of a body of a user, contactor 220 comprises a generally cylindrical shape, arranged symmetrically with respect to base 221, and starting with a region 222 of reduced diameter, followed by a bulge 223, i.e., a region of increased diameter as compared to region 222, towards its top end. Contactor 220 culminates in a (cylindrical) protrusion 224 of further reduced diameter, which protrusion 224 forms the topmost point of contactor 220. The diameter of protrusion 224 is smaller than the diameter of region 222.

[0072] Furthermore, contactor 220 comprises a concentric cylindrical cavity 225b (only shown in Fig. 2B, not in Fig. 2A), opening towards its bottom end opposite its top end. Additionally, contactor 220, in particular base 221, comprises two cylindrical apertures 225a and 225c (both not visible in Figs. 2A and 2B) arranged at opposite, far ends of base 221 and symmetrically with respect to all three axes of base 221. Cylindrical cavity 225b and cylindrical apertures 225a and 225c are arranged within contactor 220 and its base 221, respectively, such that the main axes (e.g., the rotational-symmetry axes) of cylindrical cavity 225b and cylindrical apertures 225a and 225c are parallel. Apertures 225a and 225c open up towards the top of base 221 next to region 222.

[0073] Stimulation unit 200 comprises an oscillation assembly 230. Oscillation assembly 230 guides and accelerates contactor 220 along an oscillation direction 240 (only shown in Fig. 2B, not in Fig. 2A), through aperture 212 in surface 211. In particular, oscillation assembly 230 is adapted to accelerate contactor 220 back and forth, through aperture 212, along oscillation direction 240, such that contactor 220 oscillates along oscillation direction 240. This may in turn apply a vibro-tactile stimulus to the part of the body of the user that is to be received by surface 211 and that is to be contacted by contactor 220.

[0074] Therein, oscillation direction 240 is perpendicular to surface 211 and hence also essentially perpendicular to a surface of the part of the body of the user that surface 211 is to receive and which contactor 220 is to contact.

[0075] Therein, oscillation assembly 230 comprises cylindrical rails 235a (only shown in Fig. 2A, not in Fig. 2B), 235b (only shown in Fig. 2B, not in Fig. 2A) and 235c (only shown in Fig. 2A, not in Fig. 2B) oriented along oscillation direction 240. Rails 235a, 235b and 235c are attached to housing 210. Contactor 220 is arranged to slide along rails 235a, 235b and 235c. More specifically, contactor 220 receives rail 235 a in aperture 225a, rail 235b in cavity 225b and rail 235c in aperture 225c. Rail 235b and cavity 225b as well as rails 235a, 235c and apertures 225a, 225c correspond in diameter such that contactor 220 and / or cavity 225b abut(s) on rail 235b and / or apertures 225a, 225c abut on rails 235a, 235c. This construction allows contactor 220 to move freely along rails 235a, 235b and 235c and hence along oscillation direction 240, but impedes any acceleration and / or movement of contactor 220 along any direction other than oscillation direction 240, in particular perpendicular to oscillation direction 240.

[0076] Stimulation unit 200 and / or oscillation assembly 230, respectively, comprise(s) electromagnets 231a, 231b, 231c and 23id (the latter two only shown in Fig. 2A, not in Fig. 2B). Electromagnets 231a, 231b, 231c and 23id comprise electromagnetic coils and two cores 232a and 232b arranged within the electromagnetic coils. Cores 232a and 232b generally comprise a (e.g., the same) U-shape.

[0077] The ends of core 232a extend through the electromagnetic coils of electromagnets 231a and 231c and point towards (base 221 of) contactor 220, e.g., towards a plane in which cylindrical cavity 225b and cylindrical apertures 225a and 225c and / or rails 235a, 235b and 235c lie. Electromagnets 231b and 23id as well as core 232b are arranged mirror-symmetrically to electromagnets 231a and 231c as well as core 232a, with respect to contactor 220 (and base 221 in particular). That is, the ends of core 232b extend through the electromagnetic coils of electromagnets 231b and 23id and point towards (base 221 of) contactor 220, e.g., towards a plane in which cylindrical cavity 225b and cylindrical apertures 225a and 225c and / or rails 235a, 235b and 235c lie. Electromagnets 231a, 231b, 231c and 23rd are arranged such that ends of cores 232a and 232b are colinear and oriented perpendicularly to oscillation direction 240.

[0078] A magnetic field generated by oscillation assembly 230 and / or electromagnets 231a, 231b, 231c and 23id, respectively, interacts with one or more (static) magnets 233 of contactor 220. Thereby, oscillation assembly 230 guides and / or accelerates contactor 220.

[0079] In the embodiment of Fig. 2, there are four magnets 233. Magnets 233 comprise an identical, generally cuboid shape and are arranged within contactor 220, two of them atop each other between aperture 225a and cavity 225b, two of them atop each other between aperture 225c and cavity 225b. Magnets 233 are generally aligned with ends of cores 231a and 231b, respectively.

[0080] Electromagnets 231a, 231b, 231c and 23rd maybe controlled by a control unit (not shown). Such control unit may control a current supplied to electromagnets 231a, 231b, 231c and 23rd and hence the magnetic field generated by electromagnets 231a, 231b, 231c and 23rd. This in turn allows for direct, immediate control of acceleration, movement and / or oscillation of contactor

[0081] 220. The construction of stimulation unit 200 allows contactor 220 not to be attached to oscillation assembly 230 and / or housing 210 of stimulation unit 200, neither via any elastic element such as a spring, nor otherwise. This allows oscillation assembly 230 to accelerate contactor 220 essentially along oscillation direction 240 only, enabling the desirable, stimulation-enhancing effects set out further above.

[0082] Figs. 3A and 3B shows a stimulation unit 300 for applying a vibro-tactile stimulus to a part of a body of a user according to the present invention. Similar to stimulation unit 200 of Fig. 2, stimulation unit 300 comprises a housing 310 (only shown in Fig. 3B, not in Fig. 3A). Stimulation unit 300 and / or housing 310 comprise(s) a surface 311 for receiving a part of a body of a user (not shown). Surface 311 comprises an aperture 312.

[0083] Also similar to stimulation unit 200 of Fig. 2, stimulation unit 300 comprises a contactor 320 and an oscillation assembly 330. Oscillation assembly 330 guides and accelerates contactor 320 along an oscillation direction 340 (only shown in Fig. 3B, not in Fig. 3A), through aperture 312 in surface 311. In particular, oscillation assembly 330 is adapted to accelerate contactor 320 back and forth, through aperture 312, along oscillation direction 340, such that contactor 320 oscillates along oscillation direction 340. This may in turn apply a vibro-tactile stimulus to the part of the body of the user that is to be received by surface 311 and that is to be contacted by contactor 320.

[0084] As in stimulation unit 200 of Fig. 2, oscillation direction 340 is perpendicular to surface 311 and hence also essentially perpendicular to a surface of the part of the body of the user that surface 311 is to receive and which contactor 320 is to contact.

[0085] Generally, oscillation assembly 330 guides and / or accelerates contactor 320 like oscillation assembly 230 guides and / or accelerates contactor 220, i.e., by generating a magnetic field. However, the construction of stimulation unit 300 and its contactor 320 and oscillation assembly 330 is different from the construction of stimulation unit 200 of Fig. 2 and its contactor 220 and oscillation assembly 230:

[0086] Contactor 320 generally comprises a similar shape to contactor 220 of Fig. 2. Towards its bottom end, i.e., towards the end that is opposite the end that is to be in contact with a part of a body of a user, contactor 320 comprises a generally cuboid base 321. Atop base 321, i.e., towards the end that is to be in contact with a part of a body of a user, contactor 320 comprises a generally cylindrical shape, arranged symmetrically with respect to base 321, and starting with a region 322 of reduced diameter. Atop region 322 contactor 320 comprises a bulge 323, i.e., a region of increased diameter as compared to region 322. Contactor 320 culminates in a (cylindrical) protrusion 324 of reduced diameter, which protrusion 324 forms the topmost point of contactor 320. The diameter of protrusion 324 is smaller than the diameter of region 322.

[0087] Base 321 of contactor 320 comprises two mutually parallel cylindrical apertures 325a and 325b (only shown in Fig. 3B, not in Fig. 3A), arranged at opposite, far ends of base 321 and symmetrically with respect to all three axes of base 321. Apertures 325a and 325b extend along oscillation direction 340 and are arranged symmetrically with respect to a central axis of contactor 320. Apertures 325a and 325b open up towards the top of base 321 next to region 322.

[0088] Furthermore, contactor 320 comprises one or more (static) magnets 333. In the embodiment of Fig. 3, there are two magnets 333 that both comprise an identical, generally cuboid shape. Magnets 333 are arranged atop each other along the central axis of contactor 320.

[0089] Different from oscillation assembly 230 of Fig. 2, oscillation assembly 330 comprises not three but two cylindrical rails 335a and 335b oriented along oscillation direction 340. Rails 335a and 335b are attached to housing 310. Contactor 320 is arranged to slide along rails 335a and 335b. More specifically, contactor 320 receives rail 335a in aperture 325a and rail 335b in aperture 325b. Rails 335a and 335b and apertures 325a and 325b respectively correspond in diameter such that contactor 320 and / or apertures 325a and 325b abut(s) on rail 335a and 335b, respectively. This construction allows contactor 320 to move freely along rails 335a and 335b and hence along oscillation direction 340, but impedes any acceleration and / or movement of contactor 320 along any direction other than oscillation direction 340, in particular perpendicular to oscillation direction 340.

[0090] Further different from stimulation unit 200 and its oscillation assembly 230 of Fig. 2, stimulation unit 300 and / or oscillation assembly 330, respectively, comprise(s) not four but two electromagnet 331a and 331b. Electromagnets 331a and 331b each comprise an electromagnetic coil and both comprise a common core 332 arranged within the electromagnetic coils. Electromagnets 331a and 331b are arranged on one side of contactor 320. Common core 332 generally comprises a U-shape, or a broken-O-shape. That is, common core 332 maybe thought of as comprising an O-shape, but with one edge broken / open / disconnected. The two opposite cross-sectional faces of this broken edge point towards contactor 320, are parallel to a plane in which rails 335a and 335b lie and are generally aligned with magnets 333. The edges of common core 332 perpendicular to the broken edge extend through the electromagnetic coils of electromagnets 331a and 331b, respectively.

[0091] Overall, the construction of stimulation unit 300 and / or oscillation assembly 330 is hence asymmetric.

[0092] A magnetic field generated by oscillation assembly 330 and / or electromagnets 331a and 331b, respectively, interacts with magnets 333 of contactor 320. Thereby, oscillation assembly 330 guides and / or accelerates contactor 320. Electromagnets 331a and 331b maybe controlled by a control unit, as was described above for electromagnets 231a, 231b, 231c and 23rd of Fig. 2.

[0093] Similar to the construction of stimulation unit 200, the construction of stimulation unit 300 allows contactor 320 not to be attached to oscillation assembly 330 and / or housing 310 of stimulation unit 300, neither via any elastic element such as a spring, nor otherwise. This allows oscillation assembly 330 to accelerate contactor 320 essentially along oscillation direction 340 only, enabling the desirable, stimulation-enhancing effects set out further above.

[0094] Figs. 4 through 6 relate to studies that one of the inventors surveyed to determine a preferred frequency of vibro-tactile stimuli to be applied by stimulation units according to the present invention, as well as to determine a preferred placement of a contactor of a stimulation unit with respect to a finger of a user. These studies maybe summarized as follows:

[0095] Vibro-tactile stimulation mainly targets Pacinian corpuscles. Pacinian corpuscles represent one of the four major types of mechanoreceptors (mechanoreceptors being specialized nerve endings for mechanical sensation) found in mammalian skin. Pacinian corpuscles are specialized in deep-pressure and high-frequency-vibration detection. Pacinian corpuscles are found in the subcutaneous adipose layer (Knibestol, 1973), which is deeper than where Meissner cells are found.

[0096] Pacinian cells are most sensitive to high-frequency vibrations in the range of around 50-400 Hz (Chung et al., 2013) or 250-350 Hz (Hao et al., 2015) and appear to have the lowest indentation threshold at 200 Hz. There, Pacinian corpuscle afferents respond to 10 nm of skin motion or less (Johnson, 2001). This is illustrated in Fig. 4, which shows that the threshold is lowest for frequencies around 200 Hz and that there is a damping of -15.4 dB per octave for lower frequencies (Bisben et al., 1999).

[0097] Pacinian corpuscles process broad receptor fields with indistinct borders (Johnson, 2001) and their response can be seen bilaterally in the primary (Si) and secondary (S2) somatosensory cortex, although stronger contralateral than ipsilateral activation is seen in the primary somatosensory cortex (Chung et al., 2013). Pacinian corpuscles not only respond to the onset of a stimulus but also show spiking activity when the stimulus stops (Knibestol, 1973).

[0098] In accordance with these findings, it may be advantageous to use the stimulation units according to the present invention to apply vibro-tactile stimuli with a frequency of between 200 Hz and 300 Hz, preferably between 230 Hz and 270 Hz, most preferably of 250 Hz.

[0099] Because of the extreme sensitivity and the deep location in the skin of Pacinian corpuscles, the associated afferents have almost no spatial resolution. The receptive field of a Pacinian corpuscles may include an entire hand (Johnson, 2001).

[0100] For purposes of vibro-tactile stimulation of a hand and / or fingers of a user, it is advantageous to determine the (average) distribution of Pacinian corpuscles across a hand. Stark et al. (1998) investigated the hands of ten subjects with respect to the location of Pacinian corpuscles. Six specimens came from women with a mean age of 83 years and four specimens came from men with a mean age of 71.5 year. Fig. 5 exemplarily shows the distribution of Pacinian corpuscles in a left hand of a 76-year-old female specimen.

[0101] The study found that index, middle and ring fingers comprise similar numbers of Pacinian corpuscles (62 / 63 / 60), while little (or pinky) fingers comprise only 39 Pacinian corpuscles on average. The distal phalanxes of these fingers comprise 8 to 10 Pacinian corpuscles on average, while the proximal phalanxes comprise 10 to 23 Pacinian corpuscles, i.e., twice as many. The middle phalanxes comprised only 5 to 7 Pacinian corpuscles on average. The table below summarizes these findings: MP Proximal Middle Distal Total Range

[0102] Thumb 14 12 12 38 28-50

[0103] Index 24 21 7 10 62 44-89

[0104] Middle 25 23 6 9 63 35-124

[0105] Ring 28 18 5 9 60 34-96

[0106] Little 16 10 5 8 39 25-59

[0107] Total 107 84 23 48 262

[0108] Note that within distal phalanxes the density of Pacinian corpuscles is generally slightly higher closer towards the fingertip, as can be seen in Fig. 5.

[0109] The above indicates that sensitivity to vibro-tactile stimulation at 250 Hz may be higher at a proximal phalanx than at a distal phalanx. However, applying vibro-tactile stimulation to proximal phalanxes of neighboring fingers may generally not realize the anatomical decoupling the present invention has identified to be advantageous for overall enhancement of stimulation results.

[0110] This is supported by the measurements of Brisben et al. (1999), which are summarized in Fig. 6. These measurements found lowest thresholds for the proximal phalanx of a middle finger and a palm of the hand. Thresholds the were found to be two-and-a-half times lower than for the distal phalanx of the middle finger (Brisben et al. 1999).

[0111] From the above, the following may be adduced concerning a preferred placement of a stimulation unit with respect to a hand and / or fingers of a user: As shown in Fig. 6, an activation area of Pacinian corpuscles in a distal phalanx of a (middle) finger is 1 cm2(Brisben et al. 1999). Therefore, placement of a stimulation unit does not need to occur with mm-precision.

[0112] Thus, it is proposed herein to place a contactor of a stimulation unit within 3 mm, preferably within 1 mm of a midline of a target finger and / or between 5 mm and 15 mm, preferably between 7 mm and 13 mm, most preferably between 9.5 mm and 10.5 mm from a tip of a target finger. This is illustrated in Fig. 7.

[0113] The present invention also considers a preferred shape of a surface of a stimulation unit that is to receive and guide a finger of a user, such as to ensure, or at least facilitate, the above-dis- cussed preferred placement of the stimulation unit and its contactor with respect to that finger. These considerations pertain to a width as well as to a curvature of fingers to be received. In this context, curvature refers to the palmar shape of a distal end of a distal phalanx of a finger, as illustrated (and highlighted) in Fig. 8.

[0114] Some prior-art stimulation units comprise a concave surface to receive and guide a finger of a user, which concave surface is characterized by a radius of 18.36 mm (in all directions). However, while this radius seems to provide good support to larger fingers, it may work not as well for smaller fingers.

[0115] Following data from the book “The measure of man & woman”, published by Wiley & Son in 2002, the average finger width is 18 mm in men and 15 mm in women, with 21 mm and 15 mm and 18 mm and 13 mm, respectively, representing the 99 % and 1 % percentiles. Thus, a stimulation unit serving finger widths from 13 mm to 21 mm well would satisfactorily cover 98% of all potential users.

[0116] Tests with radii down to 10.5 mm showed that concave surfaces characterized by a radius between 10 mm and 17 mm, preferably between 11.5 mm and 15.5 mm, most preferably between 13 mm and 14 mm provide a good fit and good guidance for the fingers of most users, in particular a better fit and better guidance than concave surfaces characterized by a radius of 18.36 mm as known from the prior art. These tests considered both finger width as well as finger curvature.

[0117] Figs. 9A through 9C show a device 9000 for applying vibro-tactile stimulation according to the present invention. Device 9000 may be said to comprise a generally glove-like shape, suitable, e.g., for a left hand of a user.

[0118] Device 9000 comprises four stimulation units 9ooa-9ood. Each of the stimulation units 900a- 9ood is arranged to receive (i.e., adapted to be applied to) a different finger of the (left) hand of the user, e.g., as discussed elsewhere herein: Stimulation unit 900a is arranged to receive an index finger of the (left) hand of the user, stimulation unit 900b is arranged to receive a middle finger of the (left) hand of the user, stimulation unit 900c is arranged to receive a ring finger of the (left) hand of the user, and stimulation unit good is arranged to receive a little (pinky) finger of the (left) hand of the user.

[0119] In the following, stimulation unit 900a will be discussed in more detail. The following explanations however apply mutatis mutandis to stimulation units 9oob-9ood. Stimulation unit 900a comprises an attachment portion 910a and a stimulation portion 920a. Attachment portion 910a and stimulation portion 920a are movable with respect to each other, e.g., due to a swivel joint connecting attachment portion 910a and stimulation portion 920a. Attachment portion 910a and stimulation portion 920a may be forced towards each other (closed) by one or more elastic elements, e.g., one or more springs, in attachment portion 910a, stimulation portion 920a, and / or stimulation unit 900a more generally. This may result in a force of between 1 N and 2 N being applied to the index finger of the (left) hand of the user. This may ensure a secure receiving of the index finger of the (left) hand of the user.

[0120] Stimulation unit 900a is arranged to receive the index finger of the (left) hand of the user, such that attachment portion 910a abuts, at least partly, on a dorsal surface of the index finger of the (left) hand of the user, in particular on a nail of the index finger of the (left) hand of the user, and / or such that stimulation portion 920a abuts, at least partly, on a palmar surface of the index finger of the (left) hand of the user, in particular on a palmar surface of a tip of the index finger of the (left) hand of the user. Stimulation unit 900a, its attachment portion 910a, and / or its stimulation portion 920a are sized such as to provide for a secure fit, but to avoid any limitations of movement for the user.

[0121] More specifically, attachment portion 910a comprises a cushioning element 915a that is arranged to abut, at least partly, on the dorsal surface of the index finger of the (left) hand of the user, in particular on the nail of the index finger of the (left) hand of the user. Cushioning element 915a may, e.g., comprise silicone. Cushioning element 915a maybe exchangeable, which may be beneficial for hygiene as well as maintenance. This may also allow to choose between different shapes for cushioning element 915a, such as to optimize a fit and / or wearing comfort for a user.

[0122] Meanwhile, stimulation portion 920a comprises a concave surface 925a. Concave surface 925a is shaped as discussed elsewhere herein. Concave surface 925a comprises an aperture (not shown), through which a contactor (not shown) of stimulation unit 920 may be accelerated and / or through which the contactor contacts the (palmar surface and / or tip of the) index finger of the (left) hand of the user during use, as discussed elsewhere herein.

[0123] Device 9000 comprises a wearable portion 9100 with an aperture 9110, through which aperture 9110 a thumb of a user is to extend during use of device 9000. Wearable portion 9100 is made from textile and / or elastic material to provide for wearing comfort. Wearable portion 9100 may be adjustable such as to improve a fit to the (left) hand of the user.

[0124] Device 9000 and / or wearable portion 9100 comprises a latch 9120 that may be used to secure and / or release a control unit 9200 that may thereby be releasably attached to wearable portion 9100. While control unit 9200 is secured to device 9000 and / or wearable portion 9100 in Figs. 9A and 9B, it is released (and not shown at all) in Fig. 9C.

[0125] Control unit 9200 is connected to stimulation units 9ooa-9ood via respective cables 950a-950d. Cables 950a-950d are sized to avoid any mechanical coupling between stimulation units 900a- 9ood (e.g., via wearable portion 9iooand or control unit 9200). Moreover, cables 950a-950d are sized not to restrict the fingers’ and / or the user’s freedom of movement. Note that in other embodiments, a control unit may, e.g., be connected wirelessly to one or more stimulation units.

[0126] Control unit 9200 is adapted to control (operation of) stimulation units 9ooa-9ood as described elsewhere herein. Control unit 9200 may comprise one or more control elements and / or one or more displays 9210. Control unit 9200 may power stimulation units 9ooa-9ood.

[0127] Figs. 10A through 10D show four stimulation units 1000 for applying a vibro-tactile stimulus as applied to different parts of a body of a user (Figs. 10A and 10B: medial and lateral sides of a forearm; Fig. 10C: foot, in particular foot sole; Fig. 10D: leg, in particular lower leg) in accordance with the present invention. That is, as can be seen, stimulation units 1000 are applied to the respective part of the body, such that contactors of stimulation units 1000 comprise a mutual (anatomical) distance that is based on the respectively applicable activation radius dact- That is, contactors of stimulation units 1000 comprise a mutual (anatomical) distance of at least i.6-dact, more preferably of at least i.8-dact, most preferably of at least 2-dact. In some embodiments such as those shown in Figs. 10A through 10D, this may imply a mutual (anatomical) distance of at least 40 mm, more preferably of at least 45 mm, most preferably of at least 50 mm. Figs. 10A through 10D illustrate exemplary applications / arrangements of stimulation units only. According to the present invention, there may be a different number of stimulation units, of different type(s), applied to other parts of a body of a user, e.g., an upper arm (e.g., triceps and / or biceps) of a user, a thigh of a user, a toe of a user, a dorsal part of a foot, a back of a user, a hand, in particular a dorsal or palmar surface of a finger or a fingertip, a phalanx of a finger or a heel of a hand, of a user. Stimulation units may also be applied to two or more different parts of a body of a user (concurrently).

Claims

August 26, 2025 curetec GmbH C175393WO KAU / FimClaims1. Stimulation unit for applying a vibro-tactile stimulus to a part of a body of a user, comprising: a contactor for contacting the part of the body of the user; and an oscillation assembly for guiding and accelerating the contactor along an oscillation direction; wherein the oscillation assembly is adapted to accelerate the contactor essentially along the oscillation direction only.

2. Stimulation unit according to claim 1, wherein the oscillation assembly is adapted to accelerate the contactor such as to provide kinetic energy to the contactor, wherein less than 10%, preferably less than 5%, more preferably less than 2%, most preferably less than 1% of the kinetic energy is associated with an acceleration and / or movement of the contactor perpendicular to the oscillation direction.

3. Stimulation unit according to claim 1 or 2, wherein the oscillation assembly is adapted to accelerate the contactor such that a ratio between a maximum displacement of the contactor along the oscillation direction and a maximum displacement of the contactor perpendicular to the oscillation direction is at least 10:1, more preferably at least 20:1, most preferably at least 50:1.

4. Stimulation unit according to any of the preceding claims, adapted such that the oscillation direction is essentially perpendicular to the part of the body of the user when the stimulation unit is applied to the user.

5. Stimulation unit according to any of the preceding claims, wherein the contactor is not attached to the oscillation assembly and / or a housing of the stimulation unit.

6. Stimulation unit according to any of the preceding claims, wherein the contactor is not attached to the oscillation assembly and / or a housing of the stimulation unit via any elastic element.

7. Stimulation unit according to any of the preceding claims, wherein the oscillation assembly does not comprise any spring.

8. Stimulation unit according to any of the preceding claims, wherein the oscillation assembly is adapted to generate a magnetic field to guide and / or accelerate the contactor.

9. Stimulation unit according to any of the preceding claims, wherein the oscillation assembly comprises at least one rail oriented along the oscillation direction, wherein the contactor is arranged to slide along the at least one rail.

10. Stimulation unit according to any of the preceding claims, adapted to be applied to a finger of the user; wherein a housing of the stimulation unit comprises a concave surface for receiving the finger of the user and wherein the oscillation assembly is arranged to accelerate the contactor through an aperture in the concave surface; further wherein: the concave surface is characterized by a radius between 10 mm and 17 mm, preferably between 11.5 mm and 15.5 mm, most preferably between 13 mm and 14 mm; and / or the stimulation unit and / or the concave surface is adapted to receive the finger of the user such that the aperture is located within 3 mm, preferably within 1 mm of a midline of the finger of the user and / or between 5 mm and 15 mm, preferably between 7 mm and 13 mm, most preferably between 9.5 mm and 10.5 mm from a tip of the finger of the user.

11. Stimulation unit according to any of the preceding claims, further comprising a kinematic sensor for determining a position and / or an orientation of the stimulation unit, wherein the kinematic sensor is preferably configured to provide, regularly, continuously or on demand, data on the position and / or the orientation, respectively, of the stimulation unit to a control unit.

12. Stimulation unit according to any of the preceding claims, further comprising an electrostatic sensor for interfacing with the part of the body of the user, wherein the electrostatic sensor is preferably configured to provide, regularly, continuously or on demand, data on a state of at least the part of the body of the user to a control unit.

13. Device for applying vibro-tactile stimulation to a user, comprising a glove-like shape and at least two stimulation units according to any of the preceding claims, wherein each of the at least two stimulation units is arranged to receive a different finger of the user.

14. Device for applying vibro-tactile stimulation to a user, comprising at least two stimulation units for applying a vibro-tactile stimulus to a part of a body of the user within an activation radius dact from a contactor of the respective stimulation unit, wherein the at least two stimulation units are arranged such that contactors of the at least two stimulation units comprise a mutual distance of at least i.6-dact, more preferably of at least i.8-dact, most preferably of at least2 'dact-15. Device according to claim 14, wherein the at least two stimulation units are attached to a cuff and / or a sleeve of the device.

16. Device according to claim 14 or 15, wherein the at least two stimulation units for applying a vibro-tactile stimulus are according to any of the claims 1-12.

17. Method for providing vibro-tactile stimulation to a user, comprising applying at least two stimulation units for applying a vibro-tactile stimulus to a part of a body of the user within an activation radius dact from a contactor of the respective stimulation unit, such that contactors of the at least two stimulation units comprise a mutual distance of at least i.6-dact, more preferably of at least i.8-dact, most preferably of at least 2,-dact-18. Method according to claim 17, wherein the at least two stimulation units for applying a vibro-tactile stimulus are according to any of the claims 1-12.

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