Helmet for noninvasive brain stimulation

Abstract

The invention relates to a helmet (1) for a noninvasive brain stimulation, comprising a stimulation unit (3) oriented towards a head-receiving area (2). In order to allow an individually determinable stimulation region to be precisely irradiated while nevertheless allowing the test person to have a certain degree of mobility, a suction opening (4) is proposed which is open towards the head-receiving area (1) and which is fluidically connected to a negative pressure connection (6) positioned outside of the head-receiving area (2).

Description

[0001] Helmet for non-invasive brain stimulation

[0002] Technical area

[0003] The invention relates to a helmet for non-invasive brain stimulation with a stimulation unit directed towards a head receptacle.

[0004] State of the art

[0005] Various non-invasive brain stimulation (NIBS) methods, such as transcranial magnetic stimulation (TMS), transcranial focused ultrasound (TUS), and transcranial direct current stimulation (TDCS), are known from the prior art. The helmet according to the invention can be used for these non-invasive brain stimulation methods, in particular for transcranial magnetic stimulation.

[0006] In non-invasive brain stimulation, areas of the brain are stimulated using a stimulation unit, which can then activate or inhibit these stimulation areas. For example, in transcranial magnetic stimulation, magnetic coils are held against the subject's skull so that the emitted magnetic beams reach the stimulation area. Correct alignment and placement of the stimulation unit is important because the strength of the emitted magnetic field decreases exponentially with distance from the stimulation area, which naturally also impairs the effectiveness of brain stimulation if the stimulation unit is incorrectly aligned.In order to individually adapt non-invasive brain stimulation to the different anatomies of different subjects, it is known from CN115008753A to provide a helmet adapted to the subject, on which a stimulation unit is arranged, directed at a stimulation area of ​​the brain determined by magnetic resonance imaging. The stimulation unit is arranged in a positioning holder fixed to the helmet. Similar devices are known, for example, from CN108042918A or US2015202453A1. It is also known (PARK, Tae Young, et al. Application of subject-specific helmets for the study of human visuomotor behavior using transcranial focused ultrasound: a pilot study. Computer Methods and Programs in Biomedicine, 2022, 226th vol., p. 107127. or WANG, He, et al. Individualized and clinically friendly helmet-type coil positioning method (l-Helmet) for transcranial magnetic stimulation.Brain Stimulation: Basic, Translational, and Clinical Research in Neuromodulation, 2022, Vol. 15, No. 5, pp. 1023-1025.), special helmets for transcranial brain stimulation according to the generic term in transcranial stimulation are recommended. A disadvantage of these devices, however, is that precise positioning of the stimulation unit relative to the stimulation area in the brain requires that the subjects avoid movement, which can be tiring for the subjects, especially during long treatments.

[0007] For example, it is known (SRIHASAM, Krishna, et al. Noninvasive functional MRI in alert monkeys. Neuroimage, 2010, 51st vol., no. 1, pp. 267-273) to equip the fixation helmet with integrated suction openings for the fixation of experimental animals in imaging tomography diagnostics.

[0008] Description of the invention

[0009] The invention is therefore based on the object of proposing a helmet for non-invasive brain stimulation that enables precise irradiation of an individually definable stimulation area while still allowing the subject a certain degree of freedom of movement. The invention achieves this object by providing an exhaust port open toward the head support, which is fluidly connected to a vacuum connection located outside the head support. As a result of the inventive measures, a vacuum can be generated in the head support of the helmet placed on a subject, thereby largely preventing any relative movement of the helmet relative to the subject's head.This also prevents relative movement between the stimulation unit mounted on the helmet and the subject's head and thus brain located in the helmet's head mount, even when the subject moves their head. This enables precise specification of the radiation conditions acting on a stimulation area of ​​the brain, in particular the radiation direction and the distance between the stimulation unit and the stimulation area. Advantageously, applying negative pressure to the head mount also improves the propagation of the magnetic field or ultrasound from the stimulation unit to the stimulation area, as the air gap that must be overcome can be significantly reduced. To generate negative pressure, the negative pressure connection can be connected to a vacuum pump. The stimulation unit can be a magnetic field emitter, for example a Magventure MagPro MCF B70 TMS coil.The stimulation unit can also be an ultrasound or direct current source. The suction port can extend through the helmet, allowing easy access to the vacuum port connected to it.

[0010] In order to improve the positioning accuracy of the helmet according to the invention and to establish predetermined treatment conditions more quickly, a plurality of suction openings open towards the headrest can be provided, which are fluidly connected to the vacuum connection. In this way, not only can a larger volume flow be taken from the headrest, but a more even pressure distribution is also achieved within the headrest, so that relative movement of the helmet resulting from local pressure peaks can be prevented. In principle, the vacuum connection can be fluidly connected to the respective suction openings via distribution lines. However, particularly simple connection conditions arise if the at least one suction opening is fluidly connected to the vacuum connection via a common suction chamber or if the suction openings are fluidly connected to the vacuum connection via a common suction chamber.In this way, the vacuum connection does not need to be assigned multiple distribution lines, each leading to a suction opening; it is sufficient for the vacuum connection to be fluidly connected only to the suction chamber. Furthermore, the suction chamber can act as a vacuum reservoir, further homogenizing and improving the negative pressure conditions within the head support. The suction chamber can be arranged on the top of the helmet. Preferably, the suction chamber extends at least partially around the top of the helmet. The suction chamber can be closed off from the support for the stimulation unit and preferably enclose it.

[0011] Although the head socket to be evacuated can be defined by the subject's head, the helmet, and the vacuum connection in such a way that a sufficiently sealed space for generating vacuum is created, particularly effective vacuum generation conditions are achieved by a circumferential sealing element delimiting a vacuum area. In this way, any gaps between the subject's head and the attached helmet can be closed, so that a sealed vacuum area is created in the head socket, which is defined by the subject's head, the inside of the helmet, and the sealing element. The sealing element can protrude into the head socket. In the simplest case, the sealing element can be designed as a sealing lip. In a preferred embodiment, several spaced-apart circumferential sealing elements can be provided, each of which is fluidly connected to at least one suction opening.This ensures a secure helmet fit even if one of the negative pressure areas develops a leak. For comprehensive monitoring of the subject, sensor mounts can be provided distributed around the head mount. The sensor mounts can be designed to hold and / or align sensors. Sensors such as electroencephalography sensors or near-infrared spectroscopy sensors can be used.

[0012] To enable the stimulation unit to be used with different helmets, in particular those individually adapted to the respective test subject, and conversely to enable different stimulation units to be used for one test subject depending on the application, the helmet can have a positioning receptacle arranged corresponding to a stimulation area for the detachable insertion of the stimulation unit. The arrangement of the positioning receptacle according to a stimulation area can be based on a previously determined brain model of the test subject, for example, determined by an MRI procedure. The arrangement of the positioning receptacle on the helmet is therefore such that the stimulation unit arranged in the positioning receptacle acts on the previously determined stimulation area when the helmet is worn.In the simplest case, the positioning mount can be designed so that the radiation cone of the stimulation unit is directed toward the stimulation area. The detachability between the stimulation unit and the positioning mount allows different stimulation units to be used for different applications, allowing for versatile use of the helmet. To enable unrestricted insertion and removal of the stimulation unit while simultaneously ensuring favorable sealing conditions, it is proposed that the flow connection between the at least one suction opening and the vacuum connection runs outside the positioning mount.

[0013] For the non-invasive brain stimulation carried out with the help of the helmet to be highly effective, precise alignment of the stimulation unit to the stimulation area is advantageous. For this purpose, during production of the helmet according to the invention, a stimulation area can be determined using a brain model, which in a simple case can be MRI cross-sectional images but also brain atlases and / or a 3D brain model, after which the positioning receptacle is arranged depending on the position of the stimulation area. In a simple embodiment, the stimulation area can be determined by generating an image of the brain, for example using an MRI method, and the stimulation area is defined in the image and the positioning receptacle is fixed on the helmet in such a way that the stimulation unit used stimulates this stimulation area. The suction opening orThe extraction openings can be incorporated into the helmet before or after the positioning mount is installed, although optimal conditions for unrestricted positioning of the positioning mount are achieved if the extraction openings are installed after the positioning mount is installed. To ensure a secure fit of the helmet and precise alignment of the stimulation unit to the previously defined stimulation area, the head mount, particularly the inside of the helmet that defines the head mount, can be adapted to a head model. The head model can be created by measuring the subject's head, for example, using optical measuring techniques. This further provides the advantage of improved sealing of the head mount.

[0014] The measurement process for generating the head model can be carried out using a 3D scanner as the measuring unit, which is mounted on a robotic arm. This allows the test subject to remain in a steady position during the measurement, which enables an accurate head model. Preferably, the robotic arm is mounted on a test subject chair on which the test subject sits during the measurement. The test subject chair can have fastening means for securing the test subject, in particular their head. To enable a portable device, the robotic arm can have a holder for detachable connection to the test subject chair or an anchor. To be able to be informed about the measurement progress during the 3D scanning, the 3D scanner can have an interface to a display monitor. This can display the measured head model in real time.Although the determination of the stimulation area and the definition of the positioning image can be done manually on a physical helmet model, particularly precise and advantageous manufacturing conditions arise when the helmet is modeled using computer support. For this purpose, a three-dimensional helmet model can be created and overlaid with the brain model. The positioning image is then determined in the helmet model depending on the stimulation area, and the helmet is additively manufactured from the helmet model. The preferably three-dimensional brain model can be created using an MRI process and transferred to a computing unit. The three-dimensional helmet model can be overlaid with the brain model so that the previously determined stimulation area can be projected onto the helmet model, and the positioning image is determined based on this projection.The intensity distribution of the stimulation unit to be used can also be taken into account when determining the desired intensity, ensuring the most even distribution of stimulation intensity across the stimulation area, depending on the stimulation unit used. Furthermore, the helmet model can also be virtually overlaid with a previously measured head model, allowing for individual adaptation not only to different brain anatomies, but also to different skull anatomies, resulting in a secure helmet fit and thus precise irradiation of the stimulation area. The suction openings can also be computer-modeled in the helmet model. The finished helmet model can then be manufactured into a customized helmet using an additive process. 3D printing processes can be used for this purpose.

[0015] In principle, the stimulation area on the brain model can be determined based on empirical values ​​​​researched in medicine. Certain regions of the brain are responsible for different functions, so these regions can be visualized using an MRI procedure, and the stimulation area can be determined based on the visualization. While brains are fundamentally similar in structure, there are differences in size and shape of the brain tissue, as well as different blood vessel and nerve pathways, from subject to subject. However, precisely adjusting to these individual characteristics can promote precise and effective transcranial magnetic stimulation. Incorporating these anatomical specifics can be achieved by overlaying a brain activity map on the brain model before determining the stimulation area.By overlaying the anatomical brain model with the brain activity map, the electrical activity and cerebral blood flow in the brain can be determined, allowing the identification of areas that are particularly effective for stimulation. The brain activity map can be determined using, for example, electroencephalography (EEG), functional magnetic resonance imaging (fMRI), or functional near-infrared spectroscopy (fNIRS).

[0016] To ensure comprehensive capture of the geometric data of the subject's head, it is recommended to allow the 3D scanner unobstructed access to the subject's head. However, especially if the position of the stimulation unit is already predetermined, the stimulation unit can be fixed to the target position on the subject before measuring. This eliminates the need for virtual positioning in the helmet model, allowing a specialist to perform the positioning directly on the subject, allowing for the incorporation of medical expertise and experience before the helmet model is created.This results in a method for the individual production of a helmet for non-invasive brain stimulation, wherein a stimulation area is determined using a brain model, a stimulation unit aligned with the stimulation area is arranged on the head of a test subject, after which a three-dimensional helmet model is created by measuring the head of the test subject and the stimulation unit.

[0017] The above-mentioned methods can be used to manufacture helmets for non-invasive brain stimulation, with or without negative pressure connections. To enable precise adjustment of the helmet to a test subject without relying on a 3D scanner as a measuring unit, it is proposed that a helmet section of the helmet comprise a molding compound for adapting the helmet section to the shape of the test subject's head. In this way, helmets can be prefabricated in the factory and then adapted to the test subjects on-site, which primarily facilitates private use. For this purpose, for example, the head support as a helmet section can be coated with a molding compound so that when the helmet is placed on the head under pressure, indentations are created that are adapted to the head geometry and can then be cured.Hardenable molding strips can also be used as molding material. These are arranged on the edge of the helmet as a helmet section and pressed against the test subject's head over the edge of the helmet before they harden. Synthetic support bandages are suitable for this, such as polyurethane resin-impregnated fiberglass tapes, which harden on contact with water. This is therefore particularly suitable for a helmet for non-invasive brain stimulation with a head mount without an exhaust opening open towards the head mount, which is fluidly connected to a vacuum connection arranged outside the head mount. This results in a helmet for non-invasive brain stimulation with a stimulation unit directed towards a head mount, wherein a helmet section comprises a molding material for adapting the helmet section to the shape of a test subject's head.

[0018] In order to prefabricate the positioning fixture and precisely align the stimulation unit to the stimulation area on-site, it is recommended that the positioning fixture include a molding compound for aligning the stimulation unit. Foams, synthetic support bandages, or similar materials can also be used here.

[0019] Brief description of the invention

[0020] The subject matter of the invention is illustrated by way of example in the drawing. Fig. 1 shows a schematic representation of the helmet according to the invention for non-invasive brain stimulation,

[0021] Fig. 2 is a schematic flow diagram of the method for producing the helmet according to the invention and

[0022] Fig. 3 is a schematic representation of the helmet according to the invention for non-invasive brain stimulation in a second embodiment.

[0023] Ways to implement the invention

[0024] A helmet 1 according to the invention for non-invasive brain stimulation, shown in Fig. 1, comprises a stimulation unit 3, for example a magnetic field emitter, directed towards a head support 2. According to the invention, the helmet 1 has one, in particular several, suction openings 4 open towards the head support 2, which are preferably fluidly connected to a vacuum connection 6 via a common suction chamber 5. In this way, a negative pressure can be created in the head support 2 between the head 7 of a test subject and the helmet 1, so that the helmet 1 is sucked onto the head 7, thereby enabling the helmet 1 to fit securely on the head 7. In order to achieve the most leak-proof vacuum system possible, a circumferential sealing element D can be provided.The sealing element D can extend into the head receptacle 2 and press against the subject's head 7, thereby defining a negative pressure zone U extending within the head receptacle 2, which is defined by the sealing element D, the head 7, and the inside of the helmet. Multiple sealing elements D can also be provided, defining multiple mutually sealed negative pressure zones U.

[0025] In order to enable the use of different magnetic radiators 3 in one helmet 1 and the use of a single magnetic radiator 3 for different helmets 1 and subjects, the magnetic radiator 3 can be detachably inserted into a positioning receptacle 8 arranged corresponding to a stimulation area. The suction chamber 5 can extend around this positioning receptacle 8 so that the flow connection between the suction openings 4 and the

[0026] Vacuum connection 6 runs outside the positioning holder 8.

[0027] To monitor the subject's brain during non-invasive brain stimulation or to record brain activity to determine the stimulation area, sensors 10 located in distributed sensor receptacles 9 can be used. The sensors 10 can transmit the acquired data to a computing unit (not shown).

[0028] The sequence of a method according to the invention for the individual production of the helmet 1 is schematically shown in Fig. 2. First, an image of the brain is created, for example, using an MRI method in a brain imaging step 11. In an optional brain activity detection step 12, the activity of the brain can be determined, for example, using electroencephalography (EEG) or functional near-infrared spectroscopy (fNIRS), whereby particularly active areas that can thus be stimulated particularly efficiently can be detected in the anatomical brain model. Using, for example, optical means, an image of the head 7 of a test subject can be created in a likewise optional head measurement step 13. These images acquired in steps 11-13 are used in a superimposition step 14 with a helmet model when modeling the helmet 1.For this purpose, a stimulation area is determined (step 15) based on the image of the brain determined in brain imaging step 11 and preferably based on the brain activity in the brain recorded in brain activity recording step 12. This area is then determined in a positioning step 16, after which the corresponding positioning of the positioning holder 9 is carried out. For an optimal fit of the helmet 1, the data obtained in head measurement step 13 can be used in the overlay step 14 to model the helmet 1, in particular the inside of the helmet. Since the suction openings 4 should preferably run outside the positioning holder 9, simple manufacturing conditions result if the definition 17 of the suction openings 4 takes place after the positioning step 16 of the positioning holder 9.Finally, the helmet model produced using the process can be manufactured by additive manufacturing 18, for example by means of 3D printing.

[0029] Fig. 3 shows a second embodiment of a helmet 1 with helmet sections comprising a preferably curable molding compound for adapting the helmet section to the shape of the subject's head. The molding compound can be formed, for example, by a coating 19 on the inside of the helmet or by molding strips 20, which are pressed against the head 7 over the helmet rim before they are cured. The molding compound can also be used for helmets without suction openings 4. The positioning receptacle 8 can also comprise a molding compound for aligning the stimulation unit 3.

Claims

Patent claims 1. Helmet (1) for non-invasive brain stimulation with a stimulation unit (3) directed towards a head support (2), characterized by a suction opening (4) open towards the head support (2) and fluidly connected to a vacuum connection (6) arranged outside the head support (2).

2. Helmet (1) according to claim 1, characterized in that several suction openings (4) are provided which are open towards the head receptacle (2) and are fluidly connected to the vacuum connection (6).

3. Helmet (1) according to claim 1 or 2, characterized in that the at least one suction opening (4) is fluidly connected to the vacuum connection (6) via a common suction chamber (5).

4. Helmet (1) according to one of claims 1 to 3, characterized by a circumferential sealing element (D) delimiting a negative pressure region (U).

5. Helmet (1) according to one of claims 1 to 4, characterized by sensor receptacles (9) arranged distributed around the head receptacle (2).

6. Helmet (1) according to one of claims 1 to 5, characterized by a positioning receptacle (8) arranged corresponding to a stimulation area for the detachable insertion of the stimulation unit (3).

7. Helmet (1) according to claim 6, characterized in that the flow connection between the at least one suction opening (4) and the vacuum connection (6) runs outside the positioning receptacle (9).

8. Helmet (1) according to one of claims 1 to 7, characterized in that a helmet section comprises a molding compound for adapting the helmet section to the head shape of a test subject.

9. Helmet (1) according to one of claims 6 to 8, characterized in that the positioning receptacle (8) comprises a molding compound for aligning the stimulation unit (3).

10. A method for the individual production of a helmet (1) according to one of the preceding claims, wherein a stimulation area is determined on the basis of a brain model, after which the positioning receptacle (9) is arranged depending on the position of the stimulation area.

11. Method according to claim 10, characterized in that a three-dimensional helmet model is generated and superimposed with the brain model, after which the positioning receptacle (9) is determined in the helmet model as a function of the stimulation area and the helmet is additively manufactured from the helmet model.

12. The method according to claim 10 or 11, characterized in that the brain model is overlaid with a brain activity map before the stimulation area is determined.

13. Method according to claim 11 or 12, characterized in that a head model of a test subject is measured, after which the helmet model is adapted to the head model.

14. The method according to claim 10, characterized in that a stimulation unit (3) aligned with the stimulation area is arranged on the head (7) of a test subject, after which a three-dimensional helmet model is generated by measuring the head (7) of the test subject and the stimulation unit (3).

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