System to improve signal quality in non-invasive neuroimaging modalities

Abstract

A device comprising a wearable cap comprising at least one sensor component, wherein the at least one sensor component comprises a sensor and a holder, wherein the holder is integrated into the wearable cap, wherein the holder is configured to receive the sensor, wherein a lower surface of the sensor extends through the holder and comprises a conductive element configured to contact a scalp of a wearable cap user, the at least one sensor component comprising two attachment components, wherein the attachment components are affixed to a surface of the wearable cap at opposing ends of the holder, the at least one sensor component comprising a tensioning band, wherein the tensioning band is secured at both ends to the respective attachment components, wherein the tensioning band in the secured position passes over an upper surface of the sensor and generates a downward force on the sensor and holder.

Description

[0001] SYSTEM TO IMPROVE SIGNAL QUALITY IN NON-INVASIVE NEUROIMAGING MODALITIES

[0002] Inventor: Stacey Gorniak

[0003] RELATED APPLICATION

[0004] This application claims the benefit of United States Patent Application No. 63 / 633,022, filed April 11, 2024.

[0005] TECHNICAL FIELD

[0006] The disclosure set forth herein is directed to fNIRS and EEG sensor technologies.

[0007] BACKGROUND

[0008] There has been considerable interest in applying electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS) simultaneously for multimodal assessment of brain function. EEG-fNIRS can provide a comprehensive picture of brain electrical and hemodynamic function and has been applied across various fields of brain science. The development of wearable, mechanically and electrically integrated EEG- fNIRS technology is a critical step in the evolution of this field. Manufacturers have provided combined fNIRS and EEG caps that provide wearability, patient / subject comfort, and capability for long-term monitoring. However, the wearer’s hair and other obstructions often impede contact of the sensors with the scalp.

[0009] INCORPORATION BY REFERENCE

[0010] Each patent, patent application, and / or publication mentioned in this specification is herein incorporated by reference in its entirety to the same extent as if each individual patent, patent application, and / or publication was specifically and individually indicated to be incorporated by reference. SUMMARY OF THE INVENTION

[0011] A device is described herein comprising a wearable cap, wherein the wearable comprises at least one sensor component, wherein the at least one sensor component comprises a sensor and a holder, wherein the holder is integrated into the wearable cap, wherein the holder is configured to receive the sensor, wherein a lower surface of the sensor extends through the holder and comprises a conductive element configured to contact a scalp of a wearable cap user, the at least one sensor component comprising two attachment components, wherein the attachment components are affixed to a surface of the wearable cap at opposing ends of the holder, the at least one sensor component comprising a tensioning band, wherein the tensioning band is secured at both ends to the respective attachment components, wherein the tensioning band in the secured position passes over an upper surface of the sensor and generates a downward force on the sensor and holder.

[0012] In embodiments, the holder comprises a functional near-infrared spectroscopy (INIRS) holder.

[0013] In embodiments, the sensor comprises an fNIRS sensor.

[0014] In embodiments, the holder comprises an electroencephalogram (EEG) holder.

[0015] In embodiments, the sensor comprises an EEG sensor.

[0016] In embodiments, the downward force urges the contact element of the sensor towards the scalp of the wearable cap user for increased contact.

[0017] In embodiments, the tensioning band comprises an elastic material.

[0018] In embodiments, the attachment components comprise beads.

[0019] In embodiments, the attachment components comprise hooks.

[0020] In embodiments, the attachment components comprise bobbins.

[0021] In embodiments, the bobbins are printed using a three-dimensional printing procedure.

[0022] In embodiments, the three-dimensional procedure utilizes a glycol modified version of polyethylene terephthalate. In embodiments, the tensioning band comprises a tactical rubber band.

[0023] In embodiments, the attachment components are adhesively affixed to the surface of the cap.

[0024] In embodiments, the adhesive comprises E6000® fabri-fuse fabric glue.

[0025] A method of manufacturing a wearable sensor cap is described herein comprising attaching a plurality of sensor holders to a wearable sensor cap, wherein the plurality of sensor holders are configured to receive a sensor, wherein a lower surface of the sensor extends through the plurality of holders and comprises a conductive element configured to contact a scalp of a wearable sensor cap user, affixing two attachment components to a surface of the wearable sensor cap at opposing ends of each holder of the plurality of sensor holders, and securing a tensioning band to the attachment components at both ends of the respective holder of the plurality of sensor holders, wherein the tensioning band in the secured position passes over an upper surface of a respective sensor and generates a downward force on the respective sensor.

[0026] In embodiments, the plurality of sensor holders comprises a functional nearinfrared spectroscopy (fNIRS) holder.

[0027] In embodiments, the respective sensor comprises an fNIRS sensor.

[0028] In embodiments, the plurality of sensor holders comprises an electroencephalogram (EEG) holder.

[0029] In embodiments, the respective sensor comprises an EEG sensor.

[0030] In embodiments, the attachment components comprise bobbins.

[0031] In embodiments, the bobbins are printed using a three-dimensional printing procedure.

[0032] In embodiments, the tensioning band comprises a tactical rubber band.

[0033] In embodiments, the three-dimensional procedure utilizes a glycol modified version of polyethylene terephthalate.

[0034] In embodiments, the attachment components are adhesively affixed to the surface of the cap. In embodiments, the adhesive E6000® fabri-fuse fabric glue.

[0035] A method of using the wearable cap is described herein comprising receiving the wearable cap, placing the wearable cap on a user's head, and detecting neuroimaging signals through the at least one sensor component.

[0036] BRIEF DESCRIPTION OF THE FIGURES

[0037] Figure 1 shows a NIRS sensor holder, under an embodiment.

[0038] Figure 2 shows an EEG electrode holder, under an embodiment.

[0039] Figure 3A shows a cap with NIRS sensors distributed at various locations, under an embodiment.

[0040] Figure 3B shows a cap with NIRS sensors distributed at various locations, under an embodiment.

[0041] Figure 4A shows a cap with NIRS sensors secured using a hook and band configuration, under an embodiment.

[0042] Figure 4B shows a cap with NIRS sensors secured using a hook and band configuration, under an embodiment.

[0043] Figure 4C shows cap with NIRS sensors secured using hook and band fastener configuration, under an embodiment.

[0044] Figure 4D shows cap with NIRS sensors secured using hook and band fastener configuration, under an embodiment.

[0045] Figure 5 shows a bobbin, under an embodiment.

[0046] Figure 6 shows a cap with NIRS sensors secured using a bobbin and band configuration, under an embodiment.

[0047] Figure 7 shows a cap with NIRS sensors secured using a bobbin and band configuration, under an embodiment.

[0048] Figure 8 shows a traditional approach to sensor placement in non-invasive neuroimaging, under an embodiment. Figure 9 shows use of a tensioning attachment and band, under an embodiment. The result is compression of sensor in a direction of the scalp and skull for improved signal quality in non-invasive neuroimaging, under an embodiment.

[0049] DETAILED DESCRIPTION

[0050] A device and method are described herein for improving signal quality in non- invasive neuroimaging techniques using an individual tensioning system for each electrode / optode / source / detector (referred to as “sensor” in the text) in a neuroimaging setup that measures signals through the scalp. This device improves signal quality by improving adherence of the devices to the scalp (e.g., through hair) using a compressive approach through application of tension to individual sensors.

[0051] Currently, non-invasive neuroimaging devices that measure through the scalp & derma suffer from poor signal-to-noise quality in participants who have dense hair or large amounts of hair. In terms of neuroimaging, signal-to-noise is defined as the ratio of the strength of an electrical, optical, or other signal carrying information to that of interference generated by many sources, including physiological sources (e.g., participant hair). Reduction of interference by physiological sources due to voluminous hair or hair type and / or hairstyle is important in the field of neuroimaging. Many times, studies do not include individuals with voluminous hair or specific hair types and styles to avoid this signal quality issue. In studies which do attempt to be more inclusive, poor signal-to- noise quality due to hair typically results in data being discarded. Certain populations are disproportionately impacted by these practices (e.g., women and persons of color).

[0052] Sparse solutions to the issue of data discard (or lack of data collection) exist for persons with dense hair or large amounts of hair. Several labs have attempted hair braiding solutions, but this practice is limited. Precision Neuroscopics provides a device known as “Sevo” that focuses on parting hair using clips. The Sevo device cannot be used with standard EEG and fNIRS caps; whereas the device described herein utilizes standard EEG and fNIRS caps. This device can also be made to be compatible with tDCS and MRI technologies. The combination of leveraging standard neuroimaging cap layouts and tDCS / MRI compatibility provides the opportunity for widespread adoption of the technology worldwide.

[0053] A fNIRS / EEG cap may deploy NIRS and EEG sensors simultaneously. Electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS) stand as state-of-the-art techniques for non-invasive functional neuroimaging.

[0054] Electroencephalography (EEG) is a method to record an electrogram of the spontaneous electrical activity of the brain. The bio signals detected by EEG have been shown to represent the postsynaptic potentials of pyramidal neurons in the neocortex and allocortex. It is typically non-invasive, with the EEG electrodes placed along the scalp (commonly called "scalp EEG") using the International 10-20 system, or variations of it. Clinical interpretation of EEG recordings is most often performed by visual inspection of the tracing or quantitative EEG analysis.

[0055] Functional near-infrared spectroscopy (fNIRS) is an optical brain monitoring technique which uses near-infrared spectroscopy for the purpose of functional neuroimaging. Using fNIRS, brain activity is measured by using near-infrared light to estimate cortical hemodynamic activity which occur in response to neural activity. Alongside EEG, fNIRS is one of the most common non-invasive neuroimaging techniques which can be used in portable contexts. The signal is often compared with the BOLD signal measured by fMRI and is capable of measuring changes both in oxy- and deoxyhemoglobin concentration, but can only measure from regions near the cortical surface. fNIRS may also be referred to as Optical Topography (OT) and is sometimes referred to simply as NIRS. As with EEG, NIRS sensors are placed using the International 10-20 system, or variations of it.

[0056] On a unimodal basis, EEG has poor spatial resolution while presenting high temporal resolution. In contrast, fNIRS offers better spatial resolution, though it is constrained by its poor temporal resolution. Again note that both may be used simultaneously.

[0057] The device in this disclosure is a specific modification of traditional EEG / fNIRS caps to permit compression of individual sensors for any measurement layout. The device utilizes a washable adhesive specific to stretch materials that is used to adhere different materials to the stretch material of the cap. The adhered materials may be of any composition (metal, coated metal, plastic, wood, etc).

[0058] Various shapes of adhered materials are described herein. However embodiments are not so limited and adhered materials may be of any shape capable of receiving and securing a tensioning band. Tensioning systems are described below.

[0059] Headgear or cap devices are available to deploy EEG or NIRS sensors on the scalp. Figures 3 A and 3B show a cap with NIRS sensor holders distributed at various locations. See Figure 1 for an image of an NIRS sensor holder alone, under an embodiment. Figures 3A and 3B shows holders 302 integrated into cap. Under an embodiment, bead type attachments 304 are attached to the cap using an E6000® Fabri- Fuse Fabric Glue. The beads then keep the tensioning bands in place. In use, a tensioning band is passed over and behind one bead, then over the sensor seated in the holder, and then over and behind the second bead. (Note that the band and sensor are not shown in Figure 3A and 3B but function in that same manner as the hook and bobbin tensioning embodiments described below). The beads may comprise any material including glass, wood, plastic, metal, and stone.

[0060] Under an alternative embodiment, a hook and securing tensioning band configuration may be used. Figures 4A-4D show various views of the EEG / fNIRS cap with an fNTRS sensor setup.

[0061] Figure 4A shows a view of an EEG / fNIRS cap with full fNIRS optode & detector setup, under an embodiment.

[0062] Figure 4B illustrates the anterior portion of the right hemisphere of an EEG / fNIRS cap, under an embodiment.

[0063] Figure 4C illustrates the anterior portion of left hemisphere of an EEG / fNIRS cap, under an embodiment.

[0064] Figure 4D demonstrates (in close up view) the hooks and band tensioning configuration for an individual optode sensor 404 & detector sensor 402 of the fNIRS system. (Each sensor is seated in holder 420). Figure 4D shows hook fasteners 408 located on each side of the sensors 402, 404. The hook fasteners 408 are affixed to cap using E6000® Fabri-Fuse Fabric Glue. A tensioning band 410 is secured about a hook on one end of a sensor, is passed over the sensor, and then is secured by a hook on the other end of the sensor. The secured fasteners place downward tension on the sensor. Under one embodiment, bra hooks (size 1) are used as tensioning attachments and miniature rubber bands are used as tensioning bands.

[0065] Under another embodiment, the adhered attachment component comprises a bobbin shape as shown in Figure 5. Under this embodiment, a bobbin is 3D printed using PETG material. PETG is a Glycol Modified version of Polyethylene Terephthalate (PET). (Note that alternative embodiments may comprise polycarbonate (PC) or any other suitable 3D printing material). Figures 6 and 7 show a cap with a NIRS sensor secured using a bobbin 608 and band fastener 610 configuration, under an embodiment. A lower surface of a bobbin 608 is adhered (using E6000® Fabri-Fuse Fabric Glue) to the cap stretch material on both sides of a sensor 604 seated in holder 602. A tensioning band 610 e.g., a tactical rubber band, is secured to the first bobbin, then is passed over a sensor, and then secured to the second bobbin. The tactical rubber band comprises a heavy-duty, durable rubber band designed for outdoor and survival applications. Such rubber bands may comprise ethylene propylene diene monomer (EPDM). Alternatively, silicone bands can be used. Note that these materials may be used for all embodiments of the tensioning system described herein. As seen in Figures 6 and 7, an opening at each side of the band passes over the respective bobbin’s upper circumferential lip to then secure each end within a respective bobbin. This configuration compresses the sensor in a direction of the scalp and skull for improved signal quality in non-invasive neuroimaging.

[0066] An individual sensor tensioning system is created as an elastic material is stretched between the adhered materials, which compresses the sensor underneath into the skin of the study participant / patient. The adhesive and elastic materials (i.e. E6000® F bri-Fuse Fabric Glue and tactical rubber bands) are MRI compatible. The adhered materials (3D printed bobbins or plastic hooks) are also MRI compatible. Figure 8 shows a traditional approach to sensor placement in non-invasive neuroimaging, under an embodiment.

[0067] Figure 9 shows use of a tensioning attachment and band. The result is compression of sensor in a direction of the scalp and skull for improved signal quality in non-invasive neuroimaging, under an embodiment. The tensioning system shown in Figure 9 may comprise any of the adhered attachment component and tensioning band configurations described above. Note that the embodiments above are described with respect to NIRS sensor. However, the same tensioning system may also be applied to EEG sensors placed on a wearable cap. The tensioning system may also be used for tDCS and tACS (or any other neuroimaging system using stretch cap material).

Claims

CLAIMS1. A device comprising, a wearable cap comprising at least one sensor component, wherein the at least one sensor component comprises a sensor and a holder, wherein the holder is integrated into the wearable cap, wherein the holder is configured to receive the sensor, wherein a lower surface of the sensor extends through the holder and comprises a conductive element configured to contact a scalp of a wearable cap user; the at least one sensor component comprising two attachment components, wherein the attachment components are affixed to a surface of the wearable cap at opposing ends of the holder; the at least one sensor component comprising a tensioning band, wherein the tensioning band is secured at both ends to the respective attachment components, wherein the tensioning band in the secured position passes over an upper surface of the sensor and generates a downward force on the sensor and holder.

2. The device of claim 1, wherein the holder comprises a functional near-infrared spectroscopy (fNIRS) holder.

3. The device of claim 2, wherein the sensor comprises an fNIRS sensor.

4. The device of claim 1, wherein the holder comprises an electroencephalogram (EEG) holder.

5. The device of claim 4, wherein the sensor comprises an EEG sensor.

6. The device of claim 1, wherein the downward force urges the contact element of the sensor towards the scalp of the wearable cap user for increased contact.

7. The device of claim 1, wherein the tensioning band comprises an elastic material.

8. The device of claim 1, wherein the attachment components comprise beads.

9. The device of claim 1, wherein the attachment components comprise hooks.

10. The device of claim 1, wherein the attachment components comprise bobbins.11 . The device of claim 10, wherein the bobbins are printed using a three-dimensional printing procedure.

12. The device of claim 11, wherein the three-dimensional procedure utilizes a glycol modified version of polyethylene terephthalate.

13. The device of claim 12, wherein the tensioning band comprises a tactical rubber band.

14. The device of claim 1, wherein the attachment components are adhesively affixed to the surface of the cap.

15. The device of claim 14, wherein the adhesive comprises E6000® fabri-fuse fabric glue.

16. A method of manufacturing a wearable sensor cap comprising, attaching a plurality of sensor holders to a wearable sensor cap, wherein the plurality of sensor holders are configured to receive a sensor, wherein a lower surface of the sensor extends through the plurality of holders and comprises a conductive element configured to contact a scalp of a wearable sensor cap user;affixing two attachment components to a surface of the wearable sensor cap at opposing ends of each holder of the plurality of sensor holders; securing a tensioning band to the attachment components at both ends of the respective holder of the plurality of sensor holders, wherein the tensioning band in the secured position passes over an upper surface of a respective sensor and generates a downward force on the respective sensor.

17. A method of manufacturing the wearable sensor cap of claim 16, wherein the plurality of sensor holders comprises a functional near-infrared spectroscopy (fNTRS) holder.

18. A method of manufacturing the wearable sensor cap of claim 17, wherein the respective sensor comprises an fNIRS sensor.

19. A method of manufacturing the wearable sensor cap of claim 16, wherein the plurality of sensor holders comprises an electroencephalogram (EEG) holder.

20. A method of manufacturing the wearable sensor cap of claim 19, wherein the respective sensor comprises an EEG sensor.

21. A method of manufacturing the wearable sensor cap of claim 16, wherein the attachment components comprise bobbins.

22. A method of manufacturing the wearable sensor cap of claim 21, wherein the bobbins are printed using a three-dimensional printing procedure.

23. A method of manufacturing the wearable sensor cap of claim 22, wherein the tensioning band comprises a tactical rubber band.

24. A method of manufacturing the wearable sensor cap of claim 23, wherein the three-dimensional procedure utilizes a glycol modified version of polyethylene terephthalate.

25. A method of manufacturing the wearable sensor cap of claim 16, wherein the attachment components are adhesively affixed to the surface of the cap.

26. A method of manufacturing the wearable sensor cap of claim 16, wherein the adhesive E6000® fabri-fuse fabric glue.

27. A method of using the wearable cap of claim 1, the method comprising receiving the wearable cap; placing the wearable cap on a user's head; and detecting neuroimaging signals through the at least one sensor component.

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