EEG signal measurement method and system

Abstract

A system for measuring EEG signals, comprising a wearable body adapted to be mounted on the scalp, a plurality of electrodes mounted on the wearable body, and optionally a plurality of controllable actuators for applying forces to the electrodes. A controller optionally controls each actuator or each group of actuators to apply forces to at least one electrode. A signal processor receives and processes signals from the electrodes and optionally sends control signals to the controller based on the processing.

Description

[0001] Related Applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 62 / 862,689, filed on June 18, 2019, the entire contents of which are incorporated herein by reference.

[0003] FIELD AND BACKGROUND OF THE INVENTION

[0004] The present invention relates to electroencephalography (EEG), and in some embodiments thereof, more particularly, but not limited to, methods and systems for measuring EEG signals.

[0005] The brain is a complex structure of nerve cells that generate signals called excitatory post synaptic potentials (EPSPs). These potentials are summed in the cortex and extend through the covering of the brain to the scalp, where they can be measured using appropriate electrodes. The activity measured by the rhythm represents the postsynaptic cortical neuron potential, which is synchronized by the complex interaction of a large number of cortical cells. The non-invasive recording technology EEG is one of the commonly used systems for monitoring brain activity. EEG data is collected from multiple channels simultaneously with high temporal resolution, producing a high-dimensional data matrix for representing brain activity. In addition to its unparalleled temporal resolution, EEG is non-invasive, wearable, and more economical than other neuroimaging techniques.

[0006] In some techniques, EEG signals are acquired by a head-mounted viewer (EEG headset).

[0007] A very common example of an EEG headset used in medical applications is a standard electroencephalogram cap (EEG cap), which includes a cap made of rubber or rubber-like material that is worn on the subject's head like a swimming cap. The cap has surface electrodes positioned across the cap in contact with the surface of the subject's head. Common contemporary EEG headsets require extensive preparation and professional, lengthy setup and positioning. To increase conductivity, gel or saline is often used. In some cases, uncomfortable pressure is applied to the electrodes to enhance electrical coupling. It is also known to use dry electrodes, which allow for quick and easy setup. Once the EEG headset is worn, a trial-and-error procedure is employed to ensure that the headset is properly aligned with the desired location on the scalp and properly attached to the scalp to achieve good conductivity. SUMMARY OF THE INVENTION

[0009] According to one aspect of some embodiments of the present invention, there is provided a system for measuring electroencephalogram (EEG) signals. The system comprises a wearable body adapted to be mounted on the scalp, a plurality of electrodes mounted on the wearable body at a density of at least 2 electrodes per 3 square centimeters, and a signal processor configured to detect evoked related potential (ERP) signals from the electrodes and determine the physiological position of each electrode or each group of electrodes based on the ERP signals.

[0010] According to some embodiments of the invention, the system comprises an input for receiving a signal describing stimulation of a subject wearing the wearable body from a stimulation system, wherein the signal processor is configured to determine the position based in part on the signal from the stimulation system.

[0011] According to some embodiments of the invention, the stimulation system is configured to apply electrical stimulation via at least one electrode.

[0012] According to one aspect of some embodiments of the present invention, there is provided a system for measuring EEG signals. The system comprises: a wearable body adapted to be mounted on the upper part of the scalp; a plurality of electrodes mounted on the wearable body; a plurality of stretch sensors for generating stretch data describing the stretching of the wearable body; and a signal processor configured to receive the stretch data and construct a three-dimensional map based on the stretch data, the three-dimensional map describing the physiological position of the electrodes on the wearable body once stretched.

[0013] According to some embodiments of the invention, the system comprises a plurality of physically separated sensing systems, each sensing system comprising several of the plurality of electrodes.

[0014] According to an aspect of some embodiments of the present invention, there is provided a system for measuring EEG signals. The system comprises: a wearable body adapted to be mounted on a scalp; a plurality of electrodes mounted on the wearable body; a plurality of controllable actuators for applying forces to the electrodes; a controller configured to individually control each actuator or each group of actuators to apply forces to at least one electrode; and a signal processor configured to receive and process signals from the electrodes based on the processing and send control signals to the controller.

[0015] According to some embodiments of the invention, the signal processor is configured to determine at least one of electrode-tissue impedance, signal-to-noise ratio, artifact percentage, and signal quality, and to control the force based on the determination.

[0016] According to some embodiments of the invention, at least one electrode is flexible and configured to undergo strain upon being pressed against the scalp by a force.

[0017] According to some embodiments of the invention, the actuator is configured to apply the force while establishing a rotational motion to the electrode.

[0018] According to some embodiments of the invention, at least one of the controllable actuators comprises an inflatable bladder which applies the force when inflated.

[0019] According to some embodiments of the invention, the force is periodic and applied to vibrate the electrodes or create a hammering effect.

[0020] According to some embodiments of the invention, the system comprises a plurality of physically separated sensing systems, each sensing system comprising several of the plurality of electrodes.

[0021] According to some embodiments of the invention, at least one of the sensing systems comprises a circuit board and a plurality of flexible legs, each flexible leg having a non-conductive portion and a conductive portion having a tip electrically connected to the circuit board, wherein each conductive portion is one of a plurality of electrodes.

[0022] According to some embodiments of the present invention, the circuit board and the plurality of flexible legs are separable from each other.

[0023] According to some embodiments of the present invention, the wearable body comprises an inner shell supporting a circuit board and a plurality of flexible legs and an outer shell supporting a plurality of controllable actuators.

[0024] According to some embodiments of the invention, at least one of the flexible legs has a helical shape.

[0025] According to some embodiments of the invention, the conductive portion of at least one leg of the plurality of legs is polymeric.

[0026] According to some embodiments of the invention, the conductive portion of at least one leg of the plurality of legs comprises a bundle of conductive bristles.

[0027] According to some embodiments of the invention, the system comprises a controllable vibration member configured to vibrate the leg.

[0028] According to some embodiments of the invention, at least one of the legs comprises a hydrophobic region located at an upper portion of the leg and a hydrophilic region located at a lower portion of the leg.

[0029] According to some embodiments of the present invention, the plurality of flexible legs are arranged on a base of a sensing system body, wherein the sensing system comprises an axis and a shell body mounted on the axis and configured to receive the sensing system body, and wherein the shell body comprises a rigid wall for holding the sensing system body and a flexible membrane connecting the rigid wall to the axis in a manner allowing the shell body to present a plurality of different orientations relative to the axis.

[0030] According to some embodiments of the invention, the system comprises a controller for controlling the connection status of each individual electrode.

[0031] According to some embodiments of the invention, the system comprises a wired bus interface for establishing communication between the controller and the electrodes.

[0032] According to some embodiments of the invention, the controller is configured to electrically group the electrodes into at least one group.

[0033] According to some embodiments of the invention, one or more groups form a predetermined topography on the surface of the scalp.

[0034] According to some embodiments of the invention, the group is selected in a closed loop control based on at least one of electrode-tissue impedance, signal-to-noise ratio, artifact percentage and signal quality calculated by a signal processor for signals received by the electrodes.

[0035] According to an aspect of some embodiments of the present invention, there is provided a method for measuring an EEG signal, the method comprising operating a system according to any one of claims 1 to 22, while placing the wearable body on a subject's scalp to receive the EEG signal sensed by the plurality of electrodes, thereby measuring the EEG signal.

[0036] According to an aspect of some embodiments of the present invention, there is provided a system for sensing electroencephalogram signals. The system comprises a circuit board and a plurality of flexible legs, each flexible leg having a non-conductive portion and a conductive portion having a tip electrically connected to the circuit board, wherein at least one flexible leg has a spiral shape.

[0037] According to an aspect of some embodiments of the present invention, there is provided a system for sensing electroencephalogram signals, the system comprising a circuit board and a plurality of flexible legs, each flexible leg having a non-conductive portion and a conductive portion having a tip in electrical communication with the circuit board, wherein the conductive portion of at least one of the plurality of legs comprises a bundle of conductive bristles.

[0038] According to an aspect of some embodiments of the present invention, there is provided a system for sensing electroencephalogram signals. The system comprises a circuit board and a plurality of flexible legs, each flexible leg having a non-conductive portion and a conductive portion having a tip electrically connected to the circuit board, wherein at least one leg comprises a hydrophobic region located at an upper portion of the leg and a hydrophilic region located at a lower portion of the leg.

[0039] According to some embodiments of the invention, the leg comprises an intermediate region between the hydrophobic region and the hydrophilic region, the intermediate region being less hydrophobic than the hydrophobic region and less hydrophilic than the hydrophilic region.

[0040] According to an aspect of some embodiments of the present invention, there is provided a method for measuring an EEG signal, the method comprising: detecting an evoked response potential (ERP) signal from a plurality of electrodes disposed on a scalp surface of a subject at a density of at least two electrodes per 3 square centimeters; and processing the ERP to determine a physiological position of each electrode or each group of electrodes on the surface based on the ERP signal.

[0041] According to some embodiments of the invention, the method comprises receiving a signal input from a stimulation system describing stimulation of the object, wherein the determination of the position is based in part on the signal from the stimulation system.

[0042] According to an aspect of some embodiments of the present invention, there is provided a method of measuring EEG signals, the method comprising: receiving signals from a plurality of electrodes placed on a scalp surface of a subject; and processing the signals and controlling a plurality of controllable actuators to apply forces to the electrodes based on the processing.

[0043] According to some embodiments of the invention, the method comprises determining at least one quantity selected from the group consisting of electrode-tissue impedance, signal-to-noise ratio, artifact percentage and signal quality, and increasing the force in response to a value of the at least one quantity.

[0044] According to some embodiments of the invention, the force is applied inwardly.

[0045] According to some embodiments of the invention, at least one of the controllable actuators comprises an inflatable bladder, wherein the controlling comprises inflating the bladder to apply the force.

[0046] According to some embodiments of the invention, the method comprises determining pressure in the balloon and at least one quantity selected from electrode-tissue impedance, signal-to-noise ratio, artifact percentage and signal quality, and varying the pressure in response to a value of the at least one quantity.

[0047] According to some embodiments of the invention, the controlling comprises operating an actuator to periodically apply a force to vibrate the electrode or to produce a hammering effect.

[0048] According to some embodiments of the invention, the method comprises determining at least one quantity selected from the group consisting of electrode-tissue impedance, signal-to-noise ratio, artifact percentage, and signal quality, and operating an actuator to vibrate the electrode or produce a hammering effect in response to the value of the at least one quantity.

[0049] According to some embodiments of the invention, the method comprises changing a connection state of at least one electrode.

[0050] According to some embodiments of the invention, the method comprises electrically grouping the electrodes into at least one group.

[0051] According to some embodiments of the invention, the method comprises selecting the group according to a predetermined morphology on the scalp surface.

[0052] According to some embodiments of the invention, the method comprises determining at least one quantity selected from the group consisting of electrode-tissue impedance, signal-to-noise ratio, artifact percentage and signal quality, and selecting the group in closed-loop control based on the value of the quantity.

[0053] According to one aspect of some embodiments of the present invention, there is provided a fixture system for assembling a plurality of sensing systems, each of which is configured to sense EEG signals. The fixture system comprises a scaffold having an outer surface and an inner surface, the outer surface being designed and configured to fit and accommodate a wearable body having a plurality of shell bodies mounted thereon; a plurality of recesses formed on the outer surface, each recess having a base and a through hole formed between the base and the inner surface of the scaffold, the size and shape of each recess being compatible with a disposable electrode assembly of one of the sensing systems; and a plurality of fixture shafts, each fixture shaft being introduced into one of the recesses from one side of the inner surface via a corresponding through hole.

[0054] According to an aspect of some embodiments of the present invention, there is provided a kit. The kit comprises a fixture system as shown above, optionally and preferably, a fixture system as described in detail below; and a system for measuring EEG signals, wherein the system comprises a wearable body suitable for mounting on the scalp and a plurality of housings mounted on the wearable body, each housing having a circuit board of one of the sensing systems therein and being configured to receive an electrode assembly of one of the sensing systems.

[0055] According to some embodiments of the invention, the kit includes a plurality of disposable electrode assemblies, each disposable electrode assembly being sized and shaped to be compatible with one of the recesses.

[0056] According to one aspect of some embodiments of the present invention, there is provided a method of combining a system for measuring EEG signals. The method comprises placing a plurality of disposable electrode assemblies of a corresponding plurality of sensing systems in a corresponding plurality of recesses of a fixture system, such as, but not limited to, the fixture system described above, and optionally and preferably as further described below; mounting a wearable body on the support, the wearable body having a plurality of shell bodies, each of the plurality of shell bodies being configured to receive one of the electrode assemblies, and having a circuit board of one of the sensing systems in the plurality of shell bodies so as to align the shell body with the recess; and actuating the fixture shaft to release the electrode assembly from the recess and connect the electrode assembly to the shell body.

[0057] Unless otherwise defined, all technical and / or scientific terms used herein have the same meaning as those generally understood by those of ordinary skill in the art. Although methods and materials similar or equivalent to the methods and materials described herein can be used in the practice or testing of embodiments of the present invention, exemplary methods and / or materials are described below. If there is a conflict, the patent application document, including definitions, shall prevail. In addition, materials, methods and embodiments are illustrative only and are not intended to be limiting.

[0058] The implementation of the method and / or system of the embodiment of the present invention may involve performing or completing the selected task manually, automatically or in combination thereof. In addition, according to the actual instrument and equipment of the embodiment of the method and / or system of the present invention, several selected tasks may be implemented by using the hardware, software or firmware or a combination thereof of the operating system.

[0059] For example, the hardware for performing the selected tasks according to the embodiments of the present invention can be implemented as a chip or circuit. With regard to software, the selected tasks according to the embodiments of the present invention can be implemented by a plurality of software instructions executed by a computer using any suitable operating system. In an exemplary embodiment of the present invention, one or more tasks according to the exemplary embodiments of the method and / or system described herein are performed by a data processor, such as a computing platform for executing a plurality of instructions. Optionally, the data processor includes a volatile memory and / or non-volatile memory for storing instructions and / or data, for example, a magnetic hard disk and / or removable media for storing instructions and / or data. Optionally, a network connection is also provided. A display and / or a user input device such as a keyboard or a mouse are also optionally provided.

[0060] BRIEF DESCRIPTION OF THE MULTIPLE VIEWS OF THE DRAWINGS

[0061] Some embodiments of the present invention are described with reference to the accompanying drawings by way of example only. Particular reference will now be made to the drawings where they are shown in detail, with emphasis on the details shown being by way of example and for the purpose of illustrative discussion of embodiments of the present invention. In this regard, the description in conjunction with the drawings will make it clear to those skilled in the art how to implement embodiments of the present invention.

[0062] In the attached picture:

[0063] Figure 1A and 1B is a schematic diagram of a system for measuring EEG signals according to some embodiments of the present invention;

[0064] Figure 1C is a schematic diagram showing an installation configuration of electrodes on a wearable body according to some embodiments of the present invention;

[0065] Figure 1D -F is a diagram showing that some embodiments according to the present invention are suitable for Figure 1C Schematic diagram of representative examples of electrode shapes shown in;

[0066] Figure 2A -E is a schematic diagram of a wearable body including a plurality of stretch sensors according to some embodiments of the present invention;

[0067] Figure 3A - F is a schematic diagram of a sensing system comprising several electrodes in an embodiment of the present invention in which metal wires are used;

[0068] Figure 4A -F is a schematic diagram of a sensing system including several electrodes in an embodiment of the present invention in which a bundle of conductive bristles is employed;

[0069] Figure 5A - F is a schematic diagram of a sensing system including several electrodes in an embodiment of the present invention in which conductive polymer bundles are used;

[0070] FIG6 is a schematic diagram of a spiral sensing leg according to some embodiments of the present invention;

[0071] FIG7 is a schematic diagram of a sensing leg in an embodiment of the present invention, wherein the leg includes a hydrophobic region and a hydrophilic region;

[0072] Fig. 8A -H is a schematic diagram of a system for measuring EEG signals in an embodiment of the present invention, wherein the system includes a controllable actuator for applying a force to an electrode;

[0073] Fig.9A and 9B is a schematic diagram of a system in an embodiment of the present invention, wherein the actuator includes an airbag, a shaft and a stator, and the wearable body includes an outer shell and an inner shell;

[0074] Fig. 9C is a schematic diagram of a sheet-like member and a plurality of sensing system bodies embedded therein according to some embodiments of the present invention;

[0075] Fig. 10A and 10B is a schematic diagram describing a bus interface according to some embodiments of the present invention;

[0076] Fig.11 is a flow chart describing a closed-loop process for operating an actuator to apply a compressive force on an electrode according to some embodiments of the present invention;

[0077] Fig.12 is a flow chart describing a closed-loop process for operating an actuator to vibrate an electrode according to some embodiments of the present invention;

[0078] Fig.13 is a flow chart describing a closed-loop process for operating an actuator to provide a hammering effect according to some embodiments of the present invention;

[0079] Fig.14A -F is a schematic diagram showing additional configurations of a sensing leg according to some embodiments of the present invention;

[0080] Fig.15 is a flow chart describing a combined process for operating an actuator according to some embodiments of the present invention; and

[0081] Fig.16A -D is a schematic diagram of a clamping system according to some embodiments of the present invention.

[0082] Description of the Specific Embodiments of the Invention

[0083] In some embodiments of the invention, the invention relates to EEG, and more particularly, but not limited to, to methods and systems for measuring EEG signals.

[0084] Before describing in detail at least one embodiment of the present invention, it should be understood that the present invention is not necessarily limited to the details of the construction and arrangement of the components and / or methods shown in the following description and / or drawings and / or embodiments. The present invention can be implemented or implemented in other embodiments in various ways.

[0085] The inventors have realized that there are several technical challenges in the measurement of EEG signals. EEG signals can be collected using either wet electrodes or dry electrodes. The inventors have realized that the use of wet electrodes requires time-consuming preparation, skilled and experienced operators, and a complicated process because the conductive gel should be applied to the scalp and because the preparation of the subject often requires shaving and removing dead skin from the scalp. The gel may also cause discomfort to the subject and may also cause skin irritation. In addition, since the gel dries over time, it is necessary to reapply the gel regularly (usually every hour). In addition, the amount of gel applied needs to be considered very carefully because too much gel may cause a short circuit between the electrodes and less gel may result in poor conductivity.

[0086] The inventors have recognized that the use of dry electrodes is not without certain operational limitations that are best avoided. These include the need to manually place the electrodes one by one and apply pressure on the electrodes to ensure penetration through the hair and good contact. The applied pressure may also cause discomfort as the subject may experience constant tension on the scalp. The use of dry electrodes may also cause discomfort due to entanglement between the electrodes and the hair.

[0087] Furthermore, known EEG systems include a wired cable for each electrode. This limits the subject's mobility and may also reduce signal quality, as inevitable movement of the subject may cause signal interruptions (artifacts).

[0088] Additionally, in conventional EEG systems, each electrode needs to be precisely placed at a specific location on the scalp (eg, according to the international 10-20 EEG protocol). The inventors have recognized that deviations from a specific location can reduce the accuracy of the diagnosis.

[0089] In the search for solutions to the above problems, the inventors have designed a technology for sensing and measuring EEG signals. The technology of the present embodiment can be used to investigate and / or diagnose various conditions and diseases, including but not limited to epileptic seizures, traumatic brain injury (TBI), hemorrhage, brain tumors, encephalopathy, cognitive decline, sleep disorders, ischemic pathology, such as stroke, dementia and coma levels of brain activity. The technology of these embodiments of the present invention can be used to evaluate several types of brain diseases. For example, when there is epilepsy, epileptic activity can be manifested as fast spike waves on the EEG, and when the brain includes lesions that can be caused by tumors or strokes, abnormally slow EEG waves can be detected according to the size and location of the lesions. The technology of these embodiments of the present invention can be used in biofeedback applications for various purposes, including but not limited to improving the quality of life of subjects suffering from movement disorders or motor dysfunction.

[0090] Now referring to the accompanying drawings, Figure 1A and 1Bis a schematic diagram of a system 10 for measuring EEG signals according to some embodiments of the present invention. In various exemplary embodiments of the present invention, but not necessarily, the system 10 is a dry EEG system, in the sense that the system can measure EEG signals by establishing contact with the scalp 14 of the subject 22 in a dry environment, and in particular without applying a gel between the sensing element and the skin.

[0091] The system 10 preferably includes a wearable body 12 adapted to be mounted on a scalp 14. The wearable body 12 may be rigid, flexible, or elastic, and may be made of any material that is wearable on the scalp, such as, but not limited to, synthetic fabrics, molded plastics, fiberglass, reinforced fiberglass (e.g., reinforced with Kevlar or carbon fiber).

[0092] In some embodiments of the present invention, the wearable body 12 includes an outer shell and an inner shell ( Figure 1A and 1B Not shown, see below Fig.9A and 9B In some embodiments of the present invention, at least a portion of the wearable body 12 is elastic. The system 10 also includes a plurality of electrodes 16 mounted on the wearable body 12. Preferably, but not necessarily, the system 10 includes a plurality of sensing systems 40, each sensing system 40 including several electrodes, such that the electrodes 16 are physically grouped into a plurality of separate sensing systems 40. A more detailed description of the sensing systems applicable to these embodiments of the present invention is provided below.

[0093] The number of electrodes distributed on the wearable body 12 is preferably at least 16, at least 32 or at least 64, or at least 128, or at least 256 or at least 512 or more. Preferably, the electrodes are distributed on the wearable body 12 at a density of at least two electrodes per 3 square centimeters, at least four electrodes per 3 square centimeters, or at least eight electrodes per 3 square centimeters, or at least two electrodes per 2 square centimeters, at least four electrodes per 2 square centimeters, or at least two electrodes per square centimeter, at least four electrodes per square centimeter, or at least eight electrodes per square centimeter. For at least 50%, at least 60%, or at least 80% of the electrodes, the distance between adjacent electrodes is preferably less than 3 cm, less than 2.5 cm, less than 2 cm, less than 1.5 cm, or less than 1 cm.

[0094] According to a preferred embodiment of the present invention, the use of a large number of electrodes allows the system to perform high-density electroencephalography (hdEEG), which can provide high spatial sampling density and large head coverage.

[0095] hdEEG allows recording of spontaneous or evoked brain activity with improved spatial resolution. hdEEG can provide sufficiently high spatial resolution (number of channels) for studying various conditions, such as but not limited to epilepsy, cognitive processes, brain injury and neuropsychiatric disorders, and for detecting deep brain activity. hdEEG can be used, for example, for precise localization of epileptic foci and / or for investigation of neural networks, such as evaluating functional connectivity and utilization in brain-computer interface systems.

[0096] According to some embodiments of the present invention, the electrode 16 is mounted on the wearable body 12. Figure 1C In these embodiments, the electrodes 16 are mounted on a flexible wire 32 which is attached to the wearable body 12 ( Figure 1C Not shown, see e.g. Figure 1A and 1B ). In some embodiments, the electrodes 16 are evenly distributed along the rope 32. In embodiments where the system 10 includes a plurality of sensing systems 40, each sensing system 40 includes several electrodes, the sensing systems 40 are preferably, but not necessarily, evenly distributed along the line 32.

[0097] In some embodiments of the invention, elastic band 34 is connected to wire 32. Figure 1C In the figure shown, the band 34 connects the two wires 32 so that when the band 34 is stretched (e.g., when the wearable body 12 is worn on the scalp 14), the wires 32 are displaced from each other in a direction generally perpendicular to the wires 32, as generally shown by the double-headed arrow 36. The electrodes 16 can have any shape. Representative examples of shapes suitable for electrodes 16 on the wires 32 are shown in FIG. Figure 1D -F, where the sprocket shape is shown ( Figure 1D ), tripod shape( Figure 1E ), and disc or spherical shapes ( Figure 1F ). Other shapes may also be considered in some embodiments of the present invention.

[0098] Optionally, the system 10 includes a controller 72 having a circuit configured to control the connection state of each individual electrode. For example, the controller 72 is capable of electrically grouping the electrodes into two or more groups. The grouping is electrical, i.e., the signals sensed by all electrodes in a group are coherently combined so that the combined signal represents a sensed event from an area on the scalp 14 occupied by all electrodes in the group. Groups can be defined based on one or more criteria. For example, in some embodiments of the present invention, groups are selected based on a predetermined morphology on the scalp surface, and in some embodiments of the present invention, groups are selected in a closed-loop control based on the impedance or signal-to-noise ratio of the signal received by the electrode, and in some embodiments of the present invention, groups are selected based on independent signal analysis. The grouping operation according to some embodiments of the present invention is provided in more detail below.

[0099] The system 10 optionally and preferably also includes a signal processor 18 having one or more circuits that receive and process the EEG signals sensed by the electrodes 16, and optionally and preferably sends control signals to the controller 72. The processor 18 can be configured to perform any processing operation described herein. Typically, the processor 18 includes an analog-to-digital (A2D) circuit that digitizes the signals sensed by the electrodes 16, and a digital signal processing circuit (DSP) that receives the digitized signals from the A2D circuit and applies digital signal processing operations to the digitized signals. The processor 18 preferably, but not limited to, includes dedicated circuits, such as an application-specific integrated circuit (ASIC) for performing these operations. It is also contemplated to use a field programmable gate array (FPGA) to perform at least some image processing operations.

[0100] Communication between the electrodes 16 and the processor 18 is optionally and preferably by means of a wired bus interface, as further described below. The processor 18 may be provided as a separate unit or mounted on the wearable body 12. Embodiments are also contemplated in which the processor 18 includes a first circuit mounted on the wearable body 12 and a second circuit not mounted on the wearable body 12, wherein one or more processing operations are performed by the circuit mounted on the wearable body 12 and other operations are performed by the circuit not mounted on the wearable body 12. For example, the A2D circuit may be mounted on the wearable body 12 and the DSP circuit may be remote from the wearable body 12.

[0101] In some embodiments of the present invention, the processor 18 is configured to detect evoked response potential (ERP) signals from the electrodes 16 and determine the physiological position of each electrode or each group of electrodes based on the ERP signals. In these embodiments, the density of the electrodes is preferably large (e.g., at least two electrodes per 3 square centimeters, at least four electrodes per 3 square centimeters, at least eight electrodes per 3 square centimeters, or at least two electrodes per 2 square centimeters, at least four electrodes per 2 square centimeters, at least eight electrodes per 2 square centimeters, or at least two electrodes per square centimeter, at least four electrodes per square centimeter, or at least eight electrodes per square centimeter) to improve the resolution of position determination.

[0102] An ERP is the body's psychophysiological response to a given stimulus. Since individual neurons have relatively little electrical activity associated with them, certainly not enough to be detected on the scalp, ERPs are recorded when neurons act in sync, and the electric field produced by each specific neuron is oriented so that the effects on the scalp are cumulative. The activity of neurons organized in a hierarchical open field manner (neurons with dendrites and axons oriented in the same way) is often picked up as an ERP. The stimulus that causes ERPs can be either external or internal.

[0103] The detection of ERP signals is optionally and preferably performed by the processor 18 based on signals describing stimulation of the subject 22 wearing the wearable body 12. These signals are generally received from the stimulation system 20. The processor 18 preferably synchronizes between the signals from the stimulation system 20 and the EEG signals from the electrodes 16 to identify the ERP signals in the EEG signals. The stimulation system 20 can apply any type of stimulation, including but not limited to somatosensory evoked potentials (SSEP), brainstem evoked response audiometry, visual stimulation, tactile stimulation, olfactory stimulation, and motor stimulation.

[0104] For any identified ERP signal, processor 18 may determine at which of electrodes 16 the ERP signal is sensed, and determine the location of the electrode based on the type of stimulation that induced the ERP signal. In various exemplary embodiments of the present invention, multiple stimuli are applied to subject 22, and the identification of corresponding ERP signals and the location of the electrodes that sensed the corresponding ERP signals are repeated for each of at least some of the applied stimuli. Preferably, a morphological map of the electrodes over the anatomical region of the cortex is generated based on the determined locations. Thus, unlike conventional techniques (e.g., 10-20 EEG protocols), where each electrode must be placed at a specific location, the present embodiment advantageously generates a morphological map that automatically associates each electrode or group of electrodes with a specific anatomical region of the cortex.

[0105] For example, using SSEP sensory stimulation on the motor nervous system, the maximum P20 recorded can locate the sensory cortex (postcentral gyrus). By locating several anatomical locations and knowing the structure between the electrodes and the sensing points, all electrodes can be located (mapped) and customized to the individual's anatomy. Other electrodes can be located based on their physical distance from the located electrodes. Another example is a stimulus in which a visual pattern of a specific image is displayed, such as but not limited to a check plate or a flashing light, displayed to induce a visual evoked potential that can be induced. Another example is a sound stimulus in which a specific sound (e.g., with a specific frequency, duration and / or amplitude) is presented to the subject 22. It is also conceivable that electronic stimulation is applied, such as but not limited to external stimulation to the organ, such as using a wrist stimulation device for applying electrical pulses from the wrist. This stimulation induces ERP signals in the sensory part of the brain, and can therefore be used to determine the position of the electrode that picks up the signal. Further envisioned is such an embodiment in which electrical pulses are transmitted to the scalp by one or more EEG electrodes and the ERP signal indicated by the stimulus is identified. In these embodiments, stimulation system 20 is optionally and preferably in direct communication with electrodes 16 and is configured to transmit electronic signals to the scalp via the corresponding electrode or electrodes.

[0106] Additional stimulation types and corresponding cortical regions that evoke ERP signals are described in the Examples section below.

[0107] It should be understood that multiple stimuli can be applied simultaneously or sequentially. Preferably, the applied stimuli are synchronized therein.

[0108] In some embodiments of the present invention, the wearable body 12 includes a plurality of stretch sensors. Figure 2A -E is shown. Figure 2A -E shows a stretch sensor 24 mounted on the wearable body 12. In some embodiments of the present invention, the stretch sensor 24 is woven into the wire 32 (not shown, see Figure 1C ), on which the electrode 16 is disposed. According to some embodiments of the present invention, embodiments in which a stretch sensor is employed without the wire 32 are also contemplated.

[0109] The wearable body 12 is also preferably provided with a rigid arc 26 for providing mechanical reinforcement to the body 12, and may optionally include a hardware component 28, which may include one or more bus architectures and controllers, as further described below, and / or a power source 30. Additional configurations of the wearable body 12 are described below.

[0110] The stretch sensor 24 converts the simulated motion or tension into stretch data describing the stretching of the wearable body 12. The signal processor 18 (not shown, see Figure 1A and1B ) optionally and preferably receives stretch data from the sensor 24, and once the wearable body 12 is stretched, constructs a three-dimensional map describing the location of the electrodes 16 on the scalp based on the stretch data. Sensors suitable for use as stretch sensors are disclosed in US published application 20160238368 and are commercially available from StretchSenseTM (Auckland, New Zealand).

[0111] Typically, the processor 18 also uses one or more reference points of known location to construct a three-dimensional map. In these embodiments, the wearable body is worn and stretched so that one or more reference points marked on the wearable body are aligned with specific anatomical points (e.g., ears, eyebrows, forehead midline, etc.). Preferably, the signal processor is pre-programmed with information related to the length of the elastic band 34 in a static state or the distance between the lines when the elastic band 34 is not stretched. Using this information and the stretch data from the sensor 24, the processor 18 calculates the distance between the electrodes, and using the calculated distance and the location of the reference point, the processor 18 constructs a three-dimensional map.

[0112] The three-dimensional map allows the system 10 to establish a cross-correlation between the brain activity axis system and the physical positioning of the electrodes 16, and locate specific areas of interest in the brain simulation and scalp with high accuracy.

[0113] Reference now Figure 3A -F, 4A-F and 5A-F, which are schematic diagrams of a sensing system 40 including several electrodes 16 according to various exemplary embodiments of the present invention. Figure 3A -B, 4A-B and 5A-B), cross-sectional view ( Figure 3C -D, 4C-D and 5C-D), and the system 40 in the relaxed state ( Figure 3A , 3C , 3E, 4A, 4C, 4E, 5A, 5C and 5E) and in compressed state ( Figure 3B , 3D , 3F, 4B, 4D, 4F, 5B, 5D and 5F) bottom view ( Figure 3E -F, 4E-F, and 5E-F), once compressive force 42 is applied inwardly to sensing system 40 in the direction of scalp 14. Multiple sensing systems such as system 40 can be distributed on wearable body 12 of system 10, for example along line 32, as detailed above.

[0114] The sensing system 40 generally includes a circuit board 44 (e.g., a printed circuit board) and a plurality of flexible sensing legs 46. Optionally, each leg 46 has a non-conductive portion 48 and a tip 50 in electrical communication with the circuit board 44 via a conductive portion 52. In some embodiments of the invention, the portions 48 and 52 are aligned in a core-shell relationship, wherein the non-conductive portion 48 at least partially surrounds the conductive portion 52, but this need not be the case, as in some embodiments of the invention, the portions 48 and 52 are aligned in other configurations, such as, but not limited to, a side-by-side configuration.

[0115] In some embodiments of the invention, one or more legs 46 do not include separate non-conductive portions and conductive portions. For example, one or more legs 46 may have an interwoven structure in which non-conductive regions are interwoven with conductive regions. For example, the legs may be made of a non-conductive material, such as but not limited to a non-conductive polymer material, impregnated with conductive particles, such as but not limited to carbon particles or metal (e.g., nickel) particles.

[0116] Preferably, the circuit board 44 is detachable from the legs 46. These embodiments are advantageous because they allow for making part of the system 46 disposable and part reusable. Specifically, the legs 46 that contact the scalp can be made disposable and the circuit board 44 can be made reusable. Before the system 10 is mounted on the subject's head, new disposable legs 46 are connected to the circuit board 44 so that the same legs do not have to be used for different subjects or different procedures.

[0117] The circuit board 44 is used to collect the signals of each individual portion 52 and transmit them to the processor 18, optionally and preferably via a wired bus interface, as described in further detail below.

[0118] Thus, each leg 46 of the system 40 forms one electrode 16 of the system 10. Once the wearable body 12 is worn, and once the force 42 is exerted on the legs 46, the legs 46 can have any three-dimensional shape that facilitates bending or collapsing toward the scalp 14. Figures 3A-5E The curved shape of the legs 46 is shown, wherein the compressive force 42 increases the curvature of the shape. Embodiments are also contemplated in which one or more legs 46, more preferably each leg 46, have a spiral shape. A schematic diagram of the legs 46 in these embodiments is shown in FIG6. In various exemplary embodiments of the present invention, the shape and orientation of the legs 46 are selected so that at least one of the legs 46, more preferably each leg, is oriented in a direction that does not coincide with the normal direction of the scalp 14.

[0119] In some embodiments, the circuit board 44 is configured to pre-process the signals sensed by the legs 46. For example, the circuit board 44 can include a buffer amplifier and / or be configured to provide active shielding to reduce noise.

[0120] The inventors have discovered that the sensing system 40 is able to penetrate the hair of the subject 22 and, optionally and preferably in a dry environment, provide improved contact with the scalp 14.

[0121] Preferably, legs 46 are at least partially made of a shape memory material, such as, but not limited to, a shape memory alloy. The shape memory material may be incorporated into flexible portion 48, in which case the shape memory material is preferably a non-conductive polymer or a conductive material (e.g., a conductive polymer or alloy) coated with a non-conductive coating to insulate portion 52 from other conductive portions. Alternatively or additionally, the shape memory material may be incorporated into portion 52, in which case the shape memory material is preferably a conductive polymer or alloy.

[0122] In some embodiments of the present invention, electrical conductivity between the scalp 14 and the circuit board 44 is established only after the force 42 is applied, where there is no electrical conductivity between the scalp 14 and the circuit board 44 before the force 42 is applied. These embodiments are advantageous because they prevent short circuits in the event that the ends of adjacent sensing systems overlap. These embodiments can be achieved by ensuring that the tips 50 of the legs 46 contact the scalp 14 only after the force 42 is applied. A preferred configuration for this implementation is Fig.14A and 14B The figure shows a leg 46, wherein the conductive portion 52 and the non-conductive portion 48 are arranged side by side. In the absence of force 42 ( Fig.14A ), the legs 46 are oriented and shaped such that the non-conductive portion 48 contacts the scalp 14 and maintains a gap 51 between the tip 50 and the scalp 14. After the force 42 is applied ( Fig. 14B ), the leg 46 experiences strain and assumes a shape in which the end of the conductive portion 52 contacts the scalp 14.

[0123] In some embodiments of the present invention, the tip 50 is constructed and designed so that its contact area with the scalp 14 increases after the force 42 is applied, such as Fig. 14C and 14D As shown. In the absence of force 42 ( Fig.14D ), relative to the case where force 42 exists ( Fig. 14C ), the cross-sectional area at the tip 50, which is generally parallel to the scalp 14, is smaller. The advantage of this configuration is that it improves the electrode tissue impedance. Preferably, the material of the tip 50 is sufficiently soft so that once it is driven by the force 42, its surface conforms to the shape of the skin in contact with it and fills the skin concavity or partially curls therewith ( Fig. 14C ).

[0124] In some embodiments of the present invention, legs 46 are arranged so that when compressive force 42 is applied, the legs rotate toward scalp 14. Fig.14Eand 14F , showing the leg 46 ( Fig.14E ) and a later state (FIG. 14f), wherein the legs 46 are arranged to rotate 43 in response to the force 42. The rotation can be achieved by arranging the legs 46 on the base of the body 54 of the system 40 ( Fig.14A -D not shown, see Figures 3A-5F ). For example, the legs may be arranged in a spiral manner so that once force 42 is applied, the spiral arrangement ensures that the inwardly applied force is converted into a rotational force. Optionally or more preferably, force 42 is applied while establishing a rotational motion for legs 46. Fig.14E and 14F The conductive portion 52 and the non-conductive portion 48 of the leg 46 are not shown in FIG. 1 , but one of ordinary skill, provided with the information described herein, would know how to construct the leg 46 to include the conductive portion 52 and the non-conductive portion 48 .

[0125] Also considered implementing Fig.14A -B and / or Fig. 14C -D and Fig.14E - A combination of the embodiments shown in F. In this combination of embodiments, the force 42 simultaneously rotates the legs 46 and exerts a strain on the legs 46 so that the tips 50 come into contact with the scalp 14.

[0126] Embodiments in which a separate force is applied to rotate the legs are also contemplated.

[0127] Preferably, tip 50 is made of a soft material with a low Shore hardness (e.g., Shore OO hardness from about 10 to about 100) that undergoes strain upon application of force 42, such as Fig. 14B and 14C These embodiments are useful and advantageous from a user comfort perspective because the strain increases the footprint on the scalp 14 .

[0128] Shore OO hardness describes a material's resistance to permanent indentation as defined by the Type OO durometer scale. Shore A hardness is usually measured according to ASTM D2240-00.

[0129] Representative examples of materials from which tip 50 may be made include, but are not limited to, silicon coated with AgCl, or polyurethane composites coated with metal, or carbon black, although other conductive materials are also contemplated.

[0130] In some embodiments of the present invention, the tip 50 is constructed and designed such that the friction between the tip 50 and the scalp 14 is sufficient to prevent the tip 50 from moving from its position after the force 42 is applied. Typically, but not necessarily, the tip 50 is coated with a coating having a plurality of micro- or nanostructures 56 (FIG. 5C-F) to increase the friction and also increase the surface area of ​​the tip 50, thereby increasing the conductivity of the tip 50.

[0131] Embodiments of the present invention contemplate several types of conductive portions for legs 46. In some embodiments of the present invention, conductive portion 52 of one or more legs 46 is a metal wire. Figure 3A -F. In some embodiments of the present invention, the conductive portion 52 of one or more legs 46 comprises bundles of conductive bristles. These embodiments are Figure 4A -F. In some embodiments of the present invention, the conductive portion 52 of one or more legs 46 is made of a conductive polymer. These embodiments are Figure 5A -F. It is also conceivable to implement combinations of these embodiments, for example a sensing system having at least two legs 46 having different types of parts.

[0132] Specific reference Figures 4A-4F , each bristle of portion 52 optionally and preferably has a thickness of about 0.05 mm to about 0.4 mm, such as 0.15 mm. An advantage of having a bundle of conductive bristles for portion 52 is that it facilitates penetration into the subject's hair. Another advantage is that the tip 50 of the bundle conforms to the shape of the scalp 14, whereby different bristles of the bundle can engage scalp points 14 having different heights, thereby increasing the footprint of the system 40 on the scalp. In some embodiments of the present invention, the bundles are arranged in a spiral manner ( Figure 4E and 4F ) at the base of the body 54 of the system 40 to prevent one bundle of bristles from contacting another bundle of bristles. Once the force 42 is applied, the helical device ensures that the inwardly applied force is converted into a rotational force that acts as a screw on the tips of the bristles. The advantage of using bristles is that it reduces the likelihood that the electrode will become tangled with the subject's hair.

[0133] Referring now to FIG. 7 , which is a schematic diagram of a leg 46 of the system 40 , in the embodiments described below, the non-conductive portion 48 and / or the conductive portion 52 of the leg 46 includes a hydrophobic region 62 and a hydrophilic region 64 .

[0134] Preferably, the hydrophobic region 62 is located at the upper portion of the leg 46 (not in contact with the scalp) and the hydrophilic region 64 is located at the lower portion of the leg 46 (adjacent the tip 50). An advantage of this embodiment is that humidity, such as humidity caused by sweat on the surface of the scalp 14, is concentrated near the lower portion of the leg 46, increasing conductivity with human tissue and preventing it from reaching the circuit board 44 (not shown). This embodiment is also advantageous because it prevents electrical shorting between adjacent sensor systems.

[0135] In some embodiments of the present invention, the leg 46 also includes an intermediate region 66 between the hydrophobic region 62 and the hydrophilic region 64. The intermediate region 66 is less hydrophobic than the hydrophobic region 62 and less hydrophilic than the hydrophilic region 64. For example, the intermediate region 66 is neither hydrophilic nor hydrophobic. In some embodiments, the hydrophobicity of the intermediate region 66 gradually increases in the upward direction. An advantage of having the intermediate region 66 is that the temperature difference between the scalp 14 and the wearable body 12 forms a groove near the region 64. Since the temperature at the scalp 14 is generally higher than the temperature at the wearable body 12, the air vapor 68 tends to condense at the higher part of the leg 46. Since the upper part is hydrophobic, the vapor 68 condenses at the area above the intermediate region 66 and is drawn downward by the hydrophilic region 64, which acts as a vapor groove. This prevents electrical shorts between adjacent legs of the same sensing system and / or between adjacent legs of adjacent sensing systems.

[0136] Fig. 8A -H is a schematic diagram of a system 10 according to an embodiment of the present invention, wherein the system 10 includes a controllable actuator for applying a force to an electrode. Fig. 8A In the illustrations shown in FIG. 1-H, which should not be considered limiting, the electrodes of system 10 are grouped into sensing system 40, but this is not necessarily the case, as configurations in which the electrodes are not grouped are also contemplated according to some embodiments of the present invention. For clarity of illustration, Fig. 8A Only one sensing system 40 is shown in FIG. 1 , but it should be understood that many sensing systems such as system 40 can be incorporated into EEG system 10 .

[0137] In the illustrated embodiment, the system 10 includes a plurality of controllable actuators 70 for applying forces to the electrodes 16 or legs 46. Fig. 8AAn actuator is magnified in FIG. 1 . The actuator 70 is designed and constructed to apply a compressive force (e.g., force 42), optionally and preferably a non-periodic compressive force, to the electrode 16 or leg 46. In some embodiments of the present invention, the actuator 70 can be designed and constructed to apply a periodic (e.g., sinusoidal) force to the electrode 16 or leg 46 so as to vibrate the leg or electrode or produce a hammering effect, thereby promoting penetration of the electrode or leg in the contact area between the tip and the scalp and better expansion. The hammering effect can be produced by controlling the actuator 70 to periodically apply and terminate the application of the compressive force to the electrode. In some embodiments of the present invention, the actuator 70 can be designed and constructed to apply a rotational force to the electrode 16 or leg 46 so as to, for example, rotate the leg about the longitudinal axis of the leg, such as Fig.14F shown.

[0138] Preferably, but not necessarily, each actuator 70 is mounted on top of the body 54 of the sensing system 40 .

[0139] Combinations of the above embodiments are further contemplated. For example, one or more actuators can apply a compressive force (eg, force 42), and one or more actuators can apply a periodic force to cause the leg to vibrate or create a hammering effect.

[0140] 8B-E schematically illustrate system 10 when mounted on scalp 14 of subject 22. FIG8B is a perspective view, and FIG8C, 8D, and 8E are cross-sectional views of three different states of actuator 70. Specifically, in FIG8C actuator 70 is in a relaxed state in which no force is applied to legs 46, and in FIG8D and 8E actuator 70 applies force to legs 46, wherein the state shown in FIG8E corresponds to a stronger force than the state shown in FIG8D, thereby bringing body 54 closer to scalp 14 and applying more tension to legs 46, thereby creating a higher footprint area between the tip and the scalp.

[0141] Each actuator 70 can be implemented as, for example, an inflatable balloon that applies force when inflated, a piezoelectric actuator or an electric actuator (e.g., a solenoid) or a motor that applies force when voltage is applied, a pneumatic actuator that applies force through piston movement, etc.

[0142] Fig.8F-H schematically illustrates some embodiments of the actuator 70, wherein the actuator 70 includes an inflatable airbag 71. In these embodiments, the actuator 70 may further include a retraction mechanism 73, which may be implemented as an elastic member, such as a spring, a rotating shaft 75, and an annular stator 77. The shaft 75 is located inside the stator 77. The proximal end of the shaft 75 is engaged with the airbag 71, and the distal end of the shaft 75 is connected to the body 54. Preferably, the shaft 75 is provided with one or more spiral grooves, and the inner surface of the stator 77 is provided with one or more protrusions that fit into the grooves of the stator 77, so that the stator 77 and the shaft 75 act as a pushing rotation mechanism. When the airbag 71 is inflated, the shaft 75 is retracted in the direction of the scalp ( Fig.8F -H) is pushed through the stator 77 and rotated by the stator 77. The body 54 is connected to the distal end of the shaft 75 and rotates while applying a force on the legs 46. Once the airbag 71 is deflated, the retraction mechanism 73 retracts the shaft 75 through the stator 77.

[0143] Fig.8F -H shows three states of the actuator 70. Fig.8F A force is shown applied to the leg 46, which is high enough to cause the leg to strain. Figure 8G The condition is shown where the force applied to the shaft 75 is sufficient to establish contact between the legs 46 and the scalp. Figure 8H The shaft 75 is shown fully retracted by the mechanism 73 until the legs 46 are no longer in contact with the scalp. A typical inflation pressure Pc is used to establish contact between the legs 46 and the scalp ( Figure 8G ), is a pressure differential (relative to ambient pressure) of about 2 to about 12 PSI, such as about 4 PSI. When the pressure differential within the balloon 71 is higher than Pc, the legs 46 are pressed against the scalp and experience strain ( Fig.8F ), when the pressure difference in the airbag 71 is less than Pc, the shaft 75 is retracted through the mechanism 73 ( Figure 8H Other pressure levels may also be considered. In various exemplary embodiments of the present invention, the pressure within the airbag 71 when the legs 46 are pressed against the scalp is selected so that the load of the legs 46 on the scalp does not exceed an empirical parameter (eg, 3 N / cm2).

[0144] When the actuator 70 of the system 40 includes the bladder 71, the shaft 75, and the stator 77, it optionally and preferably includes the outer shell 12a and the inner shell 12b. Fig.9A and 9B An exploded view of the system 10 is shown ( Fig.9A )、Assembly Diagram( Fig. 9B). In the illustrated embodiment, the outer shell 12a is used to support the airbag 71 and the pneumatic tube 162 for inflating and deflating the airbag 71, and the inner shell 12b is used to support the other components of the sensing system 40, including at least the stator 77, the circuit board 44, and the body 54 with the legs 46. Optionally and preferably, at least one of the shells 12a and 12b, and more preferably both shells 12a and 12b are rigid. Preferably, the size of the inner shell 12b is adjustable to fit on the scalp 14.

[0145] Typically, the system 10 also includes a wired bus interface 90 for establishing electrical contact between the various components of the system 10. The interface 90 may be mounted on the inner housing 12b. Fig. 10A and 10B A more detailed description of a bus interface suitable for the present embodiment is provided.

[0146] The circuit board 44 is preferably separable from the body 54 and can be enclosed in a housing 164 designed to accommodate the body 54. In some embodiments of the present invention, the housing 164 includes a rigid wall 165 and a flexible membrane 167 connecting the wall 165 to the shaft 75. An advantage of these embodiments is that they provide flexibility in the orientation of the housing 164 relative to the shaft 75, thereby allowing the sensing system 40 to adapt to the shape of the scalp. Male and female mating snaps 166 are optionally and preferably used to facilitate quick connection and disconnection between the circuit board 44 and the body 54. The preferred technique for connecting the body 54 to the housing 164 is by means of a clamp system, which is described below with reference to Fig.16A and 16B Give a description.

[0147] In some embodiments of the present invention, two or more sensing systems 40, optionally and preferably all, are interconnected by means of a sheet-like member 168, which optionally and preferably has a hat shape. Typically, the body 54 is embedded in the sheet-like member 168. A perspective view of the sheet-like member 168 (hat shape), as shown Fig. 9C 168 is shown embedded therein with interconnected sensing systems 40. The sheet-like member 168 is preferably flexible so as to allow independent rotational and translational movement of each sensing system 40. In some embodiments of the present invention, the body 54 is securely connected to the member 168 to form an integral structure that cannot be separated by the end user without causing physical damage (e.g., cracking, breaking).

[0148] Fig. 9B An exemplary situation is shown where the bladder 71 of one sensing system is inflated to ensure contact between the leg 46 and the scalp 14, and the bladder 71 of the adjacent sensing system is deflated so that there is no contact between the leg 46 and the scalp 14. The body 54 with the leg 46 and the optional flexible member 168 is collectively referred to herein as an electrode assembly 170.

[0149] Refer again Fig. 8A , the system 10 optionally and preferably includes a controller 72, which is configured to individually control each actuator 70 to apply force. The controller 72 receives control signals from the signal processor 18. The signal processor 18 can send a signal to the controller 72 to operate the actuator 70 after the user input, for example, when the subject 22 feels uncomfortable, the subject 22 can input a command to the processor 18 to release the pressure on the electrode or start a vibration program. Optionally or additionally, the signal processor 18 and the controller 72 operate in a closed-loop control, wherein the signal processor 18 receives and processes the EEG signal from the electrode (e.g., the leg 46 or the electrode 16 of the sensing system 40), and transmits a control signal to the controller 72 based on the processing.

[0150] Typically, signal processor 18 determines electrode-tissue impedance or one or more signal quality measurements and transmits control signals to controller 72 based on the determined impedance.

[0151] As used herein, "electrode-tissue impedance" (ETI) is the ratio of the voltage drop between two given electrodes to the current flowing between the two electrodes.

[0152] For example, when the determined impedance is above a predetermined threshold, the signal processor 18 can send a signal to the controller 72 to increase the compressive force applied by the actuator 70, otherwise release the compressive force. This allows the system 10 to always operate at a low impedance value. The controller 72 can also receive a control signal for controlling the actuator 70 when the actuator 70 vibrates the electrode or produces a hammering effect. Generally, when the determined impedance is above a predetermined threshold, the signal processor 18 sends a signal to the controller 72 to initiate a vibration or hammering protocol through the actuator 70.

[0153] An advantage of performing a vibration and / or hammering protocol is that it allows for repositioning of the sensing system and improves comfort to the user.

[0154] The signal processor 18 may also receive a signal from the actuator 70 indicating a force or pressure applied to the electrode or leg. For example, when the actuator 70 includes an inflatable balloon, the signal processor 18 may receive a signal from the actuator 70 describing the pressure within the balloon. The signal processor 18 may use the signal indicating the force or pressure to select a control signal that it sends to the controller 72. In one embodiment of the present invention, the signal processor 18 sends a signal to the controller 72 to increase the compressive force applied by the actuator 70 in response to the following determination: (i) the determined impedance is above a predetermined value, and (ii) the applied force is below a predetermined threshold; and to initiate a vibration or hammering protocol by activating the actuator 70 to apply a periodic force in response to the following determination: (i) the determined impedance is above a predetermined value, and (ii) the applied force is equal to or above a predetermined threshold. Detailed procedures suitable for implementing closed-loop control are provided below.

[0155] Reference now Fig. 10A Schematic diagram of a system 10 according to an embodiment of the present invention, wherein signal transmission between various components of the system 10 is via a bus architecture. Fig. 10A Shown in the figure are the wearable body 12, electrodes 16, processor 18, stimulation system 20 and controller 72, as described in detail above. A wired bus interface 90 is further shown. Preferably, the bus interface 90 includes a plurality of bus rows 90a, 90b, etc., each bus row 90a, 90b distributing signals to several electrodes on the wearable body 12 (e.g., a row of electrodes). Also shown are a power supply 30 and a power block 94 that distributes power to other components of the system 10, a human-machine interface 96 for allowing an operator to input commands, select parameters, or otherwise reconfigure the controller 72 and / or processor 18, and a wired data interface 98 via which communication is established between the processor 18 and the bus interface 90. The system 10 may also include a wireless communication system such as, but not limited to, Wi-Fi, A communication system 92 such as a wireless telephone or other communication technology is provided to allow the system 10 to communicate with external systems such as computers, cloud computing facilities, cloud storage facilities, etc. via a wired data interface 98 .

[0156] For each row of bus interface 90, all corresponding electrodes share the same current bus wires, and the EEG data is gated by controller 72. Fig. 10A, each row of the bus interface 90 includes a data bus 102, a control bus 104 and a plurality of bus units 100. The data bus 102 and the control bus 104 are shared by all electrodes corresponding to the corresponding bus row. The data bus 102 can be an analog or digital data bus, depending on whether digitization is performed before or after the EEG signal is sent to the processor. Each unit 100 is addressable by the controller and includes a control gate 106 that individually controls the connection state of a specific electrode 16. Optionally and preferably, each electrode publishes a digital identifier on the bus row to allow the controller 72 to identify the bus unit that controls the corresponding electrode. The controller 72 specifically addresses the corresponding bus unit 100 and sends a selection signal to switch the corresponding electrode between a connected state and an unconnected state.

[0157] When it is desired to globally collect EEG signals from an area of ​​interest on the scalp, the controller 72 electrically groups the electrodes that morphologically cover or are capable of sensing signals from the area of ​​interest by sending a gating signal to each unit, wherein the desired electrodes are switched to a connected state in parallel. Signals from electrodes that morphologically cover or are capable of sensing signals from the area of ​​interest are selectively and preferably coherently combined, thereby allowing amplification of signals collected from the area of ​​interest. The controller 72 may also electrically group the electrodes when the processor 18 determines based on signal processing analysis (e.g., based on electrode tissue impedance or signal-to-noise ratio) that the signal quality is reduced. For example, when the processor 18 determines that the impedance at the electrodes within a specific area on the scalp is above a predetermined threshold, the processor 18 may send a signal to the controller 72 to electrically group these electrodes. When the processor 18 determines that the impedance at the electrodes covering several different areas on the scalp is above a predetermined threshold, the processor 18 may send a signal to the controller 72 to electrically group each of these electrodes into one or more adjacent electrodes.

[0158] Fig. 10B 1 is a schematic diagram of the architecture of a single (out of N) row bus according to some embodiments of the present invention. The power bus provides power to all bus units 100. The power bus can be shared by all row buses. The main control unit MCU, which is part of the controller 72 ( Fig. 10A) are assigned to a specific row bus, optionally issuing commands for scanning, grouping, sampling and data retrieval based on the digital identification of electrodes via a control bus. The data bus optionally and preferably includes an analog data bus (ADBS), which can collect raw analog EEG signals to an analog-to-digital (A2D) converter in some embodiments of the present invention. If electrode grouping is used, the raw sampled signal can be a single electrode or a group of electrodes. The main control unit can use the control bus to synchronize sampling and guide the sampled signal from the electrode to the A2D converter. The digital data bus optionally and preferably collects all EEG data from the A2D converter.

[0159] One advantage of bus interface 90 ( Fig. 10A ) is that it reduces the need for separate cables that would otherwise be required for each electrode, thereby reducing the weight and complexity of the system. Another advantage of the bus interface 90 is that the mapped locations of the electrodes allow for simple routing of commands and retrieval of data from the electrodes based on specific neural events in the brain. In various exemplary embodiments of the invention, the system 10 employs high rate electronics (e.g., a sampling rate of at least 200 Hz or at least 300 Hz or at least 400 Hz or at least 500 Hz with a word length of at least 32 bits or at least 64 bits). This allows the system 10 to switch and sample each electrode at the desired EEG frequency band while digitally sampling the EEG signal by grouping the electrodes by dedicated assignments. Another advantage of the bus interface 90 is that it allows for multi-point reading of electrodes, where the readouts can be collected serially using the same bus channel. Another advantage of the bus interface 90 is improved power management because all electrodes do not need to be activated at the same time.

[0160] Fig.11 1 is a flow chart describing a closed-loop process for operating an actuator to apply a compressive force on an electrode according to some embodiments of the present invention. The process may be performed, for example, by the system 10, and in particular by the actuator 70, the electrode 16, the processor 18, and the controller 72. The process begins at 110 and continues to 111, where the electrode-tissue impedance is determined, for example, by a signal processor. The process continues to decision 112, where the impedance is compared to a first predetermined threshold R max Make a comparison.

[0161] The first predetermined threshold R max A representative example of a value of is about 50 KΩ to about 250 KΩ.

[0162] If the impedance is less than R max , the process continues to decision 119 where the impedance is compared to a second predetermined threshold value Rref.

[0163] The second predetermined threshold Rref A representative example of a value of is about 60 KΩ to about 180 KΩ.

[0164] If the impedance is greater than or equal to R ref , the process proceeds to 120, where the compressive force applied to the electrode is increased. From 120, the program loops back to 111.

[0165] If the impedance at decision 112 is greater than or equal to R max , the process continues to 113, where a value of a parameter indicative of the force applied by the actuator is obtained. For example, when the actuator includes an airbag, the process may obtain the pressure within the airbag. The process continues to decision 114, where the parameter (in this example, a pressure preset to a user threshold for comfort) is compared to a predetermined threshold value Pmax indicating an upper limit of the force to be applied (in this example, an upper limit of the pressure).

[0166] Predetermined parameter threshold P max Representative examples of values ​​are about 25 mm to about 500 cmH2O, such as about 250 cmH2O.

[0167] If the parameter is lower than P max , the process continues to 115 where an EEG signal is received from the electrodes and to 116 where the quality of the signal is determined. This is optionally and preferably done by the processor 18 and may include calculating at least one of impedance, power and frequency in the signal.

[0168] The process continues to decision 117 where the quality of the signal is compared to a quality threshold or a set of quality thresholds. For example, the data processor 18 may use the calculated quantities to calculate a score Q and compare the score to a predetermined score threshold Q. min Make a comparison.

[0169] For example, when the score Q is defined on a scale between 0 and 1, the predetermined score threshold Q min Representative examples of values ​​of are from about 0.5 to about 0.9, such as about 0.7.

[0170] Representative examples of signal quality parameters that can be used to calculate the score Q include, but are not limited to, electrode-tissue impedance, proportion of artifacts in the time domain, signal-to-noise ratio in the time domain, vertex α-wave power in the frequency domain, frontal θ-wave power effect in the frequency domain, and cognitive task power requiring vertex α-waves in the frequency domain. In some embodiments of the present invention, one or more (optionally and preferably each) of these parameters are subjected to thresholding, and the result of the thresholding can be used to calculate the score Q.

[0171] A typical threshold for artifacts in the time domain parameter is about 18% to about 22%, for example about 20%, when calculated over the entire recording duration, wherein signals having values ​​of the parameter below or equal to the threshold are assigned a higher score than signals having values ​​of the parameter above the threshold.

[0172] The signal-to-noise ratio in the time domain parameters can be calculated according to the formula SNR = 10log 10 (σ x 2 / σ e 2 ), calculated in dB, where σ x 2 and σ e 2 are the variances of the signal and noise, respectively. A typical threshold for this parameter is about -2 dB to about 0 dB, such as about -1 dB, wherein signals having a value of the parameter above or equal to the threshold are assigned a higher score than signals having a value of the parameter below the threshold.

[0173] A typical threshold value for parietal alpha wave power in a frequency domain parameter is about 3% to about 9%, for example about 6%, wherein signals having a value of the parameter above or equal to the threshold are assigned a higher score than signals having a value of the parameter below the threshold. A typical threshold value for frontal angular wave power in a frequency domain parameter is about 1% to about 5%, for example about 3%, wherein signals having a value of the parameter above or equal to the threshold are assigned a score that is higher than (the corresponding value of) signals having a value of the parameter below the threshold. A typical threshold value for parietal alpha waves requiring cognitive task power in a frequency domain parameter is about 1% to 5%, for example about 3%, wherein signals having a value of the parameter above or equal to the threshold are assigned a score that is higher than signals having a value of the parameter below the threshold.

[0174] If the quality is above the quality threshold, the process loops back to 111. If the quality is below the quality threshold at decision 117, the process continues to 118 where the force is set to zero, such as by terminating the previously applied force. From 117, the process loops back to 111.

[0175] Fig.12 1 is a flow chart describing a closed-loop process for operating an actuator to vibrate an electrode according to some embodiments of the present invention. The process may be performed, for example, by the system 10, and in particular by the actuator 70, the electrode 16, the processor 18, and the controller 72. The process begins at 130 and continues to 131, where the electrode-tissue impedance is determined, for example, by the signal processor. The process continues to 132, where a variance parameter of a signal received from a plurality of electrodes, for example, by the signal processor 18, is calculated. The process continues to decision 133, where the calculated VAR is compared to a predetermined variance range. Typically, the predetermined variance range is determined by a lower variance limit V Land upper limit of variance V U limited.

[0176] Variance lower limit V L A representative example of the impedance value is about 5KΩ to about 100,000Ω, for example about 75KΩ. U A representative example of an impedance value is about 250 KΩ to about 500 KΩ, such as about 350 KΩ.

[0177] If the calculated VAR is within this range (for example, V U >VAR>V L ), the process continues to 136 and ends there. If the calculated VAR is out of range (e.g., V AR >V U or VAR <V L ), the process continues to 134 where the signal quality is determined. This is optionally and preferably done by the processor 18 and may include calculating at least one of the power and frequency in the signal, the signal-to-noise ratio, and the percentage of artifacts. The process continues to a decision 135 where the quality of the signal is compared to a quality threshold or a set of quality thresholds. For example, the data processor 18 may calculate a score Q using the calculated quantities and compare the score to a predetermined score threshold Q. min A comparison is made, as described above. If the quality is above the quality threshold, the process continues to 136, where the process ends. If at decision 135, the quality is below the quality threshold, the program continues to 137, where the actuator is operated to initiate vibration. From 137, the program loops back to 131.

[0178] Fig.131 is a flow chart describing a closed-loop process for operating an actuator to provide a hammering effect according to some embodiments of the present invention. The process can be performed, for example, by the system 10, in particular by the actuator 70, the electrode 16, the processor 18, and the controller 72. The process starts at 140 and continues to 141, where the counter is reset. The process continues to 142, where the force applied by the actuator is terminated. If no force is applied at the beginning 140 of the process, operation 141 can be skipped. When the actuator includes a balloon, operation 141 includes reducing the pressure in the balloon to ambient pressure. The process continues to 143, where the actuator is operated to apply a compressive force with a predetermined amplitude and a predetermined profile in the time domain (e.g., ramp, sine, step, etc.). For example, when the actuator includes an inflatable balloon, the balloon is inflated to a predetermined pressure. In some embodiments of the present invention, the force applied at 143 is the maximum allowable force. At decision 144, the value of the counter is compared with a predetermined maximum count parameter. If the counter has not reached the maximum value, the counter is incremented by 1 at 145 and the process loops back to 142. If the counter has reached the maximum value, the process continues to 146 where the magnitude of the force is reduced to a predetermined reference level and continues to 146 where the process ends.

[0179] Fig.15 1 is a flow chart describing a combined process for operating an actuator according to some embodiments of the present invention. The process may be performed, for example, by the system 10, and in particular by the actuator 70, the electrode 16, the processor 18, and the controller 72. The process begins at 150 and continues to 151, where the counter is reset. The process continues to 113, where the value of a parameter indicative of the force applied by the actuator is obtained, as described in detail above. The process continues to decision 114, where the parameter is compared to a predetermined threshold value P. max The comparison is made as described in detail above. If the parameter is lower than P max , the process continues to 111 where the electrode-tissue impedance is determined as detailed above. max , the process continues to 152 where the applied force is reduced.

[0180] From 111, optionally and preferably continuing to 115 and 116, at 115, an EEG signal is received from the electrode, at 116, the quality of the signal is determined, as further detailed above. At decision 153, the quality of the signal is compared to a quality threshold or a set of quality thresholds, and the impedance is compared to a first predetermined threshold R maxA comparison is made, as described in further detail above. If at least one of the quality of the signal (according to one or more measurements described herein) and the impedance meet the corresponding criteria at 153, the procedure returns to 113. Otherwise, the procedure continues to 154, where the electrode is rotated and vibrated, and to 120, where the force is increased, as described in further detail above.

[0181] The process loops back from 154 to 113.

[0182] From 152, the process continues to 154, where the electrode rotates and vibrates. In some embodiments of the present invention, 154 is performed by reciprocating actuation of the aforementioned push-and-rotate mechanism of the stator 77 and the shaft 75. Specifically, the force 42 is repeatedly applied and released so that the electrode rotates in one direction when the force is applied and rotates in the opposite direction when the force is released.

[0183] At 155, the counter is incremented by 1, and at decision 156, the value of the counter is compared to a predetermined maximum count parameter. If the counter has not reached the maximum value, the process loops back to 113. If the counter has reached the maximum value, the process continues to 157, where the counter is reset and the force is set to zero, as described in further detail above. From 157, the process loops back to 113.

[0184] Reference now Fig.16A -D, which shows a schematic diagram of a clamp system 180 according to some embodiments of the present invention. The clamp system 180 is particularly useful for connecting the electrode assembly 170 to the housing body 164 of the sensing system to establish electrical communication between the legs 46 and the circuit board 44. The EEG system 10 and the clamp system 180 can be distributed to the user as a kit. The kit can also include one or more sets of disposable electrode assemblies 170 of the sensing system 40, each electrode assembly 170 can include a body 54 with legs 46, as further described above.

[0185] The clamp system 180 may include a bracket 182 having an outer surface 184 and an inner surface 186. The outer surface 184 is designed and constructed to properly receive the inner shell 12b ( Fig.16A -C is not shown, see Fig.9A -C), and is formed with a plurality of recesses 188, each recess 188 having a size and shape compatible with the disposable electrode assembly 170 of the sensing system 40.

[0186] The clamp system 180 also includes a plurality of clamp shafts 190, which are respectively introduced into the plurality of recesses 188 from the inner surface 186 side via through holes 192 formed in the bracket 182, so that each clamp shaft 190 can protrude through the base of the corresponding recess. When the clamp system 180 is used, the plurality of disposable electrode assemblies 170 of the sensor system 40, including the body 54 having the legs 46, are placed in the recesses 188, thereby pushing the clamp shafts 190 inwardly to protrude from the inner surface 186 of the bracket 182 ( Fig. 16B and 16C Then the inner shell 12b of the system 10 is mounted on the bracket 182 ( Fig.16D ). Preferably, the shape and size of bracket 182 and the location of recess 188 are selected so that once inner shell 12b is then mounted on outer surface 184, each of shell casing body 164 is aligned with a corresponding recess 188. Shaft 190 is then pushed outward 194 in the direction of outer surface 184 to release electrode assembly 170 from recess 188 and connect electrode assembly 170 to shell casing body 164 by means of snap member 166.

[0187] As used herein, the term "about" refers to ±10%.

[0188] The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any implementation described as “exemplary” is not necessarily to be construed as preferred or advantageous over other implementations and / or to exclude incorporation of features from other implementations.

[0189] The word “optionally” is used herein to mean “is provided in some embodiments and not provided in other embodiments.” Any particular embodiment of the present invention may include a number of “optional” features unless such features conflict.

[0190] The terms "includes," "including," "comprising," "containing," "having" and similar words mean "including but not limited to."

[0191] The term "consisting of" means "including and limited to."

[0192] The term "consisting essentially of" means that the composition, method or structure may include additional ingredients, steps and / or components that do not materially change the basic and novel characteristics of the claimed composition, method or structure.

[0193] As used herein, the singular from "a", "an", and "the" includes the plural unless the context clearly dictates otherwise. For example, the term "a compound" or "at least one compound" may include a plurality of compounds, including mixtures thereof.

[0194] Throughout the application, various embodiments of the present invention may be presented in the form of a range. It should be understood that the description in the form of a range is only for convenience and brevity and should not be interpreted as an inflexible limitation on the scope of the present invention. Therefore, the description of a range should be considered to have specifically disclosed all possible sub-ranges and individual numerical values ​​within the range. For example, when describing a range from 1 to 6, it should be understood that sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and individual numbers within the range, for example, 1, 2, 3, 4, 5 and 6, are specifically disclosed. This principle applies regardless of the width of the range.

[0195] Whenever a numerical range is indicated herein, it is meant to include any cited numerals (fractional or integral) within the indicated range. A "range from" the first indicated numeral to the second indicated numeral / a "range from the first indicated numeral to the second indicated numeral" and a "range from" the "first indicated numeral" to the "second indicated numeral" are used interchangeably herein and are meant to include the first and second indicated numerals and all fractions and integers therebetween.

[0196] It should be understood that, for the sake of clarity, certain features of the invention described in the context of separate embodiments may also be provided in combination in a single embodiment. Conversely, for the sake of brevity, various features of the invention described in the context of a single embodiment may also be provided individually or in any suitable sub-combination, or as any other described embodiment suitable for the invention. Certain features described in the context of various embodiments should not be considered essential features of those embodiments, unless the embodiment is inoperable without those elements.

[0197] Various embodiments and aspects of the present invention as delineated hereinabove and as claimed in the claims section of this application find experimental support in the following embodiments. Example

[0198] Reference is now made to the following examples, which together with the above descriptions illustrate some embodiments of the invention in a non limiting fashion.

[0199] These examples describe the types of stimulation and the corresponding cortical areas that evoked ERP signals.

[0200] Example 1

[0201] Electrical stimulation

[0202] Table 1 below lists limb stimulations and corresponding cortical locations that can induce ERP signals. The following is a representative example of a stimulation protocol that can be used for limb stimulation.

[0203] For upper extremity median nerve placement, the cathode can be placed between the tendons of the palmaris longus and flexor carpi radialis, 2 cm proximal to the wrist crease, the anode can be placed about 2 to 3 cm distal to the cathode or dorsum of the wrist, and the ground electrode can be a metal plate or circumferential belt electrode or rod placed on the electrode on the forearm, or use the ground electrode of the EEG system.

[0204] For lower extremity posterior tibial nerve placement, the cathode can be placed between the medial border of the Achilles tendon and the posterior border of the medial malleolus, and the anode can be placed 3 cm distal to the cathode.

[0205] The following parameters can be used for electrical stimulation: impedance less than 5 KΩ, ground electrode on the same limb, monophasic rectangular pulses using a constant voltage / constant current stimulator, pulse width of about 100 μs to about 300 μs, stimulation rate of about 3 Hz to about 5 Hz, median analysis time of about 40 ms and posterior tibia analysis time of about 60 ms, number of trials from about 500 to about 1000.

[0206] Table 1

[0207] Limbs Cortical area left wrist Right hand area of ​​somatosensory cortex (lateral) right wrist Hand area of ​​the left somatosensory cortex (lateral) Left ankle Leg area of ​​right somatosensory cortex (medial) Right Leg Leg area of ​​the left somatosensory cortex (medial)

[0208] Example 2

[0209] Auditory stimulation

[0210] Table 2 below lists auditory stimulations and corresponding cortical locations that can induce ERP signals. The following is a representative example of a stimulation protocol that can be used for auditory stimulation.

[0211] The stimulation may be in the form of an audio click at the subject's ear through a conformable earplug connected to a transducer or in-ear speaker or oscillator to vibrate the bone (bone conduction). Auditory stimulation with broadband clicks is preferred. The click intensity may be about 100 dB pe SPL or about 60-70 dB HL. Alternating polarity clicks may be used to reduce artifacts. The stimulation rate may be about 5 clicks per second to about 12 clicks per second. The analysis time may be about 15 ms from the start of the stimulation. The number of trials may be about 500 to about 1000. When the ears are stimulated sequentially, the non-stimulated ears are optionally masked with white noise preferably at 60 dB pe SPL or about 30 to about 35 dBHL to eliminate "crossover" responses (e.g., bone conduction responses originating from the non-stimulated ears).

[0212] Table 2

[0213] Ear Cortical area left ear Left temporal auditory cortex (+ pons + midbrain - deep brainstem) Right ear Right temporal auditory cortex (+pons+midbrain-deep brainstem)

[0214] Example 3

[0215] Visual stimulation

[0216] Table 3 below lists visual stimuli and corresponding cortical locations that can induce ERP signals. Below is a representative example of a stimulation scheme that can be used for visual stimulation. Visual stimulation can be used at a rate of about 1 Hz. Stimuli can be presented using a light stimulator lamp or LED matrix or a screen with a known pattern, optionally and preferably using a stroboscope. Preferably, the sound of the stroboscope is masked by white audio noise.

[0217] Table 3

[0218] Visual stimulation Cortical area flash Primary visual cortex (occipital lobe) pattern Calcaneal sulcus next to primary visual cortex (occipital lobe)

[0219] Although the present invention has been described in conjunction with the specific embodiments of the present invention, it is apparent that many alternatives, modifications and variations will be apparent to those skilled in the art. Therefore, it is intended to include all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.

[0220] All publications, patents and patent applications mentioned in this specification are incorporated into this specification by reference in their entirety to the same extent as each individual publication, patent or patent application is specifically and individually indicated and incorporated into this specification by reference. In addition, any reference cited or identified in this application shall not be construed as admitting that such references can be used as prior art of the present invention. In the scope of using section headings, they should not be construed as necessary limitations. In addition, any priority documents of this application are incorporated into this article by reference in their entirety.

Claims

1. A system for measuring electroencephalogram (EEG) signals, characterized in that: The system comprises: A wearable body adapted to be mounted on the scalp and having an inner shell and an outer shell; a plurality of physically separated sensing systems comprising a plurality of electrodes mounted on the wearable body, wherein each sensing system comprises a circuit board and several of the plurality of electrodes, and wherein the circuit board and the plurality of electrodes for each sensing system are separable from each other and supported by the inner housing; a plurality of controllable actuators supported by the housing and configured to apply forces to the electrodes; a controller configured to individually control each actuator or each group of actuators to apply a force to at least one electrode; and a signal processor configured to detect evoked related potential (ERP) signals from said electrodes and determine the physiological position of each electrode or each group of electrodes based on said detection of said ERP signals; The signal processor is used to receive and process the ERP signal from the electrode, and send a control signal to the controller based on the processing.

2. The system according to claim 1, characterized in that: The system also includes an input for receiving the ERP signal from a stimulation system, the ERP signal describing a stimulation condition of a subject wearing the wearable body, wherein the signal processor is configured to determine the position based in part on the ERP signal from the stimulation system.

3. The system according to claim 2, characterized in that: The stimulation system is configured to apply electrical stimulation through at least one of the electrodes.

4. The system according to any one of claims 1 to 3, characterized in that: At least one of the plurality of electrodes is flexible.

5. The system according to claim 1, characterized in that: The signal processor is configured to determine a signal quality and to control the force based on the determined signal quality.

6. The system according to claim 1, characterized in that: The force is applied inwardly.

7. The system of claim 6, wherein at least one of the electrodes is flexible and configured to undergo strain once pressed against the scalp by the force.

8. The system according to claim 1, characterized in that: The actuator is configured to apply the force to the electrode while generating a rotational motion.

9. The system according to claim 5, characterized in that: The actuator is configured to apply the force to the electrode while generating a rotational motion.

10. The system according to claim 1, characterized in that: At least one of the controllable actuators comprises an inflatable bladder that applies the force when the inflatable bladder is inflated.

11. The system according to claim 5, characterized in that: At least one of the controllable actuators comprises an inflatable bladder that applies the force when the inflatable bladder is inflated.

12. The system according to claim 1, characterized in that: The force is periodic and is applied to vibrate the electrodes or create a hammering effect.

13. The system according to claim 5, characterized in that: The force is periodic and is applied to vibrate the electrodes or create a hammering effect.

14. The system according to claim 1, characterized in that: At least one of the plurality of sensing systems includes a plurality of flexible legs, each flexible leg having a non-conductive portion and a conductive portion having a tip in electrical communication with the circuit board, and wherein each conductive portion is one of the plurality of electrodes.

15. The system according to claim 5, characterized in that: At least one of the plurality of sensing systems includes a plurality of flexible legs, each flexible leg having a non-conductive portion and a conductive portion having a tip in electrical communication with the circuit board, and wherein each conductive portion is one of the plurality of electrodes.

16. The system according to claim 14, characterized in that: The plurality of flexible legs are disposable.

17. The system according to claim 15, characterized in that: The plurality of flexible legs are disposable.

18. The system according to claim 14, characterized in that: At least one of the plurality of flexible legs has a helical shape.

19. The system according to claim 15, characterized in that: At least one of the plurality of flexible legs has a helical shape.

20. The system according to claim 14, characterized in that: The conductive portion of at least one flexible leg of the plurality of flexible legs is a polymer.

21. The system according to claim 15, characterized in that: The conductive portion of at least one flexible leg of the plurality of flexible legs is a polymer.

22. The system according to claim 14, characterized in that: The conductive portion of at least one flexible leg of the plurality of flexible legs includes a bundle of conductive bristles.

23. The system according to claim 15, characterized in that: The conductive portion of at least one flexible leg of the plurality of flexible legs includes a bundle of conductive bristles.

24. The system according to claim 14, characterized in that: The system includes a controllable vibration member configured to vibrate the flexible leg.

25. The system according to claim 15, characterized in that: The system includes a controllable vibration member configured to vibrate the flexible leg.

26. The system according to claim 14, characterized in that: At least one of the plurality of flexible legs includes a hydrophobic region located at an upper portion of the flexible leg and a hydrophilic region located at a lower portion of the flexible leg.

27. The system according to claim 15, characterized in that: At least one of the plurality of flexible legs includes a hydrophobic region located at an upper portion of the flexible leg and a hydrophilic region located at a lower portion of the flexible leg.

28. The system according to claim 26, characterized in that: At least one of the plurality of flexible legs includes an intermediate region between the hydrophobic region and the hydrophilic region, wherein the intermediate region is less hydrophobic than the hydrophobic region and less hydrophilic than the hydrophilic region.

29. The system according to claim 27, characterized in that: At least one of the plurality of flexible legs includes an intermediate region between the hydrophobic region and the hydrophilic region, wherein the intermediate region is less hydrophobic than the hydrophobic region and less hydrophilic than the hydrophilic region.

30. The system according to claim 14, characterized in that: The plurality of flexible legs are arranged on a base of a sensing system body, wherein at least one of the plurality of sensing systems comprises an axis and a shell body mounted on the axis and configured to receive the sensing system body, and wherein the shell body comprises a rigid wall and a flexible membrane, wherein the rigid wall is used to hold the sensing system body, and the flexible membrane connects the rigid wall to the axis in a manner that allows the shell body to present a plurality of different orientations relative to the axis.

31. The system according to claim 15, characterized in that: The plurality of flexible legs are arranged on a base of a sensing system body, wherein at least one of the plurality of sensing systems comprises an axis and a shell body mounted on the axis and configured to receive the sensing system body, and wherein the shell body comprises a rigid wall and a flexible membrane, wherein the rigid wall is used to hold the sensing system body, and the flexible membrane connects the rigid wall to the axis in a manner that allows the shell body to present a plurality of different orientations relative to the axis.

32. The system according to any one of claims 1 to 3, characterized in that: The controller is used to control the connection status of each individual electrode.

33. The system according to claim 4, characterized in that: The controller is used to control the connection status of each individual electrode.

34. The system according to claim 32, characterized in that: The system includes a wired bus interface for establishing communications between the controller and the electrodes.

35. The system according to claim 33, characterized in that: The system includes a wired bus interface for establishing communications between the controller and the electrodes.

36. The system according to claim 32, characterized in that: The controller is configured to electrically group the electrodes into at least one group of electrodes.

37. The system according to claim 33, characterized in that: The controller is configured to electrically group the electrodes into at least one group of electrodes.

38. The system according to claim 36, characterized in that: The at least one set of electrodes forms a predetermined pattern on the surface of the scalp.

39. The system according to claim 37, characterized in that: The at least one set of electrodes forms a predetermined pattern on the surface of the scalp.

40. The system of claim 36, wherein: The at least one group of electrodes is selected in a closed-loop control based on signal quality calculated by the signal processor for the ERP signals received by the electrodes.

41. The system according to claim 37, characterized in that: The at least one group of electrodes is selected in a closed-loop control based on signal quality calculated by the signal processor for the ERP signals received by the electrodes.

42. A method for measuring an electroencephalogram (EEG) signal, characterized in that: The method comprises operating the system according to any one of claims 1-4 while placing the wearable body on the scalp of the subject to receive the EEG signals sensed by the plurality of electrodes, thereby measuring the EEG signals.

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