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EP-3986268-B1 - METHOD AND SYSTEM FOR MEASURING EEG SIGNALS

EP3986268B1EP 3986268 B1EP3986268 B1EP 3986268B1EP-3986268-B1

Inventors

  • DEUTSCH, ISRAEL
  • LEVY, Yair

Dates

Publication Date
20260506
Application Date
20200618

Claims (15)

  1. A system (10) for measuring electroencephalography (EEG) signals, the system (10) comprising: a wearable body (12) adapted to fit over a scalp (14) and having an inner shell (12b) and an outer shell (12a); a plurality of physically separate sensing systems (40) mounted on said wearable body (12), each sensing system (40) having a circuit board (44) and a plurality of flexible legs (46) serving as electrodes for said sensing system (40), wherein said circuit board (44) and said plurality of flexible legs (46) are detachable from each other and are supported by said inner shell (12b); a plurality of controllable actuators (70) supported by said outer shell (12a) and configured for applying force (42) to said electrodes; a controller (72) configured for individually controlling each actuator (70) or group of actuators (70) to apply force (42) to at least one electrode; and a signal processor (18) configured for receiving and processing signals from said electrodes and transmitting control signals to said controller (72) based on said processing.
  2. The system (10) of claim 1, wherein said signal processor (18) is configured for determining at least one of: an electrode-tissue impedance, a signal-to-noise ratio, artifacts percentage, and a signal quality, and to control said force (42) based on said determination.
  3. The system (10) according to any of claims 1 and 2, wherein said actuator (70) is configured to apply said force (42) while establishing rotary motion to said electrodes.
  4. The system (10) according to any of claims 1-3, wherein at least one of said controllable actuators (70) comprises an inflatable balloon, applying said force (42) upon inflation thereof.
  5. The system (10) according to any of claims 1-4, wherein said force (42) is periodic and is applied to vibrate said electrodes or generate a hammering effect.
  6. The system (10) according to any of claims 1-4, wherein said force (42) is non-periodic.
  7. The system (10) according to any of claims 1-6, wherein each flexible leg (46) has a non-conductive section (48) and a conductive section (52) having a tip (50) in electrical communication with said circuit board (44), and wherein each conductive section (52) is one of said electrodes.
  8. The system (10) according to claim 7, wherein a conductive section (52) of at least one of said plurality of legs (46) comprises a bundle of conductive bristles.
  9. The system (10) according to any of claims 7-8, comprising a controllable vibrating member configured for vibrating said legs (46).
  10. The system (10) according to any of claims 7-9, wherein said plurality of flexible legs (46) is arranged on a base of a sensing system body (54), wherein at least one of said sensing systems (40) comprises a shaft (75) and a housing (164) mounted on said shaft (75) and being configured to receive said sensing system body (54), and wherein said housing (164) comprises a rigid wall (165) for holding said sensing system body (54) and a flexible membrane (167) connecting said rigid wall (165) with said shaft (75) in a manner that allows said housing (164) to assume a plurality of different orientations with respect to said shaft (75).
  11. The system (10) according to any of claims 1-10, wherein said signal processor (18) is configured to receive from said actuator (70) signals indicative of said force (42).
  12. The system (10) according to any of claims 1-11, wherein electrical conductance between said scalp (14) and said circuit board (44) is established after said force (42) is applied, and wherein before said application of said force (42) scalp (14) and circuit board (44) are devoid of electrical conductance therebetween.
  13. The system (10) according to any of claims 1-12, wherein said legs are disposable and said circuit board (44) is reusable.
  14. The system (10) according to any of claims 1-13, wherein said signal processor (18) is configured to signal said controller (72) to operate said actuator (70) following a user input.
  15. A method of measuring electroencephalography (EEG) signals, the method comprising operating the system (10) according to any of claims 1-14, while said wearable body (12) is placed on a scalp (14) of a subject, to receive EEG signals sensed by said plurality of electrodes, thereby measuring the EEG signals.

Description

RELATED APPLICATION This application claims the benefit of priority of U.S. Provisional Patent Application No. 62/862,689 filed on June 18, 2019. FIELD AND BACKGROUND OF THE INVENTION The present invention, in some embodiments thereof, relates to electroencephalography (EEG) and, more particularly, but not exclusively, to a method and system for measuring EEG signals. The brain is a complex structure of nerve cells that produce signals called excitatory post synaptic potentials (EPSP). These potentials summate in the cortex and extend through the coverings of the brain to the scalp, where they can be measured using appropriate electrodes. Rhythmical measured activity represents postsynaptic cortical neuronal potentials which are synchronized by the complex interaction of large populations of cortical cells. EEG, a noninvasive recording technique, is one of the commonly used systems for monitoring brain activity. EEG data is simultaneously collected from a multitude of channels at a high temporal resolution, yielding high dimensional data matrices for the representation of brain activity. In addition to its unsurpassed temporal resolution, EEG is non-invasive, wearable, and more affordable than other neuroimaging techniques. In some techniques, EEG signals are acquired by headsets. One very common example of an EEG headset used in medical applications is a standard EEG cap, which includes a cap made of a rubber or rubber-like material that is put on the subject's head like a swimming cap. The cap has surface electrodes positioned throughout the cap in a manner such that they come in contact with surface of the subject's head. Common contemporary EEG headsets require extensive preparation along with professional lengthy setup and positioning. In order to improve conductivity, gel or saline is typically employed. In some cases, uncomfortable pressure is applied to the electrodes to enhance the electrical coupling. Also known, is the use of dry electrodes, that allow fast and easy setup. Once an EEG headset is worn, a trial-and-error procedure is employed to ensure that the headset is properly aligned with the desired locations on the scalp and properly attached to the scalp to achieve good conductivity. SUMMARY OF THE INVENTION The invention is defined by the appended claims. According to an aspect of some embodiments of the present disclosure there is provided a system for measuring electroencephalography (EEG) signals. The system comprises a wearable body adapted to fit over a scalp, a plurality of electrodes mounted on the wearable body at a density of at least 2 electrodes per 3 cm2, and a signal processor configured for detecting Evoked Related Potential (ERP) signals from the electrodes and determining a physiological location of each electrode or each group of electrodes based on the ERP signals. According to some embodiments of the disclosure the system comprises an input for receiving from a stimulation system signals describing stimulation of a subject wearing the wearable body, wherein the signal processor configured for determining the location based in part on the signals from the stimulation system. According to some embodiments of the disclosure the stimulation system is configured to apply electrical stimulation by at least one of the electrodes. According to an aspect of some embodiments of the present disclosure there is provided a system for measuring EEG signals. The system comprises: a wearable body adapted to fit over a scalp; a plurality of electrodes mounted on the wearable body; a plurality of stretch sensors for generating stretch data describing a stretching of the wearable body; and a signal processor configured for receiving the stretch data and constructing from the stretch data a three-dimensional map describing physiological locations of the electrodes over the wearable body, once stretched. According to some embodiments of the disclosure the system comprises a plurality of physically separate sensing systems, each comprising several of the plurality of electrodes. According to an aspect of some embodiments of the present disclosure there is provided a system for measuring EEG signals. The system comprises: a wearable body adapted to fit over a scalp; a plurality of electrodes mounted on the wearable body; a plurality of controllable actuators for applying force to the electrodes; a controller configured for individually controlling each actuator or group of actuators to apply force to at least one electrode; and a signal processor configured for receiving and processing signals from the electrodes and transmitting control signals to the controller based on the processing. According to some embodiments of the disclosure the signal processor is configured for determining at least one of: an electrode-tissue impedance, a signal-to-noise ratio, artifacts percentage, and a signal quality, and to control the force based on the determination. According to some embodiments of the discl