Fundació URV

An electrode device for electroencephalography

Posted by Unitat from Fundació URVResponsive · Patents for licensing · Spain

Summary of the technology

A specific electrode has been designed for the recording of aEEG in the neonatal and pediatric ICU’s. The new electrode solves the problems of conventional commercial electrodes. The main difference of the new device is a design of suitable dimensions and shape that adapts to the cephalic surface of children and improves its support. It allows a safe replacement of the electroconductive gel, and a manipulation of the child without difficulties.

Most available surface electrodes are not properly sized for term and preterm infant’s application. Also, they are usually attached to a long wire that connects them to the bioelectric signal amplifier. This long wire electrode hinders the manipulation of the newborn by health care staff. In addition, the electrode wire is usually attached laterally to the electrode. In the lying position, the usual position of children in the ICU’s, this joint causes a lever force that facilitates the electrode decoupling.

Superficial cup electrodes available have a hole through which the electroconductive gel is replaced in order to maintain its high conductive capacity during long-term recordings. During this process, a blunt-tipped syringe is usually used to remove the old electroconductive gel and apply the new one. At this time, it is usually necessary to apply vertical pressure to beat the conductive gel layer that may have dried on the long-term recordings. This pressure can cause an involuntary contact with the scalp surface, which should be avoided in newborns due to their fragility and proximity to the fontanelles.

Disposable adhesive electrodes have the disadvantage of not allowing the replacement of the electroconductive gel and therefore they must be replaced periodically. This involves more manipulation and possible changes in the recording conditions (placement, impedance, etc.).
The subdermal needle electrodes which are often used in the aEEG to achieve low impedance recordings have the disadvantage of producing pain. Pain should always be avoided to improve comfort but in the aEEG it also has the disadvantage of not allowing the accurate assessment of a parameter as important as the latency of onset of the asleep-wake cycle. In addition, the subdermal electrodes have the same drawbacks as most surface electrodes available: are connected to a long wire to the amplifier and are easily detached.

Fundació URV

Description of the technology

Origin of the project:

Amplitude-integrated electroencephalography (aEEG) is a technique for monitoring brain function that is frequently used in neonatal and pediatric Intensive Care Units (ICUs). Electrodes commonly used during conventional electroencephalography studies are not considered suitable for (EEGa) because they do not take into account the particularities of infants in the ICUs: cephalic size and shape; fine and sensitive scalp; lying position and frequent manipulation by medical staff.

 

Challenges that technology addresses:

Conventional surface cup electrodes have a central hole through which the electroconductive gel is replaced during long-term recordings. In this process, a syringe with a blunt metal tip is usually used to replace the electroconductive gel, and a vertical pressure is usually applied to overcome the conductive gel layer that may have dried on the long-term recordings. This pressure can cause involuntary contact with the surface of the scalp, which should be avoided in babies because of its fragility and proximity to the fontanelles. In single-use adhesive electrodes, the gel cannot be replaced and the electrodes must be replaced periodically. This involves greater manipulation and possible changes in recording conditions (placement, impedance, etc.).  

The subdermal needle electrodes used in most neonatal and pediatric ICUs to perform aEEGs have the disadvantage of producing pain. Pain, apart from producing discomfort, also prevents the calculation of the beginning of the wake-sleep cycle. In addition, subdermal electrodes have the same drawbacks as most available surface electrodes: they are connected by a long cable to the amplifier making it difficult for the patient to move; and can be easily detached from the scalp for lack of effective support.

 

Technology description:

The electrode device comprises a housing fixed on an adhesive element to adhere the electrode device to the skin surface of a patient, particularly the scalp; an electrode plate placed in the housing at a certain distance from a support surface of the housing forming a hollow space; and a wire connection for the electrode.

Unlike the known proposals in the field, in the proposed electrode device the housing has two protruding parts, a first protruding part and a second protruding part.

The first protruding part includes or provides a first hole of a conical shape for injecting and replacing an electroconductive gel inside the hollow space. The first protruding part is disposed in the housing inclined outwardly at an angle between 50-degree and 70-degree with respect to the longitudinal direction of the skin surface.

The second protruding part includes or provides a second hole for the introduction of the wire connection, so that the wire connection can be attached, e.g. by means of one or more welding points, to the electrode plate. The second protruding part is disposed, substantially, on the axis of the housing. Therefore, the wire connection is maintained perpendicular or almost perpendicular (about 90º) to the skin surface when performing the measures, which allows minimizing the tangential forces that favor the inclination of the electrode plate and it’s uncoupling from the scalp. Likewise, the electrode plate is placed horizontally (i.e. flat or parallel, or substantially parallel, to the skin surface, e.g. the brain's cortex) in the housing. Hence, the sum of the postsynaptic potentials of the different pyramidal neurons oriented vertically to the brain cortex will be captured homogeneously by means of the whole surface of the electrode plate.

The proposed electrode device has a size and form adaptable to the head of the newborn. It is connected with a short wire that, once disconnected from an amplifier, facilitates the manipulation of the infant by the healthcare staff. The vertical orientation of the insertion between the electrode plate and the wire improves stability in the lying position. The conical hole prevents accidental contact of a blunt tip of a needle with the infant’s scalp and allows the safe replacement of the electroconductive gel, thus facilitating the good signal quality during long-term recordings. Furthermore, by being a surface electrode, it does not cause discomfort to the patient.

In an embodiment, the electrode plate comprises a first gap which allows the electroconductive gel to flow through and a second gap to fix the rotating position of the electrode plate to the housing using a clamping element. Hence the distance between the skin surface and the electrode plate is reduced (i.e. the mentioned hollow space is smaller).

In a particular embodiment, the first protruding part is disposed at a 60-degree angle with respect to the longitudinal direction of the skin surface.

The first protruding part can include a plug for closure thereof. Hence the properties of the electroconductive gel can be kept for a longer period of time.

The housing can be made of a polymer, ceramic or metallic material. The electrode plate can be made of, or can comprise a coating made of, Silver (Ag), Gold (Au), Silver/Silver-Chloride (Ag/AgCl), or any good electrical conductor material (e.g. Tin, Stainless Steel, Platinum, Cooper, Lead, or Nichrome).

In an embodiment, the adhesive element is a flexible adhesive pad including an adhesive layer provided on a lower surface thereof. Alternatively, the adhesive element comprises a double-sided tape.

In an embodiment, the electrode device also has a connector such as a touchproof connector or a male snap connector, among others, arranged on a distal end of the wire connector.

In an embodiment, when the electrode device has to be used in newborns or infants, the length of the wire connection is less than 50 millimeters, particularly of approximately 30 millimeters. In other embodiments, for instance when the electrode has to be used in adults the length of the wire connection can be between 0.6 and 2 meters.

In some embodiments, the wire connection can also include an insulating layer, for example made of a material comprising silicone, Polyvinyl chloride, Polypropylene, Polyethylene, XLPE (Cross-Linked Polyethylene), EPR (Ethylene Propylene Rubber), ECTFE (ethylene chlorotrifluoroethylene), PVDF (Polyvinylidene fluoride), Nylon, CPE (Chlorinated polyethylene), etc.

In yet some embodiments, one or more sealing elements can be disposed between the housing and the insulating layer of the wire connection.

In an embodiment, the surface of the housing in contact with the skin or the adhesive element has a curvature that better fits with the skull shape.

Hence, the proposed electrode device allows an easy electrode placement as well as a wire cable extension that permits an easier electrical connection. The electrode device design also allows the patient, in particular newborns, to rotate the head without difficulties. The new design allows replacing the electroconductive gel for long-term aEEG recordings.

 

Market:

The diagnostic medical electrodes market was valued at USD 560.8 Million in 2016 and is projected to reach USD 732.4 Million by 2022, at a CAGR of 4.7%. The medical electrodes market is highly competitive with the presence of several small and big players. Some of the major players in the market include 3M (US), Medtronic plc (Ireland), Ambu (US), Natus Medical Incorporated (US), Rhythmlink International, LLC (US), Koninklijke Philips N.V. (Netherlands), Cognionics, Inc. (US), CONMED Corporation (US), Leonhard Lang GmbH (acquired by DCC plc), and Nihon Kohden Corporation (Japan). The other players in this market include Compumedics Limited (Australia), General Electric Company (US), g.Tec Medical Engineering GmbH (Austria), Vermed (US), Vectracor (US), Neuro Therapeutics (US), Emotiv (US), BIONEN sas (Italy), Nikomed (US), NeuroWave Systems Inc. (US), Wearable Sensing (US), Orbital Research Inc. (US), NeuroSky (US), ANT Neuro (Netherlands), and SOMNOmedics GmbH (Germany).

Benefits:

The benefits from the electrode device in comparison with current ones are: suitable dimensions and shape that adapts to the cephalic surface of children, better adhesion, safe replacement of the electroconductive gel and easy handling of the child.

 

Applications:

A specific electrode has been designed for the recording of aEEG in the neonatal and pediatric ICU’s. The new electrode solves the problems of conventional commercial electrodes.

Current development status

Working prototypes

Desired business relationship

Technology selling

Patent licensing

Intellectual property status

Patent already applied for
EP20382317
OEPM

Technology Owner

Fundació URV

Technology Transfer Office

Related keywords

  • Magnetic and superconductory materials/devices
  • Medical Health related
  • Medical equipment
  • Electromedical and medical equipment
  • Medical instruments
  • Diagnostic equipment
  • healthcare

About Fundació URV

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