Patent Application
20230363691
The inventions described below relate to the field of brain monitoring systems for diagnosis and prognosis of epilepsy and other motor disorders.
About 1 percent of people suffer from epilepsy, and about a third of those people do not respond to medicine and might only be treated by removal of some part of the brain. Stereo-electro-encephalography (SEEG) is a method for determining whether a patient with epilepsy which has not responded to medication might have “focal epilepsy” which might be treated with brain surgery. Stereo-elector-encephalography requires short term implantation of many electrodes into the brain, in many parts of the brain, and recording of electrical activity detected by the brain in hopes of identifying an area of the brain which is the focus of the epilepsy, which is referred to as an “epileptogenic” area. If an epileptogenic area is identified after analysis of electrical activity, this indicates that the surgical resection of the epileptogenic area might result in alleviation of epileptic seizures. For example, if analysis of the electrical signals from the electrodes indicates that activity in the temporal lobe is the origin of seizures, removal of the temporal lobe may eliminate seizures altogether.
Currently, stereo-electro-encephalography is accomplished by implanting numerous electrodes deep in the brain, with electrical leads extending through the brain, through burr-holes in the skull, and then a bundle of the leads extend several feet to a console or EEG monitoring system, such as a Kohden Neurofax EEG-1200 console, which records data from the leads. The leads have to remain in place for several days (ten to thirty days, typically) to detect a sufficient number of seizures and collect enough data to confirm that an epileptogenic focus has been identified with enough certainty to justify removal or ablation of a part of the patient's brain. After data has been collected, the electrodes are removed. If analysis of the collected electro-encephalography data leads to a conclusion that resection of the “epileptogenic” area will likely lead to cessation of seizures, resection can be performed at any time after removal of the electrodes.
The devices and methods described below provide for more convenient stereo-electro-encephalography, which may allow the patient to move freely during the days-long monitoring period. The system and method also entails a lower risk of infection, more discrete usage of the system, and a lower risk of lead breakage and resultant loss of signal, and lower risk of interference because the lead length is much shorter. The system includes a number of SEEG electrodes, which are configured for implantation and explantation in the brain, and configured for use in encephalography. In one version of the system, each SEEG electrode is wirelessly connected to an EEG console, through a subcutaneous electrode which is connected to the SEEG electrode through a conductor. The subcutaneous electrode is in turn wirelessly connected to a supra-cutaneous appliance operable to obtain SEEG signals, generated by the SEEG electrode, through the subcutaneous electrode. Other wireless communication schemes may also be used. The method of use entails implantation of the SEEG electrodes deep in the brain and implantation of the subcutaneous electrodes under the scalp (with the conductor running through the brain). The patient need not be physically connected to a console or control system, and may be ambulatory for the SEEG protocol period.
The probes 3 of
In a first embodiment of the system and method, the system can be configured as described in our co-pending U.S. patent application Ser. No. 17/741,205, filed May 10, 2022, entitled Deep Brain Stimulation System with Wireless Power, the entirety of which is hereby incorporated by reference, and the electrodes may be powered and signals indicative of brain activity (EEG's, for example) obtained through the system disclosed therein. In this first system:
To establish a power circuit from a power source to the probes, and/or communicate sensor data from the probes to a control system or console, in conjunction with the electrodes 8, the patch electrode 10 is disposed on the scalp, supracutaneously on the scalp, or subcutaneously under the scalp. The patch electrode is, preferably, located such that it is not in direct physical contact with the electrodes 8, and is spaced from the electrodes 8. The patch electrode 10 is connected to the secondary (remote) coupling component 11S of a coupling assembly 11, and the primary (base) coupling component 11P is connected to the power supply and control system 12. A conductor 13 extends from the secondary (remote) coupling component 11S, through a burr-hole and into the brain, and may be an insulated wire and include an electrode 14 at its distal end (a conductive wire, insulated or bare, will suffice). An additional conductor connects the secondary (remote) coupling component 11S to the patch electrode 10. The control system is configured to provide power to the probes, for stimulation of brain tissue proximate the probes, and receive sensor data from the probe. The control system or console used to control the system and/or receive and store EEG data from the SEEG electrodes may be implemented on a dedicated console such as the Kohden Neurofax EEG-1200 console (without all the wires), and EEG monitoring system, a general purpose computer, or a mobile phone or tablet.
Preferably, the coupling assembly is an inductive coupling assembly, comprising a pair of coils. The secondary (remote) coupling component 11S may, like the patch electrode, also be installed on the scalp, supra-cutaneously, or subcutaneously under the scalp. The primary (base) coupling component 11P may be placed in proximity to the secondary coupling using a magnetic attachment or other releasable attachment means (a snap lock fitting, secured to a headband, glued to the overlying skin with a weak adhesive) or non-releasable means (stitched to the scalp, nailed or screwed to the skull, or other means not considered “releasable” attachment means which require tools for removal).
The control system 12 is operable to generate power and transmit power through the inductive coupling to the electrodes and may be further programmed to analyze the sensor data and modify control signals to the probes to control the stimulation provided by the probes in response to the sensor data. The power supply and control system 12 may be disposed in an appliance, which may be configured as headwear (disguised as a hat, head band, or wig). The power supply may be connected to the SEEG electrodes through the inductive coupling, and may be connected substantially continuously during the SEEG monitoring protocol period of several days to several weeks. The power supply is preferably not implanted subcutaneously on the patient's chest of abdomen, as is the practice with pulse generators used with DBS systems.
The system may be used in a method in which a surgeon implants a number of SEEG electrodes 3 (about 20) in the brain of a patient, in areas of the brain which may be the focus or origin of brain activity associated with a movement disorder, and places the subcutaneous electrodes under the scalp of the patient, in the subcutaneous tissue 25 of the scalp (which may include connective tissue, epicranial apaneurosis, areolar connective tissue, and periosteum), and implanting the patch electrode also subcutaneously, and implanting the secondary (remote) coupling component 11S pericutaneously (preferably subcutaneously, or perhaps supra-cutaneously), and installing the tip of the conductor 13 in the brain. After installation of these components, the surgeon or the patient may place the primary (base) coupling component 11P proximate the secondary (remote) coupling component 11S. With the primary (base) coupling component 11P coupled to the secondary (remote) coupling component 11S, the control system may be operated to collect EEG signals from the various implanted SEEG electrodes. The coupling may be maintained for the entire monitoring period, for substantially the entire period (excepting brief periods). EEG data may be collected continuously while the coupling is maintained.
An embodiment which includes memory is depicted in
Another variation of the system which includes memory is depicted in
The transponder microchip 35 may be powered through the inductive power coupling of the circuit of
In use, the system of
After installation of these components, the surgeon or the patient may place an NFC/RFID reader 32 proximate an NFC/RFID transponder 31 to interrogate the transponders and obtain EEG data stored in the memory of the transponder. The surgeon or the patient may use a different reader for each transponder, or may use a single reader to interrogate several, or all, of the transponders. The readers may be maintained proximate the transponders, for substantially the entire period, and EEG data may be collected continuously while the coupling is maintained. However, because the transponders are self-powered and are operable to store historical EEG data, the surgeon or patient may bring the readers into proximity with the transponders only periodically, and the EEG data may be collected only periodically. This leaves the patient free to engage in normal activity, interrupted occasionally to interrogate the transponders, without the need for constant use of an appliance or head wear to keep the reader installed on the head in proximity to the transponders.
As with previously described systems, this system may include memory and battery power disposed on the transponder, so that the reader may be used occasionally to collect EEG data collected over an extended period of time. The transponder may be configured without an onboard power supply, and the antenna may be applied and operated continuously to provide power to the NFC/RFID transponder 31, and the transformer may be configured without onboard memory, and the antenna used continuously to collect ECG data from the transponder.
The method of obtaining EEG data from a patient's brain described above uses several of the SEEG electrode assemblies which each comprise a SEEG electrode 3 secured to a retrieval tether (9, 52) having a first end and a second end, with the SEEG electrode 8 secured to the first end of the tether. The method includes the steps of providing a plurality of SEEG electrode assemblies (3, 9, 8; 9, 31, 52, 53) for temporary implantation into the brain, for the length of a SEEG protocol, which may be several days or weeks, and, preferably, removing the electrodes after sufficient data has been collected to diagnose a patient's condition, (2) providing a control system configured to collect and store EEG data obtained from the SEEG electrodes, (3) for each of the SEEG electrode assemblies, implanting the SEEG electrode in the patient's brain by inserting the SEEG electrode through a burr hole, with the tether running from the SEEG electrode and through the burr hole and securing the second end of the tether subcutaneously or supracutaneously outside the skull of the patient; (4) wirelessly communicating EEG data obtained from the SEEG electrodes to the control system, without connecting the SEEG electrodes to the control system with wires; and (5) after collecting EEG data from the SEEG electrodes, using the tether to remove the SEEG electrodes from the patient's brain. In this method, the SEEG electrodes are implanted in the brain in a location known to effect target disorders, or known to produce signals indicative of target movement disorders, such as epilepsy. With this method, doctors can collect EEG data and determine if the movement disorders are likely treatable with procedures such as resection of portions of the brain, stimulation of certain areas of the brain, or administration of drugs to the patient.
In one version of the method, the SEEG electrode assembly may include an NFC/RFID transponder 31 fixed to the second end of the tether, and the method may include implanting the NFC/RFID transponder 31 pericutaneously, under or on the patient's scalp and wirelessly collecting EEG data from the SEEG electrodes using an NFC/RFID reader. After collecting EEG data from the SEEG electrodes, the method preferably includes removing the NFC/RFID transponder 31 from the patient's scalp, along the removing the SEEG electrodes from the brain (although the electrodes may be left in the brain for later EEG acquisition and administration of stimulation to the brain).
In another version of the method, each SEEG electrode assembly may also comprise an electrically non-functional tab 53 fixed to the second end of the tether. This version of the method further comprises the steps of implanting the electrically non-functional tab 53 pericutaneously, under or on the patient's scalp and wirelessly collecting EEG data from the SEEG electrodes using an NFC/RFID reader, and, after collecting EEG data from the SEEG electrodes, pulling the electrically non-functional tab 53 to remove the SEEG electrode from the patient's brain.
In another version of the method, each SEEG electrode assembly may also comprises an electrode 8 fixed to the second end of the tether, wherein the tether comprises an electrical conductor, and the system includes at least one NFC/RFID transponder operable to transmit EEG data from the probes to an NFC/RFID reader. This version of the method entails implanting the electrode 8 pericutaneously, under or on the patient's scalp, wirelessly collecting EEG data from the SEEG electrodes using an NFC/RFID reader, and, after collecting EEG data from the SEEG electrodes, pulling the electrode 8 to remove the SEEG electrode from the patient's brain.
Each of the versions of the system and methods can include means for wirelessly powering the SEEG electrodes, or a battery operably connected to the SEEG electrode, and any of the several powering systems and methods may be used with any of the EEG data sensing systems and methods.
While the preferred embodiments of the devices and methods have been described in reference to the environment in which they were developed, they are merely illustrative of the principles of the inventions. The elements of the various embodiments may be incorporated into each of the other species to obtain the benefits of those elements in combination with such other species, and the various beneficial features may be employed in embodiments alone or in combination with each other. Other embodiments and configurations may be devised without departing from the spirit of the inventions and the scope of the appended claims.
