# US 10,441,223 B2 · Electrode and leakage current testing in an EEG monitor with an implantable part > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,441,223 B2 - Document ID: US10441223B2 - Status: Granted - Kind: B2 - Application number: 14/831,340 - Filed: 2015-08-20 - Published: 2015-12-10 - Granted: 2019-10-15 - Earliest claimed: 2013-02-27 - Assignees: T&W Engineering A/S - Applicants: Widex A/S - Inventors: Soren Kilsgaard; Morten Holm Jensen - Web page: https://patentgrep.com/patent/US10441223B2 ## CPC - A61B 5/7221: {Determining signal validity, reliability or quality (preventing, reducing or removing noise induced by motion artefacts A61B5/7207; noise originating from a therapeutic or surgical apparatus A61B5/7217)} - A61B 5/0006: {ECG or EEG signals} - A61B 5/0031: {Implanted circuitry} - A61B 5/293: Invasive - A61B 5/31: for electroencephalography [EEG] - A61B 5/6846: {specially adapted to be brought in contact with an internal body part, i.e. invasive} - A61B 5/7203: {for noise prevention, reduction or removal} - A61B 5/72: {Signal processing specially adapted for physiological signals or for diagnostic purposes} - A61B 2560/0266: for monitoring or limiting apparatus function - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract A personal wearable EEG monitor comprising an implantable electrode part with at least two electrodes (2,3) for measuring an EEG signal of a person. The electrode part comprises an electronic circuit arranged in a housing (1) with each electrode arranged external to the housing. The electrode part comprises a testing circuit for testing functionality of the electrode part. The testing circuit comprises a capacitor (9) coupled in serial connection to at least one of the electrodes, and a test signal generator for providing a test signal. The EEG monitor is adapted for analyzing the signal resulting from the signal generator for identification of faults in the electrode part. The invention further provides a method for detecting a leak current in an implanted EEG monitor part. ## Claims ### Claim 1 A personal wearable EEG monitor comprising an implantable electrode part with at least two electrodes adapted for measuring an EEG signal of a person, said electrode part comprising an electronic circuit arranged in a housing with each electrode arranged external to said housing, said electronic circuit being adapted for receiving an analogue EEG signal from said electrodes and being provided with an analogue to digital converter for converting the analogue EEG signal into a digital signal, said electrode part comprising a testing circuit for testing for faults in said electrode part, wherein said testing circuit comprises a capacitor coupled in serial connection to at least one of said electrodes, and a test signal generator for providing a test signal, said test signal generator being adapted for being coupled between said electrodes and said electronic circuit during a testing period, wherein said EEG monitor is adapted for analyzing the test signal from said signal generator for identification of faults in the electrode part. ### Claim 2 (depends on 1) The EEG monitor according to claim 1, wherein said test signal generator is arranged between said electrodes and an input of said analogue to digital converter, and wherein said EEG monitor is adapted for analyzing a signal at said input of the analogue to digital converter for identification of faults in the electrode part. ### Claim 3 (depends on 1) The EEG monitor according to claim 1, wherein an output, signal from said analogue to digital converter is transferred to a digital signal processing unit arranged in the electrode part. ### Claim 4 (depends on 1) The EEG monitor according to claim 1, wherein said capacitor is coupled in serial connection to the input of said analogue to digital converter. ### Claim 5 (depends on 1) The EEG monitor according to claim 1, adapted for identifying at least one of a charging and a discharging function at an input of the analogue to digital converter and thereby detecting a current leak. ### Claim 6 (depends on 1) The EEG monitor according to claim 1, wherein a resistor is arranged across an input of the analogue to digital converter. ### Claim 7 (depends on 1) The EEG monitor according to claim 1, wherein the implantable electrode part comprises a coil for an inductive coupling to a non-implantable part, said inductive coupling being adapted for transfer of data and power. ### Claim 8 (depends on 1) The EEG monitor according to claim 1, wherein said test signal generator provides a square wave test signal with frequency between 25 and 40 Hz. ### Claim 9 (depends on 1) A method for detecting a leak current in an implanted EEG monitor according to claim 1, comprising the steps of providing said test signal, subtracting an estimate of said test signal from an output of the analogue to digital converter to obtain a resulting signal, low-pass filtering the resulting signal in order to suppress EEG and noise components, transforming the low-pass filtered signal into a logarithmic domain, fitting the transformed signal to a straight line, determining an interception with y-axis of the straight line, and determining if a leak current is present based at least in part on the determined interception. ### Claim 10 (depends on 9) The method according to claim 9, wherein said low-pass filtered signal is down-sampled in order to reduce the calculation complexity. ### Claim 11 (depends on 9) The method according to claim 9, wherein said step of transforming the low-pass filtered signal comprises determining the power of the low-pass filtered signal and taking the natural logarithm of the power of the low-pass filtered signal. ### Claim 12 (depends on 9) The method according to claim 9, wherein said step of transforming the low-pass filtered signal comprises determining the absolute value of the low-pass filtered signal and taking the natural logarithm of the absolute value. ### Claim 13 (depends on 2) The EEG monitor according to claim 2, wherein said capacitor is coupled in series between said at least one electrode and an input of said analog-to-digital converter, and said test signal generator is coupled to supply said test signal to another input of said analog-to-digital converter.