# US 10,499,854 B2 · Eliminating acquisition-related artifacts in electrophysiological recording > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,499,854 B2 - Document ID: US10499854B2 - Status: Granted - Kind: B2 - Application number: 15/361,356 - Filed: 2016-11-25 - Published: 2018-05-31 - Granted: 2019-12-10 - Earliest claimed: 2016-11-25 - Assignees: Cochlear Limited - Applicants: Cochlear Limited - Inventors: Ryan Orin Melman; Justin James Gilmour; Alex von Brasch; Todd Lupton - Web page: https://patentgrep.com/patent/US10499854B2 ## CPC - A61B 5/686: {Permanently implanted devices, e.g. pacemakers, other stimulators, biochips (A61B5/6861 takes precedence)} - A61B 5/7217: {of noise originating from a therapeutic or surgical apparatus, e.g. from a pacemaker} - A61N 1/0541: {Cochlear electrodes} - A61B 5/12: Audiometering - A61N 1/36: for stimulation - A61N 1/36036: {of the outer, middle or inner ear} - A61N 1/36038: {Cochlear stimulation} - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - A61N: ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY (measurement of bioelectric currents A61B; surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body A61B18/00; anaesthetic apparatus in general A61M; incandescent lamps H01K; infrared radiators for heating H05B) ## Abstract Aspects presented herein are directed to techniques for eliminating acquisition related artifacts in electro-physiological recording. In order to eliminate artifacts in neural response recordings, a pair of recordings is made with, respectively, inverted and non-inverted polarity at one pair of electrodes. An average of the two recordings will eliminate the acquisition artifact without the need for an extra recording, such as a baseline. ## Claims ### Claim 1 A method of measuring an in vivo electrical potential, the method comprising: applying at least a first electrical stimulus to at least one stimulating electrode of an implant; acquiring, via a set of recording electrodes, a first trace corresponding to one or more signals evoked in response to the at least first electrical stimulus during one or more first recording probe epochs during which the set of recording electrodes have a first polarity; changing a polarity of the set of recording electrodes from the first polarity to a second polarity, wherein the second polarity is inverted relative to the first polarity; applying at least a second electrical stimulus to the at least one stimulating electrode of the implant; acquiring, via the set of recording electrodes, a second trace corresponding to one or more signals evoked in response to the at least second electrical stimulus during one or more second recording epochs during which the set of recording electrodes have the second polarity; and determining a difference between the first and the second traces, thereby reducing an acquisition artifact. ### Claim 2 (depends on 1) The method of claim 1, wherein the in vivo electrical potential is a signal used in calibrating the implant. ### Claim 3 (depends on 1) The method of claim 1, wherein the in vivo electrical potential is an electrophysiological response. ### Claim 4 (depends on 3) The method of claim 3, wherein the electrophysiological response is an evoked compound action potential (ECAP). ### Claim 5 (depends on 3) The method of claim 3, wherein the electrophysiological response is an acoustic reflex threshold. ### Claim 6 (depends on 1) The method of claim 1, wherein at least one stimulating electrode is the same as at least one recording electrode in the set of recording electrodes. ### Claim 7 (depends on 1) The method of claim 1, wherein the implant comprises a differential amplifier, and the second polarity arises from inverting the polarity of the recording electrodes that are in electrical contact with the differential amplifier. ### Claim 8 (depends on 1) The method of claim 1, wherein the second polarity arises from dynamically switching the polarity. ### Claim 9 (depends on 8) The method of claim 8, wherein the switching occurs in a period of time between a pair of adjacent recording epochs. ### Claim 10 (depends on 1) The method of claim 1, wherein the determining a difference comprises subtracting a trace obtained during an epoch in which the set of recording electrodes have the first polarity from a trace obtained during a corresponding epoch in which the set of recording electrodes have the second polarity, and averaging the result. ### Claim 11 (depends on 1) The method of claim 1, wherein the implant is a cochlear implant. ### Claim 12 (depends on 1) The method of claim 1, wherein the implant is selected from: a brain implant, a spinal implant, and a retinal implant. ### Claim 13 (depends on 1) The method of claim 1, further comprising: acquiring a third trace corresponding to application of both an electrical stimulus and a secondary mask stimulus; acquiring a fourth trace corresponding to application of only a secondary mask stimulus; and subtracting the third and fourth traces from half of a result of subtracting the second trace from the first trace. ### Claim 14 (depends on 13) The method of claim 13, wherein the in vivo electrical potential is an ECAP. ### Claim 15 (depends on 13) The method of claim 13, wherein the implant is an auditory prosthesis. ### Claim 16 (depends on 13) The method of claim 13, wherein the implant is selected from: a brain implant, a spinal implant, and a retinal implant. ### Claim 17 A system for measuring an evoked compound action potential (ECAP), the system comprising: an electrode array in electrical communication with a biological component, wherein the electrode array comprises a plurality of pairs of recording electrodes; a plurality of differential amplifiers, in electrical communication with the electrode array, whereby each electrode in a pair of recording electrodes is connected to an input of one of the differential amplifiers; a switching circuit in electrical communication with the differential amplifiers, and configured to invert a polarity of the inputs to one or more of the differential amplifiers; and instructions encoded in logical memory for: applying at least a first electrical stimulus via the electrode array, thereby generating an ECAP, wherein the ECAP comprises stimulus artifact, acquisition artifact, noise, and a target signal; recording, via a first pair of recording electrodes, a first trace corresponding to one or more signals evoked in response to the at least first electrical stimulus during one or more first recording probe epochs during which the first pair of recording electrodes have a first polarity; changing a polarity of the first pair of recording electrodes from the first polarity to a second polarity, wherein the second polarity is inverted relative to the first polarity; applying at least a second electrical stimulus via the electrode array; recording, via the first pair of recording electrodes, a second trace corresponding to one or more signals evoked in response to the at least second electrical stimulus during one or more second recording epochs during which the first pair of recording electrodes have the second polarity; subtracting a trace obtained during an epoch in which the first pair of recording electrodes have the first polarity from a trace obtained during a corresponding epoch in which the first pair of recording electrodes have the second polarity, and averaging the result, thereby eliminating the acquisition artifact. ### Claim 18 (depends on 17) The system of claim 17, wherein the biological component is the cochlea of a subject. ### Claim 19 (depends on 17) The system of claim 17, wherein the electrode array is in an auditory prosthesis. ### Claim 20 (depends on 17) The system of claim 17, wherein the system is selected from: a brain implant, a spinal implant, and a retinal implant. ### Claim 21 (depends on 17) The system of claim 17, wherein none of the recorded epochs is a baseline trace.