# US 9,517,345 B2 · Neuroprosthetic stimulation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,517,345 B2 - Document ID: US9517345B2 - Status: Granted - Kind: B2 - Application number: 14/763,402 - Filed: 2014-01-28 - Published: 2015-12-10 - Granted: 2016-12-13 - Earliest claimed: 2013-01-29 - Assignees: National ICT Australia Limited - Applicants: National ICT Australia Limited; The University of Melbourne - Inventors: Hamish Meffin; Anthony Burkitt; David Grayden; Behman Tayahori; Elma O'Sullivan Greene - Web page: https://patentgrep.com/patent/US9517345B2 ## CPC - A61N 1/36128: {Control systems} - A61N 1/0529: {Electrodes for brain stimulation} - A61N 1/0543: {Retinal electrodes} - A61N 1/0551: {Spinal or peripheral nerve electrodes} - A61N 1/36046: {of the eye} - A61N 1/36067: {Movement disorders, e.g. tremor or Parkinson disease (stimulating motor muscle A61N1/36003)} - A61N 1/36082: {Cognitive or psychiatric applications, e.g. dementia or Alzheimer's disease} - A61N 1/36146: {specified by the stimulation parameters} - A61N 1/36182: {Direction of the electrical field, e.g. with sleeve around stimulating electrode} - A61N 1/36185: {Selection of the electrode configuration} - G06F 3/015: {Input arrangements based on nervous system activity detection, e.g. brain waves [EEG] detection, electromyograms [EMG] detection, electrodermal response detection} - 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) - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract The present disclosure relates to a method for determining stimulation parameters for a neuroprosthetic device performed by a processor of the device. Based on (i) a desired spatial pattern of neural activity, the processor determines stimulation parameters for an array of electrodes of the neuroprosthetic device. The processor determines the stimulation parameters such that a difference between (i) the desired spatial pattern of neural activity and (ii) an estimated spatial pattern of neural activity is optimised. The estimated spatial pattern of neural activity is an estimate of a response of a target neural tissue to being stimulated by the neuroprosthetic device based on the stimulation parameters. This method allows higher resolution stimulation and allows electrode arrays with higher electrode density to be usefully employed. ## Claims ### Claim 1 A method comprising: determining, by a controller of a neuroprosthetic device, stimulation parameters for the neuroprosthetic device based on (i) a desired spatial pattern of neural activity, determining stimulation parameters for an array of electrodes of the neuroprosthetic device such that a difference between (i) the desired spatial pattern of neural activity and (ii) an estimated spatial pattern of neural activity is optimised and the estimated spatial pattern of neural activity is an estimate of a response of a target neural tissue to being stimulated by the neuroprosthetic device based on the stimulation parameters, determining the stimulation parameters further comprises estimating the response of the target neural tissue to being stimulated by the neuroprosthetic device based on the stimulation parameters using a model of how electrical stimulation evokes a spatial pattern of neural activity; and delivering by the controller, the stimulation parameters to the array of electrodes. ### Claim 2 (depends on 1) The method of claim 1, wherein determining the stimulation parameters comprises optimising a non-linear objective function to optimise the difference between (i) the desired spatial pattern of neural activity and (ii) the estimated spatial pattern of neural activity. ### Claim 3 (depends on 2) The method of claim 2, wherein optimising the objective function comprises minimising error or mean squared error in a measure of neural activity associated with the difference between (i) the desired spatial pattern of neural activity and (ii) the estimated spatial pattern of neural activity. ### Claim 4 (depends on 2) The method of claim 2, wherein optimising the objective function comprises maximising a likelihood function of (ii) the estimated spatial pattern of neural activity substantially matching with (i) the desired spatial pattern of neural activity. ### Claim 5 (depends on 2) The method of claim 2, wherein the stimulation parameters are determined subject to one or more constraints including one or more of: a threshold relating to voltage compliance is not exceeded; a threshold relating to charge per phase and/or charge density is not exceeded; a threshold relating to power limits is not exceeded; a threshold relating to current amplitude is not exceeded; a threshold relating to pulse duration is not exceeded; a threshold relating to inter-phase gap is not exceeded; and axons of passage in the target neural tissue not stimulated. ### Claim 6 (depends on 1) The method of claim 1, wherein determining the stimulation parameters further comprises estimating the response of the target neural tissue to being stimulated by the neuroprosthetic device based on the stimulation parameters using a linear-non-linear model. ### Claim 7 (depends on 6) The method of claim 6, wherein the response of the target neural tissue to being stimulated by the neuroprosthetic device based on the stimulation parameters is estimated using the linear-non-linear model by performing: a linear step, in which a spatio-temporal function is determined as a linear function of the stimulation parameters; and a non-linear step, in which using spatio-temporal pattern of neural activity is determined using the result of the linear step by passing the linear spatio-temporal function through a static non-linearity. ### Claim 8 (depends on 6) The method of claim 6, wherein the response of the target neural tissue to being stimulated by the neuroprosthetic device based on the stimulation parameters is estimated using values of membrane potential of neurons of the target neural tissue given the stimulation parameters. ### Claim 9 (depends on 8) The method of claim 8, wherein the values of membrane potential are pre-calculated using basis functions of membrane potential, each basis function being defined such that each of its constituent functions represents the membrane potential in the target neural tissue when a single electrode is active with a standard current and the remaining electrodes with zero net current through them. ### Claim 10 (depends on 8) The method of claim 8, wherein the values of membrane potential are precalculated based on values of extracellular potential in the vicinity of the target neural tissue given the stimulation parameters. ### Claim 11 (depends on 10) The method of claim 10, wherein the values of extracellular potential are pre-calculated using basis functions of extracellular potential, each basis function being defined such that each of its constituent functions represents the extracellular potential in the vicinity of the target neural tissue when a single electrode is active with a standard current and the remaining electrodes with zero net current through them. ### Claim 12 (depends on 10) The method of claim 10, wherein the values of membrane potential and/or extracellular potential are calculated using a volume conductor model defined by a partial differential equation in space and one or more boundary conditions. ### Claim 13 (depends on 10) The method of claim 10, wherein the values of membrane potential and/or extracellular potential are calculated using a bidomain model of electrical flow. ### Claim 14 (depends on 1) The method of claim 1, wherein the stimulation parameters for the array of electrodes are amplitudes of current pulses applicable by the array of electrodes on the target neural tissue. ### Claim 15 (depends on 1) The method of claim 1, further comprising, applying stimulation by the array of electrodes wherein the stimulation applied by the array of electrodes is synchronised using identical rectangular wave, charge-balanced biphasic waveforms. ### Claim 16 (depends on 1) The method of claim 1, wherein the estimated spatial pattern of neural activity represents a mean spike count, averaged over a population of neurons in the vicinity of a spatial variable associated with the target neural tissue. ### Claim 17 (depends on 1) The method of claim 1, wherein the stimulation parameters are determined in real time to dynamically adjust the stimulation parameters according to the target spatial pattern of neural activity. ### Claim 18 (depends on 1) A non-transitory computer readable medium with an executable program stored thereon that when executed causes a computer to perform the method of claim 1. ### Claim 19 A controller for determining stimulation parameters for a neuroprosthetic device, the controller comprising a processor to: based on (i) a desired spatial pattern of neural activity, determine stimulation parameters for an array of electrodes of the neuroprosthetic device such that the difference between (i) the desired spatial pattern of neural activity and (ii) an estimated spatial pattern of neural activity is optimised and the estimated spatial pattern of neural activity is an estimate of a response of a target neural tissue to being stimulated by the neuroprosthetic device based on the stimulation parameters, the processor estimating the response of the target neural tissue to being stimulated by the neuroprosthetic device based on the stimulation parameters using a model of how electrical stimulation evokes a spatial pattern of neural activity, and delivering the stimulation parameters to the array of electrodes. ### Claim 20 A neuroprosthetic device comprising: an array of electrodes to deliver electrical stimulation to a target neural tissue of a subject according to a set of stimulation parameters; and a controller of the neuroprosthetic device to determine the set of stimulation parameters, the controller comprising a processor to: based on (i) a desired spatial pattern of neural activity, determine stimulation parameters for an array of electrodes of the neuroprosthetic device such that the difference between (i) the desired spatial pattern of neural activity and (ii) an estimated spatial pattern of neural activity is optimised and the estimated spatial pattern of neural activity is an estimate of a response of the target neural tissue to being stimulated by the neuroprosthetic device based on the stimulation parameters, the processor estimating the response of the target neural tissue to being stimulated by the neuroprosthetic device based on the stimulation parameters using a model of how electrical stimulation evokes a spatial pattern of neural activity and delivering the stimulation parameters to the array of electrodes.