System for interpolating surface potential values for use in calculating current density
First Claim
1. A process for deriving the current density at points over an area of interest as a measure of the underlying neural activity comprising:
- the step of measuring physiological potentials at a limited number of points over the area of interest by means of electrodes to yield electrical signals indicative thereof;
the step of using the electrical signals to estimate the potential at each of an increased number of points over the area of interest by Kriging interpolation of the measured potentials; and
the step of deriving from said estimated potentials a current density value at each of said points.
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Accused Products
Abstract
A system for mapping and/or displaying spatiotemporal features of underlying event-related neural activity involves measuring the event-related evoked potential values at a limited number of points over the region of interest, deriving a first grid of potential values at points over the area of interest representing at least about a five fold increase in the number of points by a Kriging-type of spatial statistical interpolation, and using the first grid to derive for the region of interest a second grid of points of current density values by a Laplacian conversion. A plurality of second grids of current density values spaced apart in time are derived and displayed on a monitor in cartoon-type fashion to provide a cartoon-type display of the features of the event-related evoked response over the region of interest varying with time. Various other displays are possible for highlighting specific features.
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Citations
51 Claims
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1. A process for deriving the current density at points over an area of interest as a measure of the underlying neural activity comprising:
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the step of measuring physiological potentials at a limited number of points over the area of interest by means of electrodes to yield electrical signals indicative thereof; the step of using the electrical signals to estimate the potential at each of an increased number of points over the area of interest by Kriging interpolation of the measured potentials; and the step of deriving from said estimated potentials a current density value at each of said points. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. Apparatus for displaying the features of underlying neural activity over an area of interest comprising:
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means for measuring physiological potentials at a plurality of points and for generating electrical signals indicative thereof; a first electronic means for processing said signals to derive a grid of estimated potential values, corresponding to the area of interest, of increased density by a Kriging interpolation program; a second means for processing said grid of estimated potential values to derive a corresponding grid of current density values; and means for displaying in perspective a three dimensional image representing said grid of current density values and displaying thereby the current density features of underlying neural activity over the area of interest. - View Dependent Claims (13, 14, 15, 16, 17, 18, 51)
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19. Apparatus for displaying features of underlying neural activity over an area of interest comprising:
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an electrode array positioned over the area of interest for measuring potentials at a corresponding number of points over such area and means for generating electrical signals indicative thereof; signal processing means for providing interpolated values by a Kriging interpolation program of potentials at points intermediate between said corresponding numbers of points for providing an increased number of potential values; signal processing means for deriving a substantially corresponding number of current density values for the area of interest; and means for displaying the current density values as a perspective three dimensional display of the current density values over the area of interest. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26)
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27. Apparatus for displaying features of underlying neural activity at a desired point in an area of interest on a human or animal comprising:
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a plurality of electrodes for positioning at points over the area of interest and means for deriving therefrom electrical signals as measures of the physiological potentials at such points; a first electronic means to derive by a Kriging interpolation program a grid of estimated potential values of an area corresponding to the area of interest with a greater coordinate density than the number of original points; a second electronic means for processing said grid of estimated potential values to derive a corresponding grid of current density values; means for sampling the values of a selected point in the grid of estimated potential values and the grid of current density values corresponding to the desired point; and means for displaying said sampled values of the estimated potential and of the current density at the desired point in successive sampling intervals in a plot against time. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34)
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35. Apparatus for displaying features of underlying neural activity over an area of interest of a human or animal body comprising:
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means for measuring physiological potentials at a plurality of points and for generating electrical signals indicative thereof; a first signal processing means for deriving by a Kriging interpolation for the area of interest, potential values at a grid of points of a density greater than the measured points; a second signal processing means for deriving current density values at said grid of points; and means for displaying the current density values at points in the area of interest. - View Dependent Claims (36, 37, 38, 39, 40, 41, 42, 43)
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44. Apparatus for displaying features of underlying neural activity over an area of interest comprising:
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means for measuring physiological potentials at a plurality of points and for generating electrical signals indicative thereof; a first electronic means for processing said signals to derive a grid of estimated potential values, corresponding to the area of interest, of increased density by a Kriging interpolation program; a second electronic means for processing said grid of estimated potential values to derive a corresponding grid of current density values; and means for displaying in perspective a three dimensional image representing said grid of estimated potential values and displaying thereby potential features of underlying neural activity over the area of interest. - View Dependent Claims (45, 46, 47, 48, 49, 50)
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Specification