Method and apparatus for detecting nonlinearity in an electrocardiographic signal
First Claim
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1. An apparatus for analyzing an electrocardiograph signal to determine whether the electrocardiograph signal includes a nonlinear signal component the apparatus comprising:
- (a) a modeling system comprising;
a modeling processor for receiving the electrocardiograph signal and for representing at least a portion of the electrocardiograph signal with a first linear model having a first set of parameters and a first set of coefficients and for representing at least a portion of the electrocardiograph signal with a second model corresponding to a first nonlinear model having a second set of parameters and a second set of coefficients; and
a performance processor for computing a first performance measure of the first model and for computing a second performance measure of the second model; and
(b) a performance measurement system coupled to said modeling system said performance measurement system comprising;
a comparison processor for receiving the first and second performance measures and for comparing the first performance measure to the second performance measure; and
a selection processor for receiving an indication from said comparison processor and for identifying which of the first and second performance measures is a preferred performance measure and for providing an output signal indicating whether the electrocardiograph signal includes a nonlinear signal component.
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Abstract
A method and apparatus for detecting the presence of a nonlinear characteristic in a data sequence is provided.
132 Citations
26 Claims
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1. An apparatus for analyzing an electrocardiograph signal to determine whether the electrocardiograph signal includes a nonlinear signal component the apparatus comprising:
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(a) a modeling system comprising; a modeling processor for receiving the electrocardiograph signal and for representing at least a portion of the electrocardiograph signal with a first linear model having a first set of parameters and a first set of coefficients and for representing at least a portion of the electrocardiograph signal with a second model corresponding to a first nonlinear model having a second set of parameters and a second set of coefficients; and a performance processor for computing a first performance measure of the first model and for computing a second performance measure of the second model; and (b) a performance measurement system coupled to said modeling system said performance measurement system comprising; a comparison processor for receiving the first and second performance measures and for comparing the first performance measure to the second performance measure; and a selection processor for receiving an indication from said comparison processor and for identifying which of the first and second performance measures is a preferred performance measure and for providing an output signal indicating whether the electrocardiograph signal includes a nonlinear signal component. - View Dependent Claims (2, 3, 4)
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5. A method for detecting a nonlinear pattern in a bio-signal, the method comprising the steps of:
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representing at least a portion of the bio-signal with a linear model having a first set of parameters; representing at least a portion of the bio signal with a nonlinear model, the first nonlinear model having a second set of parameters; computing a first performance measure of the first model; computing a second performance measure of the second model; comparing the first performance measure to the second performance measure; identifying which of the first and second performance measures is a preferred performance measure; and providing an output signal indicating whether the bio-signal includes a nonlinear signal component. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12)
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13. A method for detecting nonlinearity in a data set generated by a biological system, the method comprising the steps of:
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representing the data set with a linear model having a first set of parameters and a first set of coefficients; representing the data set with a non-linear model having a first set of parameters and a first set of coefficients; computing a performance measure of the linear model; computing a performance measure of the nonlinear model; comparing the performance measure of the linear model to the performance measure of the nonlinear model; identifying which of the performance measures of the linear model and the nonlinear model is a preferred performance measure; selecting a first one of the linear and nonlinear models having the preferred performance measure;
andproviding an output signal indicating whether the data set generated by the biological system includes a nonlinear signal component. - View Dependent Claims (14, 15, 16)
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17. A method for analyzing a hemodynamic signal to determine the presence of a chaotic signal component within the hemodynamic signal, the method comprising the steps of:
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dividing the hemodynamic signal into a plurality of time segments, each of the plurality of time segments having a discrete value; representing each of the plurality of time segments of the hemodynamic signal with a first model corresponding to a first linear model; representing each of the plurality of time segments of the hemodynamic signal with a second model corresponding to a first non-linear model; computing a performance measure of the first lineary model, computing a performance measure of the first non-linear model; and comparing the performance measure of the first model to the performance measure of the second model. - View Dependent Claims (18, 19, 20)
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21. A method for analyzing an electrocardiograph signal to detect the presence of a chaotic signal component in the electrocardiograph signal, the method comprising the steps of:
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generating a linear model to represent a first sequence of data values corresponding to measured RR intervals of the electrocardiograph signal, the linear model having a first predetermined number of terms; and generating a non-linear model to represent the first sequence of data values corresponding to the series of measured RR intervals of the electrocardiograph signal, the non-linear model having a second predetermined number of terms, computing a performance measure of the linear model; computing a performance measure of the nonlinear model; and comparing the performance measure of the linear model to the performance measure of the nonlinear model. - View Dependent Claims (22, 23, 24)
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25. A method for selecting samples from a continuous parameter signal, the method comprising the steps of:
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(a) dividing the continuous parameter signal into a first plurality of discrete time intervals each of the discrete time intervals including a plurality of discrete data points; (b) selecting a first plurality of discrete data points from predetermined ones of the first plurality of discrete time intervals, each of the first plurality of discrete data points spaced by a first predetermined time interval; (c) representing the continuous parameter signal using the first plurality of discrete data points with a linear model; (d) representing the continuous parameter signal using the first plurality of discrete data points with a nonlinear model; (e) determining how well the linear model represents the continuous parameter signal by computing a performance measure of the linear model; (f) determining how well the nonlinear model represents the continuous parameter signal by computing a performance measure of the non-linear model; (g) comparing the performance measure of the linear model to the performance measure of the non-linear model; and (h) in response to the performance measure of the linear model being preferred over the performance measure of the nonlinear model, then performing the steps of; (1) selecting a next plurality of discrete data points from predetermined ones of the first plurality of discrete time intervals, each of the next plurality of discrete data points spaced by a next predetermined time interval; and (2) repeating steps (c)-(h) until a first one of the following conditions occurs; (i) the performance measure of the non-linear sequence is preferred over the performance measure of the linear sequence; and (ii) a maximum time interval is reached. - View Dependent Claims (26)
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Specification