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US 2006/0135879 A1Published application
Method of monitoring brain function
AssigneeCortical Dynamics Pty. Ltd.
InventorDavid Liley
Life of this patent
Estimating the term…
Abstract
A method for assessing brain state by analysing mammalian brain electroencephalogram (“EEG”) recordings using an eighth order autoregressive and fifth order moving average discrete time equation.
Claims26
A method for assessing brain state by analysing mammalian brain electroencephalogram (EEG) recordings using an eighth order autoregressive and fifth order moving average discrete time equation.
A method of assessing the state of a mammalian brain including the steps of:
- (i) obtaining an electroencephalogram (EEG) from the brain;
- (ii) digitising the EEG to define a digitised EEG data signal;
- (iii) segmenting the EEG data signal into time frames of fixed length, y[n];
- (iv) approximating each digitised time frame by a first equation:
- y
-
- [
- n
- ]
- =
- -
- ∑
- k
- =
- 1
- 8
-
- a
- k
-
- y
-
- [
- n
- -
- k
- ]
- +
- ∑
- k
- =
- 0
- 5
-
- b
- k
-
- u
-
- [
- n
- -
- k
- ]
- (v) solving the first equation to determine coefficients a1 to a8 and b0 to b5;
- (vi) performing a z-transform on the first equation to obtain a second, z-domain equation:
- Y
-
- (
- z
- )
- =
- ∑
- k
- =
- 0
- 5
-
- b
- k
-
- z
- -
- k
- 1
- +
- ∑
- k
- =
- 1
- 8
-
- a
- k
-
- z
- -
- k
-
- U
-
- (
- z
- )
- =
- B
-
- (
- z
- )
- A
-
- (
- z
- )
-
- U
-
- (
- z
- )
- (vii) substituting each of the values of the coefficients into the z-domain equation;
- (viii) solving A(z)=0 for z in the second equation to determine the poles;
- (ix) plotting the poles in the complex plane;
- (x) repeating steps (iv) to (ix) for each frame in the sample to determine clusters of poles in the complex plane;
- and
- (xi) assessing the state of the brain by reference to the position and distribution of at least some of said clusters of poles as mapped in the complex plane.
104 more elements
A method of assessing the state of a mammalian brain including the steps of:
- (i) obtaining an electroencephalogram (EEG) from the brain;
- (ii) digitising the EEG to define a digitised EEG data signal;
- (iii) segmenting the EEG data signal into time frames of fixed length, y[n];
- (iv) approximating each digitised time frame by a first equation:
- y
-
- [
- n
- ]
- =
- -
- ∑
- k
- =
- 1
- 8
-
- a
- k
-
- y
-
- [
- n
- -
- k
- ]
- +
- ∑
- k
- =
- 0
- 5
-
- b
- k
-
- u
-
- [
- n
- -
- k
- ]
- (v) solving the first equation to determine coefficients a1 to a8 and b0 to b5;
- (vi) performing a z-transform on the first equation to obtain a second, z-domain equation:
- Y
-
- (
- z
- )
- =
- ∑
- k
- =
- 0
- 5
-
- b
- k
-
- z
- -
- k
- 1
- +
- ∑
- k
- =
- 1
- 8
-
- a
- k
-
- z
- -
- k
-
- U
-
- (
- z
- )
- =
- B
-
- (
- z
- )
- A
-
- (
- z
- )
-
- U
-
- (
- z
- )
- (vii) substituting each of the values of the coefficients into the z-domain equation;
- (viii) solving A(z)=0 for z in the second equation to determine the poles;
- (ix) plotting the poles in the complex plane;
- (x) repeating steps (iv) to (ix) for each frame in the sample to determine clusters of poles in the complex plane;
- and
- (xi) administering an intervention to the brain;
- (xii) repeating steps (i) to (x) at least once;
- (xiii) monitoring movement of at least some of said clusters of poles in the complex plane;
- and
- (xiv) assessing the state of the brain by reference to movement of at least some of said clusters of poles as mapped in the complex plane.
108 more elements
A method of assessing the state of a mammalian brain including the steps of:
- (i) obtaining a first electroencephalogram (EEG) from the brain;
- (ii) digitising the EEG to define a digitised EEG data signal;
- (iii) segmenting the EEG data signal into time frames of fixed length, y[n];
- (iv) approximating each digitised time frame by a first equation:
- y
-
- [
- n
- ]
- =
- -
- ∑
- k
- =
- 1
- 8
-
- a
- k
-
- y
-
- [
- n
- -
- k
- ]
- +
- ∑
- k
- =
- 0
- 5
-
- b
- k
-
- u
-
- [
- n
- -
- k
- ]
- (v) solving the first equation to determine coefficients a1 to a8 and b0 to b5;
- (vi) performing a z-transform on the first equation to obtain a second, z-domain equation:
- Y
-
- (
- z
- )
- =
- ∑
- k
- =
- 0
- 5
-
- b
- k
-
- z
- -
- k
- 1
- +
- ∑
- k
- =
- 1
- 8
-
- a
- k
-
- z
- -
- k
-
- U
-
- (
- z
- )
- =
- B
-
- (
- z
- )
- A
-
- (
- z
- )
-
- U
-
- (
- z
- )
- (vii) substituting each of the values of the coefficients into the z-domain equation;
- (viii) solving A(z)=0 for z in the second equation to determine the poles;
- (ix) plotting the poles in the complex plane;
- (x) repeating steps (iv) to (ix) for each frame in the sample to determine clusters of poles in the complex plane;
- (xi) obtaining a second EEG from said brain at a later time;
- (xii) repeating steps (ii) to (x) in relation to the second EEG at least once;
- (xiii) monitoring the movement of at least some corresponding clusters of poles in the complex plane derived from the first and second EEGs respectively;
- and
- (xiv) assessing the state of the brain by reference to movement of at least some of said clusters of poles as mapped in the complex plane.
107 more elements
A method of assessing the efficacy of a cognitively active pharmaceutical agent including the steps of:
- (i) obtaining a first electroencephalogram (EEG) from the brain of a subject;
- (ii) digitising the EEG to define a digitised EEG data signal;
- (iii) segmenting the EEG data signal into time frames of fixed length, y[n];
- (iv) approximating each digitised time frame by a first equation:
- y
-
- [
- n
- ]
- =
- -
- ∑
- k
- =
- 1
- 8
-
- a
- k
-
- y
-
- [
- n
- -
- k
- ]
- +
- ∑
- k
- =
- 0
- 5
-
- b
- k
-
- u
-
- [
- n
- -
- k
- ]
- (v) solving the first equation to determine coefficients a1 to a8 and b0 to b5;
- (vi) performing a z-transform on the first equation to obtain a second, z-domain equation:
- Y
-
- (
- z
- )
- =
- ∑
- k
- =
- 0
- 5
-
- b
- k
-
- z
- -
- k
- 1
- +
- ∑
- k
- =
- 1
- 8
-
- a
- k
-
- z
- -
- k
-
- U
-
- (
- z
- )
- =
- B
-
- (
- z
- )
- A
-
- (
- z
- )
-
- U
-
- (
- z
- )
- (vii) substituting each of the values of the coefficients into the z-domain equation;
- (viii) solving A(z)=0 for z in the second equation to determine the poles;
- (ix) plotting the poles in the complex plane;
- (x) repeating steps (iv) to (ix) for each frame in the sample to determine clusters of poles in the complex plane;
- (xi) administering a dose of a cognitively active pharmaceutical agent to the subject;
- (xii) obtaining a second EEG from said brain after step (xi);
- (xiii) repeating steps (ii) to (x) in relation to the second EEG at least once;
- (xiv) monitoring the movement of at least some corresponding clusters of poles in the complex plane derived from the first and second EEGs respectively;
- and
- (xv) assessing the efficacy of the cognitively active pharmaceutical agent by reference to movement of at least some of said clusters of poles as mapped in the complex plane.
108 more elements
A method of assessing the state of vigilance or alertness of a subject including the steps of:
- (i) obtaining an electroencephalogram (EEG) from the brain of a subject;
- (ii) digitising the EEG to define a digitised EEG data signal;
- (iii) segmenting the EEG data signal into time frames of fixed length, y[n];
- (iv) approximating each digitised time frame by a first equation:
- y
-
- [
- n
- ]
- =
- -
- ∑
- k
- =
- 1
- 8
-
- a
- k
-
- y
-
- [
- n
- -
- k
- ]
- +
- ∑
- k
- =
- 0
- 5
-
- b
- k
-
- u
-
- [
- n
- -
- k
- ]
- (v) solving the first equation to determine coefficients a1 to a8 and b0 to b5;
- (vi) performing a z-transform on the first equation to obtain a second, z-domain equation:
- Y
-
- (
- z
- )
- =
- ∑
- k
- =
- 0
- 5
-
- b
- k
-
- z
- -
- k
- 1
- +
- ∑
- k
- =
- 1
- 8
-
- a
- k
-
- z
- -
- k
-
- U
-
- (
- z
- )
- =
- B
-
- (
- z
- )
- A
-
- (
- z
- )
-
- U
-
- (
- z
- )
- (vii) substituting each of the values of the coefficients into the z-domain equation;
- (viii) solving A(z)=0 for z in the second equation to determine the poles;
- (ix) plotting the poles in the complex plane;
- (x) repeating steps (iv) to (ix) for each frame in the sample to determine clusters of poles in the complex plane;
- (xi) repeating steps (i) to (x);
- (xii) monitoring movement of at least some of said clusters of poles in the complex plane;
- and
- (xiii) assessing the state of vigilance or alertness of the subject by reference to movement of at least some of said clusters of poles as mapped in the complex plane.
106 more elements
A method of assessing the state of sleep of a subject including the steps of:
- (i) obtaining an electroencephalogram (EEG) from the brain of a subject;
- (ii) digitising the EEG to define a digitised EEG data signal;
- (iii) segmenting the EEG data signal into time frames of fixed length, y[n];
- (iv) approximating each digitised time frame by a first equation:
- y
-
- [
- n
- ]
- =
- -
- ∑
- k
- =
- 1
- 8
-
- a
- k
-
- y
-
- [
- n
- -
- k
- ]
- +
- ∑
- k
- =
- 0
- 5
-
- b
- k
-
- u
-
- [
- n
- -
- k
- ]
- (v) solving the first equation to determine coefficients a1 to a8 and b0 to b5;
- (vi) performing a z-transform on the first equation to obtain a second, z-domain equation:
- Y
-
- (
- z
- )
- =
- ∑
- k
- =
- 0
- 5
-
- b
- k
-
- z
- -
- k
- 1
- +
- ∑
- k
- =
- 1
- 8
-
- a
- k
-
- z
- -
- k
-
- U
-
- (
- z
- )
- =
- B
-
- (
- z
- )
- A
-
- (
- z
- )
-
- U
-
- (
- z
- )
- (vii) substituting each of the values of the coefficients into the z-domain equation;
- (viii) solving A(z)=0 for z in the second equation to determine the poles;
- (ix) plotting the poles in the complex plane;
- (x) repeating steps (iv) to (ix) for each frame in the sample to determine clusters of poles in the complex plane;
- (xi) repeating steps (i) to (x);
- (xii) monitoring movement of at least some of said clusters of poles in the complex plane;
- and
- (xiii) assessing the state of sleep of the subject by reference to movement of at least some of said clusters of poles as mapped in the complex plane.
106 more elements
A method of assessing the state of anaesthesia of a subject including the steps of:
- (i) obtaining an electroencephalogram (EEG) from the brain of a subject while anaesthetised;
- (ii) digitising the EEG to define a digitised EEG data signal;
- (iii) segmenting the EEG data signal into time frames of fixed length, y[n];
- (iv) approximating each digitised time frame by a first equation:
- y
-
- [
- n
- ]
- =
- -
- ∑
- k
- =
- 1
- 8
-
- a
- k
-
- y
-
- [
- n
- -
- k
- ]
- +
- ∑
- k
- =
- 0
- 5
-
- b
- k
-
- u
-
- [
- n
- -
- k
- ]
- (v) solving the first equation to determine coefficients a1 to a8 and b0 to b5;
- (vi) performing a z-transform on the first equation to obtain a second, z-domain equation:
- Y
-
- (
- z
- )
- =
- ∑
- k
- =
- 0
- 5
-
- b
- k
-
- z
- -
- k
- 1
- +
- ∑
- k
- =
- 1
- 8
-
- a
- k
-
- z
- -
- k
-
- U
-
- (
- z
- )
- =
- B
-
- (
- z
- )
- A
-
- (
- z
- )
-
- U
-
- (
- z
- )
- (vii) substituting each of the values of the coefficients into the z-domain equation;
- (viii) solving A(z)=0 for z in the second equation to determine the poles;
- (ix) plotting the poles in the complex plane;
- (x) repeating steps (iv) to (ix) for each frame in the sample to determine clusters of poles in the complex plane;
- (xi) repeating steps (i) to (x);
- (xii) monitoring movement of at least some of said clusters of poles in the complex plane;
- and
- (xiii) assessing the state of anaesthesia of the subject by reference to movement of at least some of said clusters of poles as mapped in the complex plane.
106 more elements
A method of assessing the state of anaesthesia of a subject including the steps of:
- (i) obtaining a first electroencephalogram (EEG) from the brain;
- (ii) digitising the EEG to define a digitised EEG data signal;
- (iii) segmenting the EEG data signal into time frames of fixed length, y[n];
- (iv) approximating each digitised time frame by a first equation:
- y
-
- [
- n
- ]
- =
- -
- ∑
- k
- =
- 1
- 8
-
- a
- k
-
- y
-
- [
- n
- -
- k
- ]
- +
- ∑
- k
- =
- 0
- 5
-
- b
- k
-
- u
-
- [
- n
- -
- k
- ]
- (v) solving the first equation to determine coefficients a1 to a8 and b0 to b5;
- (vi) performing a z-transform on the first equation to obtain a second, z-domain equation:
- Y
-
- (
- z
- )
- =
- ∑
- k
- =
- 0
- 5
-
- b
- k
-
- z
- -
- k
- 1
- +
- ∑
- k
- =
- 1
- 8
-
- a
- k
-
- z
- -
- k
-
- U
-
- (
- z
- )
- =
- B
-
- (
- z
- )
- A
-
- (
- z
- )
-
- U
-
- (
- z
- )
- (vii) substituting each of the values of the coefficients into the z-domain equation;
- (viii) solving A(z)=0 for z in the second equation to determine the poles;
- (ix) plotting the poles in the complex plane;
- (x) repeating steps (iv) to (ix) for each frame in the sample to determine clusters of poles in the complex plane;
- (xi) administering the anaesthetic to the patient;
- (xii) obtaining a second EEG from said brain after step (xi);
- (xiii) repeating steps (ii) to (x) in relation to the second EEG at least once;
- (xiv) monitoring the movement of at least some corresponding clusters of poles in the complex plane derived from the first and second EEGs respectively;
- and
- (xv) assessing the state of anaesthesia of the subject by reference to movement of at least some of said clusters of poles as mapped in the complex plane.
108 more elements
A system having means for assessing brain state by analysing mammalian brain electroencephalographic recordings using an eighth order autoregressive and fifth order moving average discrete time model equation.
Apparatus for assessing brain state of a subject, the apparatus including a plurality of electrodes for picking up EEG signals from the brain of the subject;
- digitising means for converting the EEG signals to a digitised EEG data signal;
- computing means for:
- (i) segmenting the EEG data signal into time frames of fixed length, y[n];
- (ii) approximating each digitised time frame by a first equation:
- y
-
- [
- n
- ]
- =
- -
- ∑
- k
- =
- 1
- 8
-
- a
- k
-
- y
-
- [
- n
- -
- k
- ]
- +
- ∑
- k
- =
- 0
- 5
-
- b
- k
-
- u
-
- [
- n
- -
- k
- ]
- (iii) solving the first equation to determine coefficients a1 to a8 and b0 to b5;
- (iv) performing a z-transform on the first equation to obtain a second, z-domain equation:
- Y
-
- (
- z
- )
- =
- ∑
- k
- =
- 0
- 5
-
- b
- k
-
- z
- -
- k
- 1
- +
- ∑
- k
- =
- 1
- 8
-
- a
- k
-
- z
- -
- k
-
- U
-
- (
- z
- )
- =
- B
-
- (
- z
- )
- A
-
- (
- z
- )
-
- U
-
- (
- z
- )
- (v) substituting each of the values of the coefficients into the z-domain equation;
- (vi) solving A(z)=0 for z in the second equation to determine the poles;
- (vii) plotting the poles in the complex plane;
- and
- display means for displaying the poles, to thereby enable assessment of the brain state of the subject by reference to the position and distribution of clusters of said poles.
103 more elements
Dependencies are inferred from the claim text.