MEASUREMENT OF CEREBRAL HEMODYNAMIC PARAMETERS
First Claim
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1. A method of finding an indication of a degree of cerebro-vascular bilateral asymmetry in a subject, comprising:
- a) measuring a first impedance waveform and a second impedance waveform of the subject'"'"'s head as functions of time, in each case by finding a potential difference between two voltage electrodes associated with passing a given injected current through the head between at least two current electrodes, wherein in each case the voltage electrodes are located asymmetrically on the head with respect to the bilateral symmetry plane of the head, or the current is injected asymmetrically into the head, or both, and wherein the locations of the voltage electrodes and the distribution of current injection in measuring the second impedance waveform are mirror images, with respect to the bilateral symmetry plane of the head, of what they are in measuring the first impedance waveform; and
b) finding the indication of the degree of bilateral asymmetry from a difference between characteristics of the first and second impedance waveforms;
wherein the characteristic of the first impedance waveform comprises a ratio of a height of a first peak to a height of a second peak, relative to a minimum, of the first impedance waveform or a waveform derived from it, and the characteristic of the second impedance waveform comprises a ratio of a height of a first peak to a height of a second peak, relative to a minimum, of the second impedance waveform or a waveform derived from it.
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Abstract
A method of finding an indication of a degree of cerebro-vascular bilateral asymmetry in a subject, comprising:
- a) measuring a first impedance waveform and a second impedance waveform of the subject'"'"'s head as functions of time, in each case by finding a potential difference between two voltage electrodes associated with passing a given injected current through the head between at least two current electrodes, wherein in each case the voltage electrodes are located asymmetrically on the head, or the current is injected asymmetrically into the head, or both, and wherein the locations of the voltage electrodes and the distribution of current injection in measuring the second impedance waveform are minor images of what they are in measuring the first impedance waveform; and
- b) finding the indication of the degree of bilateral asymmetry from a difference between characteristics of the first and second impedance waveforms.
28 Citations
60 Claims
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1. A method of finding an indication of a degree of cerebro-vascular bilateral asymmetry in a subject, comprising:
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a) measuring a first impedance waveform and a second impedance waveform of the subject'"'"'s head as functions of time, in each case by finding a potential difference between two voltage electrodes associated with passing a given injected current through the head between at least two current electrodes, wherein in each case the voltage electrodes are located asymmetrically on the head with respect to the bilateral symmetry plane of the head, or the current is injected asymmetrically into the head, or both, and wherein the locations of the voltage electrodes and the distribution of current injection in measuring the second impedance waveform are mirror images, with respect to the bilateral symmetry plane of the head, of what they are in measuring the first impedance waveform; and b) finding the indication of the degree of bilateral asymmetry from a difference between characteristics of the first and second impedance waveforms; wherein the characteristic of the first impedance waveform comprises a ratio of a height of a first peak to a height of a second peak, relative to a minimum, of the first impedance waveform or a waveform derived from it, and the characteristic of the second impedance waveform comprises a ratio of a height of a first peak to a height of a second peak, relative to a minimum, of the second impedance waveform or a waveform derived from it. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 47, 49, 50, 51, 53, 54)
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10. A system for finding an indication of a degree of cerebrovascular bilateral asymmetry, comprising:
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a) an electric current source; b) a voltmeter adapted to measure potential differences between two electrodes; c) a set of at least three electrodes, at least three of them adapted to pass current from the current source through the head, and at least three of them, the same as or partly or completely different than the electrodes adapted to pass current, adapted to be used by the voltmeter for measuring a potential difference between different locations on the head; and d) a controller which, when the electrodes are placed appropriately on the head, is adapted to make a first impedance measurement by using a first subset of the electrodes, placed asymmetrically with respect to the bilateral symmetry plane of the head, to measure the voltage associated with a given current passed through the head, and to use a second subset of the electrodes to make a second impedance measurement that is a mirror image of the first impedance measurement with respect to the bilateral symmetry plane of the head, and to use a difference between characteristics of waveforms of the first and second impedance measurements to find the indication of the degree of bilateral symmetry, by finding a ratio of a height of a first peak to a height of a second peak, relative to a minimum, for the first impedance waveform, or a waveform derived from the first impedance waveform, or both, and by finding a ratio of a height of a first peak to a height of a second peak, relative to a minimum, for the second impedance waveform, or a waveform derived from the second impedance waveform, or both.
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11-38. -38. (canceled)
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39. A method of finding an indication of a degree of cerebrovascular bilateral asymmetry in a subject, comprising:
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a) measuring a characteristic of surface blood flow on the left side of the subject'"'"'s head, using at least a first sensor in a region on the left side of the head, the characteristic comprising a ratio of a height of a first peak to a height of a second peak, relative to a minimum, for a waveform of a signal of the first sensor as a function of time; b) measuring a characteristic of surface blood flow on the right side of the subject'"'"'s head, using at least a second sensor in a region on the right side of the head, the characteristic comprising a ratio of a height of a first peak to a height of a second peak, relative to a minimum, for a waveform of a signal of the second sensor as a function of time; and c) using a difference between the characteristics of the surface blood flows on the left and right sides of the head to find the indication of the degree of cerebrovascular bilateral asymmetry. - View Dependent Claims (40, 41, 44, 45, 60)
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42-43. -43. (canceled)
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46. A system for finding an indication of a degree of cerebrovascular bilateral asymmetry, comprising:
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a) a first and a second sensor adapted for measuring surface blood flow on the head; and b) a controller adapted to use the first and second sensors to measure characteristics of surface blood flow in regions respectively on the left and right sides of the head, and to use a difference between the characteristics of the measured blood flows on the left and right sides of the head to find the indication of the degree of cerebrovascular bilateral asymmetry, the characteristic of the blood flow on the left side of the head comprising a ratio of a height of a first peak to a height of a second peak, relative to a minimum, for a waveform of a signal of the first sensor as a function of time, and the characteristic of the blood flow on the right side of the head comprising a ratio of a height of a first peak to a height of a second peak, relative to a minimum, for a waveform of a signal of the second sensor as a function of time.
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48. (canceled)
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52. (canceled)
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55-59. -59. (canceled)
Specification