Method and apparatus for quantifying the hypnotic component of the depth of anesthesia by monitoring changes in optical scattering properties of brain tissue
First Claim
1. Method for non-invasively measuring neurological activity in the brain of a subject to ascertain a state of hypnosis of an anesthetized subject or a state of sedation of the subject, said method comprising the steps of:
- passing light through a portion of the brain of the subject, the light having a characteristic that subjects it to scattering during passage by tissues of the brain, the light scattering capabilities of the brain tissues varying responsive to their neurological activity;
sensing light that has passed through the portion of the brain and that has thereafter become available for sensing; and
measuring the sensed light, in the form it became available for sensing, to determine the amount of scattering present in the sensed light and resulting from the passage of the light through the brain tissue as a measurement of the state of hypnosis or sedation of the subject.
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Accused Products
Abstract
A method/apparatus for non-invasively measuring a neurological activity state in the brain of a subject to ascertain, for example, the state of the hypnotic component of the subject'"'"'s anesthesia. The method/apparatus comprises means for, or the step of, passing light through a portion of the brain of the subject, the light having a characteristic that subjects it to scattering during passage by tissues of the brain, the light scattering capabilities of the brain tissues varying responsive to their neurological activity. The light exiting the brain tissue portion is measured to determine the amount of scattering it has undergone as a measurement of the state of the hypnotic component of the subject'"'"'s anesthesia. Light having a wavelength in a range of 650-1000 nm, preferably around 800 nm may be used.
46 Citations
31 Claims
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1. Method for non-invasively measuring neurological activity in the brain of a subject to ascertain a state of hypnosis of an anesthetized subject or a state of sedation of the subject, said method comprising the steps of:
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passing light through a portion of the brain of the subject, the light having a characteristic that subjects it to scattering during passage by tissues of the brain, the light scattering capabilities of the brain tissues varying responsive to their neurological activity;
sensing light that has passed through the portion of the brain and that has thereafter become available for sensing; and
measuring the sensed light, in the form it became available for sensing, to determine the amount of scattering present in the sensed light and resulting from the passage of the light through the brain tissue as a measurement of the state of hypnosis or sedation of the subject. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. Apparatus for non-invasively measuring neurological activity in the brain of a subject to ascertain a state of hypnosis of an anesthetized subject or a state of sedation of the subject, said apparatus comprising:
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a light emitter emitting light for passage through a portion of the brain of the subject, the light having a characteristic that subjects it to scattering during passage by tissues of the brain, the light scattering capabilities of the brain tissues varying responsive to their neurological activity; and
a light detector for sensing light that has passed through the portion of the brain and that has thereafter become available for sensing, said light detector measuring the sensed light, in the form it became available for sensing, to determine the amount of scattering present in sensed light and resulting from the passage of the light through the brain tissue as a measurement of the state of hypnosis or sedation of the subject. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
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Specification