Method and apparatus for monitoring the autonomic nervous system
First Claim
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1. An apparatus for monitoring human autonomic nervous system activity using pulsatile blood volume waveform signals, said apparatus comprising:
- a photoplethysmographic probe having a light emitting element and an opposing light detecting element, and having an output signal indicating changes in blood volume on at least one alpha andrenergic receptor site of a human body;
a processor element, responsive to said output signal indicating changes in blood volume, said processor element defining a time interval for calculation of slope of blood volume waveform continuously and in real time and reducing said waveform signals to a slope value within said time interval;
said processor element containing an algorithm for normalization of the slope value;
said processor element containing an artifact rejection algorithm for eliminating from further processing slope values less than one; and
amplifier and filter circuitry for rendering output signals representative of said slope values.
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Abstract
An apparatus and method for detection and monitoring of autonomic nervous system (ANS) activity in humans, primarily in the field of sleep research. The present invention discloses a portable, simple, and cost-effective electronic device containing hardware and software that permits real-time monitoring of a pulsatile blood volume waveform obtained through use of a photoplethysmographic (optical volume detecting) probe, thereby allowing signal conditioning, waveform slope analysis, display, recording, and output of pulse transitional slope data representative of activity in the ANS.
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16 Claims
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1. An apparatus for monitoring human autonomic nervous system activity using pulsatile blood volume waveform signals, said apparatus comprising:
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a photoplethysmographic probe having a light emitting element and an opposing light detecting element, and having an output signal indicating changes in blood volume on at least one alpha andrenergic receptor site of a human body; a processor element, responsive to said output signal indicating changes in blood volume, said processor element defining a time interval for calculation of slope of blood volume waveform continuously and in real time and reducing said waveform signals to a slope value within said time interval; said processor element containing an algorithm for normalization of the slope value; said processor element containing an artifact rejection algorithm for eliminating from further processing slope values less than one; and amplifier and filter circuitry for rendering output signals representative of said slope values. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for identification of human autonomic nervous system activity, the method comprising the steps of:
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disposing a photoplethysmographic probe proximate to a single alpha andrenergic receptor site of a human body part; obtaining an electrical signal from said probe representative of pulsatile blood volume within said body part; deriving a pulsatile blood volume waveform as a function of amplitude and time; defining a time interval for calculation of a slope of the pulsatile blood volume waveform; applying an algorithm that continuously provides real-time calculation of the slope along said waveform within said time interval; dividing peak amplitude values by a time constant and eliminating slope values less than 1, whereby artifact elimination is achieved; normalizing slope values; and
providing information representative of slope values, whereby autonomie nervous system activity is monitored. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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Specification