Abstract: The present invention is directed to method and apparatus for non-invasively measuring the concentration of an unknown blood analyte present in a patient. The method involves determining the concentration of a reference analyte present in the patient. Using the non-invasive optical instrument of the invention, the concentrations of the reference analyte and unknown analyte are measured. If the measured reference analyte concentration and determined reference analyte concentration are substantially the same, then the measured unknown analyte concentration is displayed. If the measured reference analyte concentration and determined reference analyte concentration are not substantially the same, then an adjustment factor is applied to the measured unknown analyte concentration and the unknown analyte concentration is displayed.

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.