Abstract: A method and apparatus for detecting and distinguishing epochs of deep-sleep from epochs of light-sleep of a subject by sensing by a peripheral pulse signal related to the systemic circulation of the subject, preferably a peripheral arterial tone (PAT) sensor for sensing pulsatile arterial volume changes in a digit (e.g., a finger) of the subject reflecting sympathetic tone variations; analyzing the sensed pulse signals for determining therefrom a number of features, particularly seven specific variables in each of two time periods; and utilizing the results of the analysis for determining whether the epoch detected is a light-sleep epoch or a deep-sleep epoch.

Abstract: A method and apparatus for examining a subject for a particular physiological condition according to a technique which utilizes sounds generated by the subject and sensed at a predefined distance from the site of sound generation of the subject, by locating a first sound sensor, e.g., a sound level meter which measures the sound levels in decibels, on a particular region of the subject's body to produce an output corresponding to the sound level sensed thereby; modifying the output of the first sound level meter by a pre-calculated Transfer Function equating its output to that of a second sound level meter located at a predefined distance from the site of sound generation of the subject's body; and utilizing the modified output of the first sound level meter in determining the existence of the particular physiological condition.

Abstract: A method and apparatus for detecting and distinguishing epochs of deep-sleep from epochs of light-sleep of a subject by sensing by a peripheral pulse signal related to the systemic circulation of the subject, preferably a peripheral arterial tone (PAT) sensor for sensing pulsatile arterial volume changes in a digit (e.g., a finger) of the subject reflecting sympathetic tone variations; analyzing the sensed pulse signals for determining therefrom a number of features, particularly seven specific variables in each of two time periods; and utilizing the results of the analysis for determining whether the epoch detected is a light-sleep epoch or a deep-sleep epoch.

Abstract: A method and apparatus for examining a subject for a particular physiological condition according to a technique which utilizes sounds generated by the subject and sensed at a predefined distance from the site of sound generation of the subject, by locating a first sound sensor, e.g., a sound level meter which measures the sound levels in decibels, on a particular region of the subject's body to produce an output corresponding to the sound level sensed thereby; modifying the output of the first sound level meter by a pre-calculated Transfer Function equating its output to that of a second sound level meter located at a predefined distance from the site of sound generation of the subject's body; and utilizing the modified output of the first sound level meter in determining the existence of the particular physiological condition.