Abstract: Method and apparatus for monitoring the sleep state condition of an individual by using an external probe applied to a peripheral body location, such as the individual's finger or toe, for detecting changes in the peripheral vascular bed volume of the individual. A predetermined pressure field is applied to the distal end of the peripheral body location, including its distal-most extremity, to prevent the occurrence of venous pooling within and distal to the peripheral body location. The probe produces an output corresponding to changes in the peripheral arterial bed volume at the peripheral body location, which output provides an indication of the sleep state condition of the individual. Such information is useful in diagnosing and/or in treating, a number of sleep disorders as well as other conditions, such as impotence, diabetes, and various disorders in children.

Abstract: A method and apparatus for non-invasively evaluating endothelial activity in a patient, particularly for indicating the presence of an endothelial dysfunction condition, by applying an occluding pressure to a predetermined part of an arm or leg of the patient to occlude arterial blood flow therein; maintaining the occluding pressure for a predetermined time period; removing the occluding pressure after the elapse of the predetermined time period to restore arterial blood flow; monitoring a digit of the arm or leg by a digit-probe for changes in the peripheral arterial tone therein before and after the application of the occluding pressure to the arm or leg of the patient; and utilizing any detected changes in the peripheral arterial tone for evaluating endothelial activity in the patient.

Abstract: A method and apparatus for non-invasively evaluating endothelial activity in a patient, particularly for indicating the presence of an endothelial dysfunction condition, by applying an occluding pressure to a predetermined part of an arm or leg of the patient to occlude arterial blood flow therein; maintaining the occluding pressure for a predetermined time period; removing the occluding pressure after the elapse of the predetermined time period to restore arterial blood flow; monitoring a digit of the arm or leg by a digit-probe for changes in the peripheral arterial tone therein before and after the application of the occluding pressure to the arm or leg of the patient; and utilizing any detected changes in the peripheral arterial tone for evaluating endothelial activity in the patient.

Abstract: Method and apparatus for monitoring the sleep state condition of an individual by using an external probe applied to a peripheral body location, such as the individual's finger or toe, for detecting changes in the peripheral vascular bed volume of the individual. A predetermined pressure field is applied to the distal end of the peripheral body location, including its distal-most extremity, to prevent the occurrence of venous pooling within and distal to the peripheral body location. The probe produces an output corresponding to changes in the peripheral arterial bed volume at the peripheral body location, which output provides an indication of the sleep state condition of the individual. Such information is useful in diagnosing and/or in treating, a number of sleep disorders as well as other conditions, such as impotence, diabetes, and various disorders in children.

Abstract: A method and apparatus for non-invasively determining a physiological condition. The method can include steps of monitoring peripheral arterial tone using an external sensor, detecting a change in the peripheral arterial tone, and determining the physiological condition when a specific change in the peripheral arterial tone has been detected. The physiological condition may be a cardiovascular disease state or endothelial dysfunction, for example. The apparatus can include a probe applied to a subject's digit for sensing peripheral arterial tone and outputting a corresponding signal, and a processor which processes the signal and provides an output from which the physiological condition can be determined or which determines the physiological condition based on the signal.

Abstract: A method and an apparatus for non-invasive detection of a physiological state or medical condition are disclosed. The method provides an indication of such state or condition such as myocardial ischemia or sleep apnea, by detecting the peripheral arterial tone's response to such state or condition, based on monitoring changes in peripheral arterial tone and determining that a change in the condition of the patient has occurred when a specific change in the peripheral arterial tone has been detected. A static pressure field is applied around the distal part of a digit of the subject. Peripheral arterial tone changes and related volume changes in the distal part of the digit are detected to thereby detect or monitor a physiological state or medical condition. The apparatus includes a finger probe (20), in the form of a tube (3) accommodating the patient's finger, which is designed to apply pressure, and a contiguous pressure cuff (40) which extends the boundary of the pressure field.

Abstract: A simple system for determining a non-invasive sleep state of a person is described. The system comprises: (a) means for measuring the person's cardiac R-R waves interval; (b) means for calculating the power spectrum of the cardiac R-R interval, thus obtaining a ratio between spectral power in the and high frequencies; (c) means responsive to the measuring and calculating means for generating output signals, one output signal having a first value when said ratio is above a specific predetermined threshold, designated as REM sleep-and one outputs signal having a second value when the above ratio is below this threshold, designated as non-REM sleep, and (d) means responsive to the output signal for designating a time period of predetermined duration as a REM period or a non-REM period, respectively. The system enables an accurate determination of the sleep state.

Abstract: Electronic filters are applied to analog signals representative of eye movement and head movement, obtained from detectors attached to a simple headgear, to provide satisfactory information for automatically reporting an individual's sleep state. The filters determine whether there has been substantial eye and head movement in a given period. Each filter then generates binary output signals representing movement (or the absence of it). Noise filters and a comparison filter are then applied to the binary output signals to predict sleep state; REM sleep; NREM sleep; or wakefulness.