Abstract: A system is provided for determining a level of alertness of a subject, using a physiological sensor for providing physiological sensor signals which distinguish between a sleep state and an awake state of the subject. Sleep sessions are identified and their associated falling asleep and waking up times. A single representative midsleep time is obtained from multiple sleep sessions over a 24 hour period, and a circadian phase is estimated using the single representative midsleep time. A level of alertness is then obtained from the circadian phase. This system avoids the need for the use of a default circadian phase when determining a level of alertness. The system can more accurately estimate sleepiness for individuals that have irregular sleep patterns such as shift workers or people with sleep disorders. The single representative midsleep time is also able to take account of multiple sleep sessions, i.e. naps or periods of restless sleep.

Abstract: The invention relates to an apparatus (100) and a method for generating a model output x(ti) describing a circadian rhythm of a person (P) at a time ti. In a preferred embodiment, a light sensor providing the photic exposure (L(ti)) and an activity signal (A(ti)) indicating the current level of activity of the person (P) at the time ti based on motion measurements (via an accelerometer) are used to calculate a wakefulness variable (?) that indicates if the person (P) is awake or sleeping. The wakefulness variable is then used to determine a driving term (N(t)) for a driven oscillator model (135) which simulates the model output x(t) under the joint influence of light and activity.

Abstract: A method for monitoring the blood pressure of a patient, comprising the following steps: determining a pulse arrival time signal from the patient 2 based on the pulse wave velocity method; determining an accelerometer signal from the patient 2; and triggering an additional measure or deriving a blood pressure value, taking into account the pulse arrival time signal and a DC component of the accelerometer signal. In this way, a possibility for monitoring the blood pressure of a patient is provided with which false alarms and/or unnecessary additional cuff-based blood pressure measurements can be avoided.

Abstract: A method of determining sleep statistics for a subject includes the steps of: collecting cardio-respiratory information of the subject; extracting features from the cardio-respiratory information; determining sleep stages of the subject by using at least some of the extracted features; determining an estimated total sleep time of the subject based on the determined sleep stages; and determining sleep statistics of the subject using the estimated total sleep time.

Abstract: The present disclosure pertains to a light sensing system configured to determine an amount of ambient light exposure experienced by a subject. The present invention wirelessly exchanges light information between different wearable devices of the same user and/or between devices of different users. Local and/or central light profile databases are built-up by the system and are shared between the devices so that light data that is typical for a location at a specific time of day and year can be used to estimate current ambient light levels for situations in which no measurement can be taken.

Abstract: Systems and methods to estimate circadian phase of a subject use one or more sensors to track an activity level of the subject over a period. Actual light exposure need not be tracked nor used to estimate the circadian phase of the subject. One or more estimated light exposure parameters are based on the activity level. The estimated circadian phase is based on the one or more estimated light exposure parameters,possibly derived from activity measurements.

Abstract: The present invention relates to a light sensing system for sensing ambient light intensity, comprising a light sensing device with at least one light sensor and a calibration device for calibrating the sensor. The calibration device comprises at least one light source that emits light with a standard intensity. The invention is further related to a corresponding method for calibrating a light sensing device, comprising the illumination of the light sensor of the light sensing device with light that has a standard intensity, the comparison of the output intensity signal of the sensor with an expected signal that corresponds to the standard intensity, and the matching of the output intensity signal of the sensor to the expected signal by adjusting a gain parameter of the sensor.

Abstract: The present disclosure pertains to a light sensing system configured to determine an amount of ambient light exposure experienced by a subject. The present invention wirelessly exchanges light information between different wearable devices of the same user and/or between devices of different users. Local and/or central light profile databases are built-up by the system and are shared between the devices so that light data that is typical for a location at a specific time of day and year can be used to estimate current ambient light levels for situations in which no measurement can be taken.

Abstract: The invention relates to an apparatus (100) and a method for generating a model output x(ti) describing a circadian rhythm of a person (P) at a time ti. In a preferred embodiment, a light sensor providing the photic exposure (L(ti)) and an activity signal (A(ti)) indicating the current level of activity of the person (P) at the time ti based on motion measurements (via an accelerometer) are used to calculate a wakefulness variable (?) that indicates if the person (P) is awake or sleeping. The wakefulness variable is then used to determine a driving term (N(t)) for a driven oscillator model (135) which simulates the model output x(t) under the joint influence of light and activity.

Abstract: The present invention relates to a light sensing system for sensing ambient light intensity, comprising a light sensing device with at least one light sensor and a calibration device for calibrating the sensor. The calibration device comprises at least one light source that emits light with a standard intensity. The invention is further related to a corresponding method for calibrating a light sensing device, comprising the illumination of the light sensor of the light sensing device with light that has a standard intensity, the comparison of the output intensity signal of the sensor with an expected signal that corresponds to the standard intensity, and the matching of the output intensity signal of the sensor to the expected signal by adjusting a gain parameter of the sensor.

Abstract: The present invention discloses a method and signal processing device (620) for analyzing a ballistocardiogram (BCG). The actual energy content of the cardiac part of the BCG in a predefined time window is determined and compared with a reference value. A difference between the actual energy content and the reference energy content exceeding a predefined threshold is indicative of the presence of an arrhythmia in the evaluated part of the BCG because the force exerted by an arrhythmic ventricular contraction, if at all present, is typically substantially smaller than the force exerted by a ventricular contraction of a regular heartbeat. This insight facilitates a more accurate detection of the presence of arrhythmias in a BCG compared to BCG detection schemes based on a heart rate analysis.

Abstract: Information about a person's circadian rhythm is generated in terms of a difference between a reference and a specific circadian time for a specific wall-clock time or in terms of a difference between a special and a specific wall-clock time for a specific circadian time event.

Abstract: There is provided a method for analyzing a ballistocardiogram signal to determine a heart rate, the method comprising: determining an initial time estimate for a first heart beat in the ballistocardiogram signal; computing, iteratively, estimates for subsequent heart beats in the ballistocardiogram signal using the initial time estimate; wherein each iteration in the step of computing comprises evaluating a target function that comprises a weighted sum of a plurality of scoring functions; and wherein each iterative step of computing estimates for subsequent heart beats in the ballistocardiogram signal is limited to a target interval after the time estimate found in the previous iterative step of computing.

Abstract: A method for monitoring the blood pressure of a patient, comprising the following steps: determining a pulse arrival time signal from the patient 2 based on the pulse wave velocity method; determining an accelerometer signal from the patient 2; and triggering an additional measure or deriving a blood pressure value, taking into account the pulse arrival time signal and a DC component of the accelerometer signal. In this way, a possibility for monitoring the blood pressure of a patient is provided with which false alarms and/or unnecessary additional cuff-based blood pressure measurements can be avoided.

Abstract: The present invention discloses a method and signal processing device (620) for analyzing a ballistocardiogram (BCG). The actual energy content of the cardiac part of the BCG in a predefined time window is determined and compared with a reference value. A difference between the actual energy content and the reference energy content exceeding a predefined threshold is indicative of the presence of an arrhythmia in the evaluated part of the BCG because the force exerted by an arrhythmic ventricular contraction, if at all present, is typically substantially smaller than the force exerted by a ventricular contraction of a regular heartbeat. This insight facilitates a more accurate detection of the presence of arrhythmias in a BCG compared to BCG detection schemes based on a heart rate analysis.

Abstract: The invention also relates to an optical sensor for a photoplethysmography measurement, comprising a light unit 1 with a light emitter 2 for emitting light into tissue of a patient 8 and/or a light detector 3 for detecting a part of the emitted light after interaction with the tissue, wherein the light unit is embedded in an elastic material 4. The invention further relates to a device for contactless respiration monitoring of a patient 8, comprising: a distance sensor for consecutively detecting the temporal distance variations relative to the patient's chest 12, preferably based on electromagnetic waves; and a calculating unit for determining the breathing activity based on the detected temporal distance variations. The invention is especially useful for providing a reliable and easy to use possibility for simultaneously monitoring respiration action, blood pressure and heart rate with a handheld device which can be used for spot-checking the vital parameters of patients in hospitals.

Abstract: Insomnia is a prevalent sleep disturbance in the general population. As standard diagnostic method for assessing the nature and the severity of the sleep problem, a so-called sleep log or sleep diary, i.e. a questionnaire usually on paper, is used in most cases. The main drawback of this diagnostic tool is that its accuracy is affected by subjective bias of the patient, e.g. for patients it is often difficult to remember sleep and wake periods during the night correctly. The present invention proposes an automatic sleep log that uses vital body signs as input signals for assessing sleep and wake periods during the night. By using objective data, the diagnosis will be more accurate. Furthermore, this system can also be used to sleep restriction therapy, a non-pharmacological method to treat insomnia. Also in this application it can contribute to patients correctly applying this method and thus leading to a better medical outcome.

Abstract: The present invention relates to a system (1) and method for obtaining cardiopulmonary and/or activity data of a patient (3) situated in a bed (2). In order to provide a simple and reliable technique for obtaining physiological data, in particular cardiopulmonary data and/or activity data, of a patient (3) situated in a bed (2), a method is suggested, comprising the steps of: providing a bed (2) with a bed structure (4) comprising at least one elastically deformable member (6), said member (69 being deformable by the patient (3) being situated in the bed (2); in case of deformation of said member (6), acquiring deformation data (25) of said member (6); and determining physiological data of said patient (3) using said deformation data (25).