US-20260123845-A1 - CARDIOVASCULAR HEALTH MONITORING

US20260123845A1US 20260123845 A1US20260123845 A1US 20260123845A1US-20260123845-A1

Abstract

A cardiovascular monitoring apparatus, the apparatus comprising: a photoplethysmography (PPG) sensor ( 510 ), having at least one light emitting element ( 310 ) and at least one light sensing element ( 320 ), for obtaining at least one PPG signal from a patient; and a controller comprising: a determination module ( 550 ) for determining whether a signal obtained by a particular light sensing element is suitable for deriving information relevant to a patient's cardiovascular system; and a processing module ( 540 ) for processing a signal that is determined to be suitable for deriving information relevant to the patient's cardiovascular system to derive information relevant to the patient's cardiovascular system.

Inventors

Israel Ninsaw GBATI

Assignees

Biostealth Limited

Dates

Publication Date: 20260507
Application Date: 20251111
Priority Date: 20180308

Claims (20)

1 - 44 . (canceled)
45 . A cardiovascular-monitoring apparatus comprising: a photoplethysmography (PPG) sensor comprising a plurality of light-sensing elements and at least one light-emitting element; and a controller comprising: a detection module and instructions for, with the detection module, determining whether an object is proximate each light-sensing element by evaluating a parameter associated with that light-sensing element, determining whether the object is proximate the light-sensing element using the parameter, and generating an occupied-location map that identifies locations at which the object is proximate; a signal-obtaining module and instructions for, with the signal-obtaining module and subsequent to generating the occupied-location map, causing the at least one light-emitting element to provide PPG acquisition illumination only for one or more locations identified in the occupied-location map, and acquiring a PPG signal only at the one or more locations; a determination module and instructions for, with the determination module, evaluating each acquired PPG signal against at least one waveform-quality criterion and selecting at least one PPG signal that satisfies the at least one waveform-quality criterion; and a processing module and instructions for, with the processing module, processing the selected PPG signal to derive information relating to a subject's cardiovascular system.
46 . The apparatus of claim 45 , wherein the parameter is determined without acquiring a PPG waveform sufficient to derive a cardiovascular parameter, and preferably wherein the parameter relates to whether an object is detected proximate each light sensing element.
47 . The apparatus of claim 45 , wherein determining whether the object is proximate the light-sensing element comprises comparing the parameter to at least one of: a threshold; a statistic computed over time; and a spatial neighborhood of the light-sensing element; and preferably classifying the parameter using an algorithm to label the object as proximate the light-sensing element.
48 . The apparatus of claim 45 , wherein generating the occupied location map comprises ranking locations based on the parameter and designating one or more top-ranked locations as occupied.
49 . The apparatus of claim 45 , wherein the plurality of light-sensing elements are arranged at discrete locations on a sensing surface, and wherein the occupied-location map comprises a list of coordinates over the sensing surface and/or wherein the occupied-location map is updated over time and/or wherein the sensing surface is divided into a plurality of regions, and the controller is configured to restrict PPG acquisition to regions that include at least one light-sensing element determined to be proximate the object.
50 . The apparatus of claim 45 , wherein the controller is configured to de-energize the at least one light-emitting element for locations not identified in the occupied-location map when acquiring the PPG signal, and/or wherein determining whether an object is proximate each light-sensing element comprises turning the at least one light-emitting element off or driving the light-sensing element at a baseline intensity, and wherein acquiring the PPG signal comprises driving the at least one light-emitting element at a higher intensity relative to the baseline intensity only for the locations identified in the occupied-location map.
51 . The apparatus of claim 45 , wherein providing PPG acquisition illumination comprises at least one of: increasing intensity, increasing duty cycle, changing modulation, or selecting a subset of emitters of the at least one light-emitting element.
52 . The apparatus of claim 45 , wherein the PPG sensor further comprises: at least one interleaved array of the at least one light-emitting element and the plurality of light-sensing elements in plan view and/or a layered stack comprising optical apertures.
53 . The apparatus of claim 45 , wherein the at least one waveform-quality criterion comprises one or more of: waveform-shape similarity, frequency-band content, peak-to-peak interval consistency, cross-correlation, or dynamic-time-warping to a reference template and/or wherein, responsive to a failure to satisfy the at least one waveform-quality criterion at a first occupied location, the controller is configured to, using the detection module, select a different occupied location and acquire the PPG signal thereat.
54 . The apparatus of claim 45 , wherein the controller is configured to, using the processing module, restrict processing to PPG signals from locations at which no motion is detected over a stipulated time window and/or wherein the controller is configured to, using the processing module, continuously process the selected PPG signal and terminate processing when the selected PPG signal ceases to satisfy the waveform-quality criterion.
55 . The apparatus of claim 45 , wherein the plurality of light-sensing elements comprises at least four light-sensing elements.
56 . The apparatus of claim 45 , wherein the apparatus is comprised in any of: a laptop, a trackpad, a computer mouse or a wearable.
57 . A computer pointing device with a trackpad, comprising: a housing comprising a top surface defining a trackpad area; a PPG sensor disposed beneath the top surface and comprising a plurality of light-sensing elements arranged at discrete locations and at least one light-emitting element; and a controller comprising: a detection module and instructions for, with the detection module, detecting finger locations and motion on the trackpad area, and generating an occupied-location map that identifies one or more locations at which a finger is proximate by applying a presence decision rule to a parameter associated with each location; a signal-obtaining module and instructions for, with the signal-obtaining module, causing the at least one light-emitting element to provide PPG acquisition illumination only for the locations identified in the occupied-location map and acquiring a PPG signal at those locations; a determination module and instructions for, with determination module, evaluating each acquired PPG signal against at least one waveform-quality criterion and selecting at least one PPG signal that satisfies the waveform-quality criterion; and a processing module and instructions for, with the processing module, processing the selected PPG signal to derive information relating to a subject's cardiovascular system, preferably wherein detecting finger locations and motion is performed using signals from the plurality of light-sensing elements.
58 . The device of claim 57 , wherein a portion of the trackpad area overlaps a keyboard region, and wherein the controller is configured to, using the detection module, distinguish keystroke events from trackpad movement using the acquired PPG signals.
59 . The device of claim 57 , wherein the PPG sensor is arranged as an under-glass stack comprising a perforated layer forming optical apertures.
60 . The device of claim 57 , wherein the controller is configured to de-energize the at least one light-emitting element for locations not identified in the occupied-location map, and/or wherein, upon detecting no change in finger locations for a set interval, the controller selects a location for PPG acquisition and continuously processes the selected PPG signal until the selected PPG signal ceases to satisfy the waveform-quality criterion.
61 . A method comprising: determining whether an object is proximate each light-sensing element of a plurality of light-sensing elements by evaluating a parameter associated with that light-sensing element, determining whether the object is proximate the light-sensing element using the parameter, and generating an occupied-location map that identifies locations at which the object is proximate; causing the at least one light-emitting element to provide PPG acquisition illumination only for the locations identified in the occupied-location map and acquiring a PPG signal at those locations; evaluating each acquired PPG signal against at least one waveform-quality criterion and selecting at least one PPG signal that satisfies the criterion; and processing the selected PPG signal to derive information relating to a subject's cardiovascular system, preferably wherein determining whether the object is proximate the location is performed without acquiring a PPG waveform sufficient to derive a cardiovascular parameter.
62 . The method of claim 61 , wherein providing PPG acquisition illumination comprises at least one of: increasing intensity, increasing duty cycle, changing modulation, or selecting a subset of emitters of the at least one light emitting element.
63 . The method of claim 61 , further comprising de-energizing the at least one light-emitting element at locations not identified in the occupied-location map when acquiring the PPG signal.

Description

RELATED APPLICATIONS This application is a Continuation of U.S. patent application Ser. No. 16/978,720 filed on Sep. 7, 2020, which is a National Phase of PCT Patent Application No. PCT/EP 2019/055934 having International filing date of Mar. 8, 2019, which claims the benefit of priority of United Kingdom Patent Applications Nos. 1803703.6 filed on Mar. 8, 2018, and 1806659.7 filed on Apr. 24, 2018. The contents of the above applications are all incorporated by reference as if fully set forth herein in their entirety. FIELD AND BACKGROUND OF THE INVENTION The present invention relates to cardiovascular health monitoring. More specifically, the invention relates to a photoplethysmographic cardiovascular monitoring apparatus. The invention further relates to a surface for monitoring cardiovascular health of humans and other animals. The invention further relates to a trackpad device for monitoring cardiovascular health of users. Cardiovascular illnesses are the number one cause of death worldwide. This is primarily because early symptoms of cardiovascular conditions are hard to detect by human sensory means. Because of this, people more prone to having cardiovascular conditions are required to visit the hospital regularly for checkups and are also required to actively monitor their cardiovascular health at home using some form of portable handheld devices. However, there is a problem with compliance. For instance, in the United States, less than 20% of all people required by their doctors to check their blood pressure daily, check only twice a week. Owing to this and other problems relating to convenience of time and avenue for continuous cardiovascular health monitoring, there is the need to be able to monitor cardiovascular health of patients or people in general completely non-invasively without the patient or person wearing a device, initiating the process or even thinking about it. Trackpads are also sometimes called touchpads. Trackpads are mostly used with computing devices to enable interaction with the computing device. They often include a touch sensing surface mostly capacitive and or resistive where the trackpad is configured to detect the position and motion of a user's finger or fingers that are in contact with the touch sensing surface. SUMMARY OF THE INVENTION Aspects and embodiments of the present invention are set out in the appended claims. These and other aspects and embodiments of the invention are also described herein. According to at least one aspect described herein, there is provided a cardiovascular monitoring apparatus, the apparatus comprising: a photoplethysmography (PPG) sensor, having at least one light emitting element and at least one light sensing element, for obtaining at least one PPG signal from a patient; and a controller comprising: a determination module for determining whether a signal obtained by a particular light sensing element is suitable for deriving information relevant to a patient's cardiovascular system; and a processing module for processing a signal that is determined to be suitable for deriving information relevant to the patient's cardiovascular system to derive information relevant to the patient's cardiovascular system (preferably wherein the information is relevant to the patient's cardiovascular health). This may provide improved processing efficiency, in that an initial test of the usefulness of a particular signal is provided prior to full processing. This may be particularly useful where it is desired to pick from a plurality of possible signals (optionally from a plurality of possible sensors). The PPG sensor may further comprise a plurality of light sensing elements. Preferably, the determination module is arranged to determine whether signals obtained by at least a subset of the plurality of light sensing elements are each suitable for deriving information relevant to a patient's cardiovascular system. This may allow all possible signals from light sensing elements within a subset (wherein the subset is determined by some initial step e.g. by whether an object is detected proximate each light sensing element) to be tested for suitability, which may thereby facilitate a subsequent selection between signals. Optionally, the apparatus comprises a selector for performing this function. Preferably, responsive to the determination module determining that a signal obtained by a particular light sensing element is not suitable for deriving information relevant to a patient's cardiovascular system, the determination module is arranged to determine whether a signal obtained by a different light sensing element is suitable for deriving information relevant to a patient's cardiovascular system. This may allow signals from light sensing elements be tested for suitability until an appropriate signal is found, which may improve processing speed and efficiency. Preferably, determining whether a signal obtained by a particular light sensing element is suitable f