Systems and methods for measurement of heart rate and other heart-related characteristics from photoplethysmographic (PPG) signals using collision computing

• US 9,610,018 B2
• Filed: 08/10/2016
• Issued: 04/04/2017
• Est. Priority Date: 09/29/2014
• Status: Active Grant

• Current Assignee: Zyomed Holdings, Inc.
• Original Assignee: Zyomed Corp.
• Inventors: Gulati, Sandeep, Ruchti, Timothy L., Smith, John L.
• Primary Examiner(s): Kim, Kiho
• Application Number:
  US15/233,474
• Publication Number:
  US 20170035308A1
• Time in Patent Office: 237 Days
• CPC Class Codes: A61B 2560/0223 of calibration, e.g. protocols for calibrating sensors
• CPC Class Codes: A61B 5/0075 by spectroscopy, i.e. measuring spectra, e.g. Raman spectroscopy, infrared absorption spectroscopy A61B5/0071 takes precedence
• CPC Class Codes: A61B 5/024 Detecting, measuring or recording pulse rate or heart rate A61B5/0205, A61B5/021 take precedence
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence
• CPC Class Codes: A61B 5/02433 for infrared radiation
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14546 for measuring analytes not otherwise provided for, e.g. ions, cytochromes
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/1495 Calibrating or testing of in-vivo probes
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61B 5/7235 Details of waveform analysis A61B5/349 takes precedence
• CPC Class Codes: A61B 5/7253 characterised by using transforms
• CPC Class Codes: A61B 5/7264 Classification of physiological signals or data, e.g. using neural networks, statistical classifiers, expert systems or fuzzy systems neural networks per se G06N3/00; expert systems per se G06N5/00
• CPC Class Codes: A61B 5/7267 involving training the classification device
• CPC Class Codes: G01N 21/3577 for analysing liquids, e.g. polluted water
• CPC Class Codes: G01N 21/359 using near infrared light
• CPC Class Codes: G01N 21/4795 spatially resolved investigating of object in scattering medium in vivo A61B
• CPC Class Codes: G01N 21/49 within a body or fluid
• CPC Class Codes: G01N 2201/0612 Laser diodes
• CPC Class Codes: G01N 2201/062 LED's
• CPC Class Codes: G01N 2201/067 : Electro-optic, magneto-optic, acousto-optic elements
• CPC Class Codes: G01N 2201/12 : Circuits of general importance; Signal processing
• CPC Class Codes: G01N 2201/129 : Using chemometrical methods
• CPC Class Codes: G01N 33/4833 : of solid biological material, e.g. tissue samples, cell cultures tissue in vivo A61B5/00; cell suspensions G01N33/48735
• CPC Class Codes: G01N 33/49 : Blood chemical methods for determining blood cell populations G01N33/5094; chemical analysis of blood groups or blood types G01N33/80
• CPC Class Codes: G16H 50/20 : for computer-aided diagnosis, e.g. based on medical expert systems
• CPC Class Codes: G16H 50/70 : for mining of medical data, e.g. analysing previous cases of other patients

Abstract

In a noninvasive system for measurement of heart rate and other heart-related characteristics a photoplethysmogram (PPG) obtained from a tissue is divided into several feature waveforms, each corresponding to a PPG window of a particular length. Conditioned features, containing frequency components specific to heart-related events, are derived from the features by modulating a carrier kernel with such features. The conditioned features are computationally collided with one or more Zyotons that are co-dependent with the conditioned features. For each conditioned feature, one or more collisions selectively amplify frequency components in features sourced from PPG, and respective energy change values are obtained from such amplified energy portions. The resulting energy change values are analyzed to determine a smallest time-window likely containing heart rate and other heart-related events in the PPG data stream. Over time, the detected events are grouped and analyzed to determine heart rate and other heart-related characteristics.

Claims

1. A method for generating features for measurement of heart-beat rate, the method comprising:

receiving a signal based on one of reflected and transmitted radiation from a tissue during a global time interval starting at a global start time and ending at a global end time;

designating, via a processor, a first portion of the signal starting at the global start time and ending at a first end time less than the global end time as a first feature;

designating, via the processor, a second portion of the signal starting at the global start time and ending at a second end time greater than the first end time as a second feature; and

displaying the heart-beat rate computed using the first and second features.

2. The method of claim 1, further comprising:

determining that an expected end of a heart-beat cycle is absent within the first portion of the signal, designated as the first feature; and

designating the first feature as a non-analyte feature.

3. The method of claim 2, further comprising:

determining that the expected end of the heat-beat cycle is present within the second portion of the signal, designated as the second feature; and

designating the second feature as an analyte feature.

4. The method of claim 3, further comprising determining the heart-beat rate by:

colliding a first conditioned feature waveform derived from the first feature with a co-dependent Zyoton to obtain a first energy change;

colliding a second conditioned feature waveform derived from the second feature with a co-dependent Zyoton to obtain a second energy change;

computing an end of the heart-beat cycle using the first and second energy changes; and

computing the heart-beat rate using the start of the heart-beat cycle and the end of the heart-beat cycle.

5. A system for generating features for measurement of heart-beat rate, the system comprising:

a first processor; and

a first memory in electrical communication with the first processor, the first memory comprising instructions which, when executed by a processing unit comprising at least one of the first processor and a second processor, and in electronic communication with a memory module comprising at least one of the first memory and a second memory, program the processing unit to;

receive a signal based on one of reflected and transmitted radiation from a tissue during a global time interval starting at a global start time and ending at a global end time;

designate a first portion of the signal starting at the global start time and ending at a first end time less than the global end time as a first feature;

designate a second portion of the signal starting at the global start time and ending at a second end time greater than the first end time as a second feature; and

display the heart-beat rate computed using the first and second features.

6. The system of claim 5, wherein the instructions further program the processing unit to:

determine that an expected end of a heart-beat cycle is absent within the first portion of the signal, designated as the first feature; and

designate the first feature as a non-analyte feature.

7. The system of claim 6, wherein the instructions further program the processing unit to:

determine that the expected end of the heat-beat cycle is present within the second portion of the signal, designated as the second feature; and

designate the second feature as an analyte feature.

8. The system of claim 7, wherein to determine the heart-beat rate, the instructions further program the processing unit to:

collide a first conditioned feature waveform derived from the first feature with a co-dependent Zyoton to obtain a first energy change;

collide a second conditioned feature waveform derived from the second feature with a co-dependent Zyoton to obtain a second energy change;

compute an end of the heart-beat cycle using the first and second energy changes; and

compute the heart-beat rate using the start of the heart-beat cycle and the end of the heart-beat cycle.