Method and device for measuring the RSA component from heart rate data

• US 8,882,676 B2
• Filed: 06/01/2011
• Issued: 11/11/2014
• Est. Priority Date: 06/03/2010
• Status: Expired due to Fees

• Current Assignee: Zinc Software Limited
• Original Assignee: Zinc Software Limited
• Inventors: Hughes, Darran John
• Primary Examiner(s): Mallari, Patricia
• Assistant Examiner(s): Burrage, Michael J
• Application Number:
  US13/150,490
• Publication Number:
  US 20110301477A1
• Time in Patent Office: 1,259 Days
• Field of Search: 600/529, 600/543
• US Class Current: 600/501
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/02405 Determining heart rate variability
• CPC Class Codes: A61B 5/4035 Evaluating the autonomic nervous system
• CPC Class Codes: A61B 5/486 Bio-feedback A61B5/375 takes precedence
• CPC Class Codes: A61B 5/744 Displaying an avatar, e.g. an animated cartoon character

Abstract

A device for providing biofeedback information to a subject, including a receiver for receiving heart rate data from a sensor, said heart rate data corresponding to a human subject, a storage device for storing a time series of the received heart rate data, a display, and a processor that is programmed to enable access to the storage device and to perform actions including estimating an RSA strength of the subject'"'"'s heart from the time series of the received heart rate data, calculating an accumulated RSA strength from a designated starting time until the present time, determining a motion by a virtual agent based on the accumulated RSA strength at the present time, said virtual agent being a graphical object or character that represents the subject, and displaying the motion of the virtual agent determined by said determining on the display.

Claims

1. A computer-implemented method for calculating a Respiratory Sinus Arrhythmia (RSA) metric for use in biofeedback systems, comprising:

(a) sampling a subject'"'"'s heart beat during a window of time by a sensor to obtain heart beat sensor data;

(b) transmitting, by the sensor, the heart beat sensor data corresponding to each sample during the window to a computing device;

(c) calculating, by the computing device, inter beat intervals from the heart beat sensor data;

(d) determining, by the computing device, an all-pole filter model that best fits the inter beat intervals;

(e) calculating, by the computing device, positions of filter model poles;

(f) identifying, by the computing device, the pole with the largest modulus within a pre-specified sector of a unit circle; and

(g) calculating, by the computing device, an RSA metric,

designated as S_RSA, calculated according to the equation,

2. The method of claim 1 wherein the sensor is a transducer device selected from the group consisting of an electrocardiogram, a photoplethysmograph, a pressure sensor, and a microphone.

3. The method of claim 1 wherein the calculated inter beat intervals are resampled at a uniform rate.

4. The method of claim 1 further comprising de-meaning and de-trending, by the computing device, the samples in a window.

5. The method of claim 1 wherein the Burg method is used to calculate the best fit all-pole model filter coefficients.

6. The method of claim 1 wherein the pre-specified sector of the unit circle is defined by

7. The method of claim 1 wherein the pole with the largest modulus in the sector of interest is used to calculate the user'"'"'s current breathing rate according to the equation,