WEARABLE SENSING BAND

• US 20160089081A1
• Filed: 09/29/2014
• Published: 03/31/2016
• Est. Priority Date: 09/29/2014
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Morris, Dan, Saponas, T. Scott, Villar, Nicolas, Patel, Shwetak, Smith, Greg R., Tan, Desney
• Granted Patent: US 9,848,825 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 2562/0247 Pressure sensors
• CPC Class Codes: A61B 2576/023 for the heart
• CPC Class Codes: A61B 5/0006 ECG or EEG signals
• CPC Class Codes: A61B 5/0044 for the heart
• CPC Class Codes: A61B 5/0082 adapted for particular medical purposes
• CPC Class Codes: A61B 5/02007 Evaluating blood vessel condition, e.g. elasticity, compliance
• CPC Class Codes: A61B 5/02125 of pulse wave propagation time
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence
• CPC Class Codes: A61B 5/0261 using optical means, e.g. infrared light
• CPC Class Codes: A61B 5/0265 using electromagnetic means, e.g. electromagnetic flowmeter
• CPC Class Codes: A61B 5/029 Measuring or recording blood output from the heart, e.g. minute volume A61B8/065 takes precedence
• CPC Class Codes: A61B 5/1079 using optical or photographic means
• CPC Class Codes: A61B 5/282 Holders for multiple electrodes for introduction into the body A61B5/287
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]
• CPC Class Codes: A61B 5/681 Wristwatch-type devices
• CPC Class Codes: A61B 5/6823 Trunk, e.g., chest, back, abdomen, hip
• CPC Class Codes: A61B 5/6824 Arm or wrist
• CPC Class Codes: A61B 5/6828 Leg
• CPC Class Codes: A61B 5/6829 Foot or ankle
• CPC Class Codes: A61B 5/6831 Straps, bands or harnesses
• CPC Class Codes: A61B 5/7246 : using correlation, e.g. template matching or determination of similarity

Abstract

A wearable sensing band is presented that generally provides a non-intrusive way to measure a person'"'"'s cardiovascular vital signs including pulse transit time and pulse wave velocity. The band includes a strap with one or more primary electrocardiography (ECG) electrodes which are in contact with a first portion of the user'"'"'s body, one or more secondary ECG electrodes, and one or more pulse pressure wave arrival (PPWA) sensors. The primary and secondary ECG electrodes detect an ECG signal whenever the secondary ECG electrodes make electrical contact with the second portion of the user'"'"'s body, and the PPWA sensors sense an arrival of a pulse pressure wave to the first portion of the user'"'"'s body from the user'"'"'s heart. The ECG signal and PPWA sensor(s) readings are used to compute at least one of a pulse transit time (PTT) or a pulse wave velocity (PWV) of the user.

Claims

1. A wearable sensing band, comprising:

a strap which is attached to a first portion of the user'"'"'s body;

one or more primary electrocardiography (ECG) electrodes disposed on the strap such that whenever the wearable sensing band is worn by the user, the primary ECG electrodes are in electrical contact with said first portion of the user'"'"'s body;

one or more secondary ECG electrodes disposed on the strap such that whenever the wearable sensing band is worn by the user, the secondary ECG electrodes are electrically isolated from said first portion of the user'"'"'s body and are positioned so as to be contacted by a second portion of the user'"'"'s body located on the opposite side of the user'"'"'s heart from said first portion of the user'"'"'s body;

one or more pulse pressure wave arrival (PPWA) sensors disposed on the strap such that whenever the wearable sensing band is worn by the user, the PPWA sensors are in proximity to or contacting said first portion of the user'"'"'s body; and

wherein

said primary and secondary ECG electrodes detect an ECG signal whenever the secondary ECG electrodes make electrical contact with said second portion of the user'"'"'s body, and said PPWA sensors sense an arrival of a pulse pressure wave to said first portion of the user'"'"'s body from the user'"'"'s heart.

2. The wearable sensing band of claim 1, wherein said first portion of the user'"'"'s body is a place on a person'"'"'s body where movement in an underlying artery can be sensed, and where the strap can be either wrapped around and tightened or the strap can be adhered to.

3. The wearable sensing band of claim 1, wherein said first portion of the user'"'"'s body is one of a wrist, or a forearm, or an upper arm, or torso, or an upper leg, or a lower leg, or an ankle.

4. The wearable sensing band of claim 1, wherein:

there are multiple primary ECG electrodes which are electrically connected to each other;

or

there are multiple secondary ECG electrodes which are electrically connected to each other;

or

there are multiple primary ECG electrodes which are electrically connected to each other, and multiple secondary ECG electrodes which are electrically connected to each other.

5. The wearable sensing band of claim 1, wherein:

there are multiple primary ECG electrodes which are electrically isolated from each other;

or

there are multiple secondary ECG electrodes which are electrically isolated from each other;

or

there are multiple primary ECG electrodes which are electrically isolated from each other, and multiple secondary ECG electrodes which are electrically isolated from each other.

6. The wearable sensing band of claim 1, wherein at least one of said one or more pulse pressure wave arrival (PPWA) sensors is an optical sensor.

7. The wearable sensing band of claim 1, wherein at least one of said one or more pulse pressure wave arrival (PPWA) sensors is a pressure sensor.

8. The wearable sensing band of claim 1, wherein at least one of the one or more secondary ECG electrodes is of a type that established electrical contact with said second portion of the user'"'"'s body through clothing.

9. The wearable sensing band of claim 1, wherein said first portion of the user'"'"'s body is the user'"'"'s wrist, and wherein the one or more primary ECG electrodes are disposed on a part of the strap touching the underside of the user'"'"'s wrist.

10. The wearable sensing band of claim 1, wherein said first portion of the user'"'"'s body is the user'"'"'s wrist, and wherein the one or more pulse pressure wave arrival (PPWA) sensors are disposed on a part of the strap touching the underside of the user'"'"'s wrist.

11. The wearable sensing band of claim 1, wherein the one or more primary ECG electrodes are disposed on a first side of the strap, and the one or more secondary ECG electrodes are disposed on the opposite side of the strap.

12. A system for computing at least one of a pulse transit time (PTT) or a pulse wave velocity (PWV) of a user, comprising:

a wearable sensing band comprising,

a strap which is attached to a first portion of the user'"'"'s body,

one or more primary electrocardiography (ECG) electrodes disposed on the strap such that whenever the wearable sensing band is worn by the user, the primary ECG electrodes are in electrical contact with said first portion of the user'"'"'s body,

one or more secondary ECG electrodes disposed on the strap such that whenever the wearable sensing band is worn by the user, the secondary ECG electrodes are electrically isolated from said first portion of the user'"'"'s body and are positioned so as to be contacted by a second portion of the user'"'"'s body located on the opposite side of the user'"'"'s heart from said first portion of the user'"'"'s body,

one or more pulse pressure wave arrival (PPWA) sensors disposed on the strap such that whenever the wearable sensing band is worn by the user, the PPWA sensors are in proximity to or contacting said first portion of the user'"'"'s body, wherein

said primary and secondary ECG electrodes detect an ECG signal whenever the secondary ECG electrodes make electrical contact with said second portion of the user'"'"'s body, and said PPWA sensors sense an arrival of a pulse pressure wave to said first portion of the user'"'"'s body from the user'"'"'s heart, and

a computing device which executes program modules of a computer program, the computing device being directed by the program modules of the computer program to,

estimate the time a pulse pressure wave leaves the user'"'"'s heart using the ECG signal, and

establish the time said pulse pressure wave arrives at said first portion of the user'"'"'s body using the sensed arrival of the pulse pressure wave.

13. The system of claim 12, wherein the computing device is further directed by the program modules of the computer program to compute the pulse transit time (PTT) of a pulse pressure wave traveling through the user'"'"'s arteries from the user'"'"'s heart to said first portion of the user'"'"'s body by subtracting the time the pulse pressure wave left the user'"'"'s heart from the arrival time of the pulse pressure wave to said first portion of the user'"'"'s body

14. The system of claim 13, wherein the computing device is further directed by the program modules of the computer program to:

obtain an estimate of the arterial travel distance (ATD) between the user'"'"'s heart and said first portion of the user'"'"'s body; and

compute a pulse wave velocity (PWV) using the PTT and ATD estimate.

15. The system of claim 14, wherein the program module for obtaining an estimate of the ATD between the user'"'"'s heart and said first portion of the user'"'"'s body, comprises using images of the user to estimate the user'"'"'s ATD.

16. The system of claim 14, wherein the wearable sensing band further comprises:

a communication component for transmitting data representative of at least one of the computed PTT or PWV of the user via a computer network; and

wherein

the computing device is further directed by the program modules of the computer program to transmit said representative data to one or more remote computing devices.

17. The system of claim 12, wherein the wearable sensing band further comprises:

a communication component for transmitting data representative of the time the pulse pressure wave left the user'"'"'s heart and the arrival time of the pulse pressure wave arrived at said first portion of the user'"'"'s body via a computer network; and

wherein

the computing device is further directed by the program modules of the computer program to transmit said representative data to one or more remote computing devices for computation of at least one of the PTT or PWV of the user based on the transmitted representative data.

18. A computer-implemented process for estimating the arterial travel distance (ATD) from a person'"'"'s heart to a first portion of the person'"'"'s body, comprising the actions of:

using one or more computing devices to perform the following process actions, which whenever plural computing devices are used are in communication with each other via a computer network;

receiving directly-measured values of the ATD from a person'"'"'s heart to a first portion of the person'"'"'s body for a plurality of people;

receiving one or more body metrics for each of the plurality of people;

correlating the ATD estimates with the body metrics;

generating a numerical model that estimates the ATD from a person'"'"'s heart to a first portion of the person'"'"'s body based on the body metric-ATD correlations; and

estimating the ATD from a person'"'"'s heart to said first portion of the person'"'"'s body using the numerical model and values of said body metrics associated with the person.

19. The process of claim 18, wherein the body metrics comprises at least one of the person'"'"'s height, or weight, or waist circumference, or fingertip-to-fingertip span, or shoulder width, or torso height, or individual joint lengths, or gender, or race, or age.

20. The process of claim 19, wherein the body metrics further comprise an estimate of the person'"'"'s ATD derived from images of the user.