Bio-signal detection

Patent metadata

Field	Value
Publication number	US-2021177334-A1
Application number	US-201816761669-A
Country	US
Kind code	A1
Filing date	Nov 20, 2018
Priority date	Nov 24, 2017
Publication date	Jun 17, 2021
Grant date	—

Abstract

An apparatus comprising: a displacement current sensor configured to measure for a subject one or more sensed electrical signals; and circuitry configured to process the one or more sensed electrical signals to obtain an electrocardiogram signal and a variable impedance signal caused by an arterial pulse wave.

First claim

I/We claim:

1 - 15 . (canceled)

16 . An apparatus comprising:
a displacement current sensor configured to measure for a subject one or more sensed electrical signals, wherein the displacement current sensor comprises at least one electrode; and circuitry configured to process the one or more sensed electrical signals from the displacement current sensor to obtain an electrocardiogram signal and a variable impedance signal caused by an arterial pulse wave.

17 . An apparatus as claimed in claim 16 , wherein the at least one electrode is configured to be positioned adjacent the subject's skin and comprises electrical insulation for insulating the at least one electrode from the subject's skin.

18 . An apparatus as claimed in claim 16 , wherein the apparatus is configured to be worn by the subject.

19 . An apparatus as claimed in claim 16 , wherein the circuitry configured to process the one or more sensed electrical signals to obtain an electrocardiogram signal and a variable impedance signal caused by an arterial pulse wave, is configured to:
measure the variable impedance signal caused by an arterial pulse wave as a modulation of a reference signal.

20 . An apparatus as claimed in claim 16 , wherein the circuitry configured to process the one or more sensed electrical signals to obtain an electrocardiogram signal and a variable impedance signal caused by an arterial pulse wave, is configured to:
measure the variable impedance signal caused by an arterial pulse wave as a modulation of an electrical reference signal provided to the subject via a first electrode.

21 . An apparatus as claimed in claim 20 , wherein the electrical reference signal has one or more high frequency components, greater than 1 kHz.

22 . An apparatus as claimed in claim 20 , wherein the circuitry configured to process the one or more sensed electrical signals to obtain an electrocardiogram signal and a variable impedance signal caused by an arterial pulse wave is configured to:
apply a first time variable voltage to the first electrode via a first operational amplifier, measure a second time variable voltage at an output of a second operational amplifier wherein an input to the second operational amplifier is connected to a second electrode, an impedance being connected between the input and the output of the second operational amplifier, wherein at least part of the impedance between the first and second electrodes is estimated using at least the first time variable voltage and the second time variable voltage to obtain a variable impedance signal caused by an arterial pulse wave.

23 . An apparatus as claimed in claim 22 , wherein an ECG signal received at a first ECG electrode adjacent and guarded by the first electrode and adjacent and guarded by the second electrode provides a virtual earth to the first operational amplifier and the second operational amplifier.

24 . An apparatus as claimed in claim 16 , wherein the circuitry configured to process the one or more sensed electrical signals to obtain an electrocardiogram signal and variable impedance signal caused by an arterial pulse wave is configured to:
obtain an Imaginary part of a signal dependent upon an impedance between first and second guard electrodes of an ECG electrode.

25 . An apparatus as claimed in claim 16 , wherein the circuitry configured to process the one or more sensed electrical signals to obtain an electrocardiogram signal and a variable impedance signal caused by an arterial pulse wave is configured to:
measure the variable impedance signal caused by an arterial pulse wave as a modulation of an ECG signal.

26 . An apparatus as claimed in claim 25 wherein the displacement current sensor comprises a displacement current electrode having a capacitance that varies with varying arterial blood volume under the displacement current sensor when in situ;
wherein the circuitry configured to process the one or more sensed electrical signals to obtain an electrocardiogram signal and a variable impedance signal caused by an arterial pulse wave, is configured to:
process the signal at the displacement current electrode to measure the variable impedance signal caused by an arterial pulse wave.

27 . An apparatus as claimed in claim 26 , wherein the displacement current electrode comprises resiliently flexible dielectric.

28 . An apparatus as claimed in claim 26 , wherein
the circuitry configured to process the one or more sensed electrical signals to obtain an electrocardiogram signal and a variable impedance signal caused by an arterial pulse wave, is configured to: in the frequency domain, remove the variable impedance signal from the one or more sensed electrical signals to obtain the electrocardiogram signal.

29 . An apparatus as claimed in claim 16 , wherein the circuitry is configured to use the variable impedance signal dependent upon an impedance between first and second guard electrodes of an ECG electrode as an external reference signal for an adaptive filter for filtering the sensed signal.

30 . An apparatus as claimed in claim 16 , wherein the electrocardiogram signal and the variable impedance signal are obtained substantially simultaneously.

31 . A method comprising:
using a displacement current sensor configured to sense, for a subject, one or more electrical signals, wherein the displacement current sensor comprises at least one electrode; and processing the one or more sensed electrical signals from the displacement current sensor to obtain an electrocardiogram signal and a variable impedance signal caused by an arterial pulse wave.

32 . A method as claimed in claim 31 , wherein the electrocardiogram signal and the variable impedance signal are obtained substantially simultaneously.

33 . A method as claimed in claim 31 , further comprising using the variable impedance signal dependent upon an impedance between first and second guard electrodes of an ECG electrode as an external reference signal for an adaptive filter for filtering the sensed signal.

34 . A non-transitory computer readable medium comprising program instructions stored thereon for performing at least the following:
using a displacement current sensor configured to sense, for a subject, one or more electrical signals, wherein the displacement current sensor comprises at least one electrode; and processing the one or more sensed electrical signals from the displacement current sensor to obtain an electrocardiogram signal and a variable impedance signal caused by an arterial pulse wave.

35 . A non-transitory computer readable medium as claimed in claim 34 , further comprising program instructions stored thereon for performing at least:
obtaining the electrocardiogram signal and the variable impedance signal substantially simultaneously.

Assignees

• Nokia Technologies Oy

Inventors

• Salo Antti
• Blomqvist Kim

Classifications

• A61B5/277

  Capacitive electrodes · CPC title

• A61B5/28 Primary

  for electrocardiography [ECG] · CPC title

• A61B5/308

  for electrocardiography [ECG] · CPC title

• A61B5/302

  for capacitive or ionised electrodes, e.g. metal-oxide-semiconductor field-effect transistors [MOSFET] · CPC title

• A61B5/02108

  from analysis of pulse wave characteristics · CPC title