Sensing Circuit with Cascaded Reference

• US 20170215745A1
• Filed: 12/30/2016
• Published: 08/03/2017
• Est. Priority Date: 12/31/2015
• Status: Active Grant

• Current Assignee: Biopause LLC
• Original Assignee: Biopause LLC
• Inventors: Chertok, Leslie Ann, Shimayo, Laureli, Verma, Vandana, Felix, Jason
• Granted Patent: US 10,368,756 B2
• Time in Patent Office: Days
• CPC Class Codes: A61B 5/02438 with portable devices, e.g. worn by the patient
• CPC Class Codes: A61B 5/0245 by using sensing means generating electric signals, i.e. ECG signals
• CPC Class Codes: A61B 5/0255 Recording instruments specially adapted therefor
• CPC Class Codes: A61B 5/30 Input circuits therefor
• CPC Class Codes: A61B 5/308 for electrocardiography [ECG]
• CPC Class Codes: A61B 5/486 Bio-feedback A61B5/375 takes precedence
• CPC Class Codes: A61B 5/681 Wristwatch-type devices
• CPC Class Codes: A61B 5/7214 using signal cancellation, e.g. based on input of two identical physiological sensors spaced apart, or based on two signals derived from the same sensor, for different optical wavelengths
• CPC Class Codes: A61B 5/7225 Details of analog processing, e.g. isolation amplifier, gain or sensitivity adjustment, filtering, baseline or drift compensation A61B5/30, A61B5/316 take precedence; transformers for specific applications H01F38/00; amplifiers H03F
• CPC Class Codes: A61B 5/725 using specific filters therefor, e.g. Kalman or adaptive filters A61B5/316 take precedence
• CPC Class Codes: A61B 5/7275 Determining trends in physiological measurement data; Predicting development of a medical condition based on physiological measurements, e.g. determining a risk factor
• CPC Class Codes: A61B 5/7282 Event detection, e.g. detecting unique waveforms indicative of a medical condition A61B5/4094, A61B5/4818, A61B5/349, A61B5/0823 take precedence
• CPC Class Codes: A61B 5/743 Displaying an image simultaneously with additional graphical information, e.g. symbols, charts, function plots
• CPC Class Codes: A61B 5/7465 Arrangements for interactive communication between patient and care services, e.g. by using a telephone network telemetry of measured physiological signal A61B5/0002

Abstract

This disclosure provides cascaded reference circuits and low amplitude signal sensing circuits that are useful in wearable devices. Circuits for measuring electrovesselgram (EVG) and subdermal spectrogram (SSG) are provided, as well as methods for using these circuits to determine quantities and qualities of a person'"'"'s moods, such as how much and what kinds of stress they experience. The provided devices are useful on limbs and appendages, such as in a smart watch that is worn on the wrist. Methods are provided for using the devices of this disclosure to privately alert wearers to an increase in bad stress in the moment when they can take actions to reduce their stress and physiological stress responses. These devices are useful for measuring and increasing the effectiveness of relaxation techniques. As a result of using methods and devices of this disclosure, people are healthier, they make more response-able decisions, and relationships improve.

Claims

1. A circuit that provides a cascaded reference comprising:

a first reference generator comprising;

a first pair of resistive elements configured to inject a driven first reference containing a DC voltage and power supply noise to a second reference generator or to amplifying and filtering circuitry; and

said second reference generator comprising;

a second pair of resistive elements configured to inject a driven second reference containing a combined output of the first reference generator and an arbitrary input into a specimen or amplifying and filtering circuitry.

2. The circuit of claim 1 further comprising:

a low amplitude signal sensing circuit including a sensing circuit configured to be electrically connected to said cascaded reference circuit through said specimen, said sensing circuit comprising;

one or more sensing electrodes configured to receive electrical stimulus from said specimen, said stimulus comprising a low amplitude signal; and

a filtering element selected from the group comprising;

a filter, a series of filtering elements, and a series of filtering elements and amplifiers that is configured to reference said cascaded reference thereby making said low amplitude signal more detectable and measurable.

3. A circuit for sensing an electrovesselgram (EVG) signal comprising:

a. a first circuit for providing a cascaded reference comprising;

i. a first reference generator comprising;

a first pair of resistors configured to inject a driven first reference containing a DC voltage and noise selected from the group comprising;

power supply noise, system noise, and both power supply noise and system noise, to a second reference generator;

ii. said second reference generator comprising;

a second pair of resistors configured to inject a driven second reference containing the combined output of the first reference generator and an arbitrary input into an organism;

b. a second circuit for acquiring EVG signals, electrically connected to said first circuit, comprising;

i. one or more sensing electrodes configured to receive a signal from said organism;

ii. a low-pass filter configured to receive said organism signal from said one or more sensors;

iii. a first amplifier configured to receive the low-pass filter output;

iv. a high-pass filter configured to receive said the first amplifier output; and

v. a second amplifier configured to receive the high-pass filter output and configured to output an amplified and filtered EVG signal;

wherein said first circuit is, independently of said organism, electrically connected to said second circuit.

4. The circuit of claim 3 wherein one or more of the group comprising:

said low pass filter, said first amplifier and said second amplifier is referenced to one or more of the group comprising;

said first reference generator, said second reference generator, and both said first and second reference generators.

5. The circuit of claim 3 wherein said second circuit is also configured to be electrically connected to said first circuit through said organism at two points that are:

a. far enough away from the organism'"'"'s heart to eliminate substantial muscle noise including cardiac muscle noise or far enough away from other organs to reduce respiration noise and motion artifact;

b. on an appendage selected from the group comprising of;

wrist, forearm, finger, thumb, upper arm, ear, calf, ankle, knee, foot, toe, neck, and tail; and

c. far enough apart from each other that relevant physiological parameters are measurably different at said two points and close enough to each other so that there is not too much noise or artifact when measuring physiological parameters.

6. The circuit of claim 3 also comprising a number of electrodes configured to be in electrical connection with said organism, said number selected from the group consisting of 3 or more electrodes, fewer than 4 electrodes, 2-3 electrodes, fewer than 3 electrodes, and no more than 2 electrodes.

7. The circuit of claim 6 further comprising 1 sensing electrode and 1 reference electrode.

8. The circuit of claim 3 wherein said first circuit is configured to provide said cascaded reference proximal to where said one or more sensing electrodes receive said organism signal.

9. The circuit of claim 8 wherein said first circuit and one or more sensing electrodes are configured to be proximal to a blood vessel in said organism compared to said second circuit.

10. The circuit of claim 3 that is configured to be body worn and configured to be isolated from earth ground.

11. The circuit of claim 3 further comprising one or more of the group comprising:

a second circuit protection resistor configured to be in series with said one or more sensing electrodes, a second circuit AC coupling capacitor configured to be in series with said one or more sensing electrodes, and a second low-pass filter after said second circuit.

12. The circuit of claim 3, wherein the circuit is configured to perform operations for measuring a physiological characteristic of said organism, the operations comprising:

a. selecting said physiological characteristic from a group including EVG, EEG, brain characteristics, heart characteristics, and muscle characteristics;

b. providing a circuit of claim 3 electrically connected to said organism at a reference electrode and at a sensing electrode;

c. selecting a setting of said low pass filter to a setting from the group consisting of;

about 100 KHz, about 10 KHz, about 10 KHz, about 1000 Hz, about 500 Hz, about 250 Hz, about 100 Hz, less than about 100 Hz, less than about 90 Hz, less than about 80 Hz, less than about 60 Hz, less than about 50 Hz, less than about 40 Hz, less than about 30 Hz, and less than about 20 Hz;

d. selecting a setting of said high pass filter to a setting that is lower than said low pass filter setting by an amount from the group consisting of;

less than 90 KHz, less than 9 KHz, less than 1000 Hz, less than 750 Hz, about 500 Hz, less than 500 Hz, less than about 200 Hz, about 200 Hz, about 100 Hz, less than 100 Hz, about 75 Hz, about 50 Hz, less than 50 Hz, about 30 Hz, less than 30 Hz, about 20 Hz, less than 20 Hz, about 10 Hz, and less than 10 Hz;

e. scaling said DC voltage containing power supply noise through said first pair of resistors and said amplifier to produce a noisy reference;

f. providing an arbitrary waveform to said second reference generator;

g. injecting said cascaded reference into said organism;

h. electrically connecting, independently of said organism, said EVG signal receiving circuit to one of the group consisting of said first reference generator, said second reference generator and both said first reference generator and said second reference generator; and

j. simultaneously filtering, amplifying and referencing said organism signal comprising;

i. receiving said organism signal comprising an organism-modified version of said cascaded reference with said one or more sensors;

ii. delivering said organism signal to said low-pass filter and low-pass filtering it;

iii. delivering said low-pass filtered signal to said first amplifier and first amplifying it;

iv. delivering the low-pass filtered, first amplified signal to said high-pass filter and high-pass filtering it;

v. delivering said low-pass filtered, first amplified, high-pass filtered signal to said second amplifier and second amplifying it to produce an amplified and conditioned signal; and

vi. referencing said amplified and conditioned signal to said cascaded reference; and

k. providing an amplified and conditioned signal;

l. providing tools for analysis of said signal and analyzing said signal to determine said physiological characteristic.

13. A method for sensing an electrovesselgram (EVG) signal comprising:

a. providing a cascaded reference comprising

i. providing DC voltage containing noise selected from the group comprising;

power supply noise, system noise, and both power supply noise and system noise;

ii. providing a first reference generator comprising a first pair of resistors and an amplifier;

iii. scaling said DC voltage containing power supply noise through said first pair of resistors and said amplifier to produce a noisy reference;

iv. providing an arbitrary waveform;

v. providing a second reference generator comprising a second pair of resistors configured to receive said arbitrary waveform and said noisy reference; and

vi. combining said noisy reference with said arbitrary waveform in said second reference generator to produce a cascaded reference configured for injection into an organism;

b. providing an EVG signal receiving circuit comprising;

i. providing one or more sensing electrodes configured to receive a signal from said organism;

ii. providing a low-pass filter configured to receive said organism signal from said one or more sensors;

iii. providing a first amplifier configured to receive the low-pass filter output;

iv. providing a high-pass filter configured to receive said first amplifier output; and

v. providing a second amplifier configured to receive the high-pass filter output and configured to output an amplified and filtered signal comprising EVG;

c. electrically connecting said EVG signal receiving circuit to said organism;

d. electrically connecting said cascaded reference to said organism;

e. injecting said cascaded reference into said organism;

f. electrically connecting, independently of said organism, said EVG signal receiving circuit to one of the group consisting of said first reference generator, said second reference generator and both said first reference generator and said second reference generator; and

g. simultaneously filtering, amplifying and referencing said organism signal comprising;

i. receiving said organism signal comprising an organism-modified version of said cascaded reference with said one or more sensors;

ii. delivering said organism signal to said low-pass filter and low-pass filtering it;

iii. delivering said low-pass filtered signal to said first amplifier and first amplifying it;

iv. delivering the low-pass filtered, first amplified signal to said high-pass filter and high-pass filtering it;

v. delivering said low-pass filtered, first amplified, high-pass filtered signal to said second amplifier and second amplifying it to produce an amplified and conditioned signal; and

vi. referencing said amplified and conditioned signal to said cascaded reference; and

thereby providing an amplified and conditioned EVG signal.

14. The method of claim 13 comprising electrically connecting and injecting said cascaded reference into and electrically connecting said EVG signal receiving circuit to said organism at a location proximal to and on opposite sides of one or more blood vessels in said organism.

15. The method of claim 14 further comprising determining the differential voltage generated by the expansion and contraction of one or more cells in the cell wall of said one more blood vessels, said determining the differential voltage including:

a) performing the method of claim 14 at a first and at a second time point; and

b) comparing said first and second amplified and conditioned EVG signals.

16. The method of claim 14 comprising contacting said organism on a limb or appendage, wherein said limb is a wrist.

17. The method of claim 13 also comprising measuring the frequency spectrum of said amplified and conditioned EVG signal.

18. The method of claim 13 further comprising producing a subdermal spectrogram (SSG) signal by:

a. performing the method of claim 13;

b. extracting a sensed arbitrary waveform from said organism signal or said amplified and conditioned EVG signal; and

c. performing a spectral analysis of said sensed arbitrary waveform.

19. The method of claim 18 further comprising determining a mood characteristic selected from the group comprising:

the quantity, quality, change in quantity and change in quality of stress, determining a mood characteristic comprising;

a. performing the method of claim 18 in a wearable device on the wrist of an organism that is a human doing an activity, proximal to one or more blood vessels in said wrist; and

b. comparing and analyzing a first set of data comprising an amplified and conditioned EVG signal and a first SSG signal measured at a first time point to a second set of data selected from the group comprising;

i. a second amplified and conditioned EVG signal and second SSG signal, both from a second time point from said human wherein said human is doing the same said activity;

ii. a second amplified and conditioned EVG signal and second SSG signal from a second time point from said human wherein said human is doing a second and different activity;

iii. comprising calculated or averaged data from a plethora of EVG and SSG signals from said human collected at a plethora of time points;

iv. a database of a plethora of EVG and SSG signals calculated or averaged from one or more other humans; and

v. a second amplified and conditioned EVG signal and a second SSG signal measured on a different part of the human'"'"'s body at about the first time point.

20. The method of claim 19 further comprising decreasing stress in a human by:

a. performing the method of claim 19;

b. providing a stress thresholds database;

c. comparing the analysis of said first and second data sets to said stress thresholds database; and

d. alerting said human, prompting them to take an action to change the quality or quantity of the stress they are experiencing.