Eyeglasses to detect abnormal medical events including stroke and migraine

• US 10,638,938 B1
• Filed: 08/26/2019
• Issued: 05/05/2020
• Est. Priority Date: 06/14/2015
• Status: Active Grant

• Current Assignee: Facense Ltd.
• Original Assignee: Facense Ltd.
• Inventors: Tzvieli, Ori, Frank, Ari M, Tzvieli, Arie, Thieberger, Gil
• Primary Examiner(s): Porta, David P
• Assistant Examiner(s): Boosalis, Fani
• Application Number:
  US16/551,654
• Time in Patent Office: 253 Days
• CPC Class Codes: A61B 2562/0271 Thermal or temperature sensors
• CPC Class Codes: A61B 2562/0276 comprising a thermosensitive compound
• CPC Class Codes: A61B 2576/00 Medical imaging apparatus involving image processing or analysis A61B1/00009, A61B6/52 and A61B8/52 take precedence; image processing per se G06T; details of algorithms for analysing medical images G06T7/0012
• 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 5/0077 Devices for viewing the surface of the body, e.g. camera, magnifying lens
• CPC Class Codes: A61B 5/015 By temperature mapping of body part
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence
• CPC Class Codes: A61B 5/02438 with portable devices, e.g. worn by the patient
• CPC Class Codes: A61B 5/165 Evaluating the state of mind, e.g. depression, anxiety
• CPC Class Codes: A61B 5/6803 Head-worn items, e.g. helmets, masks, headphones or goggles
• CPC Class Codes: A61B 5/6814 Head
• 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 5/748 Selection of a region of interest, e.g. using a graphics tablet
• CPC Class Codes: G01J 2005/0077 Imaging
• CPC Class Codes: G01J 5/0025 Living bodies ear thermometers G01J5/0011; detecting, measuring or recording for diagnostic purposes A61B5/00
• CPC Class Codes: G01J 5/0265 Handheld, portable ear thermometers G01J5/049
• CPC Class Codes: G01J 5/12 using thermoelectric elements, e.g. thermocouples
• CPC Class Codes: G01J 5/485 Temperature profile

Abstract

System and Method to detect an abnormal medical event based on an asymmetrical change to blood flow. The system includes right-side and left-side head-mounted devices to measure signals indicative of photoplethysmographic signals (PPG signals) on the right and left sides of a user'"'"'s head, and a computer that detects the abnormal medical event based on an asymmetrical change to blood flow recognizable in the PPG signals. Optionally, the asymmetrical change to the blood flow corresponds to a deviation of the PPG signals compared to a baseline that is based on previous measurements of PPG signals of the user, taken before the abnormal medical event.

Claims

1. A system configured to detect an abnormal medical event, comprising:

at least one right-side head-mounted device configured to measure at least two signals indicative of photoplethysmographic signals (PPG_SR1 and PPG_SR2, respectively) at first and second regions of interest (ROI_R1 and ROI_R2, respectively) on the right side of a user'"'"'s head;

wherein ROI_R1 and ROI_R2 are located at least 2 cm apart;

at least one left-side head-mounted device configured to measure at least two signals indicative of photoplethysmographic signals (PPG_SL1 and PPG_SL2, respectively) at first and second regions of interest (ROI_L1 and ROI_L2, respectively) on the left side of the user'"'"'s head;

wherein ROI_L1 and ROI_L2 are located at least 2 cm apart; and

a computer configured to detect the abnormal medical event based on an asymmetrical change to blood flow recognizable in PPG_SR1, PPG_SR2, PPG_SL1, and PPG_SL2.

2. The system of claim 1, wherein the asymmetrical change to the blood flow corresponds to a deviation of PPG_SR1, PPG_SR2, PPG_SL1, and PPG_SL2 compared to a baseline based on previous measurements of PPG_SR1, PPG_SR2, PPG_SL1, and PPG_SL2 of the user, taken before the abnormal medical event.

3. The system of claim 2, wherein the computer is further configured to generate feature values based on data comprising:

(i) PPG_SR1, PPG_SR2, PPG_SL1, and PPG_SL2 of the user, and (ii) the previous measurements of PPG_SR1, PPG_SR2, PPG_SL1, and PPG_SL2 of the user; and

wherein the computer is further configured to utilize a model to calculate, based on the feature values, a value indicative of whether the user is experiencing the abnormal medical event.

4. The system of claim 3, wherein the feature values comprise a certain feature value indicative of a difference in maximal amplitudes of one or more of the following pairs:

(i) PPG_SR1 and PPG_SR2, (ii) PPG_SR1 and PPG_SL1, and (iii) PPG_SR1 and PPG_SL2.

5. The system of claim 3, wherein the feature values comprise a certain feature value indicative of a difference in a pulse arrival time between the following pairs of regions of interest:

(i) ROI_R1 and ROI_R2, (ii) ROI_R1 and ROI_L1, and (iii) ROI_R1 and ROI_L2.

6. The system of claim 2, wherein the abnormal medical event is ischemic stroke, and the deviation involves an increase in asymmetry between blood flow on the left side of the head and blood flow on the right side of the head, with respect to baseline asymmetry of the user between blood flow on the left side of the head and blood flow on the right side of the head.

7. The system of claim 2, wherein the abnormal medical event is ischemic stroke, and the deviation involves a monotonic increase in a variation between blood flow at ROI_R1 and ROI_R2, with respect to a baseline variation between blood flow at ROI_R1 and ROI_R2, during a period longer than 10 minutes.

8. The system of claim 7, wherein ROI_R1 is located in proximity of the mastoid process behind the right ear, and ROI_R2 is located before of the right ear.

9. The system of claim 2, wherein the abnormal medical event is migraine attack, and the deviation is indicative of a pattern of a certain change to facial blood flow, which is associated with a pattern of a change to facial blood flow of at least one previous migraine attack, determined based on data comprising previous PPG_SR1, PPG_SR2, PPG_SL1, and PPG_SL2, which were measured starting from at least 5 minutes before the previous migraine attack.

10. The system of claim 2, wherein the abnormal medical event is headache, and the deviation is indicative of at least one of:

a change in directionality of facial blood flow, and an asymmetrical reduction in blood flow to one side of the face.

11. The system of claim 2, wherein the at least one right-side head-mounted device comprises first and second contact photoplethysmographic devices (PPG₁, PPG₂, respectively), and the at least one left-side head-mounted device comprise third and fourth contact photoplethysmographic devices (PPG₃, PPG₄, respectively);

wherein PPG₁, PPG₂, PPG₃, and PPG₄ are physically coupled to an eyeglasses frame, PPG₁ and PPG₃ are in contact with the nose, and PPG₂ and PPG₄ are in contact with regions in the vicinities of the ears, respectively.

12. The system of claim 2, wherein the at least one right-side head-mounted device comprises first and second contact photoplethysmographic devices, and the at least one left-side head-mounted device comprise third and fourth contact photoplethysmographic devices.

13. The system of claim 2, wherein the at least one right-side head-mounted device comprises a first inward-facing camera located more than 0.5 cm away from ROI_R1 and ROI_R2, and PPG_SR1 and PPG_SR2 are recognizable from color changes in regions in images taken by the first inward-facing camera;

and wherein the at least one left-side head-mounted device comprise a second inward-facing camera located more than 0.5 cm away from ROI_L1 and ROI_L2, and PPG_SL1 and PPG_SL2 are recognizable from color changes in regions in images taken by the second inward-facing camera.

14. The system of claim 13, wherein each of the first and second inward-facing cameras utilizes a sensor having more than 30 pixels, and each of ROI_R1 and ROI_L1 covers an area greater than 6 cm{circumflex over ( 

)}2 on the user'"'"'s right and left cheeks, respectively, which is illuminated by ambient light.

15. The system of claim 13, wherein each of the first and second inward-facing cameras utilizes a sensor having more than 20 pixels, and each of ROI_R1 and ROI_L1 covers an area greater than 4 cm{circumflex over ( 

)}2 on the right and left sides of the user'"'"'s forehead, respectively, which is illuminated by ambient light.

16. The system of claim 2, further comprising first and second outward-facing head-mounted cameras configured to take images of the environment to the right and left of the user'"'"'s head, respectively;

and wherein the computer is further configured to utilize the images of the environment to improve the accuracy of detecting the abnormal medical event.

17. The system of claim 1, further comprising right and left head-mounted thermometers, located at least 2 cm to the right and to the left of a vertical symmetry axis that divides the face, respectively, and are configured to provide right and left temperature measurements, respectively;

and the computer is further configured to detect the abnormal medical event also based on a deviation of the right and left temperature measurements from a baseline temperature for the user;

wherein the baseline temperature for the user is calculated based on data comprising previous right and left temperature measurements of the user, taken more than a day before the abnormal medical event; and

wherein the abnormal medical event is selected from a group comprising cellulitis and dermatitis.

18. The system of claim 1, further comprising right and left head-mounted thermometers, located less than 4 cm from the right and left earlobes, respectively, and are configured to provide right and left temperature measurements, respectively;

and the computer is further configured to detect the abnormal medical event also based on a deviation of the right and left temperature measurements from a baseline temperature for the user;

wherein the baseline temperature for the user is calculated based on data comprising previous right and left temperature measurements of the user, taken more than a day before the abnormal medical event.

19. The system of claim 18, wherein the abnormal medical event is selected from a group comprising ear infection, cerebrovascular accident, and mastoiditis.

20. A method for detecting an abnormal medical event, comprising:

measuring, utilizing at least one right-side head-mounted device, at least two signals indicative of photoplethysmographic signals (PPG_SR1 and PPG_SR2, respectively) at first and second regions of interest (ROI_R1 and ROI_R2, respectively) on the right side of a user'"'"'s head;

wherein ROI_R1 and ROI_R2 are located at least 2 cm apart;

measuring, utilizing at least one left-side head-mounted device, at least two signals indicative of photoplethysmographic signals (PPG_SL1 and PPG_SL2, respectively) at first and second regions of interest (ROI_L1 and ROI_L2, respectively) on the left side of the user'"'"'s head;

wherein ROI_L1 and ROI_L2 are located at least 2 cm apart; and

detecting the abnormal medical event based on an asymmetrical change to blood flow recognizable in PPG_SR1, PPG_SR2, PPG_SL1, and PPG_SL2, relative to a baseline based on previous measurements of PPG_SR1, PPG_SR2, PPG_SL1, and PPG_SL2 of the user, taken before the abnormal medical event.