Electro-optical system, apparatus, and method for ambulatory monitoring

• US 9,504,394 B2
• Filed: 07/12/2006
• Issued: 11/29/2016
• Est. Priority Date: 07/28/2005
• Status: Active Grant

• Current Assignee: The General Hospital Corporation (Mass General Brigham, Inc.)
• Original Assignee: The General Hospital Corporation (Mass General Brigham, Inc.)
• Inventors: Zhang, Quan, Strangman, Gary
• Primary Examiner(s): NEGIN, RUSSELL SCOTT
• Application Number:
  US11/995,352
• Publication Number:
  US 20080208013A1
• Time in Patent Office: 3,793 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: A61B 5/0002 Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network A61B5/07 takes precedence; transmission systems for measured values G08C; transmission H04B; transmission of digital information H04L; wireless communication networks H04W
• CPC Class Codes: A61B 5/0059 using light, e.g. diagnosis by transillumination, diascopy, fluorescence A61B5/0093, A61B5/1455, A61B5/02416 and A61B5/0261 take precedence
• CPC Class Codes: A61B 5/02438 with portable devices, e.g. worn by the patient
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/4094 Diagnosing or monitoring seizure diseases, e.g. epilepsy
• CPC Class Codes: A61B 5/4509 Bone density determination
• CPC Class Codes: A61B 5/7232 involving compression of the physiological signal, e.g. to extend the signal recording period
• CPC Class Codes: G16B 45/00 ICT specially adapted for bioinformatics-related data visualisation, e.g. displaying of maps or networks
• CPC Class Codes: G16B 5/00 ICT specially adapted for modelling or simulations in systems biology, e.g. gene-regulatory networks, protein interaction networks or metabolic networks
• CPC Class Codes: G16B 5/30 Dynamic-time models

Abstract

An electro-optical system, apparatus, and method allow long-term, ambulatory measurements to be made on a patient using light transmitted into the patient and resulting light received from the patient.

Claims

1. An electro-optical monitoring system comprising:

a light transceiver comprising;

a first light source configured to generate light having a first wavelength, the first light source coupled to receive a first periodic electrical signal having a first frequency, the first periodic electrical signal amplitude modulating the first light source to generate first amplitude modulated light, the first light source to transmit the first amplitude modulated light into biological tissue of a person at a transmission rate of at least 0.1 light transmissions per second;

a second light source configured to generate light having a second different wavelength, the second light source coupled to receive a second periodic electrical signal having a second different frequency, the second periodic electrical signal amplitude modulating the second light source to generate second amplitude modulated light, the second light source to transmit the second amplitude modulated light into the biological tissue of the person at a rate of at least 0.1 light transmissions per second; and

a light receiver configured to receive light from the biological tissue, the received light indicative of a combination of the first amplitude modulated light and the second amplitude modulated light having passed into and out of the biological tissue, the light receiver adapted to provide an electronic transceiver output signal indicative of at least one characteristic of the received light; and

a processing/storage circuit, comprising;

a first electronic signal source to generate the first periodic electrical signal;

a second electronic signal source to generate the second periodic electrical signal;

an amplitude demodulator configured to amplitude demodulate the transceiver output signal to provide a first demodulated signal representative of a first characteristic of the received light and to provide a second demodulated signal representative of a second different characteristic of the received light;

a signal processor coupled to said amplitude demodulator and adapted to process the first demodulated signal and the second demodulated signal to generate a processed signal, wherein the processed signal includes signal samples having a sample rate of at least 0.1 samples per second;

and

a storage device coupled to said signal processor and adapted to store at least four hours of the processed signal as a stored-processed signal, wherein the stored-processed signal has a stored signal duration sufficient to detect an intermittent medical condition of the person having an occurrence period of at least four hours.

2. The electro-optical monitoring system of claim 1, wherein said light transceiver includes at least four light sources for providing at least two different light wavelengths and at least two light receivers.

3. The electro-optical monitoring system of claim 1, wherein said signal processor includes at least two of:

a physiology measurement processor adapted to measure at least one of a heart rate, a respiration rate, a Mayer wave, a heart beat interval, a respiration interval, or a Mayer wave period of the person in response to the transceiver output signal;

a concentration measurement processor adapted to measure a concentration of at least one of oxyhemoglobin, deoxyhemoglobin, water, cytochrome, lipid, or a fluorescent molecule of the person in response to the transceiver output signal;

an oxygenation measurement processor adapted to measure a tissue oxygenation of the person in response to the transceiver output signal;

a blood volume measurement processor adapted to measure a blood volume of the person in response to the transceiver output signal;

a scattering measurement processor adapted to measure a scattering characteristic of the person in response to the transceiver output signal;

a molecule property measurement processor adapted to measure the change in at least one of a concentration, a lifetime, or a quantum yield of a fluorochrome molecule;

a drug processor adapted to measure at least one of a pharmacodynamic characteristic or a pharmacokinetic characteristic of a drug;

a sudden infant death syndrome detection processor adapted to detect a drop in oxygenation level of the person in response to the transceiver output signal;

a seizure detection processor adapted to detect a seizure of the person in response to the transceiver output signal;

a vasomotor symptom detection processor adapted to detect a vasomotor symptom of the person in response to the transceiver output signal;

a dizzy spell detection processor adapted to detect a dizzy spell of the person in response to the transceiver output signal;

an ischemia detection processor adapted to detect ischemia of the person in response to the transceiver output signal;

a stroke recovery detection processor adapted to characterize a stroke recovery of the person in response to the transceiver output signal;

a hemorrhage detection processor adapted to detect a hemorrhage of the person in response to the transceiver output signal;

a heart condition detection processor adapted to detect a heart condition of the person in response to the transceiver output signal;

a hallucination episode detection processor adapted to detect characteristic brain activity associated with a hallucination of the person in response to the transceiver output signal;

or

a density change processor adapted to detect a density change in the biological tissue in response to the transceiver output signal.

4. The electro-optical monitoring system of claim 1, wherein said storage device comprises a data transfer/marking software module adapted to store at least one of a time tag or a detection tag with the stored processed data, wherein the time tag is stored in response to at least one of an event detection by said signal processor or a manual indication by the person, and the detection tag is stored in response to the detection by said signal processor.

5. The electro-optical monitoring system of claim 1, wherein said storage device comprises a data compression software module adapted to compress the processed signal.

6. The electro-optical monitoring system of claim 1, wherein said storage device comprises:

a recirculating buffer memory coupled to said signal processor; and

a capture memory coupled to the recirculating buffer memory, wherein the contents of the recirculating buffer memory are transferred to the capture memory in response to at least one of an event detection by said signal processor or a manual indication.

7. The electro-optical monitoring system of claim 1, wherein the processing/storage circuit further comprises an event input device coupled to said storage device and adapted to receive a manual indication from the person that a symptom associated with a medical condition is occurring, wherein a time tag is stored to the stored data in response to the manual indication.

8. The electro-optical monitoring system of claim 1, wherein further comprising a reference sensor adapted to sense a characteristic of at least one of the person or said light transceiver and to provide a reference signal indicative of the characteristic, and wherein the signal processor is adapted to process the transceiver output signal and the reference signal to provide the processed signal.

9. The electro-optical monitoring system of claim 8, wherein the reference sensor comprises a motion sensor, the characteristic comprises a motion, and the reference signal comprises a motion signal.

10. The electro-optical monitoring system of claim 1, wherein said light transceiver has an adhesive surface such that said light transceiver can be directly adhesively coupled to the person.

11. The electro-optical monitoring system of claim 1, further comprising an external computing platform coupled to and apart from the light transceiver or the processing/storage circuit, which is coupled to receive at least one of the transceiver output signal, the processed signal, or the stored processed signal.

12. The electro-optical monitoring system of claim 11, wherein the external computing platform is further coupled to receive at least one of an event detection signal from said signal processor or a reference signal indicative of a characteristic of at least one of the person or said light transceiver.

13. The electro-optical monitoring system of claim 11, wherein the external computing platform includes at least two of:

a physiology measurement processor adapted to measure at least one of a heart rate, a respiration rate, a Mayer wave, a heart beat interval, a respiration interval, or a Mayer wave period of the person in response to the transceiver output signal;

a concentration measurement processor adapted to measure a concentration of at least one of oxyhemoglobin, deoxyhemoglobin, water, cytochrome, lipid, or a fluorescent molecule of the person in response to the transceiver output signal;

an oxygenation measurement processor adapted to measure a tissue oxygenation of the person in response to the transceiver output signal;

a blood volume measurement processor adapted to measure a blood volume of the person in response to the transceiver output signal;

a scattering measurement processor adapted to measure a scattering characteristic of the person in response to the transceiver output signal;

a molecule property measurement processor adapted to measure the change in at least one of a concentration, a lifetime, or a quantum yield of a fluorochrome molecule;

a drug processor adapted to measure at least one of a pharmacodynamic characteristic or a pharmacokinetic characteristic of a drug in response to the transceiver output signal;

a sudden infant death syndrome detection processor adapted to detect a drop in oxygenation level of the person in response to the transceiver output signal;

a seizure detection processor adapted to detect a seizure of the person in response to the transceiver output signal;

a vasomotor symptom detection processor adapted to detect a vasomotor symptom of the person in response to the transceiver output signal;

a dizzy spell detection processor adapted to detect a dizzy spell of the person in response to the transceiver output signal;

an ischemia detection processor adapted to detect ischemia of the person in response to the transceiver output signal;

a stroke recovery detection processor adapted to characterize a stroke recovery of the person in response to the transceiver output signal;

a hemorrhage detection processor adapted to detect a hemorrhage of the person in response to the transceiver output signal;

a heart condition detection processor adapted to detect a heart condition of the person in response to the transceiver output signal;

a hallucination episode detection processor adapted to detect characteristic brain activity associated with a hallucination of the person in response to the transceiver output signal;

or

a density change processor adapted to detect a density change in the biological tissue in response to the transceiver output signal.

14. The electro-optical monitoring system of claim 1, wherein the signal processor comprises:

an artifact removal processor configured to remove an artifact from the transceiver output signal, wherein the artifact is a result of movement of facial muscles of the patient.

15. The electro-optical monitoring system of claim 1, wherein the light transceiver and the processing/storage circuit are contained in respective structures, each structure having a respective selected size, a respective selected shape, and a respective selected weight, each selected to be wearable by the person under ambulatory conditions.

16. The electro-optical monitoring system of claim 1, wherein the light transceiver comprises at least two light receivers, each light receiver adapted to provide a respective electronic transceiver output signal, wherein the processing/storage circuit comprises a plurality of amplitude demodulators, each amplitude demodulator configured to amplitude demodulate one of the transceiver output signals.

17. The electro-optical monitoring system of claim 16, wherein the light transceiver is operable to vary the amplitude of each of the amplitude modulated lights in two periodic binary amplitude states, one of the states having zero amplitude.

18. The electro-optical monitoring system of claim 1, wherein said signal processor comprises:

a concentration measurement processor adapted to measure a concentration of at least one of oxyhemoglobin, deoxyhemoglobin, water, cytochrome, lipid, or a fluorescent molecule of the person in response to the transceiver output signal.

19. The electro-optical monitoring system of claim 1, wherein said signal processor comprises:

a physiology measurement processor adapted to measure at least one of a heart rate, a respiration rate, a Mayer wave, a heart beat interval, a respiration interval, or a Mayer wave period of the person in response to the transceiver output signal.

20. The electro-optical monitoring system of claim 1, wherein the signal processor comprises a concentration measurement processor to use the first and second demodulated signals to determine a concentration of oxyhemoglobin, a concentration of deoxyhemoglobin, and a concentration of total hemoglobin, wherein the processed signal is generated in accordance with the determined concentration of oxyhemoglobin, the determined concentration of deoxyhemoglobin, and the determined concentration of total hemoglobin.

21. A method of monitoring a person under ambulatory conditions, comprising:

generating a first periodic electrical signal having a first frequency;

generating a second periodic electrical signal having a second different frequency;

amplitude modulating a first light source in response to the first periodic electrical signal to generate first amplitude modulated light, the first light source configured to generate light having a first wavelength;

modulating a second light source in response to the second periodic electrical signal to generate a second amplitude modulated light, the second light source configured to generate light having a second different wavelength;

transmitting the first amplitude modulated light into biological tissue of the person at a light transmission rate of at least 0.1 transmissions per second;

transmitting the second amplitude modulated light into the biological tissue of the person at a light transmission rate of at least 0.1 transmissions per second;

receiving light from the biological tissue, the received light indicative of a combination of the first amplitude modulated light and the second amplitude modulated light having passed into and out of the biological tissue;

generating an electronic transceiver output signal indicative of a characteristic of the received light;

amplitude demodulating the transceiver output signal to provide a first demodulated signal representative of a first characteristic of the received light and to provide a second demodulated signal representative of a second different characteristic of the received light;

processing the first demodulated signal and the second demodulated signal to provide a processed signal wherein the processed signal includes signal samples having a sample rate of at least 0.1 samples per second; and

storing at least four hours of the processed signal as a stored-processed signal, wherein the stored-processed signal has a stored signal duration sufficient to detect an intermittent medical condition of the person having an occurrence period of at least four hours.

22. The method of claim 21, wherein said light transceiver includes at least four light sources for providing at least two different light wavelengths and at least two light receivers.

23. The method of claim 21, wherein the processing includes at least two of:

measuring physiology parameter of the person in response to the transceiver output signal;

measuring a concentration of a molecule in the body of the person in response to the transceiver output signal;

measuring a tissue oxygenation of the person in response to the transceiver output signal;

measuring a blood volume of the person in response to the transceiver output signal;

measuring a scattering of a tissue of the person in response to the transceiver output signal;

measuring at least one of a concentration, a lifetime, or a quantum yield of a fluorochrome molecule in response to the transceiver output signal;

measuring at least one of a pharmacodynamic characteristic or a pharmacokinetic characteristic of a drug in response to the transceiver output signal;

detecting a sudden infant death syndrome of the person in response to the transceiver output signal;

detecting a vasomotor symptom of the person in response to the transceiver output signal;

detecting a dizzy spell of the person in response to the transceiver output signal;

detecting an ischemia of the person in response to the transceiver output signal;

characterizing a stroke recovery of the person in response to the transceiver output signal;

detecting a hemorrhage of the person in response to the transceiver output signal;

detecting a heart condition of the person in response to the transceiver output signal;

detecting a hallucinogenic episode of the person in response to the transceiver output signal;

or

detecting a density change in the biological tissue in response to the transceiver output signal.

24. The method of claim 21, wherein said storage device comprises a data transfer/marking software module adapted to store at least one of a time tag or a detection tag to the stored processed data, wherein the time tag is stored in response to at least one of an event detection by said signal processor or a manual indication, and the detection tag is stored in response to the detection by said signal processor.

25. The method of claim 21, wherein said storage device comprises a data compression software module adapted to compress the processed signal.

26. The method of claim 21, wherein the storing comprises:

storing the processed signal in a recirculating buffer memory; and

transferring contents of the recirculating buffer memory to a capture memory, wherein the contents of the recirculating buffer memory are transferred to the capture memory in response to at least one of an event detection by said signal processor or a manual indication.

27. The method of claim 21, further comprising receiving a manual indication from the person that a symptom associated with a medical condition is occurring, wherein a time tag is stored to the stored data in response to the manual indication.

28. The method of claim 21, further comprising:

sensing a characteristic of at least one of the person or said light transceiver to provide a reference signal indicative of the characteristic; and

processing the transceiver output signal and the reference signal to provide the processed signal.

29. The method of claim 28, wherein the characteristic comprises a motion and the reference signal comprises a motion signal.

30. The method of claim 21, wherein the transmitting light and the receiving light include adhesively coupling a light transceiver to the person.

31. The method of claim 21, wherein the method further comprises:

receiving at least one of the transceiver output signal, the processed signal, or the stored processed signal with an external computing platform; and

processing that least one of the transceiver output signal, the processed signal, or the stored processed signal with the external computing platform.

32. The method of claim 31, wherein the processing with the external computing platform includes at least two of:

measuring physiology parameter of the person in response to the transceiver output signal;

measuring a concentration of a molecule in the body of the person in response to the transceiver output signal;

measuring a tissue oxygenation of the person in response to the transceiver output signal;

measuring a blood volume of the person in response to the transceiver output signal;

measuring a scattering of a tissue of the person in response to the transceiver output signal;

measuring at least one of a concentration, a lifetime, or a quantum yield of a fluorochrome molecule in response to the transceiver output signal;

measuring at least one of a pharmacodynamic characteristic or a pharmacokinetic characteristic of a drug in response to the transceiver output signal;

detecting a sudden infant death syndrome of the person in response to the transceiver output signal;

detecting a vasomotor symptom of the person in response to the transceiver output signal;

detecting a dizzy spell of the person in response to the transceiver output signal;

detecting an ischemia of the person in response to the transceiver output signal;

characterizing a stroke recovery of the person in response to the transceiver output signal;

detecting a hemorrhage of the person in response to the transceiver output signal;

detecting a heart condition of the person in response to the transceiver output signal;

detecting a hallucinogenic episode of the person in response to the transceiver output signal;

or

detecting a density change in the biological tissue in response to the transceiver output signal.

33. The method of claim 21, wherein the processing comprises:

removing an artifact from the transceiver output signal, wherein the artifact is a result of movement of facial muscles of the patient.

34. The method of claim 21, wherein the amplitude modulated light comprises two periodic binary amplitude states, one of the states having zero amplitude.

35. The method of claim 21, wherein the processing comprises:

measuring a concentration of at least one of oxyhemoglobin, deoxyhemoglobin, water, cytochrome, lipid, or a fluorescent molecule of the person in response to the transceiver output signal.

36. The method of claim 21, wherein the processing comprises:

measuring physiology parameter of the person in response to the transceiver output signal, wherein the physiology parameter comprises at least one of a heart rate, a respiration rate, a Mayer wave, a heart beat interval, a respiration interval, or a Mayer wave period of the person in response to the transceiver output signal.

37. The method of claim 21, wherein the processing comprises determining, from the first and second demodulated signals, a concentration of oxyhemoglobin, a concentration of deoxyhemoglobin, and a concentration of total hemoglobin, wherein the processed signal is generated in accordance with the determined concentration of oxyhemoglobin, the determined concentration of deoxyhemoglobin, and the determined concentration of total hemoglobin.