SLEEP MONITORING USING A PHOTOPLETHYSMOGRAPH

• US 20070213620A1
• Filed: 05/17/2007
• Published: 09/13/2007
• Est. Priority Date: 11/22/2004
• Status: Active Grant

• Current Assignee: Widemed Technologies Ltd.
• Original Assignee: Widemed Ltd.
• Inventors: Reisfeld, Daniel
• Granted Patent: US 7,674,230 B2
• Time in Patent Office: Days
• US Class Current: 600/484
• CPC Class Codes: A61B 5/08 Detecting, measuring or recording devices for evaluating the respiratory organs A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/082 Evaluation by breath analysis, e.g. determination of the chemical composition of exhaled breath A61B5/083, A61B5/091 take precedence
• CPC Class Codes: A61B 5/1135 by monitoring thoracic expansion
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]
• CPC Class Codes: A61B 5/4809 Sleep detection, i.e. determining whether a subject is asleep or not
• CPC Class Codes: A61B 5/4812 Detecting sleep stages or cycles
• CPC Class Codes: A61B 5/4815 Sleep quality
• CPC Class Codes: A61B 5/681 Wristwatch-type devices
• CPC Class Codes: A61B 5/6826 Finger
• CPC Class Codes: A61B 5/6838 Clamps or clips
• CPC Class Codes: A61B 5/7207 of noise induced by motion artifacts
• CPC Class Codes: A61B 5/7232 involving compression of the physiological signal, e.g. to extend the signal recording period
• CPC Class Codes: A61B 5/7264 Classification of physiological signals or data, e.g. using neural networks, statistical classifiers, expert systems or fuzzy systems neural networks per se G06N3/00; expert systems per se G06N5/00
• CPC Class Codes: A61B 5/7267 involving training the classification device
• CPC Class Codes: G16H 50/20 for computer-aided diagnosis, e.g. based on medical expert systems

Abstract

A method for diagnosis includes receiving from a sensor coupled to a body of a sleeping patient a photoplethysmograph signal. The photoplethysmograph signal is processed independently of any other physiological measurements in order to identify sleep stages of the patient.

Claims

1. A method for diagnosis, comprising:

receiving from a sensor coupled to a body of a sleeping patient a photoplethysmograph signal;

processing the photoplethysmograph signal independently of any other physiological measurements in order to identify sleep stages of the patient.

2. The method according to claim 1, and comprising processing the photoplethysmograph signal in order to measure a vasomodulation in the body.

3. The method according to claim 1, and comprising processing the photoplethysmograph signal in order to measure a heart rate of the patient.

4. The method according to claim 1, and comprising processing the photoplethysmograph signal in order to detect an artifact that is characteristic of motion of the patient.

5. A method for diagnosis, comprising:

receiving a signal associated with blood oxygen saturation of a patient during sleep;

processing the signal to detect occurrences of a pattern of Cheyne-Stokes breathing;

processing the signal to identify sleep stages of the patient; and

analyzing occurrences of the pattern relative to the identified sleep stages so as to determine a distribution of the Cheyne-Stokes breathing per sleep stage.

6. Apparatus for diagnosis, comprising:

a sensor, which is configured to be coupled to a body of a sleeping patient and to output a photoplethysmograph signal; and

a processor, which is coupled to process the photoplethysmograph signal independently of any other physiological measurements in order to identify sleep stages of the patient.

7. The apparatus according to claim 6, wherein the processor is configured to process the photoplethysmograph signal in order to measure a vasomodulation in the body.

8. The apparatus according to claim 6, wherein the processor is configured to process the photoplethysmograph signal in order to measure a heart rate of the patient.

9. The apparatus according to claim 6, wherein the processor is configured to process the photoplethysmograph signal in order to detect an artifact that is characteristic of motion of the patient.

10. Apparatus for diagnosis, comprising:

a sensor, which is configured to output a signal associated with blood oxygen saturation of a patient during sleep; and

a processor, which is coupled to process the signal to detect occurrences of a pattern of Cheyne-Stokes breathing and to identify sleep stages of the patient, and to analyze occurrences of the pattern relative to the identified sleep stages so as to determine a distribution of the Cheyne-Stokes breathing per sleep stage.

11. A computer software product, comprising a computer-readable medium in which program instructions are stored, which instructions, when read by a computer, cause the computer to receive a photoplethysmograph signal from a body of a sleeping patient, and to process the photoplethysmograph signal independently of any other physiological measurements in order to identify sleep stages of the patient.

12. The product according to claim 11, wherein the instructions cause the computer to process the photoplethysmograph signal in order to measure a vasomodulation in the body.

13. The product according to claim 11, wherein the instructions cause the computer to process the photoplethysmograph signal in order to measure a heart rate of the patient.

14. The product according to claim 11, wherein the instructions cause the computer to process the photoplethysmograph signal in order to detect an artifact that is characteristic of motion of the patient.

15. A computer software product, comprising a computer-readable medium in which program instructions are stored, which instructions, when read by a computer, cause the computer to receive a signal associated with blood oxygen saturation of a patient during sleep, and to process the signal to detect occurrences of a pattern of Cheyne-Stokes breathing and to identify sleep stages of the patient, and to analyze occurrences of the pattern relative to the identified sleep stages so as to determine a distribution of the Cheyne-Stokes breathing per sleep stage.

16. Apparatus for monitoring a patient, comprising:

a plethysmographic sensor, which is configured to fit over a finger of the patient and to output a signal associated with blood oxygen saturation of the patient; and

a control unit, which is configured to be fastened to a forearm of the patient and is coupled to receive the signal from the plethysmographic sensor, and which comprises;

a memory;

a signal processor, which is coupled to digitize and process the signal so as to generate data indicative of a pattern of breathing by the patient and to store the data in the memory;

an interface, which is configured to be coupled to an external processor for upload of the data from the memory to the external processor; and

a power source, which is coupled to provide electrical power to the signal processor and the sensor so as to enable collection of the data while the interface is disconnected from the external processor.

17. The apparatus according to claim 16, wherein the plethysmographic sensor is configured as a ring, which fits over the finger.

18. The apparatus according to claim 16, wherein the control unit is configured to be fastened around a wrist of the patient.

19. The apparatus according to claim 16, wherein the control unit comprises an actigraph sensor, for sensing movement of the patient.

20. The apparatus according to claim 16, wherein the power source is rechargeable, and wherein the interface comprises a charging circuit for recharging the power source using electrical power received via the interface while the interface is coupled to the external processor.

21. The apparatus according to claim 16, wherein the signal processor is configured to process the signal so as to detect episodes of periodic breathing.