Detecting sleep

• US 20050222522A1
• Filed: 03/16/2005
• Published: 10/06/2005
• Est. Priority Date: 03/16/2004
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Heruth, Kenneth T., Miesel, Keith A.
• Granted Patent: US 7,775,993 B2
• Time in Patent Office: Days
• US Class Current: 600/587
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/4809 Sleep detection, i.e. determining whether a subject is asleep or not
• CPC Class Codes: A61B 5/686 Permanently implanted devices, e.g. pacemakers, other stimulators, biochips A61B5/6861 takes precedence
• CPC Class Codes: A61M 2005/1726 the body parameters being measured at, or proximate to, the infusion site
• CPC Class Codes: A61M 2230/10 Electroencephalographic signals
• CPC Class Codes: A61M 2230/40 Respiratory characteristics
• CPC Class Codes: A61M 2230/62 Posture
• CPC Class Codes: A61M 2230/63 Motion, e.g. physical activity
• CPC Class Codes: A61M 5/14276 specially adapted for implantation
• CPC Class Codes: A61N 1/36078 Inducing or controlling sleep or relaxation non-implantable stimulator A61M21/00
• CPC Class Codes: A61N 1/36135 using physiological parameters
• CPC Class Codes: G16H 20/30 relating to physical therapies or activities, e.g. physiotherapy, acupressure or exercising
• CPC Class Codes: G16H 40/63 for local operation

Abstract

A system includes one or more sensors and a processor. Each of the sensors generates a signal as a function of at least one physiological parameter of a patient that may discernibly change when the patient is asleep. The processor monitors the physiological parameters, and determines whether the patient is asleep based on the parameters. In some embodiments, the processor determines plurality of sleep metric values, each of which indicates a probability of the patient being asleep, based on each of a plurality of physiological parameters. The processor may average or otherwise combine the plurality of sleep metric values to provide an overall sleep metric value that is compared to a threshold value in order to determine whether the patient is asleep.

Claims

1. A method comprising:

monitoring a plurality of physiological parameters of a patient; and

determining a value of a sleep metric that indicates a probability of the patient being asleep based on the physiological parameters,

wherein the physiological parameters comprise at least one of electrocardiogram morphology, core temperature, or subcutaneous temperature, muscular tone, brain electrical activity, or eye motion.

2. The method of claim 1, wherein determining a value of a sleep metric comprises determining a value for each of a plurality of sleep metrics, each of the values determined based on a respective one of the physiological parameters.

3. The method of claim 2, wherein determining a value of a sleep metric comprises determining a value of an overall sleep metric based on the plurality of sleep metric values.

4. The method of claim 3, wherein determining a value of an overall sleep metric comprises applying a weighting factor to a value of at least one of the plurality of sleep metrics.

5. The method of claim 1, further comprising:

comparing the value of the sleep metric to a threshold value; and

determining whether the patient is asleep based on the comparison.

6. The method of claim 5, further comprising:

comparing the value of the sleep metric to a plurality of thresholds; and

determining a sleep state of the patient based on the comparison.

7. The method of claim 6, wherein determining a sleep state of the patient comprises determining whether the patient is in one of a rapid eye movement (REM) sleep state and a nonrapid eye movement (NREM) sleep state.

8. A medical system comprising:

a plurality of sensors, each of the sensors generating a signal as a function of at least one physiological parameter of a patient; and

a processor that monitors a plurality of physiological parameters of the patient based on the signals output by the sensors, and determines a value of a sleep metric that indicates a probability of the patient being asleep based on the physiological parameters,

wherein the physiological parameters comprise at least one of electrocardiogram morphology, core temperature, or subcutaneous temperature, muscular tone, brain electrical activity, or eye motion.

9. The system of claim 8, wherein the processor determines a value of each of a plurality of sleep metrics, each of the plurality of values determined based on a respective one of the physiological parameters.

10. The system of claim 9, wherein the processor determines a value of an overall sleep metric based the values of the plurality of sleep metrics.

11. The system of claim 10, wherein the processor applies a weighting factor to at least one of values of the plurality of sleep metrics.

12. The system of claim 8, further comprising a memory to store a threshold value, wherein the processor compares the value of the sleep metric to a threshold value and determines whether the patient is asleep based on the comparison.

13. The system of claim 12, wherein the memory stores a plurality of threshold values, and the processor compares the value of the sleep metric to each of the threshold values and determines a sleep state of the patient based on the comparison.

14. The system of claim 13, wherein the processor determines whether the patient is in one of a rapid eye movement (REM) sleep state and a nonrapid eye movement (NREM) sleep state.

15. The system of claim 8, further comprising an implantable medical device that includes the processor.

16. The system of claim 15, wherein the implantable medical device comprises at least one of an implantable neurostimulator or an implantable pump.

17. A system comprising:

means for monitoring a plurality of physiological parameters of a patient; and

means for determining a value of a sleep metric that indicates a probability of the patient being asleep based on the physiological parameters,

wherein the physiological parameters comprise at least one of electrocardiogram morphology, core temperature, or subcutaneous temperature, muscular tone, brain electrical activity, or eye motion.

18. A computer-readable medium comprising instructions that cause a programmable processor to:

monitor a plurality of physiological parameters of a patient; and

determine a value of a sleep metric that indicates a probability of the patient being asleep based on the physiological parameters,

wherein the physiological parameters comprise at least one of electrocardiogram morphology, core temperature, or subcutaneous temperature, muscular tone, brain electrical activity, or eye motion.