Devices and methods for monitoring physiological information relating to sleep with an implantable device

• US 8,538,514 B2
• Filed: 01/02/2013
• Issued: 09/17/2013
• Est. Priority Date: 02/09/2007
• Status: Active Grant

• Current Assignee: Neuropace Inc.
• Original Assignee: Neuropace Inc.
• Inventors: Sun, Felice, Pless, Benjamin D., Gibb, Barbara
• Primary Examiner(s): DIETRICH, JOSEPH M
• Application Number:
  US13/733,055
• Publication Number:
  US 20130123584A1
• Time in Patent Office: 258 Days
• Field of Search: 600/544, 600/545
• US Class Current: 600/544
• CPC Class Codes: A61B 5/01 Measuring temperature of body parts ; Diagnostic temperature sensing, e.g. for malignant or inflamed tissue clinical contact thermometers G01K13/20
• 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 5/02438 with portable devices, e.g. worn by the patient
• CPC Class Codes: A61B 5/026 Measuring blood flow A61B3/1233, A61B3/1241 take precedence
• CPC Class Codes: A61B 5/11 Measuring movement of the entire body or parts thereof, e.g. head or hand tremor, mobility of a limb for measuring pulse A61B5/02 ;A61B5/1038 takes precedence; motion detection to correct for motion artifacts in physiological signals A61B5/721
• CPC Class Codes: A61B 5/1118 Determining activity level
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/291 for electroencephalography [EEG]
• CPC Class Codes: A61B 5/293 Invasive
• CPC Class Codes: A61B 5/374 Detecting the frequency distribution of signals, e.g. detecting delta, theta, alpha, beta or gamma waves
• CPC Class Codes: A61B 5/4812 Detecting sleep stages or cycles
• CPC Class Codes: A61B 5/4815 Sleep quality
• CPC Class Codes: A61B 5/686 Permanently implanted devices, e.g. pacemakers, other stimulators, biochips A61B5/6861 takes precedence
• CPC Class Codes: A61N 1/36082 Cognitive or psychiatric applications, e.g. dementia or Alzheimer's disease
• CPC Class Codes: A61N 1/36135 using physiological parameters

Abstract

Described here are implantable devices and methods for monitoring physiological information relating to sleep. The implantable devices are generally designed to include at least one sensor for sensing physiological information, a processor for processing the physiological information using low computational power to detect a sleep stage, and a battery. The detected sleep stage information may then be used to indicate sleep quality, identify or monitor a medical condition, or guide treatment thereof.

Claims

1. An active implantable medical device for monitoring physiological information relating to sleep comprising:

at least one sensor configured to sense physiological information; and

a processor coupled to the at least one sensor and configured to process the physiological information to detect at least one sleep state or stage, the processor;

configured to detect a plurality of half waves in the sensed physiological information;

wherein each detected half wave is characterized by a half wave amplitude and a half wave duration;

configured to sort each detected half wave into one of a plurality of bins in a histogram based on whether each half wave amplitude falls between a predetermined minimum amplitude and a predetermined maximum amplitude and whether each half wave duration falls between a predetermined minimum duration and a predetermined maximum duration;

configured to associate at least some of the histogram bins with a unique frequency band;

configured with a histogram counter to keep track of a time interval over which the detected half waves are sorted; and

configured to determine whether the sensed physiological information is representative of a sleep state based on the density of detected half wave in the one or more unique frequency band histogram bins.

2. The active implantable medical device of claim 1 wherein the unique frequency bands include a delta frequency band, a theta frequency band, and an alpha frequency band.

3. The active implantable medical device of claim 1 wherein the sleep state includes stage 1 sleep, stage 2 sleep, stage 3 sleep and stage 4 sleep.

4. The active implantable medical device of claim 1 wherein the unique frequency bands include one or more of a delta frequency band, a theta frequency band, and an alpha frequency band, and the processor is further configured to determine an absolute quantity of detected half waves, if any, for each of the unique frequency bands to determine whether the sensed physiological information is representative of a sleep state.

5. The active implantable medical device of claim 1 wherein the unique frequency bands include one or more of a delta frequency band, a theta frequency band, and an alpha frequency band, and the processor is further configured to determine a ratio of detected half waves in a first unique frequency band histogram bin, if any, to the detected half waves in at least a second unique frequency histogram bin, if any, to determine whether the sensed physiological information is representative of a sleep state.

6. The active implantable medical device of claim 1 wherein the physiological information comprises one or more of information corresponding to electrical activity of cardiac tissue, electrical activity of neural tissue, blood oxygen saturation, partial physiological pressure of oxygen within blood, core temperature, head movement, cerebral metabolic rate, and cerebral blood flow.

7. The active implantable medical device of claim 1, further comprising:

at least two sensors configured to sense physiological information.

8. The active implantable medical device of claim 7 wherein the at least two sensors sense the same type of physiological information.

9. The active implantable medical device of claim 7 wherein the at least two sensors sense a different type of physiological information.

10. The active implantable medical device of claim 1 wherein the processor is further configured so that the histogram counter provides a measure of an average power in each unique frequency band over the time interval.

11. The active implantable medical device of claim 10 wherein the processor is further configured to determine whether the sensed physiological information is representative of a sleep state based on the average power in each unique frequency band over the time interval.

12. The active implantable medical device of claim 1 wherein the processor is further configured to detect a line length with which the sensed physiological information is characterized over the time interval and to determine whether the sensed physiological information is representative of a sleep state based on the detected line length.

13. The active implantable medical device of claim 1 wherein the processor is further configured to detect an area with which the sensed physiological information is characterized over the time interval and to determine whether the sensed physiological information is representative of a sleep state based on the detected area.