Home-based system and method for monitoring sleep state and assessing cardiorespiratory risk

• US 5,902,250 A
• Filed: 03/31/1997
• Issued: 05/11/1999
• Est. Priority Date: 03/31/1997
• Status: Expired due to Fees

• Current Assignee: Beth Israel Deaconess Medical Center, Inc. (Beth Israel Lahey Health, Inc.)
• Original Assignee: Beth Israel Deaconess Medical Center, Inc. (Beth Israel Lahey Health, Inc.), President and Fellows of Harvard College (Harvard Corporation)
• Inventors: Lovett, Eric G., Hobson, J. Allan, Pace-Schott, Edward F., Verrier, Richard L.
• Primary Examiner(s): Kamm, William E.
• Assistant Examiner(s): EVANISKO, GEORGE ROBERT
• Application Number:
  US08/828,633
• Time in Patent Office: 771 Days
• Field of Search: 600/481, 600/483, 600/509, 600/513, 600/515, 600/484, 600/529
• US Class Current: 600/515
• 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 5/024 Detecting, measuring or recording pulse rate or heart rate A61B5/0205, A61B5/021 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 5/1103 Detecting eye twinkling
• CPC Class Codes: A61B 5/4818 Sleep apnoea
• CPC Class Codes: A61B 5/6814 Head
• CPC Class Codes: A61B 5/6821 Eye
• CPC Class Codes: G16H 40/63 for local operation
• CPC Class Codes: G16Z 99/00 Subject matter not provided for in other main groups of this subclass

Abstract

A method for determining the sleep state of a patient includes monitoring heart rate variability of the patient and determining sleep state based on the heart rate variability. The method also may include monitoring the frequency of eyelid movements and making the sleep state determination based also on the frequency of eyelid movements. A method for determining respiratory pattern includes monitoring heart rate variability by receiving heart beat signals and determining respiratory pattern from the strength of the signals. A home-based, wearable, self-contained system determines sleep-state and respiratory pattern, and assesses cardiorespiratory risk, of a patient based on the frequency of eyelid movements, the frequency of head movements, and heart rate variability of the patient.

Claims

1. A method of determining sleep states of a patient comprising the steps of:

monitoring a heart rate of the patient through receipt of heart beat signals;

monitoring a frequency of eyelid movements of the patient through receipt of eyelid signals; and

monitoring a frequency of head movements of the patient through receipt of head signals;

using a single, wearable, self-contained processing system, temporally synchronizing and processing the heart beat signals, eyelid signals and head signals to determine the sleep state of the patient and to assess cardiorespiratory risk.

2. The method claimed in claim 1 wherein step of monitoring the frequency of eyelid movements includes applying an eyelid sensor the eyelid of the patient which eyelid sensor produces an eyelid signal each time the eyelid moves.

3. The method claimed in claim 2 wherein step of monitoring heart rate includes applying at least one heart sensor to a chest wall of the patient, which heart sensor produces a heart beat signal each time the heart beats.

4. A home-based, self-contained, wearable processing system comprising:

an eyelid sensor adapted to be applied to an eyelid of the patient to produce eyelid signals representing eyelid movements;

a head movement sensor adapted to be applied to the head of the patient to produce head signals representing head movements;

at least one heart sensor adapted to be applied to the chest wall of the patient to produce heart beat signals representing heart beats; and

a processor that temporally synchronizes, records and analyzes the eyelid, head and heart beat signals to assess cardiorespiratory risk.

5. The system claimed in claim 4 wherein the processor also determines a sleep state of the patient based on the eyelid, head and heart beat signals.

6. The system claimed in claim 4 wherein the processor also determines a breathing pattern of the patient based on the heart beat signals.

7. The system claimed in claim 4 further including an alarm coupled to the processor, that is triggered to produce an alarm signal when a dangerous cardiorespiratory state is detected.