Method and System for the Monitoring of Respiratory Acitivity and for the Treatment of Breathing Disorders Such as Sleep Apnea
A method and system for sensing the vagus nerve in order to monitor respiratory activity, treating breathing disorders, such as, for example, sleep apnea and a generic bio-interfacing platform that may be adapted for either open-loop or closed-loop applications.
1 . A method for monitoring the respiratory activity of a subject, comprising the steps of:
recording an electroneurogram signal from the vagus nerve of the subject;
amplifying the electroneurogram signal;
computing an amplitude envelope of the amplified electroneurogram signal;
applying a matched filter to the amplitude envelope; and
computing a time between successive peaks of the filtered amplitude envelope;
wherein the time between successive peaks is indicative of the respiratory activity of the subject.
2 . A method for monitoring the respiratory activity of a subject, comprising the steps of:
recording an electroneurogram signal from the vagus nerve of the subject;
amplifying the electroneurogram signal;
computing an amplitude envelope of the amplified electroneurogram signal;
applying a matched filter to the amplitude envelope; and
computing a time between successive peaks of the filtered amplitude envelope;
wherein the time between successive peaks is indicative of the respiratory activity of the subject.
3 . A method according to claim 1 , further comprising the step of displaying the time between successive peaks.
4 . A method according to claim 1 , wherein the electroneurogram signal is recorded from a portion of the vagus nerve located between the head and the pulmonary branches of the subject.
5 . A method according to claim 1 , wherein the electroneurogram signal is recorded from a portion of the vagus nerve located in the neck of the subject.
6 . A method according to claim 1 , wherein the amplitude envelope computing step includes includes the application of a low-pass filter.
7 . A method according to claim 1 , wherein the amplitude envelope computing step includes applying a filter selected from a group consisting of a matched filter, a simple averaging filter and a finite-impulse-response filter.
8 . A method according to claim 1 , wherein the amplitude envelope computing step includes includes applying a rectification and bin integration algorithm to the amplified electroneurogram signal.
9 . A method according to claim 8 , wherein the amplitude envelope computing step includes further includes applying a moving average filter to the amplified electroneurogram signal after the application of the rectification and bin integration algorithm.
10 . A method according to claim 9 , wherein the amplitude envelope computing step includes further includes optimizing the result of the moving average filter using the solution to the Wiener-Hopf equation.
11 . A method according to claim 1 , further comprising the steps of:
comparing the time between successive peaks with a sleep apnea event threshold;
reporting a sleep apnea event should the compared time between successive peaks be greater than the sleep apnea event threshold.
12 . A method according to claim 11 , wherein the apnea event threshold is set individually for each subject according to the normal respiration rate of the subject during sleep.
13 . A method according to claim 11 , wherein the apnea event threshold is set to about 10 seconds.
14 . A method according to claim 11 , wherein the reporting step includes triggering an airway opening stimulation.
15 . A method according to claim 14 , wherein the airway opening stimulation includes stimulation of the genioglossus muscle.
16 . A method according to claim 14 , wherein the airway opening stimulation includes stimulation of the hypoglossal nerve.
17 . A method according to claim 14 , wherein stimulation is applied to the phrenic nerve in order to maintain respiration.
18 . A method for maintaining airway patency of a subject through stimulation, comprising the steps of:
recording an electroneurogram signal from the vagus nerve of the subject;
amplifying the electroneurogram signal;
computing an amplitude envelope of the amplified electroneurogram signal;
applying a matched filter to the amplitude envelope;
detecting a positive peak in the filtered amplitude envelope;
waiting for a duration equal to a first offset value;
triggering an airway opening stimulation;
detecting a negative peak in the filtered amplitude envelope;
waiting for a duration equal to a second offset value; and
stopping the airway opening stimulation.
19 . A method according to claim 18 , wherein the first and second offset values are computed from a previously obtained respiratory rhythm.
20 . A method according to claim 18 , wherein the electroneurogram signal is recorded from a portion of the vagus nerve located between the head and the pulmonary branches of the subject.
21 . A method according to claim 18 , wherein the electroneurogram signal is recorded from a portion of the vagus nerve located in the neck of the subject.
22 . A method according to claim 18 , wherein the airway opening stimulation includes stimulation of the genioglossus muscle.
23 . A method according to claim 18 , wherein the airway opening stimulation includes stimulation of the hypoglossal nerve.
24 . A method according to claim 18 , wherein the amplitude envelope computing step includes the application of a low-pass filter.
25 . A method according to claim 18 , wherein the amplitude envelope computing step includes applying a filter selected from a group consisting of a matched filter, a simple averaging filter and a finite-impulse-response filter.
26 . A method according to claim 18 , wherein the amplitude envelope computing step includes applying a rectification and bin integration algorithm to the amplified electroneurogram signal.
27 . A method according to claim 26 , wherein the amplitude envelope computing step further includes applying a moving average filter to the amplified electroneurogram signal after the application of the rectification and bin integration algorithm.
28 . A method according to claim 27 , wherein the amplitude envelope computing step further includes optimizing the result of the moving average filter using the solution to the Wiener-Hopf equation.
29 . A method for detecting hypopnea during the respiratory activity of a subject, comprising the steps of:
recording an electroneurogram signal from the vagus nerve of the subject;
amplifying the electroneurogram signal;
computing an amplitude envelope of the amplified electroneurogram signal;
applying a matched filter to the amplitude envelope;
computing a deviation of the signal resulting from the application of the matched filter to the amplitude envelope from a predictor, the predictor being based on previously obtained respiration activity;
reporting a hypopnea event should the deviation be greater than a hypopnea event threshold.
30 . A method according to claim 29 , wherein the deviation is an increase in amplitude.
31 . A method according to claim 29 , wherein the deviation is an increase in respiratory rhythm.
32 . A method according to claim 29 , wherein the electroneurogram signal is recorded from a portion of the vagus nerve located between the head and the pulmonary branches of the subject.
33 . A method according to claim 29 , wherein the electroneurogram signal is recorded from a portion of the vagus nerve located in the neck of the subject.
34 . A system for monitoring the respiratory activity of a subject, comprising:
an electrode for detecting an electroneurogram signal from the vagus nerve of the subject;
a transceiver;
an implantable control unit operatively connected to to the electrode and the transceiver, the implantable control unit including:
a signal amplifier for amplifying the electroneurogram signal;
a rectifier for rectifying the amplified electroneurogram signal;
a monitoring and detection module for:
computing an amplitude envelope of the amplified electroneurogram signal;
applying a matched filter to the amplitude envelope; and
computing a time between successive peaks from filtered amplitude envelope; and
transmitting the computed time between successive peaks using the transceiver;
wherein the time between successive peaks is indicative of the respiratory activity of the subject.
35 . A system according to claim 34 , wherein the electrode includes a cuff electrode assembly adapted to surround part of the vagus nerve of the subject.
36 . A system according to claim 35 , wherein the cuff electrode assembly is provided with multiple chambers having electrodes therein.
37 . A system according to claim 34 , further comprising an external control unit including a transceiver for communication with the transceiver of the implantable control unit, the external control unit allowing interaction with the implantable control unit.
38 . A system according to claim 37 , wherein the external and implantable control units further include respective power interfaces for transferring power from the external control unit to the implantable control unit.
39 . A system according to claim 34 , wherein the implantable control unit further includes a power source.
40 . A system according to claim 34 , wherein the algorithm further includes:
comparing the time between successive peaks with a sleep apnea event threshold;
transmitting the occurrence of a sleep apnea event using the transceiver should the compared time between successive peaks be greater than the sleep apnea event threshold.
41 . A system according to claim 40 , wherein the apnea event threshold is set individually for each subject according to the normal respiration rate of the subject during sleep.
42 . A system according to claim 40 , further comprising a second electrode and wherein the algorithm further includes triggering an airway opening stimulation using the second electrode.
43 . A system according to claim 42 , wherein the second electrode is configured to be positioned in contact with the genioglossus muscle.
44 . A system according to claim 42 , wherein the second electrode is configured to be positioned in contact with the genioglossal nerve.
45 . A system according to claim 42 , wherein the second electrode is configured to be positioned in contact with the phrenic nerve.
46 . A system for maintaining airway patency of a subject through stimulation, comprising:
a first electrode for recording an electroneurogram signal from the vagus nerve of the subject;
a second electrode;
a transceiver;
an implantable control unit operatively connected to the first and second electrodes and to the transceiver, the implantable control unit including:
a signal amplifier for amplifying the electroneurogram signal;
a rectifier for rectifying the amplified electroneurogram signal;
a monitoring and detection module for:
computing an amplitude envelope of the amplified electroneurogram signal;
applying a matched filter to the amplitude envelope;
detecting a positive peak in the filtered amplitude envelope;
waiting for a duration equal to a first offset value;
triggering an airway opening stimulation using the second electrode;
detecting a negative peak in the filtered amplitude envelope;
waiting for a duration equal to a second offset value; and
stopping the airway opening stimulation.
47 . A system according to claim 46 , wherein the first and second offset values are determined from an observed respiratory rhythm.
48 . A system according to claim 46 , wherein the airway opening stimulation includes stimulation of the genioglossus muscle.
49 . A system according to claim 46 , wherein the airway opening stimulation includes stimulation of the hypoglossal nerve.
50 . A system according to claim 46 , wherein the first electrode includes a cuff electrode assembly adapted to surround part of the vagus nerve of the subject.
51 . A system according to claim 50 , wherein the cuff electrode assembly is provided with multiple chambers having electrodes therein.
52 . A system according to claim 46 , further comprising an external control unit including a transceiver for communicating with the transceiver of the implantable control unit, the external control unit allowing interaction with the implantable control unit.
53 . A system according to claim 52 , wherein the external and implantable control units further include respective power interfaces for transferring power from the external control unit to the implantable control unit.
54 . A system according to claim 46 , wherein the implantable control unit further includes a power source.
55 . A system for detecting hypopnea during the respiratory activity of a subject, comprising:
an electrode for recording an electroneurogram signal from the vagus nerve of the subject;
a transceiver;
an implantable control unit operatively connected to the electrode and the transceiver, the implantable control unit including:
a signal amplifier for amplifying the electroneurogram signal;
a rectifier for rectifying the amplified electroneurogram signal;
a monitoring and detection module for:
computing an amplitude envelope of the amplified electroneurogram signal;
applying a matched filter to the amplitude envelope;
computing a deviation of the signal resulting from the application of the matched filter to the amplitude envelope from a predictor, the predictor being based on previously obtained respiration activity;
transmitting the occurrence of a hypopnea event using the transceiver should the deviation be greater than a hypopnea event threshold.
56 . A system according to claim 55 , wherein the deviation is an increase in amplitude.
57 . A system according to claim 55 , wherein the deviation is an increase in respiratory rhythm.
58 . A system according to claim 55 , wherein the electrode includes a cuff electrode assembly adapted to surround part of the vagus nerve of the subject.
59 . A system according to claim 58 , wherein the cuff electrode assembly is provided with multiple chambers having electrodes therein.
60 . A system according to claim 55 , further comprising an external control unit including a transceiver for communicating with the transceiver of the implantable control unit, the external control unit allowing interaction with the implantable control unit.
61 . A system according to claim 60 , wherein the external and implantable control units further include respective power interfaces for transferring power from the external control unit to the implantable control unit.
62 . A system according to claim 55 , wherein the implantable control unit further includes a power source.
63 . A method for monitoring the respiratory activity of a subject, comprising the steps of:
recording an electroneurogram signal from the vagus nerve of the subject;
amplifying the electroneurogram signal;
extracting respiratory activity information from the amplified signal; and
providing the extracted respiratory activity information.
64 . A system for monitoring the respiratory activity of a subject, comprising:
an electrode for detecting an electroneurogram signal from the vagus nerve of the subject;
a transceiver;
an implantable control unit operatively connected to to the electrode and the transceiver, the implantable control unit including:
a signal amplifier for amplifying the electroneurogram signal;
a rectifier for rectifying the amplified electroneurogram signal;
a monitoring and detection module for:
extracting respiratory activity information from the amplified signal; and
transmitting the extracted respiratory activity information using the transceiver.