Method and apparatus for closed-loop stimulation of the hypoglossal nerve in human patients to treat obstructive sleep apnea

• US 6,587,725 B1
• Filed: 03/26/2001
• Issued: 07/01/2003
• Est. Priority Date: 07/27/1998
• Status: Expired due to Term

• Current Assignee: Case Western Reserve University
• Original Assignee: Case Western Reserve University
• Inventors: Durand, Dominique, Sahin, Mesut, Haxhiu, Musa A.
• Primary Examiner(s): EVANISKO, GEORGE ROBERT
• Application Number:
  US09/744,640
• Time in Patent Office: 827 Days
• Field of Search: 607/1, 607/2, 607/42, 607/48, 607/58, 607/62, 607/63, 607/116, 607/118, 607/134, 607/148, 128/848, 600/529, 600/538, 600/590, 600/26
• US Class Current: 607/42
• CPC Class Codes: A61N 1/3601 of respiratory organs

Abstract

This invention is a fully implanted functional electrical stimulator (20) apparatus, a method for treatment of obstructive sleep apnea that provides for both reliable detection/prediction or airway occlusion that relieves, and/or prevents same by selective, direct electrical stimulation of the hypoglossal nerve (HG). The method, and apparatus sense hypoglossal nerve electro-neurogram activity for purposes of detecting or predicting obstructive sleep apnea. The sensed hypoglossal nerve activity, itself, is used to trigger functional electrical stimulation of the hypoglossal nerve in order to improve upper airway patency. Further, an improved hypoglossal nerve stimulation electrode (10) interface (IC) is provided that allows for simultaneous hypoglossal nerve activity sensing, and stimulation by eliminating stimulation artifacts that would otherwise trigger further erroneous stimulation.

Claims

1. A method of treating obstructive sleep apnea in a human patient, said method comprising:

monitoring said human patient for at least partial occlusion of upper airways of said patient associated with obstructive sleep apnea by sensing electroneurogram activity of a hypoglossal nerve of the patient; and

,

directly electrically stimulating the hypoglossal nerve of the patient when at least partial occlusion of the upper airways of the patient occurs as indicated by said sensed electroneurogram activity of said hypoglossal nerve.

2. The method of treating obstructive sleep apnea as set forth in claim 1 wherein said step of monitoring said human patient for occlusion of the upper airways comprises:

identifying at least partial occlusion of the upper airways of the patient when said sensed hypoglossal nerve electroneurogram activity rises above a baseline electroneurogram activity level of said hypoglossal nerve by a select amount, said baseline electroneurogram level corresponding to a level of electroneurogram activity of said hypoglossal nerve present when said upper airways of said patient are not at least partially occluded.

3. The method of treating obstructive sleep apnea as set forth in claim 1 further comprising:

amplifying said sensed electroneurogram activity of said hypoglossal nerve to obtain an amplified electroneurogram signal; and

,

using said amplified electroneurogram signal to trigger said direct electrical stimulation of said hypoglossal nerve.

4. The method of treating obstructive sleep apnea as set forth in claim 1 wherein stimulating the hypoglossal nerve of the patient is accomplished with a train of stimulus pulses each having an amplitude of greater than 0.2 mA.

5. The method of treating obstructive sleep apnea as set forth in claim 1 wherein said step of directly electrically stimulating said hypoglossal nerve comprises:

connecting a nerve electrode to said hypoglossal nerve so that said nerve electrode at least partially encircles said hypoglossal nerve; and

passing electrical stimulation pulses between first and second contacts of said nerve electrode through tissue of said hypoglossal nerve.

6. The method of treating obstructive sleep apnea as set forth in claim 5 wherein said step of monitoring said human patient for at least partial occlusion of the upper airways by sensing electroneurogram activity of said hypoglossal nerve comprises:

sensing electroneurogram activity of said hypoglossal nerve with a third contact of said nerve electrode, said third contact arranged relative to said first and second contacts so that a first impedance defined between said first contact and said third contact through said tissue of said hypoglossal nerve is substantially equal to a second impedance defined between said second contact and said third contact through said tissue of said hypoglossal nerve.

7. An apparatus for treatment of obstructive sleep apnea in a human patient, said apparatus comprising:

means for detecting at least partial occlusion of upper airways of said human patient by sensing electroneurogram activity of a hypoglossal nerve of the patient; and

,

means for directly electrically stimulating the hypoglossal nerve of the patient in response to at least partial occlusion of the upper airways of the patient as indicated by said means for detecting at least partial airway occlusion.

8. The apparatus for treatment of obstructive sleep apnea as set forth in claim 7 wherein said means for detecting at least partial airway occlusion detects at least partial occlusion of the upper airways of the patient when said sensed hypoglossal nerve electroneurogram activity rises above a baseline electroneurogram activity level of said hypoglossal nerve by a select amount, said baseline electroneurogram level corresponding to a level of electroneurogram activity of said hypoglossal nerve present when said upper airways of said patient are not at least partially occluded.

9. The apparatus as set forth in claim 7 further comprising:

means for amplifying said sensed electroneurogram activity of said hypoglossal nerve to obtain an amplified electroneurogram signal; and

,

trigger means for receiving said amplified electroneurogram signal and triggering said direct electrical stimulation of said hypoglossal nerve when said amplified signal exceeds a baseline activity level of said signal by a select amount.

10. The apparatus as set forth in claim 7, wherein said means for electrically stimulating the ypoglossal nerve of the patient stimulates the hypoglossal nerve with a train of stimulus pulses each having an amplitude of greater than 0.2 mA.

11. The apparatus as set forth in claim 7 further comprising:

a nerve electrode having two contacts, said electrode adapted to be connected to and at least partially encircling said hypoglossal nerve, wherein said means for electrically stimulating said hypoglossal nerve passes electrical stimulation pulses between said first and second contacts of said nerve electrode through tissue of said hypoglossal nerve.

12. The apparatus as set forth in claim 11 further comprising a third contact on said electrode, wherein said means for detecting at least partial occlusion of said patient'"'"'s airways senses electroneurogram activity of said hypoglossal nerve with said third contact of said nerve electrode, said third contact arranged relative to said first and second contacts so that a first impedance defined between said first contact and said third contact through said tissue of said hypoglossal nerve is substantially equal to a second impedance defined between said second contact and said third contact through said tissue of said hypoglossal nerve.