Apparatus and methods for assisting breathing

1. A method of treating a subject comprising: (a) sensing an onset of the subject's expiratory phase of breathing with one or more sensors; and (b) delivering a stimulus to the subject's lower anterior thorax or abdomen during at least part of the expiratory phase of breathing in response to said sensing, said stimulus being delivered by mechanical compression using a device comprising an inflatable compartment and effective to cause a contraction in the subject's abdominal muscle so as to assist the subject with ventilation with the proviso that a stimulus is not delivered while the subject is inhaling.

2. The method of claim 1 , wherein performing the method decreases the subject's end expiratory lung volume (EELV) as compared with the subject's EELV when unassisted.

3. The method of claim 1 , wherein the subject suffers from a disorder that impairs exhalation.

4. The method of claim 1 , wherein the subject suffers from chronic obstructive pulmonary disease (COPD).

5. The method of claim 1 , wherein the subject has an abnormally high EELV in the absence of the stimulus.

6. The method of claim 1 , wherein the subject suffers from dynamic hyperinflation in the absence of the stimulus.

7. The method of claim 1 , wherein step (a) comprises detecting respiratory movement of the subject's thorax or abdomen using inductive plethysmography or a strain guage or both.

8. The method of claim 1 , wherein the sensor is incorporated into an adhesive patch suitable for placement on the subject's skin.

9. The method of claim 1 , wherein the sensing occurs externally to the subject and the stimulus is delivered externally to the subject.

10. The method of claim 1 , wherein the sensor, device, or both are incorporated into a garment or belt.

11. The method of claim 1 , wherein the sensor and the device are incorporated into the same garment or belt.

12. The method of claim 1 , wherein the stimulus is delivered during some but not all respiratory cycles within a session.

13. The method of claim 1 , wherein the method comprises analyzing a subject's breathing pattern or activity level and adjusting one or more stimulus parameters based at least in part on the analysis.

14. An apparatus comprising: (a) one or more sensors suitable for detecting when a subject is exhaling; and (b) a device comprising an inflatable compartment adapted to deliver a stimulus to the subject's thorax or abdomen by mechanical compression of the inflatable compartment during at least part of an expiratory phase of the subject's breathing in response to a signal generated by said one or more sensors, said stimulus effective to cause a contraction in the subject's abdominal muscle, with the proviso that the apparatus does not include a device adapted to deliver a stimulus during inhalation.

15. The apparatus of claim 14 , wherein the one or more sensors are selected from a strain gauge, a respiratory inductive plethysmography sensor, a piezoelectric sensor, and combinations thereof.

16. The apparatus of claim 14 , wherein at least one sensor is incorporated into an adhesive patch suitable for placement on the subject's skin.

17. The apparatus of claim 14 , wherein the apparatus is capable of operating in two or more modes, wherein at least one mode comprises delivering, in response to signals generated by said sensor, tactile stimuli that are sufficient to be felt by the subject.

18. The apparatus of claim 17 , wherein timing of the tactile stimuli is selected so as to prompt the subject to exhale at least a specified volume or for at least a specified time.

19. The apparatus of claim 18 , wherein the apparatus comprises a controller that determines an appropriate stimulus, based at least in part on analyzing the subject's breathing over one or more preceding breathing cycles.

20. A biofeedback method for training a subject to breath more effectively, the method comprising: utilizing the apparatus according to claim 18 .