Abdominal SEMG Feedback for Diaphragmatic Breathing: A Methodological Note

Many psychophysiological disorders are associated with breathing dysregulation such as shallow, rapid or irregular breathing, predominantly in the chest, increased sighing or, breath-holding patterns triggered as a defensive reaction to an actual or perceived stressor. This defensive, anxious breathing reaction usually includes a concomitant tightening of the lower abdomen and the pelvic floor. When respiratory strain gauges alone are used to measure breathing without also measuring lower abdominal muscles related to breathing, many clients may appear to breathe diaphragmatically, yet they may still not expand or relax muscles of the lower abdominal wall and/or, the pelvic floor. For example, lower abdominal muscles that affect breathing may remain contracted because of a previous abdominal injury (e.g., hernia repair, cesarean or appendectomy) or pelvic floor discomfort (e.g., vaginal infections or difficulty during childbirth). As compared to measuring respiration with a strain gauge and/ or with trapezius/scalene SEMG sensor, this paper describes a methodology for recording muscle activity from the transverse abdominis SEMG as a non-invasive technique to monitor the lower abdominal wall during respiration. During inhalation as the abdominal wall expands and relaxes, the transverse abdominal SEMG decreases, particularly at the end of the exhalation when the abdominal wall contracts and the abdominal circumference decreases and the SEMG slightly increases. For patients with pelvic floor pain, this methodology may be used as a surrogate marker for pelvic floor tension. SEMG can be recorded either from the right or left transverse abdominis or, with wide placement of electrodes from the right and left transverse abdominis muscles. Discussed is a methodology of electrode placement over the transverse abdominis muscle. For example, the electrodes should be placed midway between the crest of the iliac (iliac crest) and acetabulum. The participant is asked to loosen material around the waist (e.g. beltline), fold the clothing down on the side where the electrode is placed. Even in adipose individuals, the transverse abdominis SEMG activity can usually be recorded when placed on a boney prominence. In addition, the SEMG signal from the contraction of the diaphragm can be observed as an artifact because the electrode locations (e.g. iliac crest vs. diaphragm) are far enough apart. If the wide electrode placement is used, an EKG artifact may be observed, however t