J Korean Acad Rehabil Med.  2005 Oct;29(5):457-461.

Motor Unit Action Potentials of the Rectus Abdominis Muscle according to Changes of Abdominal Pressure

• Seo JH
• Kim KM
• Ko MH
• Park SH
• Kim NG

Abstract

OBJECTIVE
In current urodynamic studies, rectal catheters can cause erroneous result affecting detrusor pressure, and the catheter itself is not comfortable to the patients. To reduce these problems we investigated the relationship between the motor unit action potentials (MUAP) of rectus abdominis muscle and the abdominal pressure measured by rectal catheter. METHOD: Healthy seven men and three women volunteers (mean age: 49 years) with no neurological abnormality were enrolled. Possible maximal abdominal pressure (Pmax) was attained by Valsalva maneuver for 5 seconds. The MUAPs of the rectus abdominis muscle were recorded with surface electrodes for analysis. These recordings were done on 100, 80, 60, 40, and 20% of Pmax. The parameters of MUAP such as mean frequency, median frequency, turns, mean amplitude, and RMS (root mean square) were measured. RESULTS: Turns, mean amplitude, and RMS were increased in a proportion to the increment of abdominal pressure in all subjects(R=0.840, 0.879, and 0.984, respectively). CONCLUSION: These findings suggested that the surface MUAP of rectus abdominis muscle might be used indirectly for more convenient measurement of the abdominal pressure.

Keyword

Urodynamic study; Abdominal pressure; Rectal catheter; Rectus abdominis muscle; Motor unit action potential

MeSH Terms

Action Potentials*
Catheters
Electrodes
Female
Humans
Male
Rectus Abdominis*
Urodynamics
Valsalva Maneuver
Volunteers