Correlation of Digital Palpation and Transabdominal Ultrasound for Assessment of Pelvic Floor Muscle Contraction

Pelvic floor muscle (PFM) dysfunction has been commonly associated with urinary disorders and lumbo-pelvic pain. Transabdominal (TA) ultrasound is currently used by physical therapists to assess PFM function. Controversy exists regarding the correlation between TA ultrasound measurement and vaginal palpation for assessment of PFM contraction, and this relationship has not yet been examined concurrently during the same contraction. The purpose of this study was to determine the correlation of digital palpation and TA ultrasound to assess PFM contraction when recorded 1) simultaneous to digital palpation during one contraction and 2) following digital palpation testing in another contraction. A descriptive correlational design was used to describe the relationship between variables. A total of 19 women (both asymptomatic women and those with incontinence or lumbo-pelvic pain) participated in the study. The modified Oxford scale was used to grade PFM contraction in digital palpation testing. The amount of bladder base movement on ultrasound was measured and considered as an indicator of PFM activity. Two trials were performed for TA ultrasound measurement: 1) simultaneous to digital palpation during one contraction, and 2) following digital palpation testing in another contraction. Spearman's correlation coefficient was used for analysis. There was a significant correlation between digital palpation and TA ultrasound for PFM assessment when measured simultaneously in one contraction (rho=0.62, p=0.01) and separately in a different contraction (rho=0.52, p=0.02), with a stronger correlation found in simultaneous testing. In conclusion, digital palpation and TA ultrasound measurement are significantly correlated and measure comparable parameters in evaluation of PFM contraction.