ICS 2022: A Pressure Sensor Array Can Be Used To Show Maximal Pelvic Floor Muscle Contraction In Different Postures

(UroToday.com) The perineometer, a balloon pressure-type type device, was first described by Dr. Arnold Kegel in the 1940s and since then has been used extensively to determine ‘the strength’ and ‘function’ of the pelvic floor muscles (PFMs). However, due to the design of these devices, the pressure changes reflect global pressure change within the vagina, making it impossible to discriminate between an increase in abdominal pressure and that induced by the PFMs. This study investigated the Femfit®, an intravaginal biofeedback device, consisting of eight pressure sensors (positioned at 10 mm intervals), that measures the vaginal pressure profile, and detects different vaginal pressure zones, thus enabling discrimination between abdominal and PFM pressures. It can also provide biofeedback on PFM training technique. The study’s aim was to determine if a pressure sensor array is more effective at measuring PFM contractions, and which of the distal sensors measured peak PFM pressure when the person contracts in supine and upright positions.

This is a secondary analysis of a prospective interventional randomized pilot study of women (n=60), with predominately stress urinary incontinence (SUI) with leakage at least 3 times per week over the last 3 months, randomized into two groups; 1) biofeedback group used the Femfit® system to complete the PFM training (device and mobile application) intervention for 12 weeks and 2) non-biofeedback control used the same mobile application and PFM training but did not use a Femfit®. The Femfit® measured pressure generated by the pelvic floor during a voluntary maximal PFM contraction while supine and repeated while upright (3 × 5 second contractions in each position). The device (distal 1 to 6) captured PFM function characteristics, peak PFM pressure (during maximal voluntary PFM contraction) in both supine and upright positions. Multiple distal sensors detected a peak PFM pressure during maximal voluntary PFM contraction.

The vaginal pressure profile changes depend on posture, device placement, anatomical adjustment to an internal device and natural anatomical movement. The array of eight pressure sensors used in this study can accommodate this variation. The authors noted that a global pressure change (measured by a perineometer) would not capture the magnitude of PFM pressure generated during a voluntary PFM contraction, whereas a pressure sensor array can. The authors concluded that there is intra-participant sensor variation when detecting peak PFM pressure across a posture change, and inter-participant variability when comparing PFM contractions in similar and different postures. Overall, the Femfit® pressure sensor array enables users to identify peak PFM pressures and this information can help to determine effective PFM contraction.

Presented by: Laura Pedofsky, Auckland Bioengineering Institute, University of Auckland, New Zealand

Written by: Diane Newman, DNP, CRNP, FAAN, BCB-PMD, Urologic Nurse Practitioner, Adjunct Professor of Urology in Surgery, Senior Research Investigator, Perelman School of Medicine, University of Pennsylvania during the International Continence Society Annual Meeting, September 7-10, 2022, Vienna, Austria.


  1. Cacciari et al (2020) Reliability and validity of intravaginal pressure measurements with a new intravaginal pressure device: The FemFit® Neurourol Urodyn. Jan;39(1):253-260.  doi: 10.1002/nau.24179
  2. Guaderrama NM, Nager CW, Liu J, Pretorius DH, Mittal RK. The vaginal pressure profile. Neurourology and Urodynamics. 2005;24(3):243-7. 2.