The American Urogynecologic Society/The Society of Gynecologic Surgeons
A comparison of perineometer to brink score for assessment of pelvic floor muscle strength

https://doi.org/10.1016/j.ajog.2004.11.015Get rights and content

Objective

The Brink scale is a commonly used digital assessment of pelvic floor muscle strength. The Peritron perineometer, a compressible vaginal insert that records pressure in centimeters of water, offers an objective method for this evaluation. This study evaluates the inter- and intrarater reliability of perineometry measurements and correlates those values with Brink scores.

Study design

Subjects were prospectively enrolled and underwent pelvic floor muscle strength assessment by 2 examiners each using a perineometer and the Brink scale. Perineometer measurements of maximum pressure, average pressure, and total duration were recorded for 3 consecutive pelvic floor muscle contractions (Kegels). The Brink assessment was performed by placing 2 fingers vaginally during a single Kegel contraction. Brink scores consisted of 3 separate 4-point rating scales for pressure, vertical finger displacement, and duration. The order of the examiners and the 2 assessment methods were randomized, and each examiner was blinded to the results of the other. Pearson and Spearman correlation coefficients were used for analysis as appropriate. Repeated-measures analysis of variance was used to assess intrarater reliability between repeated perineometer measurements.

Results

One hundred women were consecutively enrolled and completed the study. Interrater reliability for the perineometer maximum squeeze pressure (r = 0.88) and baseline resting pressure (r = 0.78) was high. Maximum squeeze pressure correlation was unaffected by the presence or absence of estrogen (r = 0.89 versus r = 0.85), nulliparity versus parity (0.85 versus 0.88), or genital hiatus 4 or greater or less than 4 (r = 0.96 versus r = 0.86). Total Brink score and each individual submeasurement showed good correlations (total: r = 0.68; pressure: r = 0.68; displacement: r = 0.58; duration: r = 0.44). The correlation between maximum squeeze pressure and total Brink score during the first and second exams was good (r = 0.68 versus r = 0.71). For intrarater reliability, there were no significant differences among the 3 maximum squeeze pressures recorded during the first exam (P = .11), but for the second exam, the first squeeze was significantly stronger than the successive 2 (P = .009) attempts.

Conclusion

Perineometer measurements of pelvic floor muscle contractions show very good inter- and intrarater reliability. The Brink total and pressure scores had a slightly lower interrater reliability. Variables such as estrogen status, parity, and genital hiatus did not appear to affect correlation. There was good correlation between the maximum perineometer pressure and the total Brink score, suggesting that these 2 methods of assessment have similar levels of reproducibility. Additionally, the perineometer demonstrated good short-term test-retest reliability.

Section snippets

Material and methods

After institutional review board approval was obtained, 100 women were prospectively enrolled in a sequential fashion. All women seen at the University of North Carolina at Chapel Hill for general gynecologic or pelvic floor complaints were eligible for enrollment. Exclusion criteria included a latex allergy, a genital hiatus or vaginal cavity size inadequate to comfortably accommodate the perineometer insert (28 mm in diameter), a degree of pelvic organ prolapse sufficient to prevent

Results

One hundred women were prospectively enrolled and completed the study. Median age was 48 years (22 to 85) and median parity was 2 (0 to 5). There were 18 nulliparous women (18%) and 82 parous women (82%). Forty-six women (46%) reported being postmenopausal, although 22 were currently using oral or vaginal estrogen replacement on a regular basis (Table I).

Interrater reliability for both perineometer and Brink scores is shown in Table II. The correlations of perineometer maximum squeeze pressure

Comment

Vaginal digital palpation represents the most commonly used method to clinically assess pelvic floor muscle strength. It is both a straightforward and clinically practical means of assessing pelvic floor muscle function because it is inexpensive, minimally invasive, and well tolerated and requires no special equipment.

Data are lacking on both the inter- and intrarater reliability of perineometers. The value of an objective, reproducible, and reliable tool to assess pelvic floor strength lies in

Conclusion

This study assesses the inter- and intrarater reliability of readings obtained from a perineometer measuring pressure in centimeters water. Our data suggest excellent interrater reliability, given the high correlation among numerous measurement parameters between paired examiners. Perineometer readings were also well correlated to Brink scores, currently the most commonly used method for clinical assessment of pelvic floor muscle strength. We found a high degree of correlation between

References (14)

  • A.H. Kegel

    Progressive resistance exercise in the functional restoration of the perineal muscles

    Am J Obstet Gynecol

    (1948)
  • K. Strohbehn et al.

    Magnetic resonance imaging of the levator ani with anatomic correlation

    Obstet Gynecol

    (1996)
  • P.E. Chiarelli

    Incontinence. The pelvic floor function

    Aust Fam Physician

    (1989)
  • C.A. Brink et al.

    A digital test for pelvic muscle strength in older women with urinary incontinence

    Nurs Res

    (1989)
  • K. Bo et al.

    Vaginal palpation of pelvic floor muscle strength: inter-test reproducibility and comparison between palpation and vaginal squeeze pressure

    Acta Obstet Gynecol Scand

    (2001)
  • C.A. Brink et al.

    A digital test for pelvic muscle strength in women with urinary incontinence

    Nurs Res

    (1994)
  • O. Contreras Ortiz et al.

    Dynamic assessment of pelvic floor function in women using the intravaginal device test

    Int Urogynecol J Pelvic Floor Dysfunct

    (1996)
There are more references available in the full text version of this article.

Cited by (86)

  • Pelvic floor muscle strength and the incidence of pelvic floor disorders after vaginal and cesarean delivery

    2020, American Journal of Obstetrics and Gynecology
    Citation Excerpt :

    The average peak pressure (in centimeters of water) and contraction duration (in seconds) were recorded. Our protocol for perineometer measurement is based on that described by Hundley et al.13 Peak pressure was classified into 2 groups (<20 cm H2O and ≥20 cm H2O) based on tertiles (one-third of all participants had a peak pressure of <20 cm H2O). Women reporting a latex allergy were excluded, as the tubing used with this device contains latex.

View all citing articles on Scopus

Presented at the Joint Scientific Meeting of the Society of Gynecologic Surgeons and the American Urogynecologic Society, San Diego, California, July 29-31, 2004.

View full text