Vol. 3, Issue 5 (2018)
Reliability and validity of new instrument measuring pelvic floor muscle squeeze pressure
Author(s): Dr. Shivani Chowdhury Salian PT, Priyal Ved
Abstract: Background and Purpose: Present study was conducted to assess the validity and reliability of a new instrument measuring pelvic floor muscle contraction pressure projected as the strength of pelvic floor muscles (PFM). Perineometers are usually available in foreign markets, which are high in cost and so, it is not commonly used by physiotherapists in India. This perineometer is an Indian version which is indegeniously designed to assess the PFM strength which will be cost effective and easily available in the markets. Objectives: To assess inter and intra reliability and validity of the new instrument measuring PFM contraction pressure. To assess the specificity and sensitivity of the indegeniously designed instrument used for measuring pelvic floor muscle strength. To assess the difference of PFM strength amongst nulliparous, primiparous and multiparous women between the age group of 18-35 years. Methodology: A cross sectional study was conducted in which 120 women comprising nulliparous, primiparous and multiparous asymptomatic women between the age group of 18-35 years were enrolled via convenient sampling (N=120, n=40). Women were evaluated for PFM strength by per-vaginal digital assessment and also by using new instrument measuring pelvic floor muscle contraction pressure. The digital PFM strength was graded using Laycock (Modified Oxford) scale of grading. An indigeniously designed perineometer was used by two investigators to assess the PFM strength in the form of PFM squeeze pressure measured in mm of Hg. Thereafter, the instrument was assessed for the reliability, validity and accuracy in the form of specificity and sensitivity. Results: The mean difference in PFM Perineometer readings for nulliparous and primiparous women recorded by two investigators was 0.32mm Hg, in multiparous women was 0.15mm HG. Difference between inter and intra perineometer readings was statically insignificant at p=0.75, Interclass correlation coefficient (ICC) inter and intra-rater agreement measure shows a value of 0.941 and 0.94 respectively which signifies excellent reliability of the indigenously designed Perineometer. Sensitivity and Specificity was assessed for Grades 2, 3, and 4 of Modified Oxford Scale with respect to the Perineometer readings. The co-ordinated values of Perineometer with Modified Oxford Scale was found to be 23.5mmHG for Grade 2, 28.5mmHG for Grade 3 and 29.5 mmHG for Grade 4 Oxford Scale of PFM strength assessment. Validity was assessed based on the findings of Bland Altman graph and the ROC graphs. The graphical representation in Bland Altman graph suggest that all the observations lie in the range mean difference +/- 1.96 x SD which is in the acceptable range, while the ROC curves confirms the accuracy of the tool. The mean pelvic floor muscle squeeze pressure in nulliparous women was 31.58 mm Hg, primiparous women was 31.25 mm Hg and multiparous women was 26.28 mm Hg. Anova test revealed significant difference between the three parity groups.