Reliability of different electromyographic normalization methods for pelvic floor muscles assessment.

Abstract

To evaluate the reliability of different methods to normalize pelvic floor muscles (PFM) electromyography (EMG). Thirty nulliparous women (23.9 ± 3.2 years), free from PFM dysfunction, completed two test sessions 7 days apart. For EMG normalization, signals were acquired during four different tasks using a vaginal probe in situ: PFM maximal voluntary contraction (MVC) and three daily activities with increased intra-abdominal pressure (coughing, Valsalva maneuver, and abdominal contraction). The intraclass correlation coefficients (ICC), standard error of measurement (SEM), relative standard error of measurement (%SEM), and minimal detectable change (MDC) were calculated for each variable. ICC values for test-retest reliability of normalization methods ranged from 0.61 to 0.95. The highest values were obtained for mean root mean square (RMS) of the abdominal contraction and peak RMS of PFM-MVC. Normalization using RMS of PFM-MVC showed the lowest values of SEM and MDC. The normalization of EMG data is considered a fundamental part of EMG investigations. These findings suggest that the normalization of PFM-EMG by either peak RMS of PFM-MVC or mean and peak RMS of abdominal contraction has excellent reliability and it can be applied in studies involving the evaluation of young women.