Reliability of different electromyographic normalization methods for pelvic floor muscles assessment

Area of Science:

• Physiology
• Biomechanics
• Medical Engineering

Background:

• Electromyography (EMG) normalization is essential for accurate physiological signal interpretation.
• Pelvic floor muscle (PFM) dysfunction affects a significant portion of the population, necessitating reliable assessment methods.
• Standardized EMG normalization protocols are vital for reproducible research and clinical evaluation of PFM function.

Purpose of the Study:

• To assess and compare the test-retest reliability of various normalization methods for PFM electromyography (EMG).
• To identify the most reliable normalization techniques for PFM-EMG data in healthy nulliparous women.
• To provide evidence-based recommendations for PFM-EMG data processing in research and clinical settings.

Main Methods:

• Thirty healthy nulliparous women participated in two EMG testing sessions separated by seven days.
• Vaginal probe in situ recorded PFM EMG signals during maximal voluntary contraction (MVC) and three daily activities (coughing, Valsalva, abdominal contraction).
• Intraclass correlation coefficients (ICC), SEM, %SEM, and MDC were calculated to evaluate reliability.

Main Results:

• Test-retest reliability (ICC) for normalization methods ranged from 0.61 to 0.95.
• Highest reliability was observed for mean RMS of abdominal contraction and peak RMS of PFM-MVC.
• Normalization using PFM-MVC RMS yielded the lowest SEM and MDC values, indicating superior precision.

Conclusions:

• Normalization of PFM-EMG using peak RMS of PFM-MVC or mean/peak RMS of abdominal contraction demonstrates excellent reliability.
• These recommended normalization methods are suitable for studies evaluating PFM function in young women.
• Establishing reliable EMG normalization enhances the validity and comparability of PFM research.