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Ballmer C1, Eichelberger P1, Leitner M1, Moser H1, Luginbuehl H1, Kuhn A2, Radlinger L1
1Bern, University of Applied Sciences, Department of Health Professions, Divison of Physiotherapy, Bern, Switzerland, 2Bern University and University Hospital, Women's Hospital, Urogynaecology, Bern, Switzerland
Background: Assessment of the neuromuscular function of the pelvic floor muscles (PFM) is of great clinical and scientific importance to understand PFM functioning and disorders. Surface electromyography (EMG) is one of the most common methods used. Two different bipolar configurations are currently applied in PFM EMG. "True differential" configuration (TD) has two electrodes on each side of the PFM inside the vagina, measuring the left and right side separately. “Faux differential” configuration (FD) has only one electrode placed on each side of the PFM. It is not yet conclusively determined if the PFM can be considered as a functional entity and can be measured two-sided with FD or must be measured separately for each side with TD.
Purpose: To explore the relevance of using either electrode configuration in continent and incontinent women, this study investigated the differences as well as the relationship of PFM EMG activity measured by TD and FD.
Methods: The research question was answered with an exploratory post-hoc data analysis of a cross-sectional study which examined PFM activity in 28 continent (CON) and 22 slightly stress urinary incontinent (SUI) women. EMG was measured during two maximal voluntary (MVC) and five fast voluntary (FVC) contractions. TD and FD were explored with amplitude- and time-related EMG parameters, cross-correlation coefficients R(0) and statistical parametric mapping (SPM) in both groups of CON and SUI separately.
Results: In a total of 62 possible comparisons of EMG parameters of MVC and FVC only one comparison in the CON group showed significant differences between TD and FD (p = 0.015). Cross-correlation coefficients were very high in both CON and SUI and for all MVC and FVC variables (R(0) ≥ 0.989). SPM did detect three out of 28 comparisons with short (0.124-0.404 sec.) significant supra-threshold clusters (p 0.025).
Conclusion(s): Very high cross-correlation coefficients and limited significant results from EMG parameters together with very short significant supra-threshold clusters from SPM suggest that TD and FD differ only randomly. It can be assumed that in the measured sample the choice of TD or FD remains practically irrelevant. Since the symptoms and muscle weakness of the SUI group were rather slight, the results might not be generalizable to the whole population of SUI women.
Implications: To gain further insights that could be used for the development of new probes, the comparisons should be re-evaluated on a SUI sample with lower PFM Oxford Grading Scores or more severe incontinence.
Keywords: urinary incontinence, vaginal probe, muscle activation
Funding acknowledgements: This work was not supported by funding sources.
Purpose: To explore the relevance of using either electrode configuration in continent and incontinent women, this study investigated the differences as well as the relationship of PFM EMG activity measured by TD and FD.
Methods: The research question was answered with an exploratory post-hoc data analysis of a cross-sectional study which examined PFM activity in 28 continent (CON) and 22 slightly stress urinary incontinent (SUI) women. EMG was measured during two maximal voluntary (MVC) and five fast voluntary (FVC) contractions. TD and FD were explored with amplitude- and time-related EMG parameters, cross-correlation coefficients R(0) and statistical parametric mapping (SPM) in both groups of CON and SUI separately.
Results: In a total of 62 possible comparisons of EMG parameters of MVC and FVC only one comparison in the CON group showed significant differences between TD and FD (p = 0.015). Cross-correlation coefficients were very high in both CON and SUI and for all MVC and FVC variables (R(0) ≥ 0.989). SPM did detect three out of 28 comparisons with short (0.124-0.404 sec.) significant supra-threshold clusters (p 0.025).
Conclusion(s): Very high cross-correlation coefficients and limited significant results from EMG parameters together with very short significant supra-threshold clusters from SPM suggest that TD and FD differ only randomly. It can be assumed that in the measured sample the choice of TD or FD remains practically irrelevant. Since the symptoms and muscle weakness of the SUI group were rather slight, the results might not be generalizable to the whole population of SUI women.
Implications: To gain further insights that could be used for the development of new probes, the comparisons should be re-evaluated on a SUI sample with lower PFM Oxford Grading Scores or more severe incontinence.
Keywords: urinary incontinence, vaginal probe, muscle activation
Funding acknowledgements: This work was not supported by funding sources.
Topic: Women's & men's pelvic health
Ethics approval required: Yes
Institution: Bern University of Applied Siences, Switzerland
Ethics committee: Cantonal Ethics Commitee Bern, Switzerland
Ethics number: KEK-No. 319/14
All authors, affiliations and abstracts have been published as submitted.
