Pelvic floor muscle activation amplitude at rest, during voluntary contraction, and during Valsalva maneuver—a comparison between those with and without provoked vestibulodynia
Bibliographic record
Abstract
BACKGROUND: The neuromuscular contribution to increased tone of the pelvic floor muscles (PFMs) observed among those with provoked vestibulodynia (PVD) is unclear. AIM: To determine if PFM activity differs between those with provoked PVD and pain free controls, and if the extent of PFM activation at rest or during activities is associated with pain sensitivity at the vulvar vestibule, psychological, and/or psychosexual outcomes. METHODS: This observational case-control study included forty-two volunteers with PVD and 43 controls with no history of vulvar pain. Participants completed a series of questionnaires to evaluate pain, pain catastrophizing, depression, anxiety and stress, and sexual function, then underwent a single laboratory-based assessment to determine their pressure pain threshold at the vulvar vestibule and electromyographic (EMG) signal amplitudes recorded from three PFMs (pubovisceralis, bulbocavernosus, and external anal sphincter). OUTCOMES: EMG signal amplitude recorded at rest, during maximum voluntary contraction (MVC), and during maximal effort Valsalva maneuver, pressure pain threshold at the vulvar vestibule, and patient-reported psychological (stress, anxiety, pain catastrophizing, central sensitization) and psychosexual (sexual function) outcomes. RESULTS: Participants with PVD had higher activation compared to controls in all PFMs studied when at rest and during Valsalva maneuver. There were no group differences in EMG amplitude recorded from the pubovisceralis during MVC (Cohen's d = 0.11), but greater activation was recorded from the bulbocavernosus (d = 0.67) and the external anal sphincter(d = 0.54) among those with PVD. When EMG amplitudes at rest and on Valsalva were normalized to activation during MVC, group differences were no longer evident, except at the pubovisceralis, where tonic EMG amplitude was higher among those with PVD (d = 0.42). While those with PVD had lower vulvar pressure pain thresholds than controls, there were no associations between PFM EMG amplitude and vulvar pain sensitivity nor psychological or psychosexual problems. CLINICAL IMPLICATIONS: Women with PVD demonstrate evidence of PFM overactivity, yet the extent of EMG activation is not associated with vulvar pressure pain sensitivity nor psychological/psychosexual outcomes. Interventions aimed at reducing excitatory neural drive to these muscles may be important for successful intervention. STRENGTHS AND LIMITATIONS: This study includes a robust analysis of PFM EMG. The analysis of multiple outcomes may have increased the risk statistical error, however the results of hypothesis testing were consistent across the three PFMs studied. The findings are generalizable to those with PVD without vaginismus. CONCLUSIONS: Those with PVD demonstrate higher PFM activity in the bulbocavernosus, pubovisceralis, and external anal sphincter muscles at rest, during voluntary contraction (bulbocavernosus and external anal sphincter) and during Valsalva maneuver; yet greater activation amplitude during these tasks is not associated with greater vulvar pressure pain sensitivity nor psychological or psychosexual function.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".