Pelvic floor muscle reflex activity during coughing - an exploratory and reliability study

Psychometric evaluation and cross-cultural adaptation of the Australian Pelvic Floor Questionnaire (APFQ-IR) in Iranian reproductive age women

Pelvic floor disorders (PFDs), as a silent alert, is one of the pervasive debilitating health concerns among women all over the world, such that in developed countries, one in four women, suffers from PFDs. Validity and reliability of the Australian Pelvic Floor Questionnaire (APFQ) has not been determined in Iran, so to determine APFQ's psychometric characteristics, we decided to conduct this study on women of reproductive age in Tabriz city, Iran. This methodological cross-sectional study was intended to determine the psychometric properties of the Persian version of the APFQ-IR in 5 steps including "translation process, content validity, face validity, construct validity (exploratory and confirmatory factor analyses and examination of ceiling and floor effects) and reliability" on 400 reproductive age women referring to health centers in Tabriz city, Iran, with cluster random sampling method in the period between May 2022 to September 2022. The translation process was done based on two approaches, Dual panel, and Beaton et al.'s five steps. Then, in order to evaluate content validity, face validity, and construct validity, 10 instrument and PFDs experts, 10 women from the target group investigated the instrument's items, and 400 eligible women completed the instrument. Finally, to determine the reliability, two internal consistency methods, (Cronbach's alpha and McDonald's omega) and test-retest method (ICC) were used. In the present study, content validity assessment of APFQ-IR, showed a good level of validity (CVR = 0.96, CVI = 0.94). To assess construct validity, exploratory factor analysis results on 36 items, led to the identification of 4 factors including bladder function, bowel function, prolapse symptom and sexual function, which explained 45.53% of the cumulative variance and indicated the sufficiency of the sample size (Kaiser-Meyer-Olkin = 0.750). Implementing confirmatory factor analysis, (RMSEA = 0.08, SRMR = 0.08, TLI = 0.90, CFI = 0.93, χ2/df = 3.52) confirmed the model fit indices. Finally the internal consistency and reliability was high for the entire instrument (Cronbach's alpha = 0.85; McDonald's omega (95% CI) = 0.85 (0.83-0.87) and Intraclass Correlation Coefficient (95% CI) = 0.88 (0.74-0.94)). The Persian version of the APFQ-IR, has a good validity and reliability and has acceptable psychometric properties, thus can be used both for research purposes and for clinical evaluation of pelvic floor disorders symptoms in health centers.

Neutral posture education during cough can reduce urine leakage in women with cough-related stress urinary incontinence

BACKGROUND

Current literature highlights the difficulty in identifying an optimal educational technique for maintaining continence during cough.

OBJECTIVE

To characterize the effects of an educational intervention focusing on neutral posture during cough in women with cough-induced urinary incontinence (UI).

METHODS

This interventional study design included women with cough-induced UI. We recorded PFMs surface electromyographic (sEMG) peak activity, and assessed symptoms and quality of life (QoL) 6 weeks after the intervention. The effect of the experimental situation was estimated using a linear mixed model, sEMG measurements during coughing were indexed to each situation and adjusted to the resting value at, and a moderation analysis was used.

RESULTS/FINDINGS

Eighteen participants were included. The measurement situations (control versus experimental) did not have a statistically significant impact on sEMG peak activity during coughing: mean effect [95% CI] 3.42 [-1.28; 7.66]. Six weeks post-intervention, participants reported statistically significant decrease in urinary symptoms (P=0.0246) and significant improvement in QoL (P=0.00776). This was also particularly marked on the dimension related to effort activities (P=0.00162).

CONCLUSION

This study suggests that a brief educational intervention focusing on neutral posture during cough, without voluntary pre-contraction of the PFMs, has no clinically significant influence on sEMG peak activity of the PFMs in women with cough-induced UI. However, this intervention can lead to a significant improvement in urinary symptoms and QoL at 6 weeks. These improvements seem to be independent of electromyographic PFMs peak activity recorded during cough. As such, our preliminary results pave the way for future research.

LEVEL OF EVIDENCE

NP4.

Translation and measurement properties of the pelvic floor distress inventory-short form (PFDI-20) in Iranian reproductive age women

BACKGROUND

Every year, millions of women worldwide suffer in silence from pelvic floor disorders (PFDs) as an annoying health problem. Despite the high prevalence rate and negative effects of PFDs on the quality of life, the validity and reliability of pelvic floor distress inventory-short form (PFDI-20) has not been confirmed for Iranian women of reproductive age. Hence, this study aimed to determine measurement properties of PFDI-20 among women of reproductive age in Tabriz, Iran.

METHODS

The current study was cross-sectional research that selected 400 women of reproductive age referring to health centers in Tabriz City, by using cluster random sampling from May 2022 to September 2022. Measurement properties of the Persian version of PFDI-20 were determined and evaluated through five steps, including content and face validity within two quantitative and qualitative parts, structural validity by using exploratory factor analysis (EFA) and confirmatory factor analysis (CFA), and reliability testing through internal consistency, test-retest reliability, and measurement error. Moreover, ceiling and floor effects were investigated.

RESULTS

In this research, CVI (content validity index) and CVR (content validity ratio) of PFDI-20 equaled 0.94 and 0.97, respectively. In addition, the EFA process was applied to 20 items and derived the structure of three factors, which explained 58.15% of the total variance. In CFA phase, values of fit indicators (RMSEA = 0.07, SRMR = 0.07, TLI = 0.97, CFI = 0.99, x2/df = 3.19) confirmed the model validity. To determine reliability, Cronbach's alpha = 0.84; McDonald's omega (95% CI) = 0.84 (0.82 to 0.87) and Intraclass Correlation Coefficient (95% CI) = 0.98 (0.97 to 0.99) were obtained. Also, the SEM was 2.64, and the SDC indicating the smallest individual change was 8.91. Regarding the inventory feasibility, the ceiling effect was not observed in total value and subscales, while the floor effect in the total score of PFDI-20 equaled 24.0. The latter rate equaled 45.8, 38.3, and 50.8 for subscales POPDI-6, CRADI-8, and UDI-6, respectively.

CONCLUSIONS

Persian version of PFDI-20 is a valid and reliable scale used to evaluate PFDs in Iranian women of reproductive age. Healthcare professionals can use this scale to screen PFDs, and researchers can consider it a reliable tool for their studies.

Multifunctional Evaluation Technology for Diagnosing Malfunctions of Regional Pelvic Floor Muscles Based on Stretchable Electrode Array Probe

The pelvic floor dysfunction (PFD) has become a serious public health problem. Accurate diagnosis of regional pelvic floor muscle (PFM) malfunctions is vitally important for the prevention and treatment of PFD. However, there is a lack of reliable diagnostic devices to evaluate and diagnose regional PFM abnormality. In this work, we developed a multifunctional evaluation technology (MET) based on a novel airbag-type stretchable electrode array probe (ASEA) for the diagnosis of malfunctions of regional PFM. The inflatable ASEA has specifically distributed 32 electrodes along the muscles, and is able to adapt to different human bodies for tight contact with the muscles. These allow synchronous collection of high-quality multi-channel surface electromyography (MC-sEMG) signals, and then are used to diagnose regional PFM malfunctions and evaluate inter-regional correlation. Clinical trial was conducted on 15 postpartum stress urinary incontinence (PSUI) patients and 15 matched asymptomatic women. Results showed that SUI patients responded slowly to the command and have symptoms of muscle strength degeneration. The results were consistent with the relevant clinical manifestations, and proved the reliability of MET for multifunctional PFM evaluation. Furthermore, the MET can diagnose malfunctions of regional PFM, which is inaccessible with existing technology. The results also showed that the dysfunction of PSUI patients is mainly located in iliococcygeus, pubococcygeus, and urethral sphincter regions, and there is a weak correlation between these specific regions and nearby regions. In conclusion, MET provides a point-of-care diagnostic method for abnormal function of regional PFM, which has a potential for the targeted point-to-point electrical stimulation treatment and PFD pathology research.

Involuntary reflexive pelvic floor muscle training in addition to standard training versus standard training alone for women with stress urinary incontinence: a randomized controlled trial

Introduction and hypothesis

Although involuntary reflexive pelvic floor muscle contractions seem crucial during stress urinary incontinence-provoking situations, hitherto existing guidelines feature voluntary pelvic floor muscle training only. Two pelvic floor muscle protocols were compared regarding their effect on stress urinary incontinence in women: one focusing on standard physiotherapy with voluntary pelvic floor muscle training, the other additionally including involuntary reflexive pelvic floor muscle training.

Methods

This study was designed as a triple-blind prospective randomized controlled trial with women suffering from stress urinary incontinence with two physiotherapy intervention groups (control group: standard physiotherapy, n = 48, experimental group: standard physiotherapy plus involuntary reflexive pelvic floor muscle training triggered by whole-body movements such as jumps n = 48). Both interventions lasted 16 weeks (9 personal physiotherapy consultations and 78 home training sessions). Group differences and development over time were analyzed concerning the primary outcome International Consultation on Incontinence Modular Questionnaire Urinary Incontinence short form (ICIQ-UIsf) by mixed effect regression models.

Results

The ICIQ-UIsf score decreased significantly over time for both groups by about 3 points from about 10 to about 7 points with no group differences at any point in time.

Discussion

This trial did not find any additional benefit for stress urinary incontinence by adding involuntary reflexive pelvic floor muscle training to standard training. Both training protocols showed similar clinically relevant improvements; however, there was still moderate incontinence after interventions. Future studies should test and apply pelvic floor muscle function-oriented training methods for pelvic floor muscle hypertrophy, intramuscular coordination, and power, which are more in line with conventional skeletal muscle training, i.e., performed with higher intensities and workout.

An assessment of techniques and practices used to elevate intra-abdominal pressure when assessing pelvic floor dysfunction

AIMS

To determine terminology and methods for raising intra-abdominal pressure (IAP) currently used by clinicians to assess pelvic floor dysfunction (PFD) and to measure the effect of these maneuvers on IAP.

METHODS

Three-hundred questionnaires were distributed at two scientific meetings in the United Kingdom to determine methods clinicians used to raise IAP and their perceptions of these methods. Twenty healthy volunteers were also recruited to measure the effect of two methods of raising IAP: Valsalva maneuver (VM) and bear down maneuver (BDM). IAP pressure was measured with rectal catheters connected to pressure sensors. The IAP was measured during each maneuver in both standing and supine positions.

RESULTS

Maneuvers used in practice were cough (79%), BDM (60%), and VM (38%). 44% of clinicians felt patients found it difficult to raise their IAP. There was uncertainty among clinicians as to which method was the most effective in raising IAP and whether the different methods produced the same rise in IAP. On testing IAP in 20 healthy volunteers, median (interquartile range) IAP generated during BDM; 101 (59.1) cmH₂ O was significantly higher than that generated during VM; 80.3 (43.6) cmH₂ O (p < .0001).

CONCLUSION

Clinicians varied widely in the maneuvers they used to raise patients' IAP to test for PFD and there was uncertainty about the maneuvers' effect on IAP. In healthy volunteers, BDM produced significantly higher IAP than VM. We recommend standardization of terminology and techniques used to raise IAP when assessing PFD, to ensure consistency of diagnosis and assessment of treatment outcomes.

Reliability of different electromyographic normalization methods for pelvic floor muscles assessment

AIMS

To evaluate the reliability of different methods to normalize pelvic floor muscles (PFM) electromyography (EMG).

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Electromyography of pelvic floor muscles with true differential versus faux differential electrode configuration

INTRODUCTION AND HYPOTHESIS

In pelvic floor muscle (PFM) electromyography (EMG) two different bipolar configurations are applied: "true differential" configuration (TD) measures neuromuscular activity with two ipsilateral electrodes, whereas "faux differential" configuration (FD) has two electrodes placed on each side of the PFMs. The aim of the study was to determine possible differences and the relationship between both configurations.

METHODS

A secondary data analysis of 28 continent (CON) and 22 stress urinary incontinent (SUI) women was performed. Surface EMG was measured using a vaginal probe during maximal voluntary (MVC) and 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).

RESULTS

Of a total of 62 comparisons of EMG parameters of MVC and FVC, only one comparison showed significant differences between the two configurations (CON group, FVC_4peak TD versus FD, p = 0.015). R(0) were high in both groups for all MVC and FVC variables (R(0) ≥ 0.989). SPM detected 3 out of 28 comparisons with short (0.124-0.404 s) significant supra-threshold clusters (p < 0.025).

CONCLUSIONS

The findings suggest that TD and FD might measure neuromuscular activity almost the same. Very high cross-correlation coefficients and a very limited number of significant results from EMG parameters, as well as SPM, suggest that in the measured sample the choice of TD or FD might remain practically irrelevant. To gain further insight into the scientific and clinical relevance of choosing either of the electrode configurations, the comparisons should be re-evaluated on a sample with more severe incontinence symptoms.

Task-specific differences in respiration-related activation of deep and superficial pelvic floor muscles

The female pelvic floor muscles (PFM) are arranged in distinct superficial and deep layers that function to support the pelvic/abdominal organs and maintain continence, but with some potential differences in function. Although general recordings of PFM activity show amplitude modulation in conjunction with fluctuation in intra-abdominal pressure such as that associated with respiration, it is unclear whether the activities of the two PFM layers modulate in a similar manner. This study aimed to investigate the activation of the deep and superficial PFM during a range of respiratory tasks in different postures. Twelve women without pelvic floor dysfunction participated. A custom-built surface electromyography (EMG) electrode was used to record the activation of the superficial and deep PFM during quiet breathing, breathing with increased dead space, coughing, and maximal and submaximal inspiratory and expiratory efforts. As breathing demand increased, the deep PFM layer EMG had greater coherence with respiratory airflow at the frequency of respiration than the superficial PFM (P = 0.038). During cough, the superficial PFM activated earlier than the deep PFM in the sitting position (P = 0.043). In contrast, during maximal and submaximal inspiratory and expiratory efforts, the superficial PFM EMG was greater than that for the deep PFM (P = 0.011). These data show that both layers of PFM are activated during both inspiration and expiration, but with a bias to greater activation in expiratory tasks/phases. Activation of the deep and superficial PFM layers differed in most of the respiratory tasks, but there was no consistent bias to one muscle layer. NEW & NOTEWORTHY Although pelvic floor muscles are generally considered as a single entity, deep and superficial layers have different anatomies and biomechanics. Here we show task-specific differences in recruitment between layers during respiratory tasks in women. The deep layer was more tightly modulated with respiration than the superficial layer, but activation of the superficial layer was greater during maximal/submaximal occluded respiratory efforts and earlier during cough. These data highlight tightly coordinated recruitment of discrete pelvic floor muscles for respiration.

Pelvic floor muscle activity during fast voluntary contractions in continent and incontinent women

AIMS

Stress urinary incontinence (SUI) has also been attributed to a lower speed of contraction of the pelvic floor muscles (PFM). Therefore, PFM assessment and training implement fast voluntary contractions (FVC). The purpose of the study was to explore FVC regarding feasibility, on-/offset and rate of activity determination, as well as differences between continent (CON) and stress urinary incontinent (SUI) women.

METHODS

Fifty women were included and examined by means of PFM EMG during rest, maximum voluntary contractions (MVC), and five FVC. MVC-peak activity was used to normalize EMG-data. On-/offset of muscle activity was determined as mean of rectified rest activity plus 1 standard deviation. Linear regression was calculated for rate of activity from onset to peak, peak to offset, and within 200 ms after both onset and peak. Peak activity and time variables related to onset, peak, and offset were calculated.

RESULTS

On-/offsets were evaluable for 234/222 of 250 FVC by a computer-based algorithm, 16/28 on-/offsets had to be determined manually. There was no significant difference between groups (CON/SUI) regarding FVC peak (92.1/99.3 %MVC), time to peak (514.2/525.6 ms), and increase of activity (182.8/182.1 %MVC/s). The SUI group showed a significantly slower activity decrease (-120.7/-74.4 %MVC/s).

CONCLUSIONS

FVC analyses were shown to be feasible. The significant difference observed between the groups did not refer to activity increase but instead to a prolonged relaxation phase in the SUI group. This prompts to reconsider the interpretation of FVC in PFM testing and training.

Increase in intra-abdominal pressure during airway suctioning-induced cough after a successful spontaneous breathing trial is associated with extubation outcome

Background

A patient’s ability to clear secretions and protect the airway with an effective cough is an important part of the pre-extubation evaluation. An increase in intra-abdominal pressure (IAP) is important in generating the flow rate necessary for a cough. This study investigated whether an increase from baseline in IAP during a coughing episode induced by routine pre-extubation airway suctioning is associated with extubation outcome after a successful spontaneous breathing trial (SBT).

Methods

Three hundred thirty-five (335) mechanically ventilated patients who passed an SBT were enrolled. Baseline IAP and peak IAP during successive suctioning-induced coughs were measured with a fluid column connected to a Foley catheter.

Results

Extubation was unsuccessful in 24 patients (7.2%). Unsuccessful extubation was 3.40 times as likely for patients with a delta IAP (ΔIAP) of ≤ 30 cm H₂O than for those with a ΔIAP > 30 cm H₂O, after adjusting for APACHE II score (95% CI, 1.39–8.26; p = .007).

Conclusion

ΔIAP during a coughing episode induced by routine pre-extubation airway suctioning is significantly associated with extubation outcome in patients with a successful SBT.

Trial registration UMIN-CTR Clinical Trial, UMIN000017762. Registered 1 June 2015.