The evaluation of bioelectrical activity of pelvic floor muscles depending on probe location: a pilot study

Techniques for Registration of Myoelectric Activity of Women's Pelvic Floor Muscles: A Scoping Review

INTRODUCTION AND HYPOTHESIS

Surface electromyography is commonly applied to measure the electrophysiological activity of the neuromuscular system. However, there is no consensus regarding the best protocol to assess pelvic floor muscles.

METHODS

A scoping literature review was carried out in six databases, using MeSH descriptors. It included studies with electromyographic assessment in adult women presenting or not with pelvic floor dysfunction. The results were presented in categories to contribute to the development of a protocol considering the most used parameters for non-invasive assessment of myoelectric activity of pelvic floor muscles.

RESULTS

A total of 1,074 articles were identified, and 146 studies were selected for analysis. The intravaginal probe was used in 80.8% of the studies, the bipolar sensor with metallic plates placed on both sides of the vagina was the most frequent (71.3%), with a reference electrode positioned on the anterior superior iliac spine (33.5%). The supine position with hip and knee flexed (45.2%) was the most frequent position used. Of the studies, 44.5% normalized the data by maximum voluntary contraction (MVC) whereas 44.5% performed an average of 3 MVCs.

CONCLUSIONS

The most frequently used protocol for the pelvic floor is the bipolar intracavitary probe with metal plates positioned at 3-9 o'clock and introduced distally to the vaginal introitus with the volunteer in the supine position and the hip and knee flexed with the reference placed on the anterior-superior iliac spine.

The influence of one-time biofeedback electromyography session on the firing order in the pelvic floor muscle contraction in pregnant woman–A randomized controlled trial

Many women are initially unable to contract the pelvic floor muscles (PFMs) properly, activating other muscle groups before, or instead of, PFM. Numerous authors have proved that biofeedback can be an ideal tool supporting learning of the PFM contraction. However, there is currently a lack of scientific data on how many biofeedback sessions are necessary in this educational process. In this study we aimed at assessing the effects of one-time electromyography (EMG) biofeedback session on the order in which PFM are activated (so called firing order) during conscious contractions in relation to selected synergistic muscles in pregnant, continent women. A randomized controlled trial was conducted in 90 healthy nulliparous women with uncomplicated pregnancies and without diagnosed urinary incontinence. We divided the participants into a biofeedback group (50) and a control group (40). They were, respectively: 30 ± 4 and 30 ± 4 years old, at their 23 ± 5 or 25 ± 7 week of gestation and presented 23 ± 5 or 24 ± 5 kg/m² BMI value (M + SD). Surface EMG with vaginal probes has been used to assess the PFM firing order in selected tasks: in five 3-s maximal contractions (quick flicks), five 10-s contractions, and in a 60-s contraction (static hold). We used the 1–5 scale, where “1” meant the best score, awarded when PFM was activated first in order. The most important finding of our study is that a single EMG biofeedback substantially improved the PFM contractions in pregnant women. First, when applying one-time biofeedback session, more women maintained correct technique or improved it in the second assessment, compared to the control group (73 vs. 65%). Secondly, using the quantitative and qualitative analysis with the Chi-square McNamara B/C test, in the biofeedback group we observed a statistically significant improvement of PFM firing order in four tasks: in the first quick flicks (p = 0.016), third quick flicks (p = 0.027), fifth quick flicks (p = 0.008), and in the first 10-s contractions (p = 0.046). In the control group we observed better outcome only in one motor task: in the fourth 10-s contraction (p = 0.009). Given the positive effects of a single session of EMG biofeedback on the firing order in the PFM contractions, it should be recommended for pregnant women without urinary incontinence to teach them how to perform PFM exercises correctly.

Exercise Professionals Improve Their Poor Skills in Contracting Pelvic-Floor Muscles: A Randomized Controlled Trial

A quick, well-timed pelvic-floor muscle contraction during physical effort is recommended for active women to prevent urine leakage.

PURPOSE

We address two research questions: how well do future female exercise professionals contract the pelvic-floor muscles, and whether the biofeedback session is necessary to train them to contract pelvic-floor muscles?

METHOD

Participants were 84 nulliparous future exercise professionals (age 23 ± 3 years, mean ± SD), randomly allocated into biofeedback (n = 27), usual-advice (n = 26), and control (no advice, n = 21) groups. Contraction of pelvic-floor muscles on a 4-point scale (1 = incorrect through 4 = correct) was assessed in all groups by surface electromyography (sEMG) with a vaginal probe before and after 6 weeks of intervention.

RESULTS

In pretest, almost one in five participants (17%) could not activate the pelvic floor and less than half of them (45%) presented correct technique. The technique score for the three groups was 3.1 ± 1.1 (mean ± SD). After training, both intervention groups presented better technique score by 0.6 (90% confidence limits ± 0.5) relative to the control group, and two-thirds (65%) of the intervention groups presented the correct technique.

CONCLUSIONS

Future exercise professionals displayed poor skills in contracting pelvic-floor muscles. Both training interventions (with and without biofeedback) were effective for this study group.

High-Low Impact Exercise Program Including Pelvic Floor Muscle Exercises Improves Pelvic Floor Muscle Function in Healthy Pregnant Women - A Randomized Control Trial

Background: Pregnancy and high-impact activity are considered as risk factors for pelvic floor dysfunctions, including urinary incontinence.

Aim: To investigate whether a structured exercise program, including high- and low-impact aerobics and supported by pelvic floor muscle exercises, improves the neuromuscular activity of the pelvic floor and does not reduce the quality of life in terms of urinary incontinence in healthy pregnant women.

Methods: This was a randomized control trial among 97 Caucasian healthy nulliparas in uncomplicated pregnancies (age 30 ± 4 years, 21 ± 5 weeks of gestation; mean ± SD). Women were assessed for pelvic floor muscle functions with surface electromyography (EMG) using vaginal probes and using the Incontinence Impact Questionnaire (IIQ). Only women able to contract pelvic floor muscles and with good quality of life based on IIQ were included for the study. Seventy women in the experimental group took part in a supervised exercise program including high-low impact aerobics and pelvic floor muscle exercises three times a week. Twenty-seven controls did not receive any exercise intervention. After 6 weeks both groups were re-tested with EMG and IIQ. Post- and pre-exercise program changes in each group were analyzed using a repeated-measures ANOVA.

Results: Women in the experimental group improved the neuromuscular activity of the pelvic floor in some motor tasks without any adverse outcomes of the intervention. After the exercise program we observed in the experimental group significantly higher EMG amplitude in the pelvic floor muscles during 3-s contractions (p = 0.014). We also noticed a beneficial trend in the increase of neuromuscular activity during 10- and 60-s contractions, but the changes were not statistically significant. The exercising women substantially improved their abilities for relaxation following 3- and 10-s contractions (p = 0.013 and p < 0.001). In controls, we reported no statistically significant improvement in either of the motor tasks. All study participants maintained good quality of life related to urinary incontinence.

Conclusion: Prenatal exercise programs that include high- and low-impact aerobics and are supported by pelvic floor muscle exercises should be recommended for pregnant women, especially those who are accustomed to higher exercise intensity before pregnancy. Nevertheless, these recommendations can be directed to continent women who can properly contract pelvic floor muscles.

ISRCTN. DOI: 10.1186/ISRCTN92265528: “Pelvic floor muscle training with surface electromyography”, retrospectively registered on the 25th of July, 2016.

Effectiveness of Intra-anal Biofeedback and Electrical Stimulation in the Treatment of Children With Refractory Monosymptomatic Nocturnal Enuresis: A Comparative Randomized Controlled Trial

Purpose

To compare the effects of intra-anal biofeedback (BF) and intra-anal electrical stimulation (ES) on pelvic floor muscles (PFMs) activity, nocturnal bladder capacity, and frequency of wet night episodes in children with refractory primary monosymptomatic nocturnal enuresis (PMNE).

Methods

Ninety children of both sexes aged 8–12 years with refractory PMNE participated in this study. They were randomly assigned to 3 groups of equal number: control group (CON) that underwent behavioral therapy and PFM training, and 2 study groups (BF and ES) that underwent the same program in addition to intra-anal BF training and intra-anal ES, respectively. PFMs activity was assessed using electromyography, nocturnal bladder capacity was evaluated by measuring the first morning voided volume, and a nocturnal enuresis diary was used for documenting wet night episodes before treatment and after 3 months of treatment.

Results

After training, all groups showed statistically significant improvements in all measured outcomes compared to their pretreatment findings. The ES group showed significantly greater improvements in all measured outcomes than the CON and BF groups.

Conclusions

Both intra-anal BF training and ES combined with behavioral therapy and PFMs training were effective in the treatment of PMNE, with intra-anal ES being superior to BF training.

Effects of low- vs high-volume swimming training on pelvic floor muscle activity in women

This study examined the effects of different training loads on pelvic floor muscle (PFM) activity in swimming. Twelve female swimmers were included in this study (23.71±1.44 y.o.; 167±5.89 cm; 62.05±8.89 kg). They took part in an experiment with two different stages of load in swimming training. For the pelvic floor muscle assessment the Glazer Protocol was used. To assess swimming technique, David Pyne’s Stroke Mechanics Test was used. A statistically significant increase in surface electromyography (sEMG) values appeared in the fifth R (rest after contraction) in the quick flick stage of the measurement protocol of PFM at the third measurement time (7.71±4.49 μV) compared to the first measurement time (6.25±4.43 μV) with p≤0.05. Increasing the training load may cause unwanted changes in the level of electrical activity of pelvic floor muscles.

Six-Week Pelvic Floor Muscle Activity (sEMG) Training in Pregnant Women as Prevention of Stress Urinary Incontinence

BACKGROUND Pelvic floor muscle exercises are a widely used and well-established form of stress incontinence treatment, with success rates varying from 21% to 84%, although with a better subjective than objective outcome. MATERIAL AND METHODS "Incontinence Impact Questionnaire" (IIQ), PFM EMG assessment was done at the beginning and after the 6-week training program. RESULTS Statistically significant differences appeared in the BASE and R values. In the symptomatic group (with SUI symptoms), the value of BASE was 3.26 µV, and after training it was 3.95 µV. The R values before and after training were 4.55 µV and 4.25 µV. In the symptomatic group (without SUI symptoms), the value of BASE was 2.88 µV and 3.52 µV and R values were 7.16 µV and 3.92 µV. In the control group, BASE was 3.05 µV and 4.11 µV and R was 7.82 µV and 4.39 µV. CONCLUSIONS The results indicate that a 6-week training process influences PFM EMG activity in pregnant women. During Q, the value of PFM activity after a training session tended to increase in the symptomatic and control groups, but in the symptomatic group it remains practically unchanged. Our results show the probable process of decreasing control of PFM activity during long-lasting contractions in symptomatic and control women. The comparison of BASE before and after training averaged the values of R after five 10-s contractions and showed an increase in the Base and decrease in the R.

Functional assessment of the pelvic floor muscles by electromyography: is there a normalization in data analysis? A systematic review

ABSTRACT This study aims to evaluate the method of analysis of electromyographic data considering the functional assessment of pelvic floor muscles (PFM). We have included in our search strategy the following databases: Medline, PubMed, Cochrane Central Register of Controlled Trials and Cochrane Database of Systematic Reviews, PEDro, and IBECS, considering articles published in the last ten years (2004-2014). The identified articles were independently examined by two evaluators, according to these inclusion criteria: (1) population: female adults; (2) PFM assessment by electromyography (EMG) with vaginal/anal probe; and (3) description of how electromyographic data analysis is performed. The Newcastle-Ottawa Scale (NOS) was used to assess the risk of bias. We identified 508 articles, of which 23 were included in the review. The data showed differences between the collection protocols, and a significant number of studies did not normalize the electromyographic data. Physiotherapists are among the clinicians who most frequently use EMG to evaluate the function and dysfunction of the neuromuscular system. Although some previous studies have provided an overview to guide the evaluator in the assessment, few succeeding studies followed their recommendations.

Crosstalk considerations in studies evaluating pelvic floor muscles using surface electromyography in women: a scoping review

PURPOSE

Surface electromyography (sEMG) using intravaginal probes is of widespread use for assessing pelvic floor muscles (PFM) activity in women. Although considered as a reliable method, its validity has been called into question due to the presence of a phenomenon called crosstalk. Crosstalk is described as the recording of sEMG activity originating from neighboring muscles rather than coming exclusively from the muscles being investigated. The purpose of this review was to provide an overview of existing literature about crosstalk during intravaginal surface electromyographic recordings.

METHODS

A scoping review was performed according to the Arksey and O'Malley framework. An electronic search was conducted on six relevant databases. Additionally, authors were directly contacted to identify grey literature. Data extraction consisted of descriptive numeric analysis as well as thematic analysis, which were conducted by two independent reviewers.

RESULTS

Forty-nine references written by 34 authors coming from 13 different countries constitute the body of evidence of the present review. Eight main themes have been identified through the thematic analysis. The included material varies greatly in terms of methodology, approach to the crosstalk problem and depth of analysis.

CONCLUSIONS

A gap in knowledge affecting the validity of the current sEMG investigation methods was identified. Literature addressing the crosstalk problem is scarce and often flawed. Definitive conclusions are regularly drawn from an insufficient basis of evidence. Further research is, therefore, deeply necessary, although it remains unclear whether this issue can be solved at all with current technology.

Assessment of bioelectrical activity of synergistic muscles during pelvic floor muscles activation in postmenopausal women with and without stress urinary incontinence: a preliminary observational study

OBJECTIVE

Muscles such as adductor magnus (AM), gluteus maximus (GM), rectus abdominis (RA), and abdominal external and internal oblique muscles are considered to play an important role in the treatment of stress urinary incontinence (SUI), and the relationship between contraction of these muscles and pelvic floor muscles (PFM) has been established in previous studies. Synergistic muscle activation intensifies a woman's ability to contract the PFM. In some cases, even for continent women, it is not possible to fully contract their PFM without involving the synergistic muscles. The primary aim of this study was to assess the surface electromyographic activity of synergistic muscles to PFM (SPFM) during resting and functional PFM activation in postmenopausal women with and without SUI.

MATERIALS AND METHODS

This study was a preliminary, prospective, cross-sectional observational study and included volunteers and patients who visited the Department and Clinic of Urology, University Hospital in Wroclaw, Poland. Forty-two patients participated in the study and were screened for eligibility criteria. Thirty participants satisfied the criteria and were categorized into two groups: women with SUI (n=16) and continent women (n=14). The bioelectrical activity of PFM and SPFM (AM, RA, GM) was recorded with a surface electromyographic instrument in a standing position during resting and functional PFM activity.

RESULTS

Bioelectrical activity of RA was significantly higher in the incontinent group than in the continent group. These results concern the RA activity during resting and functional PFM activity. The results for other muscles showed no significant difference in bioelectrical activity between groups.

CONCLUSION

In women with SUI, during the isolated activation of PFM, an increased synergistic activity of RA muscle was observed; however, this activity was not observed in asymptomatic women. This may indicate the important accessory contribution of these muscles in the mechanism of continence.

Impact of different body positions on bioelectrical activity of the pelvic floor muscles in nulliparous continent women

We examined pelvic floor muscles (PFM) activity (%MVC) in twenty nulliparous women by body position during exercise as well as the activation of abdominal muscles and the gluteus maximus during voluntary contractions of the PFMs. Pelvic floor muscle activity was recorded using a vaginal probe during five experimental trials. Activation of transversus abdominis, rectus abdominis, and gluteus maximus during voluntary PFM contractions was also assessed. Significant differences in mean normalized amplitudes of baseline PFM activity were revealed between standing and lying (P < 0.00024) and lying and ball-sitting positions (P < 0.0053). Average peak, average time before peak, and average time after peak did not differ significantly during the voluntary contractions of the PFMs. Baseline PFM activity seemed to depend on the body position and was the highest in standing. Pelvic floor muscles activity during voluntary contractions did not differ by position in continent women. Statistically significant differences between the supine lying and sitting positions were only observed during a sustained 60-second contraction of the PFMs.

Efficacy of physiotherapy for urinary incontinence following prostate cancer surgery

The study enrolled 81 with urinary incontinence following radical prostate-only prostatectomy for prostatic carcinoma. The patients were divided into two groups. The patients in Group I were additionally subdivided into two subgroups with respect to the physiotherapeutic method used. The patients of subgroup IA received a rehabilitation program consisting of three parts. The patients of subgroup IB rehabilitation program consist of two parts. Group II, a control group, had reported for therapy for persistent urinary incontinence following radical prostatectomy but had not entered therapy for personal reasons. For estimating the level of incontinence, a 1-hour and 24-hour urinary pad tests, the miction diary, and incontinence questionnaire were used, and for recording the measurements of pelvic floor muscles tension, the sEMG (surface electromyography) was applied. The therapy duration depended on the level of incontinence and it continued for not longer than 12 months. Superior continence outcomes were obtained in Group I versus Group II and the difference was statistically significant. The odds ratio for regaining continence was greater in the rehabilitated Group I and smaller in the group II without the rehabilitation. A comparison of continence outcomes revealed a statistically significant difference between Subgroups IA versus IB. The physiotherapeutic procedures applied on patients with urine incontinence after prostatectomy, for most of them, proved to be an effective way of acting, which is supported by the obtained results.