The effectiveness of biofeedback in treatment of women with stress urinary incontinence : a systematic review

Objectives: to assess whether pelvic-floor muscle training associated with biofeedback is more effective in the treatment of women with stress urinary incontinence, when compared to exercise alone. Methods: a research of articles published in the last 20 years in Lilacs, PubMed and SCIRUS databases, using the descriptors "urinary incontinence, stress” and “biofeedback” was conducted. Randomized clinical trials comparing pelvic-floor muscle training with and without biofeedback were included. Results: the study involved three randomized clinical trials involving 169 patients. A physical therapist was responsible for conducting the treatment using electromyographic or pressure biofeedback, and exercises were performed in the clinic or at home. The assessment methods, treatment times and protocols used were heterogeneous. Statistical analysis and rates of cure/improvement were similar between the groups of articles analyzed. Two studies had a score 8, and the third had 6 points according to PEDro’s Scale. Conclusions: examination of the studies found suggests that adding biofeedback to pelvic-floor muscle training appears not to bring about a significant difference in terms of the success of treatment, when compared to perineal exercises performed in isolation.


Introduction
Stress urinary incontinence (SUI) is defined as the involuntary loss of urine during physical exercise, sneezing or coughing. 1In practical terms, SUI can occur as a result of hypermobility of the bladder neck and proximal urethra or by sphincter failure.As it is considered an anatomical incontinence, the main structures that can be damaged in hypermobility of the bladder neck are the pelvic-floor muscles, the endopelvic fascia and the ligaments. 2he prevalence of SUI is approximately 23.7% of the population, reaching a peak in the fifth decade of life. 3] In recent years, non-surgical treatment of SUI has received special attention.][8][9] Exercises for the pelvic-floor muscles (PFM), also known as kinesiotherapy, have been used for conservative treatment of SUI for over 60 years, since Kegel, 10 in 1948, presented his results.Recently, a systematic review was published as a way of determining the effects of training of the pelvic-floor muscles in incontinent women. 11These authors concluded that the studies selected suggested that greater therapeutic effectiveness could be found in the treatment of women with SUI who took part in a program of kinesiotherapy for the perineal muscles.
At present, biofeedback is one of the most commonly used procedures in clinical practice to retrain the perineal muscles, showing the incontinent woman by way of visual signs and/or sounds which group of muscles is to be worked on. 12Various studies in which the patient was able to follow the treatment protocol in special clinics or at home have been conducted, using the pressure or electromyographic biofeedback device.] Conservative treatment with kinesiotherapy in association with the use of biofeedback seems to be a good practice, in view of the possibility of reducing the intensity of the symptoms and reducing the need for surgery, and thereby promoting the social rehabilitation of the incontinent patient.This systematic review aims to examine whether exercises for the PFM in association with biofeedback constitute a more effective treatment of SUI in women, compared to kinesiotherapy for PFM alone.

Methods
A computerized bibliographical study was carried out in May and April 2010.The selected articles were published between 1980 and 2010. in the Lilacs, PubMed and SCIRUS databases.The descriptors used for the research, based on the Medical Subjects Heading (MeSH), were "urinary incontinence, stress" and "biofeedback", with the Boolean operator "AND" between the words.To facilitate the search for articles, it was limited to "humans" and "female".
The study covered randomized clinical trials published in English, Portuguese and Spanish.It was restricted to female patients, aged over 18 years, who had been diagnosed with stress urinary incontinence.It should be pointed out that the articles selected were restricted to those where exercise of the pelvic-floor muscles in isolation or in association with biofeedback, in a comparative fashion.The protocol used (type of biofeedback, description of PFM exercises, length of therapy and number of sessions), and the professional who conducted the treatment needed specification.
Likewise, the articles had to include a description of the clinical outcome and the methods used to evaluate patients using at least one of the following methods: evaluation of the strength of the PFM, an urodynamic study, pad test bladder diary, evaluation of urinary loss, an evaluation of social activity and a quality of life questionnaire.
Articles that used as it sample patients with neurological disorders or those with other types of incontinence or pregnant women were excluded, along with studies that used another kind of conservative treatment and/or surgery for SUI.
The information contained in the studies found was evaluated by independent reviewers.At first, relevant articles were identified from the title and abstract.A second, more detailed analysis of the text was carried out to establish whether the studies could be included in the systematic review.In the case of disagreements a third reviewer was consulted.The quality of the methodology of the clinical trials was established by way of analysis carried out by the reviewers, taking as their point of reference the PEDro scale descriptors. 15The PEDro scale assesses 11 items, although only ten are give points.The clinical trial was thus given a score from 0 to 10.For inclusion in this review, the clinical trial needed to attain a score of more than five points.

Results
311 articles were found in the electronic databases.Ten studies were selected for full evaluation of the text.Six of these were excluded, two for including in the sample patients with mixed urinary incontinence, two for not having used the same exercise protocol for the two groups, with the groups being differentiated only by the addition of biofeedback in the treatment group, one for having assigned patients to the feedback control group on the basis of touching the vaginal and abdominal regions, and one for including a group undergoing hormone treatment.A seventh article was excluded for attaining a score of only 3 on the PEDro scale.Finally, three randomized clinical trials involving 169 patients in total were chosen for more detailed analysis: Berghmans et al., 16 Morkved et al., 17 e Aukee et al. 18 (Figure 1).
Table 1 shows the characteristics of the selected studies.Tables 2 and 3 describe the PFM exercises and the results of the analysis of the studies, respectively.• 3 series of 10 maximum contractions sustained for 6 to 8seconds, plus 3 -4 rapid contractions at the peak of sustained contraction Home: • 3 series of 10 maximum contractions Outpatients: • 3 five-second contractions with 10 second interval Home: • Exercises for muscular fibers type I and type II (details not given)

Biofeedback in treatment of women with urinary stress incontinence
So far as the quality of the methodology of the articles was concerned, two articles [16][17] received a score of eight and the third 18 a score of six on the PEDro scale.In all the articles, one physiotherapist was the professional responsible for conducting the treatment and the patients received explanations regarding the anatomy of the pelvis and the contraction of the pelvic-floor muscles.

Discussion
The present review suggests that non-medication based conservative treatment -kinesiotherapy in isolation or in association with biofeedback -of SUI has been shown to be effective.However, it can be seen that there have been an insufficient number of randomized clinical trials dealing with this subject.Only three studies were included in this review and it was observed that the evaluation methods and treatment protocols were still quite heterogeneous.
None of the articles examined can be considered double-blind, since both the patient and the therapist were aware of the kind of treatment that was being given.Only the assessors were blind, which is why these studies did not receive the maximum score on the scale.It can be considered that the studies are good in terms of methodology, since they received a score of over 50% overall on the scale.
The mean age of the patients who received treatment was similar.The women included had a clinical history of urine loss under stress, which was confirmed by urodynamic examination.Only one of the studies examined 16 partially included in the sample patients with a diagnosis of SUI based on clinical history and physical examination.In one of the articles selected 17 some patients reported symptoms of urgency-incontinence, which was not confirmed by urodynamic examination.In two of the studies [16][17] the degree of severity of the SUI was stratified according to the results of the pad test.The International Continence Society (ICS) and the International Urogynecological Association (IUGA) recommend that the investigation and classification of UI be carried out by a combination of the patientreported symptoms and the results of a urodynamic examination. 19bjective evaluation of the improvement in urinary continence also varied among these studies.7] In one of the studies selected, 18 the authors conducted a reevaluation of the incontinent women after a follow-up period of one year.This study is of special importance, since it is difficult to follow-up such patients in the long-term and it is important to verify whether the improvement achieved by the end of the treatment is maintained during the follow-up period.In this article, it was confirmed that the reduction in the index of urine loss was associated with a reduction in the risk of the need for surgery to correct stress urinary incontinence.However, these authors did not report the statistical results for the variables (electromyographic analysis of the PFM and urine loss index) analyzed immediately after intensive treatment.
At present, apart from the result for interventions being evaluated in an objective fashion, by looking at morbidity and mortality, subjective parameters are also used to determine what patients understand regarding quality of life and well-being.1] None of the studies analyzed used a validated quality of life questionnaire.However, the assessors questioned the incontinent women to determine the urine loss index, 17 the detrimental effects on social activity 17 and the patients' perceptions regarding UI. 16 Morkved et al. 17 used pressure biofeedback with the patients in the treatment group, while Berghmans et al. 16 and Aukee et al. 18 used electromyographic biofeedback.The two types of biofeedback have been shown to be effective in treatment of SUI.3] Despite involving the use of cumbersome equipment, electromyographic biofeedback is more specific for muscle fibers, as it identifies electrical potential generated both in a state of rest (characterized by the base muscle tone) and during the phase of muscular contraction.] In two of the studies analyzed, [17][18] the treatment was carried out by following up exercises carried out under guidance in the home of the patient.The patients periodically visited the physiotherapy where there was a training session.In only one study 16 was there outpatient treatment associated with the guided exercises in the patient's home.When the treatment carried out in the patient's home is supervised, it is possible to achieve greater adherence.Regular visits to the therapist provided greater motivation for the patient to continue to do the exercises and enabled the results to be monitored. 26However, it should be pointed out that there is some difficulty in controlling these patients, since, when the therapist does not directly monitor the session, it is difficult to be sure that the patient has done all the exercises for the length of time and the number times recommended.The fact that two studies included were not monitored directly by the therapist was a limitation of the articles covered by this systematic review.
The studies were not homogeneous so far as the treatment protocol and exercises used were concerned.The positioning of the patient for the perineal exercises and the length of treatment varied from study to study.The number of exercises carried out weekly and the frequency and duration of contractions of the PFM also varied.Two studies 16- 17 described the PFM contraction protocol, covering both type I and type II muscle fibers.Only one study 18 did not describe the PFM contraction exercise protocol, although the authors point out that they used exercises for both slow and fast muscle fibers.In SUI, type II (rapid) fibers are the ones that are more damaged.The training of patients should give priority to this type of fiber, although patients should be encouraged to exercise the whole group of muscles, in order to help achieve conscious and effective contraction, as well as improving the contraction reflex. 27espite the differences found, all the articles analyzed reported similar results.The signs and symptoms of the women with SUI improved after treatment involving perineal exercises, both when these were in isolation and when they were combined with biofeedback.7][18] Only one study 18 described that preservation of the integrity of PFM function during therapy is important for avoiding stress urinary incontinence corrective surgery, after a period of one year following intensive treatment.7][18] There is, therefore, no scientific basis for the theory that the addition of biofeedback provides more effective treatment of SUI.
Berghmans et al. 16 report that therapy associated with biofeedback is important mainly in the first two weeks of treatment.Morkved et al. 17 claim that treatment with biofeedback provides greater motivation for the incontinent women to continue treatment and that it is thus a good option for clinical practice.Aukee et al. 18 report that biofeedback is beneficial in so far as it enables the therapist to check whether the patient has performed the exercises at home, while ensuring privacy and helping the patient to increase muscle activity.
The results found in this review are similar to those of Berghmans et al. 28 who carried out a systematic review of studies published between 1980 and 1998.These authors used different criteria for the inclusion of articles from those used by the present systematic review and identified five randomized clinical trials that compared PFM exercises in isolation and in association with biofeedback.These authors found strong evidence that the addition of biofeedback does not increase the effectiveness of treatment for SUI patients.

Conclusions
The studies analyzed in this review suggest that biofeedback produces improvement of the symptoms in patients with SUI.However, when compared to PFM exercises in isolation, the addition of biofeedback does not appear to lead to any significant difference in the success of the treatment.
The scarcity of randomized clinical trials and the heterogeneity of the studies found were two of the limitations of this systematic review.
It is suggested that future studies be carried out in a controlled fashion, with adequate randomization and masking of the assessors.The samples should be homogenous and the evaluation methods and treatment used should be validated and standardized, thereby allowing for reliable comparison of the results.

Figure 1 Flowchart
Figure 1Flowchart of search process and selection of articles.

Table 1
Characteristics of the selected studies.

) sample Mean age ± SD Diagnosis Classification of SUI Method of evaluation loss (years) SUI=
stress urinary incontinence; GC= control group (kinesiotherapy); GT= treatment group (kinesiotherapy with biofeedback); UL= urine loss; abdominal leak point pressures; PFM= pelvic floor muscles.*The calculations for the age of patients and clinical outcomes were based on a total of 94 incontinent women.

Table 2
Description of pelvic-floor muscle exercises.

Table 3
Results of selected studies.