Urinary Stress Incontinence and Biofeedback

By Carmen Tamayo, MD

Urinary incontinence is defined as an inability to hold urine until getting to the toilet. It is a symptom, not a disease, and the treatment method depends on the severity of the problem.

Women experience incontinence twice as often as men. Pregnancy and childbirth, menopause, and the structure of the female urinary tract account for this difference. Neurologic injuries, birth defects, strokes, multiple sclerosis, and physical problems associated with aging can cause both women and men to become incontinent.1 Urinary incontinence has been reported to affect 35% of American women 50 years of age or older, and almost 15% of these women experience leakage daily.2 Incontinence is a distressing condition with significant medical, social, and economic implications.

The two most common types of urinary incontinence are stress urinary incontinence (SUI) and urge incontinence. Approximately 60% of women with incontinence will have SUI caused by problems with the muscles that help hold and release urine. SUI usually is caused by anatomical defects in the structures that support the bladder and the urethra. Leakage results when the urethra is not closed off properly during exertion because of dysfunction of the neuromuscular components that help control urethral pressure. In women with genuine SUI, the symptoms include involuntary but frequent leakage of small amounts of urine during physical exertion with increased intra-abdominal pressure, such as coughing, sneezing, laughing, exercise, lifting, or sitting.

Urge incontinence is the leakage of large amounts of urine at unexpected times, including during sleep, for no apparent reason. Sufferers often report feeling the sudden need or urge to urinate. The most common cause of urge incontinence is inappropriate and involuntary bladder contractions that occur as a result of damage to the nerves of the bladder, to the nervous system, or to the muscles themselves. Multiple sclerosis, Parkinson’s disease, Alzheimer’s disease, stroke, and injury—including injury that occurs during surgery—all can harm bladder nerves or muscles.

Regardless of the cause, incontinence is controllable and in most cases treatable at all ages. Approximately 80% of those affected by urinary incontinence can be cured or improved through diet, changes in medications, or a combination of medicine, behavioral modification, pelvic muscle re-education, collection devices, absorbent products, and physical therapies.3

Biofeedback and Physical Therapies

Physical therapies—such as Kegel exercises, pelvic floor muscle (PFM) training, weighted vaginal cones, pelvic floor electric microstimulation therapy, bladder retraining, magnetic therapy, and biofeedback—have been used to treat SUI. The aim of PFM training is to improve the strength and/or timing of voluntary PFM contractions by strengthening the external urethral sphincter.

Biofeedback has been defined as "a group of experimental procedures where an external sensor is used to give an indication on bodily processes, usually in purpose of changing the measured quality."4 Biofeedback is not a treatment on its own, but rather is a "teaching technique that facilitates learning by providing patients with immediate and observable information about physical performance."5 Biofeedback is also a component of behavioral interventions, including physical therapies, bladder training, educational sessions, and voiding diaries, that are used to control or treat urinary incontinence. A wide variety of biofeedback apparatus, including pressure perineometers with visual or auditory display and electromyography from vaginal probes, are used commonly in clinical practice to assist with PFM training. Biofeedback can be visual or verbal. Voluntary control of PFMs during voiding can be obtained by relaxation biofeedback (visualization of the electromyographic registration of relaxation and contraction of the pelvic floor by a curve on a display), uroflow biofeedback (observation of the flow curve during voiding), and electromyographic (EMG) biofeedback (bio-electrical muscle activity that is recorded through surface or needle electrodes placed directly against or inside the target muscle’s sensory signals and is used to induce a motor-learning process).

Evidence of Effectiveness

Systematic Reviews. To date several systematic and narrative reviews have been conducted to assess the efficacy of physical therapies for first-line use in the treatment and prevention of SUI in women. Four of these concluded that PFM training is of benefit to women with urinary leakage.6-9

The effect of biofeedback with PFM training also has been evaluated in systematic reviews in women with SUI. De Kruif and van Wegen reviewed four randomized trials (n = 189), two quasi-experimental studies (n = 47), and four uncontrolled studies (n = 522).10 Six of these studies compared exercise therapy with and without myofeedback, with two of these studies reporting significant differences in improvement. The combined interventions produced the largest improvement. However, only one of the 10 studies in the review looked at improvement in continence. The authors concluded that exercise therapy with EMG myofeedback has to be considered as a possible treatment method for women suffering from SUI.

A systematic review of 11 randomized controlled trials (RCTs) studying prevention and treatment of SUI with PFM exercises found strong evidence supporting the use of PFM exercises for reducing SUI symptoms.7 The authors found no apparent benefit of biofeedback-assisted training over PFM training alone at post-treatment assessment. However, the findings suggested that the biofeedback group experienced more rapid improvement. There was limited evidence for the efficacy of a high-intensity vs. a low-intensity regimen of PFM exercises and there was no evidence that PFM exercises with biofeedback are more effective than PFM exercises alone. The authors indicated that biofeedback alone seems to be more effective in controlling urge incontinence than SUI.

Weatherall et al questioned the conclusion reached by Berghmans and re-evaluated the findings using pooled data from three of the five trials that examined biofeedback combined with PFM exercises compared to PFM exercises alone.11 The odds ratio for biofeedback combined with PFM exercises leading to cure was 2.1 (95% confidence interval 0.99-4.4). Although the effect of biofeedback-assisted PFM training did not reach statistical significance, the authors concluded that there was a trend in favor of biofeedback.11

The Cochrane Incontinence Group conducted a systematic review of RCTs published from 1983 to 1999.9 The authors evaluated 43 trials that compared the effects of PFM training to no treatment or other treatment options in women with symptoms or urodynamic diagnoses of stress, urge, and mixed incontinence. Thirty-one trials involved women with SUI but only 23 trials included women with a urodynamic diagnosis of genuine SUI. Ten randomized trials compared PFM training with biofeedback (n = 209) vs. PFM training alone (n = 180). The number of treatments, methods, and duration of biofeedback treatments was highly variable. In the trials with clinic-based biofeedback, the number of sessions per week ranged from one to 12 weeks. The daily home-based programs ranged from two weeks to three months. Half of the trials used biofeedback from a vaginal probe with EMG electrode and the other half used a pressure-sensitive intravaginal device. None of the three measured outcomes (self-reported cure, self-reported cure/improvement, and leakage episodes in 24 hours) found any statistically significant difference between PFM training and PFM training/biofeedback groups.

Three trials, all in women with SUI only, included a short pad test. All found significant reductions in leakage in both groups. In two trials this favored the biofeedback group although the difference was not significant.

One of the two trials that included women with genuine SUI, with or without detrusor muscle instability, measured PFM activity and found that sustained contraction strength was greater in the biofeedback than PFM training group. Overall, the authors concluded that PFM training appeared to be consistently better than no treatment and placebo treatments for women with both stress and/or mixed incontinence. It appears that adding biofeedback to PFM training does not increase the benefit. Anecdotally, many clinicians report that biofeedback is a useful addition to PFM training, but from the review it is not clear what benefit it offers. Long-term outcomes of PFM training are unclear. Side effects were uncommon and reversible.

Recent Clinical Trials. The largest clinical trial comparing PFM training with and without biofeedback to date was conducted in Norway.12 In this single-blind, randomized trial, 103 women between ages 30 and 70 years and who had experienced symptoms from 1-25 years completed six months of PFM training that consisted of doing three sets of 10 contractions three times per day under a physical therapist’s supervision. One group trained with a biofeedback apparatus at home, the other without biofeedback. Data from 94 women were analyzed. Women training with and without biofeedback showed a statistically significant reduction in leakage on pad test (P < 0.01) after six months of PFM training. Objective cure (2 g or less of leakage) in the total group was 58% in women training with biofeedback and 46% in women training without biofeedback. In the subgroup of women with urodynamic SUI alone, objective cure was seen in 69% of women training with biofeedback and 50% of women training without biofeedback. Cure rate was high, and the reduction in urinary leakage after treatment was statistically significant in both groups. However, there was no statistically significant difference in the effect of individual pelvic floor muscle training with and without biofeedback.

A prospective randomized pilot study compared EMG-assisted biofeedback to PFM training alone in female patients with SUI.13 Participants were 31-69 years of age and had no previous incontinence operations. The biofeedback group received an EMG-guided biofeedback device for home training and the PFM group trained without any device at home. All patients were advised to practice for 20 minutes per day five times a week for 12 weeks. Muscle forces increased significantly in both supine (P < 0.001) and standing (P < 0.001) positions. In the supine position, the increase was significantly higher in the biofeedback group (P = 0.024). The results showed close to a significant decrease in the leakage index in the biofeedback group (P = 0.068), but no change occurred in the PFM group. The results of this study demonstrate the efficacy of PFM exercises alone and in combination with a biofeedback device in increasing muscle activity. The decrease in the leakage index and the increase in PFM activity were better in the biofeedback group, a clear indication that adjunctive biofeedback is more effective than PFM training alone. The authors conclude that the biofeedback group showed a significant improvement in PFM training outcome measures (PFM activity, leakage index) compared to the patients doing PFM training alone. The benefit of the EMG feedback is that this device facilitates the acquisition of physiologic responses that otherwise are undetected.

A three-year long-term efficacy study evaluated pelvic floor re-education (PFR) with EMG-controlled biofeedback in the treatment of female genuine SUI or mixed incontinence.14 Between 1995 and 1998, 36 women completed three to six months of PFM training with a biofeedback device. A mean of 26 months later, a follow-up examination was performed. Immediately after the program, 25 women reported cure or improvement of stress incontinence, but at the long-term follow-up, only 17 women reported the same result. About half of the patients receiving PFR with biofeedback remain cured after 26 months.

Other studies have suggested that biofeedback therapy, particularly with electrical stimulation, produces better subjective outcomes, improvements in quality of life, and higher contraction pressures of PFMs.15,16 However, the effect on continence has not been evaluated thoroughly.

Conclusion

Biofeedback is clearly an effective tool for teaching proper PFM training techniques. In addition, biofeedback may help the patient learn how to contract faster by use of either EMG or pressure measurements.

Based on evidence from systematic reviews and meta-analyses, it seems that PFM training exercises are effective for stress incontinence, but adding biofeedback to PFM training may not result in additional improvement. The effectiveness of biofeedback-assisted PFM training is not clear, but on the basis of the evidence available there did not appear to be any benefit over PFM alone. Nevertheless, recent clinical trials suggest that the positive effect of biofeedback using electrical stimulation may last over longer periods of time, particularly in women who maintain regular training. The efficacy of PFM exercises, with or without other adjuncts, for the prevention of SUI is uncertain.

Most trials to date have studied the effect of treatment in younger, premenopausal women. Very few trials have addressed cost-benefit analysis. Interestingly, since October 2002, the Centers for Medicare and Medicaid Services approved a national coverage for the use of biofeedback and PFM electrical stimulation for the treatment of urinary incontinence.17

Large multicenter studies using the same inclusion and exclusion criteria, biofeedback protocol, and methodology are needed to demonstrate the real effectiveness of biofeedback.18 Trials measuring the effect of biofeedback-assisted PFM training in women with SUI who are not able to voluntarily contract their PFMs are needed. In addition the rate of improvement in biofeedback-assisted training vs. PFM training alone should be evaluated.

Hay-Smith et al recommend that future research trials should select or develop outcomes that matter to women and that cover a range of outcome domains, and use tools that have established reliability and validity for women with urinary incontinence.9 Domains that require particular attention in future research are quality of life and socioeconomics.

Urinary incontinence is a distressing and life-altering condition that has significant medical, social, and psychologic implications for women. Continence management requires a sensitive, comprehensive, and holistic approach.19 More research of high methodological quality is required to further evaluate the effects of physical therapies used to treat and prevent SUI.

Dr. Tamayo is Director, Division of Complementary and Alternative Medicine, Foresight Links Corp., London and Dundas, Ontario, Canada.

References

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