Critical Reviews

Urinary Incontinence:
Evaluation and Biofeedback Treatment

by Jeannette Tries and Eugene Eisman

Chapter 23 in Biofeedback: A practitioner's Guide, by Mark S. Schwartz and Associates. (New York: The Guilford Press, 1995) pp 597-632 (Second Edition)

Reviewed by John D. Perry

In addition, at several critical points in this comprehensive chapter, pet theories are introduced to support the eventual commercialization of the author's patented products.  The result is a less than impartial review, at least in certain areas, which will be examined in detail.  A notable example is the authors' reliance on a general-purpose "polygraph-like" biofeedback device, when in fact 98 percent of clinicians treating incontinence today use a structured computer program that collects -- and allows comparison -- of three standard evaluation measures (flicks, holds and endurance).  Regrettably, Tries' previously-owned Biocomp did not allow quantitative measures of these industry-standard values.  As a result, readers who follow this chapter's guide will find themselves in a distinct minority.  More importantly, however, they will not be able to compare patient data with other clinicians and researchers.

Overall, the chapter is an excellent summary of the early practice of using biofeedback to treat urinary incontinence, as first established by Kathy Burgio, a clinical psychologist.  Upon her graduation in 1981, Dr. Burgio was hired by NIA's Biofeedback Guru Bernard Engle, and his associate, William Whitehead, to translate the NIA's highly successful fecal incontinence protocols to the treatment of urinary incontinence.  It should be noted that Burgio was constrained to use the manometric methods that had been developed for the treatment of fecal incontinence; as a result, she was unable to use home trainers, for example, and because the manometric system was inherently extremely uncomfortable, most patients would not tolerate more than 3 or 4 feedback sessions.  As a result of these limitations, Burgio's overall cure rate was less than 30 percent, although she did achieve impressive 76-94 percent symptom reduction (leaks-per-week) rates.  According to Burgio, Engle vetoed her proposed project to compare manometrics and EMG directly. 

Introduction

Chapter 23 begins by noting the high economic cost of urinary incontinence, and its role in nursing home admissions.  Anatomy and Physiology of Micturition and Storage are well explained.  After a review of the factors most discussed by urologists, the authors include a good summary of the additional influence of specific pelvic floor muscle groups.   The "types" of incontinence; stress, urge, and mixed, are presented clearly.  With well-chosen words, the authors point out that the traditional treatments -- drugs and surgery -- "have risks and side effects" and "often do little to alter the basic underlying problem", which biofeedback does address. 

Review of Biofeedback Research

Tries and Eisman then discuss the contributions of Arnold Kegel and his "pressure perineometer", and appropriately lament that "unfortunately, clinicians taught Kegel exercises without the use of his biofeedback device".  [A point first made in 1988 by Perry in The Bastardization of Dr. Kegel's Exercises). They overlook, however, the fact that Kegel's perineometer was first and foremost a home training biofeedback device; after ramping up, each patient was expected to practice 300 contractions in three sessions every day, using Kegel's biofeedback instrument. 

The authors then review the published literature on biofeedback, starting with Cardoza et al's (1978) research using cystometric [bladder-filling] biofeedback.  Although Cardoza obtained modest good results at first, in a 5-year follow-up, there was a substantial relapse.   Our authors correctly point out that this failure was probably due to the researcher's failure to train the pelvic muscles, which ordinarily are responsible for inhibition of bladder contractions. 

Then they turn to an overview of well-known pelvic muscle rehabilitation biofeedback projects, such as Baigis-Smith, Burns, Castleden, Fisher, Henderson & Taylor, Susset, and  Rose.  They state that these studies "made little effort to isolate the effect of the biofeedback from bladder exercises and home exercises". (p. 604).   Back in English Lit, I learned that it is inappropriate to criticize a poet solely for choosing to write in couplets, instead of writing in my favorite pentameter.   These studies had legitimate purposes that didn't happen to include what Tries is now looking for. 

Even worse, they state that "an interpretive problem arises when one measures only perivaginal muscle contractions and does not control for changes in inter-abdominal pressure." (604) They claim "Unless one measures interabdominal contractions separately, the transmission of abdominal artifacts to perineal measures invalidates pelvic floor measures as indices of change." [emphesis added.] Actually, the "transmission of abdominal artifacts to perineal measures" does occur -- but only with the old-fashioned manometric (pressure) systems, not with EMG.   The only reference to support this rather extreme position is Tries' prior statement of the same opinion; there is no collaboration from any other source.  In fact, Tries' own printouts show rather conclusively that such crosstalk does not occur with EMG! 

Although many clinicians do, in fact, measure abdominal contractions (as an index of inter-abdominal pressure transfer), the majority find it unnecessarily intrusive.  Unlike the pelvic muscles themselves, the contraction of abdominal muscles can readily be detected by simply pressing a fingertip into the abdominal wall, and observing any movement during pelvic muscle contractions. 

The reason it is unnecessary to "measure" abdominal contractions is that -- unlike pelvic muscle contractions -- they are "binary".   That is, any contraction of the abdominal wall is "bad", it really doesn't matter whether it is 3, 6, or 9 microvolts, so why bother to measure it?  [In addition, there are serious problems in "measuring" abdominal contractions with EMG, since fatty tissue greatly attenuates the EMG signal there, and manual palpation may, in fact, be a better measure.   In any case, the clinical superiority of taking a second EMG  has not been established in any empirical study.]

The authors review Susset's use of a manometric biofeedback device, achieving 87% objective (pad test) reduction in symptoms, but fail to mention that the Susset study involved the daily use of a home trainer -- which distinguishes Susset from most other studies reviewed.  Susset did not, of course, monitor abdominal muscles, so it is difficult to see -- if Tries is correct -- how he could achieve such great results.

Burns et al is discussed, and it is noted that the biofeedback group achieved only 61% reduction, whereas a verbal-instruction group achieved 54% reduction, a non-significant difference.  Tries and Eisman blame this mediocre biofeedback result on their failure monitor abdominal muscles.  There is no justification for this conclusion; a number of real flaws in Burns' biofeedback procedure are much more likely culprits.  [Burns is tied for last place in producing the least significant improvement in symptoms using biofeedback; her 61% ranks well below Burgio's 82-95% for comparable populations, for example.] 

Tries next turns to the work of her mentor, Kathy Burgio, who measured inter-abdominal pressure through an inserted rectal balloon.  She specifically mentions Burgio's 76% improvement in a biofeedback group, compared with 51% in a verbal feedback group.  [It is important to note here that the "control" group received extensive verbal feedback of vaginally-palpated contractions -- this was not a "verbal instruction only" control group.  The labor-intensive services of an experienced nurse providing extensive feedback may even be more costly than computerized biofeedback.] 

When describing the "contradictory" evidence produced by Burton et al, the authors quite correctly point out that Burton's subject were largely urge, not stress, incontinence patients, so the behavioral interventions used by Burton may have been more appropriate than the limited pelvic muscle biofeedback afforded by Burgio's ano-rectal manometry technique.

In summarizing the biofeedback research, however, they go far beyond the data they have reviewed.  They flatly state "single-channel measurement techniques are typically not sufficient for increasing the strength of pelvic muscles in patients with bladder dysfunction." (607)  While this is a pet theory of Tries, she is forced to overlook many contradictory studies -- such as Susset, Henderson & Taylor, Perry, Shepherd, Williams -- to retain her private conclusion.  [See comparison.htm.]

The casual reader may be thinking that there is much support for Tries' "multi-modal biofeedback is best" opinion in the Guidelines issued by the Agency for Health Care Policy and Research (1992, 1996).  But the informed reader is already aware that the similarity is due primarily to the presence of Jeanette Tries on the panel that wrote those guidelines.  As the most knowledgeable biofeedback researcher on the panel, Tries was able to get her personal agenda published there, too.  An extensive critique of the 1996 document is presented on our website.

Instrumentation

In spite of having just reviewed the dismal history of cystometric biofeedback, Tries and Eisman turn first to a review of the instrumentation of cystometry, which Tries learned from Burgio.  Once again, we are admonished to measure inter-abdominal pressure using a pressure transducer or abdominal EMG, although absolutely no data is presented to show any incremental advantage for doing so. 

The most popular vaginal and anal EMG sensors -- used by many tens of thousands of clinicians around the world, are pictured but dismissed in a scant three lines of text; apparently because "They provide [only] a single measure of pelvic floor muscle activity." (607)  Actually, the contents of Figure 23.3 are quite curious.  On the left are depicted  two experimental sensor prototypes, made for Tries' personal use, by McGowan.  These devices were never approved by the FDA, and have never been commercially available, a fact which is not disclosed in the text. 

On the right are shown Perry brand vaginal and anal sensors.   However, the sensors shown (in this 1995 publication) were manufactured about 1985 and 1989, and were discontinued in 1992.  They were replaced in that year with the "Single-User" Perry brand sensors, manufactured by Self Regulation Systems. According to Frost and Sullivan's market research report (1993) these (SRS) products accounted for 69% of the biofeedback market; yet these authors fail to mention them, and show a ten-year-old product in their place.  Curious.

In contrast, a half-page diagram, a half-page of text, and a 2/3 page photograph of Tries and Eisman's own patented invention, the "MEP" sensor, and a "vaginal cone with electrodes", are presented.  In other words,  instead of mentioning a products actually used by more than two-thirds of practitioners in the treatment of incontinence, they devote nearly two pages to advance publicity for their own commercial products.  And this was accepted for publication more than three years before the MEP prototypes were first shown (full production has not yet begun).  In addition, there are still no production plans for the "vaginal cone" electrode that received such prominent display in this chapter.  

Tries and Eisman on Assessment

The final section of this chapter is an overview of the various elements that make up a comprehensive assessment and application of biofeedback to incontinence.   The Medical Assessment, "often by the referring physician", is described.   The Verbal Interview, essentially incontinence history-taking, is well done and follows the form described by Burgio in the 1984 NIA film designed to teach nurses and others how to apply biofeedback and behavioral strategies to incontinence.

The "assessment with instrumentation" section, however, unnecessarily follows the highly invasive protocol used by Burgio for ano-rectal manometry. The patient is first disrobed, and placed in the lithotomy position (females) or left-lateral position (males).  The patient is then examined vaginally or rectally (in spite of prior medical clearance which renders this redundant).  Traditional "PT" grading of the vaginal muscles is recommended, in spite of the EMG evaluation which comes next.  [Subjective "grading" of muscles  is notoriously imprecise and unnecessary when using standard EMG evaluations; however, Tries does not use standard EMG evaluations.] 

Tries' concept of an "evaluation" is rather loose.   Fortunately, she does agree on the industry-standard "10-second contraction" as the basic measurement, but that's the extent of her standardization, the amplitude of the contraction is not quantified.. The 10-second hold is followed by "a period of relaxation" of indeterminate length.  Then, in a minor concession to psychometric principles, she advocates a single repetition of the "relaxation, contraction, and again relaxation" sequence.  In contrast, the sequence defined in The Perry Protocol and followed more or less faithfully by most manufacturers [for the sake of making data comparisons possible across brands], advocates five or six repetitions, with the highest and lowest values excluded, and the remaining values averaged.  Like Burgio before her, Tries doesn't use "numbers".  But Burgio didn't have any absolute-scale numbers (since she used mamometry); Tries has access to absolute EMG values, but she doesn't use them.

Rather than relying on objective measurements [based on computerized instruments from either SRS, Hollister, Verimed, Neuromed, EMPI, Prometheus or others], Tries advises us to eye-ball the screen display, observing the "amplitude and stability" of the resting baseline, the "latency" to contract and release, the "maximum amplitude of of contraction", and the "stability" of contractions.  Curiously, she mentions that this can be ascertained with "by observation or using the standard deviation", but does not tell us how.  To my knowledge she has never reported a standard deviation.

In avoiding the use of objective (numerical) measures, Tries' concept of the expert's role is more of an artist than a scientist.  Unfortunately, science already takes a back seat in the practices of too many nurses and physical therapists, and while they may in fact resonate to this highly subjective style of measurement, it is not really at home in the field of biofeedback.  We always report peripheral temperature in degrees, and not on a 0 to 5 scale, for example.  Yet Tries actually advocates using Laycock's 0-5 scale subjective estimates instead of "microvolts", as is standard in EMG work. 

The most serious consequence of Tries' subjective approach to evaluation is that it is impossible to compare her findings with anyone else's findings.  We are shown screen after screen of patient records, but (except for the highly irrelevant "peak" recordings), we are forced to take Tries' word that one contraction is "better" than another.  On page 617, for example, we are shown two attempts to produce a "ramping" up contraction, four months apart.  Now it is clear that there is a visual difference after four months of practice, but one can only wonder how much different the ramps were at WEEKS 2, 3, and 4, for example. In our experience, small but real improvements in weekly assessments are an essential motivating factor in biofeedback patients.   In contrast to her totally subjective approach,   one standardized program based on the J&J system presents a "staircase" ramp for the patient to trace using her pelvic muscles; the program automatically calculates the second-to-second discrepancies between the staircase and the patient, and presents it as a single, precise digital value.  Thus a "350" score in week two is better than a "400" discrepancy the week before.   Tries, on the other hand, has to wait four months before clear visual differences are apparent.

Stated differently, I think that the computer is much more competent to calculate the root mean square of the area under the curve than any clinician's eyeballs.

She concludes with this opinion: "the best way to assess a voiding dysfunction is to observe the patient void with the recording electrodes in place".   There is no research presented, however, to indicate that this is in fact true, and there is abundant anecdotal evidence that most people cannot "urinate normally" when another person is staring at their genitalia and taking notes.  [Originally, advocates of biofeedback for the treatment of fecal incontinence filled their patients' rectums with oatmeal paste, and forced them to defecate it while being observed.  The application of general biofeedback principles of "training" and "generalization" has made these crude practices obsolete.]

Biofeedback Treatment Goals

In discussing biofeedback treatment goals, the authors present sensible short and long term goals, namely to increase the amplitude of contractions, and to reduce the frequency of incontinent episodes.  In an apparent lapse of confidence in their own methods, the authors contend that "we do not yet know the degree to which these physiological measures correlate with function improvement", so documentation of symptom reduction is the "most meaningful way to represent the overall effect of treatment" (615).  However, it is important to point out that Tries' protocol does not include weekly quantification of the standard evaluation, so the "physiological measures" are hidden from her.  Those who perform a standard EMG evaluation, using any of the various computerized protocols mentioned, have the necessary data to estimate symptom reduction based on muscle improvement.

The Problem of Isolation

Tries and Eisman devote almost three and a half pages to the topic of training isolation of the Perineal Contractions, a theme which Burgio first promoted (and with which almost all practitioners today agree).  There are three interesting elements to her isolation theory.  First, she advocates placing EMG electrodes directly on the abdominal wall.  We have always considered this an unnecessary invasion of the patient's privacy, and believe it sufficiently distracting as to cause additional difficulties in training.

The technique which we have used --- without any problems --- is to teach the patient to depress the abdominal wall by pressing a finger inward, at a point midway between the pubic bone and the umbilicus, as if pointing at the spine.  Then, when a pelvic contraction is made, if there is any abdominal recruitment, the depressed finger is easily observed moving away from the spine!  Except for the most obese patients, the method is cheap, easy, reliable, and most important -- can be practiced readily at home. [Indeed, even if one uses abdominal EMG in the clinic, one ought to teach this simple technique for use at home.]  After treating hundreds of patients, we have yet to find one patient for whom this very simple "biofeedback" technique was not sufficient. 

Second, Tries advocates training patients to make sub-maximal contractions, initially, because she believes that in doing so they are less likely to recruit abdominal muscles.  In order to facilitate this, she fiddles with range controls on her Biocomp, so that 6 microvolt PC contractions appear huge (and, therefore, sufficient) and then "shapes" abdominal contractions by changing the range.   Personally, I have attended at least a dozen presentations of these slides by Tries and Eisman, and I always find it disconcerting to have to take several seconds -- or more -- to try to figure out the amplitude of the contractions shown.  I can only wonder how the poor patients ever get a clear picture of what the display in showing.    This technique, by the way, is a direct extension of the uncalibrated "set it to full scale" polygraph technique demonstrated by Burgio in her 1984 instructional video. 

Finally, Tries advocates a "ramping up" contraction, leading up to a full 30 seconds.  In our experience, many elderly patients especially can only produce "ramping up" contractions, as it takes considerable time for them to mentally recruit the necessary muscle fibers.  We have instead advocated making maximal contractions on signal, as a way of training and developing fast-twitch fibers.   In this technique, the object is to display a "square wave" on the screen.  Initially, of course, the 10-second interval is composed of three or four discrete mountains; after a week or two, it becomes first two and after three or four weeks a single strong contraction.  With additional practice, the 10-second score becomes even higher, as the standard deviation becomes smaller (i.e, the variations become less).

Unfortunately, there is absolutely no empirical research that yet addresses the question of which training technique is actually superior; in the interim, most of us have only our strong personal opinions to guide us.

Dyssynergia

Tries and Eisman next address the topic of dyssynergia, which is sometimes secondary to a "neurological disorder", but most often a "learned behavior".  After the section on instrumentation, this short section is arguably the weakest part of the whole chapter.  First, they mistakenly confuse "dyssynergia", which is correctly identified as  inappropriate contraction during micturition, with "urethral syndrome", which is Schmidt and Tanago's 1979 term for chronic pelvic tension --- at all times, not just during micturitiion.  The two are very different puppies, and require different approaches.  Then they mistakenly assert that "there has been no research to date examining the effectiveness of biofeedback for [dyssynergia]."   In fact, dyssynergia was one of the first urological conditions ever treated successfully by biofeedback (Maizels & Furlit, 1979, Maizels, Kaplan et al, 1983, and several other studies in the urological journals). 

One reason dyssynergia was treated first -- with the crude and un-quantified EMG channel available on early urodynamic instruments -- is that any EMG activity during micturition is "bad", it really doesn't matter how much (in microvolts).  Therapy consists of inhibiting any contraction at all, it is is pretty easy to accomplish.  Urologists with no biofeedback training have been doing it for years.   [The discerning reader will notice that the exact same situation applies to the use of abdominal muscles during pelvic contractions -- any muscle activity during contractions is bad, it really doesn't matter how many microvolts!    Incidentally, the same "any vs. none" issues are involved in the treatment of functional constipation, but that's another chapter!]

In contrast, the biofeedback treatment of "urethral syndrome" is quite different, since an elevation of only one or two microvolts above normal resting levels [ca. 2 microvolts, narrow band RMS] is sufficient either to cause urinary tract infections, or to mimic them [called "urethral syndrome"], or both.  Tries' lack of attention to numbers makes this point difficult for her to grasp.

Additional confusion is generated by Tries' assertion that a modified form of Progressive Relaxation is useful in treating dyssynergia (actually, it is useful in treating chronic tension instead.)  She describes this as "systematically contract[ing] at lower and lower levels".  That certainly is "borrowed", and carried quite some distance, from Progressive Relaxation, which actually teaches maximal, sustained contractions which are then gradually, not quickly, "let go".   Glazer, for example, uses this approach to cause muscle fatigue, to teach extreme relaxation in the treatment of vulvodynia. 

The Cystometrogram

Tries does into some detail to present cystometrogram techniques, which she has modified from Burgio to include abdominal EMG instead of a rectal balloon.   In describing the filling of the bladder with sterile water, she fails to mention that Burgio reported a 5 percent infection rate among subjects exposed to the procedure [at the 1988 Consensus Development Conference].  Whether one considers a one-in-20 chance of a bladder infection an acceptable risk depends, we suppose, on whether it is my bladder or hers.  The CMG is described as "a very useful biofeedback technique", but once again there is no research presented to support this personal opinion. 

The purpose of the CMG is to allow direct visual feedback of bladder contractions through an hydraulic display.  When bladder contractions are observed, the therapist coaches the patient to relax and "contract the perineal muscles" (620).  Missing from the description, however, is any awareness of the fact that bladder contractions can also be inhibited simply by learning to do proper pelvic muscle exercises whenever a sense of urge is felt.  While this approach is admittedly not as "elegant" as the CMG, it is has a zero infection rate and the same outcome.   Filling bladders with water is just as invasive as pumping the rectum full of oatmeal paste with a chalking gun; both practices have now been largely abandoned as unnecessarily invasive. 

There are also serious questions about which practitioners are legally able to perform the CMG or several other invasive procedures, such as insertion of the manometric rectal balloons, advocated by Tries.  Clinical Psychologist Kathy Burgio, a Ph.D.,  popularized these techniques while working as an employee of the National Institutes of Health.  Although totally outside the scope of practice for a psychologist, Burgio could not be sued because she was working for the federal government.   Tries, as an Occupational Therapist with a Masters in Psychology, has been on much shakier ground.  Most of Tries' early work was with spinal cord injured patients, and most people would have nothing but praise and admiration for such dedicated and compassionate professional service.  However, as she branches out to more general populations, and increasingly becomes an advocate for her own commercial products, that veil of respect may not be sufficient to protect her when one of those one-in-20 infections becomes serious.  As the old saying goes, if something has a one in a million chance of happening, and you engage in the practice one million times, it is likely to happen!  Readers should, therefore, check  their profession's practice statutes and their malpractice insurance before undertaking risky therapies.

The Home Program

Chapter 23 turns next to the "home program", which, for Tries, like her mentor Burgio, is without the benefit of home trainers.  This is somewhat surprising, since (unlike Burgio), Tries' background is in biofeedback itself, where home trainers (EMGs, Thermometers, etc.) are almost always advocated as the most effective therapy for most conditions. 

Fortunately Tries does differ from Burgio in offering a slightly more aggressive program; whereas Burgio advocated only 53 contractions (3 x 17) a day, Tries advocates "at least 60" at the start; and furthermore, "should be increased to 120 per day" as strength improves.   This is still a "whimpy" prescription by Kegel's standards [increase quickly to 300 contractions a day] but it is better than 53.

Tries' "second step" is to advocate the use of both flicks (1-2 seconds) and holds (5-30 seconds) in order to develop both fast twitch and slow twitch fibers.  In the first months of our own clinical trials, we, too, advocated both flicks and holds.  Two things changed our mind.  First, we found that very few patients [at our ambulatory out-patient clinic] had any trouble with fast twitch fibers; what they had trouble with was sustaining contractions for more than a few seconds. In other words, few of our patients needed to do "flicks". [Your mileage may vary.]  Second, when we reviewed homework records, we often found patients who reported "Oh, I didn't have TIME to do the long contractions that day, so I just did the short ones!"  We began to eliminate the prescription of flicks, and subsequent clinical observations suggested that this was a smart move.

Curiously, Tries seems to be aware of the problem of monitoring abdominal contractions at home, but she has a novel approach.  She suggests "having the patient place a hand on the lower abdomen" as a way to guard against accessory recruitment.  This sounds like something out of therapeutic touch; for the life of me I can't figure out how it provides any useful information.  Our technique, in contrast, involves having the patient depress the abdominal wall about an inch.  This provides vivid feedback of accessory involvement.

Tries then notes that this reviewer and his partner (Perry & Talcott, 1990) advocate the use of pelvic floor home trainers, but insists that "there is no specific research on the usefulness of these devices" (621). Apparently she is unaware of our other 1990 publication, "The Role of Home Trainers in Kegel's Exercise Program of the Treatment of Incontinence (Ostomy/Wound Management, Vol. 30, September/October 1990).  [Ok, so it's not a prestigious journal, but it is peer-reviewed, and therefore should have been cited, by APA standards! (It is unethical for a psychologist to omit contrary evidence in publications.) ] 

In that article we reviewed 14 research reports and concluded that "projects that utilize home trainers (as Kegel first proposed and practiced) are shown to have higher success rates and cure rates than projects that rely only on a few office training sessions" (p. 55).   A more recent review, published on our website (only), shows that researchers using home trainers -- even without office instruments -- obtain substantially better results than those who use office instruments without home trainers!   See http://www.incontinet.com/comparison.htm.

Tries acknowledges that home trainers might "improve compliance", but in a strange twist of logic faults them for not monitoring accessory muscles.  First of all, they certainly do increase compliance, probably because it is impossible to "pretend" you did your exercises; either you took the device out of the case, plugged in your sensor, and recorded data -- or your didn't.  Secondly, we have already pointed out that "finger-monitoring" the abdominals is quite successful.  However, Tries has simply overlooked the fact that there were two-channel EMG units on the market in 1995 -- and there are quite a few more today.   Anyone who wants to monitor accessory muscles with a second EMG channel at home can easily do so, today as in 1995. 

It is difficult to understand the resistance of Tries and Eisman to the use of home trainer in this one area of biofeedback.  There is no magic or mystery to the data which shows home trainers produce superior results.  At three practice sessions a day, the home trainer patient gets almost one hundred biofeedback opportunities every month.  Of which patient would we expect better results -- one who got 4 biofeedback sessions in the office, or one that got those four sessions plus 100 biofeedback sessions at home?  Initially home trainers were often described as too expensive (in capital outlay) for widespread use.  But since 1988 there have been national distributors who rented trainers direct to patients.  (Today the rental business is so strong that most major manufacturers also provide rental services.)

Tries -- apparently grasping for straws -- claims that a further disadvantage of "home trainers" is that they "typically use a 100-200 Hertz bandpass filter", as if this were a liability.  First of all, it isn't true; many home trainers were available at the time this chapter was written that used wide bandpass, and in the past few years, many more wide bandpass models have been introduced.   Secondly, the whole "bandwidth controversy" is really quite bogus. 

A full explanation is beyond the scope of this review, but consider this: With integrated surface EMG we are merely "sampling" EMG signals anyway.   While it is true that the median frequency of a muscle's EMG begins to drop sharply at the point of fatigue, all that this really means is that a patient who practiced past the point of fatigue would suddenly start to get slightly lower EMG scores when using a narrow band instrument.  Since everyone agrees that patients should discontinue practicing when the muscle becomes fatigued, this would seem to be an advantage, not a disadvantage, to using narrow bandpass instruments.  A wide-band device would give slightly more accurate readings at the end of a practice session, but it would not alert the patient to fatigue.  Since the narrow band device has, as it were, a built-in fatigue monitor, we can push our patients -- quite properly -- to their limits, and obtain better results more quickly.  We simply tell them that if it suddenly appears that your contractions are not as strong as they were in the beginning and middle of the session, it is time to quit practicing for this session. 

Incidentally, many people think that the introduction of "wide-bandpass" instruments was merely a clever marketing ploy on the part of biofeedback instrument makers, whose market had become saturated.  There are, after all, only slightly more than 2,000 members of the AAPB, and probably almost all of them already own a "narrow band-pass" EMG!   By introducing this "new feature", they were able to make thousands of perfectly good EMG devices obsolete, and thereby increase their very stagnant revenues.  In any case, no one has yet shown any incremental clinical advantage to wide-band devices in the pelvic muscle field, where the simplest, most basic EMG devices provide so much more information about these hidden and inaccessible muscles that most people can learn to control their incontinence in under two months.

Other behavioral strategies, such as training for urge incontinence, are discussed next.  The authors are polite but appropriately skeptical of "vaginal weights" and "electrical stimulation" which are only "potentially effective methods".  They mistakenly state that "controlled outcome research ... is limited."  In fact there is an abundance of such studies, and they uniformly show that cones and estim are far inferior to either EMG or manometric biofeedback.  See our critique of the AHCPR Guideline on e-stim, and our comparison of biofeedback with estim and cones research for more details.  Many people have been misled by statistics which cite the percentage of patients "cured or improved" by such methods, which is dramatically inflated over Burgio's standard of "percentage of symptom reduction". 

Frequency of Sessions

In their discussion of the frequency of training sessions, we find our first hint that the methods and strategies discussed by these authors may be considerably less effective than those more commonly employed in the treatment of incontinence.   They state that "6-8 sessions" over a "3-month period" is "usually" sufficient to attain maximum benefit from biofeedback procedures.   Moreover, severe cases "may require 6 months of exercise to produce optimal changes in muscle function" (623). 

In contrast, Susset, using the less effective manometric biofeedback, obtained a respectable 87% reduction in symptoms in just 6 weeks, less than half as long as Tries predicts; but Susset used home trainers, which Tries rejects.  Perry et al obtained a 98% reduction in symptoms in only 4 weeks using EMG home trainers.  (Perry treated patients until they had been dry for 30 consecutive days, therefore, the 8 weeks initially reported (in 1988) includes four weeks of "overtraining" to prevent relapses.)  

Despite the frequency with which Tries and Eisman present their unique views of incontinence therapy at domestic and international professional meetings, this is the first clue we have concerning the low effectiveness of their techniques. 

Their Conclusions

The Chapter concludes with the assertion that "biofeedback protocols must be tailored to individual patients to adjust for idiosyncratic factors, such as muscle strength, coordination, endurance, and bladder characteristics" (623).   Unfortunately, their estimates of the time required for therapy (3 months) suggest that this "individually tailored" approach may, in fact, be considerably less effective and more time-consuming that more standardized protocols which place greater demands upon, and achieve higher compliance from, their patients. 

Non-standard, individualized therapy is also a theme promoted by another Biocomp user, Barbara Woolner, RN.  Woolner reports only a 61 to 67 percent symptom reduction rate.  This means, to be most clear, that if you were using three pads a day before therapy, you are only using one pad a day after "treatment".   That's certainly an improvement, but certainly not a fundamental change in incontinence status.  [In sympathy, Woolner typically treats much older, more demented, patients, so her mediocre results may not be as bad as they look.]

Our conclusions

Chapter 23 contains an abundance of experience and wisdom and ought to be read by every clinician contemplating the use of biofeedback for the treatment of incontinence.  Unfortunately, it is severely crippled by the presentation of idiosyncratic and archaic methods and self-serving promotion for future commercial products that could be quite misleading for newcomers to the field.  The beginning therapist would do well to supplement this chapter by participating in one or another (or preferably several) of the nationally advertised seminars and workshops offered for doctors, nurses and physical therapists by other experts in the field. 

This is an InContiNet "Critical Review".   InContiNet welcomes opposing viewpoints, and will publish without cost appropriate critical commentary, in the hopes of stimulating scholarly discussion of these very important issues.  Please send suggestions and comments to DrPerry@IncontiNet.com. 

Copyright 1998 by InContiNet.  This page was downloaded from http://www.incontinet.com/tries.htm
This edition was last revised on Wednesday, May 04, 2005.  To return to our home page, click here.