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with permissionApplied Psychophysiology and Biofeedback, Vol. 29, No. 3, September 2004 ( C 2004)Biofeedback Treatment for Functional AnorectalDisorders: A Comprehensive Efficacy ReviewOlafur S. Palsson,1,2 Steve Heymen,1 and William E. Whitehead1This review aimed to critically evaluate the literature on the efficacy of biofeedback forfunctional anorectal disorders, rate these biofeedback applications according to establishedguidelines, and make recommendations for this field based on the literature. TheMedline and PsychInfo databases were searched to obtain all papers published from 1975to 2003 that included the terms “biofeedback” and either “constipation,” “pelvic floordyssynergia,” “fecal incontinence,” or “anorectal pain.” Adult and pediatric papers in anylanguage were screened. Prospective studies with five or more participants and a descriptionof the treatment protocol and outcome were selected for review. Seventy-four studies qualifiedfor review: 33 trials on fecal incontinence (FI), 38 on pelvic floor dyssynergia (PFD)or functional constipation, and 3 on anorectal pain. Only 20% of studies were controlledoutcome trials. Treatment protocols, etiological subgroups studied and outcome measuresvaried greatly. The overall average probability of successful treatment outcome for patientstreated with biofeedback was 67.2% for functional FI and 62.4% for constipation. Therewere insufficient data to warrant such calculation for anorectal pain. According to standardefficacy rating criteria, biofeedback treatment is efficacious for functional constipation orPFD in children and probably efficacious in adults; probably efficacious for functional FI;and possibly efficacious for anorectal pain. Utilizing data from all applicable studies, wefound that success rate per subject is significantly higher for biofeedback treatment thanfor standard medical care for PFD/functional constipation, and FI (p < .001 for both).Biofeedback treatment may therefore be viewed as a valuable adjunct to medical managementof functional PFD/constipation and incontinence. A number of recommendations forfuture investigations are made based on the review.KEY WORDS: biofeedback; fecal incontinence; constipation; anorectal pain; electromyography; manometry;pelvic floor; visceral sensation.INTRODUCTIONThe functional anorectal disorders are a subset of functional gastrointestinal disorders,and are characterized by symptoms thought to be indicative of dysfunction in anal and rectal1Department of Medicine, Center for Functional Gastrointestinal and Motility Disorders, The University of NorthCarolina at Chapel Hill, Chapel Hill, North Carolina.2Address all correspondence to Olafur S. Palsson, Department of Medicine, CB# 7080, Room 1105 C, BioinformaticsBuilding, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7080; e-mail:eek:lafur palsson###med.unc.edu.1531090-0586/04/0900-0153/0 C 2004 Springer Science+Business Media, Inc.154 Palsson, Heymen, and Whiteheadphysiological activity. In the current Rome II diagnostic criteria, three anorectal disordersare recognized: functional fecal incontinence (FI), functional anorectal pain, and pelvic floordyssynergia (PFD; Whitehead et al., 2000). These disorders are diagnosed primarily basedon the patients’ report of symptoms and are of unknown etiology. By definition they arethought not to involve anatomical or biological pathology, and such competing causal explanationsoften need to be ruled out by means of tests before definite diagnosis can be made.Biofeedback (BF) has been reported to be an effective treatment for fecal incontinenceand PFD-type constipation in numerous published studies in the past 25 years. Past reviewsof biofeedback for FI and constipation have generally not attempted to separate BF trialstreating fecal incontinence and constipation of functional nature from those evaluatingtreatment of similar symptoms due to identified pathophysiology. Recent reviews havegenerally concluded that BF shows high degree of success for both fecal incontinence(Heymen et al., 2001; Hinninghofen&Enck, 2003; Norton&Kamm,2001) and constipation(Heymen et al., 2003; Jorge, Habr-Gama, & Wexner, 2003; Rao, 2003, etc.), based mostlyon the many uncontrolled studies in each area. They have, however, also noted a number ofmethodological limitations endemic in this body of literature, such as the varied criteria usedto define successful outcome, the heterogeneity of participants, the varying and inconsistentfollow-up assessments reported, and the relative dearth of controlled studies. The last pointis underscored by the findings of a recent Cochrane review of BF and pelvic floor exercisesfor FI (Norton, Hosker, & Brazelli, 2003), which only evaluated evidence from randomizedand quasi-randomized studies and concluded that there was insufficient evidence to judgewhether BF is helpful for FI.Biofeedback interventions have been far less studied for anorectal pain than the otherfunctional anorectal disorders. In contrast with FI and constipation, each of which has beentreated in more than 30 published BF trials, we only found three prospective studies in theliterature on BF for anorectal pain, and none of these was a controlled trial.Conservative medical management is effective in improving the symptoms of approximatelyhalf of patients with functional FI and constipation, but is ineffective in treatinganorectal pain (Whitehead et al., 2000; Whitehead, Wald, & Norton, 2001). Because ofthe large bodies of published BF trials with positive outcomes for constipation and fecalincontinence, and because BF is a remarkably benign treatment that is relatively inexpensivecompared to other medical interventions, BF is often applied in clinical settings totreat these disorders. However, limitations in the standards of evidence offered by the bulkof the research literature on BF treatment for these conditions have hampered insurancereimbursement.Global efficacy ratings have not been applied in a systematic review of functionalanorectal disorders to date.Nature and Prevalence of the Functional Anorectal DisordersPelvic Floor DyssynergiaThis disorder, which has also been called anismus, outlet obstruction constipation orspastic pelvic floor syndrome, is a type of constipation characterized by a failure in chronicallyconstipated patients to execute the relaxation of the puborectalis sling muscle andthe external anal sphincter that is required for successful defecation. Instead, PFD patientsparadoxically contract these muscles, effectively inhibiting defecation. This “dyssynergia”Biofeedback for Functional Anorectal Disorders 155of muscle activity is associated with symptoms of straining and incomplete or blockedevacuation. Diagnosis of PFD requires physiologic confirmation of the characteristic abnormaldefecation dynamics through electromyographic (EMG), manometric (pressure) orradiologic testing, as well as exclusion of other causes for the constipation symptoms.Because PFD requires clinical tests to confirm diagnosis, the population prevalence isnot well known, but PFD is thought to account for 25–50% of chronic constipation cases(Lestar, Penninck, & Kerremans, 1989; Wald, Caruana, Freimanis, Bauman, & Hinds,1990) and may be present in 50% of childhood constipation. This would indicate that PFDis very common, because constipation problems are prevalent in the general population. Forexample, Irvine, Ferrazzi, Pare, Thompson, & Ranu (2002) found in a random telephonesurvey of 1,149 individuals 18 years or older in Canada that 14.9% met Rome II criteria forfunctional constipation and twice as many, or 27.2%, had self-described constipation.Constipation is often associated with psychological symptoms of anxiety and depressionand significant impairment in quality of life (Burnett, Whitehead, & Drossman, 1998;Irvine et al., 2002). Constipation is more common in women than men across the life span,and the prevalence rises with age, especially after middle age.Functional fecal incontinence (FI) is defined by the Rome II criteria as recurrentuncontrolled passage of fecal material in an individual with a developmental age of at least4 years, that is associated with fecal impaction, diarrhea, or nonstructural anal dysfunction(Whitehead et al., 2000). The etiology of functional FI is varied, and includes disturbancein intestinal motility (diarrhea or constipation), poor compliance or impaired sensation inthe rectum, or weakened pelvic floor muscles. Muscle or nerve damage, for example dueto disease processes or trauma such as obstetric injuries, as well as anatomical conditionslike rectal prolapse, often causes or contributes to fecal incontinence, and these must beexcluded as the primary symptom causes in order to diagnose functional FI. However, thefact that pathophysiology and physiological dysfunction may coexist as synergistic factorsin FI complicates the diagnostic picture of many patients. Furthermore, functional fecalincontinence often coincides with PFD: Studies indicate that up to half of functional FI casesexhibit abnormal defecation dynamics. These patients have a mixed symptom presentationof chronic constipation punctuated by incontinence episodes due to fecal impaction.Fecal incontinence is more common in women than men. This is partly due to thepelvic changes and trauma associated with childbirth, which increases the risk of FI 2.5to 3 times regardless of delivery method (MacLennan, Taylor, Wilson, & Wilson, 2000).Secondly, FI is often causally related to irritable bowel syndrome and constipation, both ofwhich affect women more frequently than men.The prevalence of functional fecal incontinence, specifically, is not well known, asepidemiological studies have not distinguished between causes of FI. Prevalence estimatesagree, however, that significant accidental passage of fecal matter for any reason occurs inabout 1% of the general population: Nelson, Norton, Cautley, and Furner (1995) reported,based on a telephone sample of 2,570 households, that loss of solid stool was reported in0.8% and liquid stool in 1.2% of individuals. A stratified nationwide postal survey of 5,430U.S. adults performed by Drossman and colleagues (Drossman et al., 1993) found that 0.7%reported frequent incontinence of at least two teaspoons of fecal matter. Milder cases offecal incontinence are far more common, however. In Drossman et al.’s sample (Drossmanet al., 1993), 6.9% of adults reported frequent fecal staining of underwear.The distribution of fecal incontinence is demographically uneven: It is more commonin women than men, and is most prevalent at both ends of the age spectrum. The prevalence156 Palsson, Heymen, and Whiteheadof FI among seven-year-old children is 1.5% (Bellman, 1966; Schaefeer, 1979) and in suchpediatric cases, FI is almost always related to fecal impaction (Lowery, Srour, Whitehead,&Schuster, 1985). FI prevalence rises to about 7% in adults over the age of 65(Drossman et al.,1993; Kinnunen, 1991). It is a leading cause of institutionalization of elderly individuals.For that reason, and because dementia and immobility increase the risk of FI, the conditionis much more prevalent in nursing homes, afflicting 45–47% of U.S. nursing home residents(Dey, 1997; Nelson, Furner, & Jesudason, 1998).Because of the embarrassing and socially limiting nature of the symptoms, FI mostlikely has greater psychological and life impact than the other functional anorectal disorders.Several studies have demonstrated that FI has a broad and measurable adverse impact onpatients’ quality of life and is often associated with depression, social isolation, impairmentof intimate relationships, and poor self-esteem (Burnett et al., 1998; Miner, 2004).Functional Anorectal PainTwo types of functional anorectal pain are recognized, which may overlap but havedifferent presentation in regard to symptom duration, frequency, and intensity. Levator anisyndrome generally presents as a dull or indistinct feeling of pressure, ache or pain in theupper rectum. Rome II diagnostic criteria require this to have been experienced 12 weeks outof the last 12 months and for the duration of the episodes to be at least 20 min (Whiteheadet al., 2000). It has been reported to affect 6.6% of the general population (Drossmanet al., 1993), is more common in women than men and most commonly affects individualsbetween the ages of 30 and 60. Proctalgia fugax presents as sudden, severe anal or lowerrectal pain that lasts from a few seconds to a few minutes. The pain is often intense enoughto disrupt normal life activities (Thompson & Heaton, 1980) but rarely occurs more oftenthan 5 times a year. Population prevalence estimates for proctalgia fugax vary from 8 to14% (Drossman et al., 1993; Panitch & Schofferman, 1975) but because of the brief andinfrequent nature of the episodes, few sufferers seek medical attention for the condition.AimsThe aims of this review were: (1) to comprehensively examine the level of evidencefor efficacy of biofeedback treatment of functional anorectal disorders in the publishedempirical world literature; (2) to rate treatment efficacy according to standard guidelines;and (3) to make recommendations based on the findings.Review MethodologyThe conditions of interests (COI) in this review were the three anorectal disorders describedabove. Medline and Psychinfo searches were used to identify all published empiricalpapers from 1975 through 2003 in all languages on adult and pediatric samples matchingthe search term “biofeedback” with the terms “pelvic floor dyssynergia,” “constipation,”“fecal incontinence,” “anismus,” or “anorectal pain.” Papers were manually screened toselect for review only prospective studies of biofeedback treatment that had at least fiveparticipants per group and provided a description of the treatment protocol and treatmentoutcomes. Studies where the anorectal conditions of all patients studied were recognized toBiofeedback for Functional Anorectal Disorders 157be secondary to physical trauma (such as obstetric injury) or structural pathology, postsurgicalin nature or related to a major medical disorder (such as diabetes, multiple sclerosis,or spina bifida) were excluded, but studies on participant groups with anorectal problems ofmixed etiology that were likely to include patients with the COIs were included for review.This inclusion of mixed etiology samples was deemed necessary as the majority of thestudies found were on mixed groups and in many cases a definite etiological separation offunctional anorectal conditions from other causal factors is difficult as the symptoms areoften (especially in FI) multifactorial in nature. Because few studies on constipation BFseparated outcomes for PFD and other constipation, we treated PFD and other functional(idiopathic) constipation as a single COI for the purposes of the review.This search and screening methodology resulted in the identification of 33 studiesof BF for fecal incontinence, 38 studies on constipation, and three studies on functionalanorectal pain. The studies were categorized according to their design into randomizedcontrolled trials, nonrandomized controlled trials, or uncontrolled trials. As this reviewfocused on clinical efficacy, which requires comparison with other treatments, only studiesthat had one or more nonbiofeedback groups internal to the study design were classified ascontrolled outcome trials (thus, several studies that merely compared different variants ofbiofeedback were not regarded as controlled trials for the present purposes).The overall success rate ofBFfor each of the anorectal COIwas calculated by averagingthe success rates reported in all studies that provided that statistic after they had beenweighted according to the number of participants in each study. It must be acknowledgedthat there was no common standard for defining treatment responder across studies, andmost reports did not provide adequately detailed results to make it possible to apply anycommon standard in calculation. However, most of the studies reported the percentage ofpatients who were determined to have successful treatment outcome according to somestandard, and these percentages were used regardless of the responder definition. Somestudies reported multiple percentages based on different criteria for positive outcome, andin such cases, we selected a commonly used criterion, which was the percentage of patientswith ≥75% improvement in symptoms. This was the middle of the range of criteria from50 to 100% improvement used in the studies reviewed.The overall success rate for standard medical care control groups was calculated inthe same weighted way as described above, for PFD and FI trials (no such control groupoutcome was available for anorectal pain). The proportions of patients improving from BFand standard medical care, respectively, were statistically compared for each condition,using chi-square tests.Finally, an overall efficacy rating for BF treatment of each of the three functionalanorectal disorders was performed using published standard guidelines for evaluation ofclinical efficacy of psychophysiological interventions (La Vaque et al., 2002).Biofeedback Protocols Used for Anorectal DisordersBiofeedback for PFDBiofeedback interventions for PFD are directed at teaching patients to relax theirpelvic floor muscles while simultaneously applying a downward intraabdominal pressureto generate propulsive force (Valsalva maneuver). This is done with the aid of visual or158 Palsson, Heymen, and Whiteheadauditory feedback to the patients providing information from either electromyography sensors(EMG) measuring electric activity in the external anal sphincter, an anal canal pressuresensor device, or both of these.Biofeedback for Fecal IncontinenceThe maintenance of continence depends on adequate rectal sensation to detect distentionof the rectum, as well as on the capability to synchronously contract the external analsphincter in response to the reflexive inhibition of the internal anal sphincter that occurswhen the rectum fills (Whitehead, Engel, & Schuster, 1980). Biofeedback for fecal incontinenceaims to enhance or restore these key functions. A variety of treatment protocolshave been employed for this purpose, and these methods can be divided into three treatmentapproaches. The relative frequency of use of these approaches in published studies has beencomprehensively reviewed recently by Heymen et al. (2001).The most commonly reported training method is the use of variants of the coordinationtreatment protocol first developed at Johns Hopkins (Engel, Nikoomanesh,&Shuster, 1974).This involves training patients to coordinate or synchronize contractions of the pelvic floormuscles in response to intrarectal distention by simultaneously using pressure feedbackfrom intrarectal balloon distension and pressure feedback from pelvic floor muscle contraction,and is performed with a balloon-tipped water-perfused catheter or a three-balloonprobe.Second in frequency of use is strength training, which aims to strengthen the externalanal sphincter without employing rectal distension. Strength training is accomplished withthe aid of either anal canal pressure feedback or intraanal or perianal electromyographic(EMG) feedback.A third and far less often reported training approach involves systematically teachingpatients to improve their ability to sense diminishing rectal distentions without trainingPFMcontractions. This is done by using controlled amounts of intrarectal pressure applied viaa computer-inflated balloon. Such sensory training is rarely done alone, but complementsotherBFtraining, and several studies have suggested that including it may enhance outcomes(Glia, Glyin, Golberg, & Lindberg, 1997; Latimer, Compbell, & Kasperski, 1984; Miner,Donnelly, & Read, 1990).Biofeedback for Anorectal PainAll three of the prospective studies of BF for anorectal pain used pressure feedbackfrom the external anal sphincter.Regardless of the specific biofeedback protocols used to treat anorectal disorders,the inclinic biofeedback training is almost invariable supplemented with other potentiallytherapeutic components. These often include advice, reassurance and patient education,prescribed pelvic floor home exercises, practice with balloon defecation, laxatives, enemas,fiber supplements, or the use of EMG biofeedback home trainer devices.The number of BF sessions used in published studies to treat patients for functionalanorectal disorders varies greatly, and ranges from 1–12 sessions. Many studies reportedhigh success rates with as few as 3 or 4 sessions per patient.Biofeedback for Functional Anorectal Disorders 159Research on the Relative Effects of Different BF ProtocolsThree studies have attempted to compare the relative benefits from coordination training,strength training, and sensory training for incontinence. Two of these (Latimer et al.,1984; Miner et al., 1990) used complex crossover designs that were inadequate for providingconclusions in regard to the relative effect of different treatment components (for example,did not control for order effects and were not adequately powered for multiple group comparisons).Heymen and colleagues (2000) randomized patients to four parallel groups, tocompare EMG strength training alone, EMG training with a home trainer, and combinedEMG and pressure feedback (coordination training) with or without a home trainer. Theyfound no difference in outcome between the four groups, all of which improved significantlyin incontinence after treatment.Heymen et al. (2001) conducted a metaanalysis weighted by the number of participants,comparing FI treatment outcomes (measured in frequency of incontinence episodes) of 19BF studies using coordination training versus 12 studies using strength training, and foundno advantage for one treatment strategy over another.Within the subset of strength trainingstudies, they also compared the six studies using EMG training to the six utilizing pressurefeedback, and found EMG to produce significantly more favorable outcomes.Three studies have compared EMG and pressure feedback training for PFD(Bleijenberg & Kuijpers, 1994; Glia et al., 1997; Wang, Luo, Qi, & Dong, 2003). OnlyBleijenberg and Kuijpers (1994) found a difference in outcome, reporting EMG training toresult in far higher success rate (73% vs. 22%) but their group sizes were quite small (11 and9 participants, respectively). In contrast, a metaanalysis by Heymen et al. (2003) comparingoutcomes in 13 studies using pressure feedback to those of 18 studies using EMG feedbackfound pressure feedback to be associated with significantly better outcomes on the average.Review of BF Trials for PFD or Functional ConstipationA total of 38 studies on PFD or constipation without recognized organic causes metinclusion criteria for review (see Table I). Eight of these (23%) were controlled outcomestudies. All except one of the controlled studies were studies on children.Randomized Controlled TrialsIn the only controlled study of adult PFD, Koutsomanis et al. (1995) compared atreatment protocol using perianal EMG biofeedback plus balloon defecation training versusballoon defecation alone in a randomized study of 60 adult constipation participants, mostof whom had evidence of PFD. Patients with structural causes for their constipation wereexcluded. They found no difference in outcome between the groups. participants were treatedin an average of three sessions with BF and two sessions for the balloon defecation practice.Loening-Baucke (1990a) randomized 43 children age 5–16 who all had PFD definedby documented abnormal contraction of the external anal sphincter and pelvic floor duringdefecation attempts to receive either coordination-type biofeedback plus conventional medicalcare or only conventional care. All the children had fecal impaction and encopresis.The conventional care given to both groups included initial enema for disimpaction, dailylaxatives, toileting schedule, and increased fiber in the diet.160 Palsson, Heymen, and WhiteheadTable I. Biofeedback Trials for Functional Constipation or PFDAuthors & year # of patients (f/m) Age range Biofeedback method Control treatment Outcome comparisonA. Randomized controlled trialsKoutsomanis Lennard-Jones, Roy, and Kamth (1995) 60 (53/7) 20–64 paEMG (n = 30) Balloon defecation 69%/64% no differenceLoening-Baucke (1990a) 41 (10/31) 5–16 coord. (n = 22) Medical management 55%/5% BF superiorNolan, Catlo-Smith, Coffey, and Wells (1998) 29 4–14 coord. (n = 14) Medical management 29%/40% no differenceWald, Chandra, Gabel, and Chiponis (1987) 50 (40/10) 6–15 press. (n = 24) Mineral oil (n = 26) 54%/54% no differencevan der Plas, Benninga, Redirop, et al. (1996) 192 5–16 coord. (n = 98) Medical management 32%/33% no differenceSunic-Omejc et al. (2002) 49 (22/27) M = 7.5 coord. (n = 25) Medical management 84%/62.5% BF superiorB. Nonrandomized controlled trialsCox et al. (1994) 26 (8/18) 4–16 paEMG (n = 13) Medical management 88%/60% BF superiorLoening-Baucke (1995) 129 M = 9 coord. (n = 61) Medical management 44%/62% no differenceC. Uncontrolled trialsBeminga Buller, and Taminiau (1993) 29 (12/17) 5–16 paEMG 55Bleijenberg and Kuijpers (1987) 10 19–48 iaEMG 70Bleijenberg and Kuijpers (1994) 20 (15/5) 20–50 iaEMG/press. 73/22Dahl et al. (1991) 14 (10/4) 6–60 iaEMG 93Dailianas et al. (2000) 11 press. 64Emery et al. (1988) 65 (5/34) 5–77 paEMG 80Fleshman et al. (1992) 9 (8/1) 35–62 iaEMG 89Glia et al. (1997) 26 (23/3) 28–78 iaEMG, press., coord. 58Heymen et al. (1999) 36 (26/10) 18–82 iaEMG/press./coord. not reported; significantimprovementHo, Tan and Goh (1996) 62 (38/24) M = 48 press. 90Hibi, Iwai, Kimura, Sasaki, and Tsuda (2003) 10 60Karlbom, Hallden, Eig-Olofsson, Pahlman, and Graf (1997) 28 (23/5) 22–72 iaEMG 43Kawimbe, Papachrysostomou, Binnie, Clare, and Smith (1991) 15 (12/3) 22–76 iaEMG not reported; significantimprovementKeck et al. (1994) 12 (10/2) press. 25Keren, Wagner, Heldenbert, and Golan (1988) 12 press. 100Ko et al. (1997) 17 iaEMG 76Koutsomanis, Lennard-Jones, and Kamm (1994) 20 (18/2) adults iaEMG 85Loening-Baucke (1991) 38 (10/28) 6–15 paEMG 37Lestar et al. (1991) 16 (10/6) M = 42.5 press. 56McKee, Mcenvoe, Anderson, and Finlay (1999) 30 (30/0) 15–55 press. 32Papachrysostomou and Smith 122. iaEMG 86Patankar et al. (1997) 116 (88/28) 33–85 iaEMG 84Rao, Enck, and Loening-Baucke (1997) 25. coord., press., sens. 60Rhee et al. (1999) 45 (32/13) 21–72 iaEMG 69Rieger, Watlchow, Sarre, Saccone (1997b) 19 (18/1) 16–78 iaEMG 13Turnbull and Ritro (1992) 7. press. 86Veyrac, Granel, Parelon, and Michel (1987) 12. press. 83Wang et al. (2003) 50 (36/14) 16–71 coord., paEMG 62Weber, Ducrotte, Touchais, Roussigno and Denis (1987) 42 press. 65Wexner, Cheape, Jorge, Heymen and Jagelman (1992) 18 iaEMG 89Note. coord. = cordination biofeedback training; press. = Pressure biofeedback training; paEMG = perianal EMG biofeedback; iaEMG = Intraanal EMG biofeedback; MM = Medical management;PFE = Pelvic floor exercises; HT = Home trainer; M = mean.Biofeedback for Functional Anorectal Disorders 161One child dropped out of each group. The children who receivedBF showed higher rateof successful symptom resolution at seven months than controls (55% vs.5%at 7 months and50% vs. 16% at 12 month follow-up). The biofeedback group also exhibited a far higher rateof normalization of defecation dynamics (77% vs. 13%). This report is exemplary in manyways; It studied a well-defined PFD population in a successfully randomized (comparablegroups) sample of adequate size with well-defined outcome criteria and a well-demarcatedand uniform follow-up, and used a well-described biofeedback procedure.Sunic-Omejc et al. (2002) randomized 49 children under the age of 5 with well-definedchronic constipation without organic pathology to 12-week treatment regimens consistingof standard medical management either with or without BF. Abnormal defecation dynamicswere found in 56% of BF participants and 58% of controls at baseline. Standard managementincluded oral laxatives, disimpaction, high-fiber diet, and toilet scheduling. The biofeedbackgroup received coordination feedback training in the clinic and practiced Kegel exercisesat home. participants in the two groups were comparable in clinical and demographic characteristics.At the end of 12 weeks, significantly more children in the BF group (84% vs.62.5%) had successful treatment outcome according to well-defined bowel symptom criteria.Clinical improvement was correlated with normalization of manometry findings anddefecation dynamics. The absence of a medium-term or long-term follow-up was the mainshortcoming in this otherwise well-conducted study. The young age of the participants inthe study is noteworthy, as clinicians sometimes consider age 5 to be the lowest age suitedfor BF training of this kind.van der Plas, Benninga, Redekop, et al. (1996a) randomly divided children aged 5–16 years who had been diagnosed with pediatric constipation into a group that receivedstandard medical care plus five biofeedback sessions using anal canal pressure and EMGfeedback (98 patients), and a group that only received standard medical care (94 patients).About 60% of the study sample had abnormal defecation dynamics on manometric testing(PFD) prior to treatment.Treatment involved the same number of clinic visits for both groupsand both received the same standard care, including laxatives, dietary advice, toilet training,and the keeping of a bowel habit diary. After treatment, 32% of the BF group and 33% ofthe standard care group had successful symptom resolution, defined as defecation at least3 week, soiling and/or encopresis less than twice a month, and no laxative use. Both groupsalso had equivalent outcomes at 6, 12 and 18-month follow-ups, although the success ratewas higher at these points, or about 50% for both groups. In contrast with the equal clinicaloutcome between the groups, the group that received biofeedback-augmented treatmenthad a significantly greater rate of normalization of defecation dynamics after treatment(a change from 38% to 86% of participants) compared to the standard care group (41to 52%). This normalization of physiological activity, however, was unrelated to clinicaloutcome.Nolan et al. (1998) compared standard medical care alone or with the addition of 3–4session coordination biofeedback in 29 children with PFD between the ages of 4 and 14.There were no significant differences in outcomes between the two groups; 4 out of 14 BFchildren and 6 out of 15 controls improved. However, like van der Plas, Benninga, Redekop,et al. (1996) above, these investigators found that the biofeedback training group showedgreater normalization of paradoxical defecation activity, even though this did not translateinto greater symptom improvement.Wald et al. (1987) randomized a mixed group of 50 children to either pressure biofeedbackor mineral oil treatment. All but three participants had fecal impaction or stool retention,162 Palsson, Heymen, and Whiteheadand 16 had manometric evidence of PFD. The two groups were comparable on all clinicaland demographic characteristics. The investigators found no difference in outcome aftertreatment or at follow-up, but there was a nonsignificant trend for the PFD children to dobetter with biofeedback and those with normal defecation physiology to respond better tomineral oil.Nonrandomized Controlled TrialsCox et al. (1994) compared 13 children receiving 1–6 sessions of perianal biofeedbackand standard medical care to 13 age- and gender matched controls receiving only standardmedical care. All the children had PFD and ranged in age from 4 to 16 years. Unlike in moststudies, the BF group was weaned off the standard care during the BF intervention. Thechildren received 1–6 biofeedback training sessions with perianal EMG, and conductedparent-supervised sphincter exercises at home. The biofeedback group was significantlymore improved at 16-month follow-up in regard to constipation and encopresis and ratedlower on laxative use and pain during defecation.Loening-Baucke (1995) compared long-term treatment outcomes for PFD childrentreated with an intensive standard medical management program alone to 63 children whoalso received 1–6 biofeedback sessions to train normalization of defecation dynamics.At 3–5 year follow-up, 62% of conventionally treated children and 50% of those who hadsucceeded in biofeedback (the differencewas not significant between those two groups) wereimproved. A significantly lower proportion (23%) of children who had failed biofeedbacktraining improved. Twenty-one of the children in the BF group had been randomized tothat treatment as a part of the author’s previous trial. The remaining 42 BF recipients(2/3 of the BF group) were only provided with BF after 6 months of standard medicalmanagement efforts had failed to produce results. The author concluded that biofeedbackdoes not enhance long-term symptom outcomes in PFD, but this conclusion is hardlyjustified, due to the flawed comparison: Applying BF to a subset of children who have beenunresponsive to intensive multimodal treatment effort for 6 months is hardly a fair test ofthe value of this treatment modality as an adjunct to standard medical management.Uncontrolled TrialsTwenty-nine uncontrolled studies on functional constipation were found in the literature.These are summarized in Table I ©. Seventeen of these were on BF for adultparticipants, five were on children, and eight included both adults and child participants.Reported success rates varied greatly, ranging from 13 to 100%, but most of the uncontrolledstudies reported 50% or better success rate. Two studies (see Table I ©) did not reportsuccess rates or present data to calculate these, but both reported significant improvementfrom BF treatment.Review of BF Trials for Fecal IncontinenceAtotal of 34 studies met inclusion criteria for review(see Table II). Five of these (15%)were controlled outcome studies.Biofeedback for Functional Anorectal Disorders 163Table II. Biofeedback Trials for Functional Fecal IncontinenceAuthors & year # of patients (f/m) Age range Biofeedback method Control treatment Outcome comparisonA. Randomized controlled trialsNorton et al. (2003) 171 (159/12) 26–85 sens., coord., press. (n = 49) MM/MM+PFE/MM+ BF:53%, MM 54% no groupPFE+BF/MM+PFE+BF+HT differencesvan der Plas, Benninga, Buller, et al. (1996) 71 5–16 perianal EMG (n = 38 ) MM/MM+BF 39%/19%, no group differenceMiner et al. (1990b) 25 (17/8) 17–76 sens. press./coord. (n = 12) Ballon inflation w/o feedback Only BF group improved;76% (44%)B. Nonrandomized controlled trialsLoening-Baucke (1990b) 17 35–78 coord. MM 50%/56% no group differencesGuilllemot et al. (1995) 24 (19/5) 39–78 press. MM 56%∗/0%∗ BF superiorshort-term% improved (% symptom-free)C. Uncontrolled trialsArhan et al. (1994) 47 5–18 coord. 69Buser and Miner (1986) 13 (7/6) 13–66 coord. 92 (92)Cerulli, Nikoomanesh, and Schuster (1979) 50 (36/14) 6–97 coord. 72 (40)Chiariaoni, Seattolini, Bonafante, 14 (10/4) 24–75 coord. 86 (64)and Vantini (1993)Enck, Daublin, Lubke, and Strohmeyer (1994) 18 (14/4) 33–83 coord. (22)Engel et al. (1974) 7 (5/2) 6–54 coord. (71) 57Faure, Ferriere, Maurauge, and Rolland (1995) 26 coord. 62Fox et al. (1991) 59 EMG 84 (78)Glia et al. (1998) 22 (22/4) 32–82 coord. 64Heymen et al. (2000) 34 (23/11) 36–88 EMG., press, coord. not reported, no significantimprovementKeck et al. (1994) 15 (13/2) 29–65 press. 73 (27)Ko et al. (1997) 25 (21/4) 31–82 EMG 92 (44)Latimer et al. (1984) 8 (4/4) 8–72 Press/Sens/Coord. 100(88)MacLeod (1987) 113 (67/46) 25–88 EMG 63McLeod (1983) 50 (26/24) M = 55 EMG 72Magrini, Pallotta, Koch, and Capurso (1997) 6 (5/1) M = 50 press. 100(100)Martinez-Puente, Pascual-Montero, 53 (42/11) 26–83 sens., press., coord. 66and Garcia-Olmo (2003)Nicastro et al. (1997) 116 (85/31) 11–86 EMG 81Norton, Chelvanayagama, Wilson-Barmett, 100 (84/16) 14–82 press. 67 (43)Redfern, and Kamm (2003)Olness, Mcferland, and Piper (1980) 50 4–15 coord. 60Patankar et al. (1997a) 72 (43/29) 34–87 EMG 85Rao, Welcher, and Pelsang (1996) 19 15–78 press/sens/coord. 53 (53)Rieger et al. (1997a) 30 (28/2) 29–85 EMG 67 (20)Ryn et al. (2000) 37 (36/1) 22–82 EMG 60Sangwan et al. (1995) 28 (22/6) 30–74 press. 75Wald (1981) 17 (11/6) 10–79 coord. 71 (59)Whitehead, Burgio, and Engel (1985) 18 (15/3) 65–92 coord. 67Note. coord. = cordination biofeedback training; press. = Pressure biofeedback training; paEMG = perianal EMG biofeedback; iaEMG = Intraanal EMG biofeedback; MM = Medical management;PFE = Pelvic floor exercises; HT = Home trainer; M = mean.164 Palsson, Heymen, and WhiteheadRandomized Controlled TrialsNorton et al. (2003) randomly assigned 171 well-characterized adult FI patients tofour groups: (1) a standard care group; (2) standard care plus instruction in anal sphincterexercises taught verbally and via digital examination; (3) standard care, anal sphincterexercises plus computer-assisted BF involving coordination techniques with visual feedbackof sphincter contractions; or (4) same as group 3 plus daily use of an EMG hometrainer device. Outcome measures were wide-ranging, and included symptom diary, qualityof life and psychological questionnaires, continence score, patient’s self-assessment ofsymptom improvement, and repeated anal manometry testing. Nineteen percent of participantsdropped out before completing the study. About half of participants in all groups whocompleted the study improved after treatment, with no significant group differences on anyoutcome measures after treatment nor at 1-year follow-up: 53% of patients improved fromstandard care alone compared to 54% in the biofeedback group (group 3). Improvementwas seen across a wide range of bowel symptom, psychological and physiological outcomemeasures, and most treatment responders still showed improvement at 1-year follow-up.Interestingly, anal canal pressures improved across all groups, including the standard caregroup.This trial appears to have been methodologically sound in most regards, includinggroup sizes, outcome measures, effective randomization to treatments, and characterizationof participants. It is the largest trial comparing BF to other treatments to date. However,the report lacked detail in regard to the biofeedback protocol used, and the number ofbiofeedback sessions completed by the BF group participants was not provided.van der Plas, Benninga, Buller, et al. (1996) allocated 71 children who had wellcharacterizedchildhood FI without constipation to standard care and laxatives or standardcare, laxatives, and biofeedback. The biofeedback group showed a nonsignificant trendtoward more clinical improvement (39% vs. 19%, p = .07) after treatment. At 12 and 18months approximately half of the children in both groups showed successful symptomresolution. This study was generally adequate in design and methods, although a largersample might have revealed a significant short-term outcome advantage for biofeedback.Miner and colleagues (1990) randomized 25 adults to either three-session sensorybiofeedback training or the same amount of balloon inflations in the bowel without feedbackor instruction. This was followed by a complicated crossover design where patients in bothinitial groups received other biofeedback components. However, the first part of the studyconstituted a controlled comparison of active sensory feedback versus no feedback, andthe investigators found that only the active biofeedback group significantly reduced thefrequency of fecal incontinence episodes from pre- to posttreatment evaluation. However,because of the small sample in this underpowered trial, the group comparison was notsignificant.Nonrandomized Controlled TrialsGuillemot et al. (1995) treated 16 patients with constipation of varied etiology withbiofeedback and compared them to eight patients who were treated with medications. Allpatients were adults. participants were allowed to select which treatment they received.Significant improvements relative to baseline was found in the biofeedback group only atBiofeedback for Functional Anorectal Disorders 1656-month follow-up, but the improvement was no longer significant at the last follow-up at24–36 months. The authors did not report a statistical group comparison of outcome. Theydid not report success rate either. However, as they presented individual summary scoresfor fecal incontinence for all participants, we were able to calculate a 56% 6-month successrate for biofeedback, using ≥75% reduction in incontinence summary score as a criterion,versus 0% success for the control group.Loening-Baucke (1990b) compared nine incontinent adult patients treated with standardmedical management to eight patients who received pressure BF in addition to standardcare, and found no advantage in the addition of biofeedback (50% success rate forBF versus 56% for conventional therapy at 3 months, and 38% versus 55% at 1-yearfollow-up).Uncontrolled TrialsTwenty-seven uncontrolled studies on fecal incontinence were found in the literature.These are summarized in Table II ©. Fifteen of these were on BF for adult participants,three were on children, and eight included both adults and children. One paper (Glia et al.,1998) did not report success rate, but stated that there was no significant success after BFtreatment. All the remaining studies except one (Enck et al., 1994) reported success ratesabove 50% for BF.Review of BF Trials for Anorectal PainRandomized Controlled TrialsThree clinical trials of BF for functional anorectal pain were found in the literature(see Table III), none of which were randomized.Nonrandomized Controlled Clinical TrialsOnly one study was found in the literature that examined biofeedback treatment in anykind of controlled fashion. In that study, Ger and colleagues (2002) provided three differenttreatments to adults who had anorectal pain without organic pathology and had failed conservativemedical management; biofeedback (14 patients) electrogalvanic stimulation (29patients), and steroid caudal block (11 patients). At follow-up 2–36 months after treatmentcompletion, 43% of BF patients versus 38% of those who had electrogalvanic stimulationand 18% of patients who had steroid block treatment reported successful pain relief. Theseresults were not statistically different between groups. Apart from the lack of randomizationinto groups and the broad variability in follow-up time points across participants, theconclusions that may be made from this study are very limited due to the confound thatmany participants received more than one of the test treatments, in varying order.Uncontrolled TrialsA couple of uncontrolled studies have offered a suggestion that BF may be successfullyused to treat anorectal pain. Grimaud and colleagues (1991) treated 12 patients with166 Palsson, Heymen, and WhiteheadTable III. Biofeedback Trials for Functional Anorectal PainAuthors & year # of patients (f/m) Age range Biofeedback method % improvedUncontrolled trials (no controlled outcome trials were found in the literature)Grimaud, Bouvier, Naudy, 12 (8/4) 24–66 press. 100Guien, and Salducci (1991)Heah, Ho, Tan, and Leong (1997) 16 (7/9) 39–66 press. % not reported, significant improvementNonrandomized controlled trials Outcome comparison: CommentsGer et al. (1993) 38 (17/21) M = 71 press. Electrogalvanic stimulation, No group difference; 43%steroid caudal block improved after BFNote. coord. = cordination biofeedback training; press. = Pressure biofeedback training; paEMG = perianal EMG biofeedback; iaEMG = Intraanal EMG biofeedback; MM = Medical management;PFE = Pelvic floor exercises; HT = Home trainer; M = mean.Biofeedback for Functional Anorectal Disorders 167functional anorectal pain with pressure biofeedback to enhance control of the external analsphincter, and reported that all patients improved, with a mean of eight sessions neededto achieve benefit. The improvement was maintained in 11 of the 12 patients beyond a16-month follow-up.Heah et al. (1997) treated 16 patients with balloon pressure biofeedback. The patientswere significantly lower on pain scores as a group after treatment. Success ratewas not statedin this report. However, it was noted that all but two out of the 16 patients discontinued useof analgesics after treatment.Assessment of the Quality of the LiteratureA critical examination of the reviewed studies highlighted five major shortcomingsshared by the majority of the published studies on BF treatment of functional anorectaldisorders to date.1. The great majority of studies did not use non-BF control groups.Of all the identifiedstudies meeting selection criteria, 80% had no non-BF control group. Uncontrolledoutcome studies, no matter how numerous, offer little help in establishing theefficacy of a treatment because they do not allow the necessary direct assessment ofthe relative impact of the treatment tested on the problem compared to other types ofintervention. Additionally, uncontrolled trials are highly vulnerable to bias that mayinflate success rates, such as self-selection of the most highly motivated or mostqualified patients into the experimental treatment. Uncontrolled studies adding BFto standard medical management are especially problematic in studies of disorderslike PFD and functional FI where, as mentioned above, a substantial proportion ofpatients are known to respond well to conventional medical management (whichmay involve such things as practical symptom management advice, diet changes,habit training, and laxatives). In the absence of direct comparison with patientsreceiving standard care only, treatment response must be very high to offer anyassurance that it is in excess of what might be expected from standard care. Only aminority of the uncontrolled studies in the literature provided BF to patients whohad failed to benefit standard medical care, which seems more reasonable in studieswithout control groups (making patients their own controls) to be able to attributethe observed treatment response to the BF intervention.2. Sample sizes were often too small for full utility of the results. Studies employingcontrolled comparisons or crossover designs sometimes clearly lacked power toreach the conclusions that they aimed for. Uncontrolled studies were often toosmall to allow analysis of factors that might predict outcome, such as demographicvariables or manometric findings.3. Outcome measures and treatment responder definitions varied greatly. The mostcommon report of clinical outcome was the proportion of patients who were “improved”after treatment or at follow-up by some specified or nonspecified standard.The lack of uniformity in what is deemed clinical improvement in this body ofresearch makes comparison of outcomes across studies very difficult.4. Enrollment criteria varied greatly across studies and were often overly inclusive.In many of the studies reviewed, participants with functional anorectal disorders168 Palsson, Heymen, and Whiteheadwere mixed with similar symptoms due to other conditions (for example, symptomsattributable to bowel surgery or obstetrical sphincter tear). Likewise, patients withslow-transit constipation were sometimes grouped together with PFD-type constipationpatients in constipation BF trials, even when the biofeedback treatmenttested aimed at normal
 
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