Results

PATIENT CHARACTERISTICS

All patients were contacted and agreed to participate in the study (table 1). Median age was 38 years and median duration of multiple sclerosis symptoms 10 years (range 7–20 years). All had constipation, and nine had additional faecal incontinence. The median length of follow up from completing the course of biofeedback to the time of interview was 14 months (range 5–23 months).

Five patients were mildly to moderately disabled (DSS⩽5 and CAMBS D1-D2). Eight patients were severely disabled and dependent on others for care (DSS>5 and CAMBS D3-D4).

Bowel dysfunction was marked. Ten patients had an EDSS of 4 or more, and nine had an ISS for bowel of 3 or more. ISS for bladder demonstrated the whole range of bladder dysfunction, with eight patients using an indwelling or external catheter. There was no correlation between the severity of bowel and bladder dysfunction, rated by EDSS or by ISS, and the severity of impairment and disability, rated by DSS or CAMBS.

ANORECTAL PHYSIOLOGY STUDIES

Most patients had abnormal physiological studies compared with our normal values.15 Maximum anal resting pressure (reflecting internal anal sphincter function) was normal for most patients (77%), but most (62%) had a weak voluntary squeeze pressure, including six out of the nine patients complaining of faecal incontinence. Nearly all patients (85%) had impaired pelvic floor coordination on straining. Sensation to rectal distension was impaired in two patients and to an electrical stimulus in one of these patients. Both patients with impaired sensation were severely disabled.

BIOFEEDBACK

Each patient had one full course of biofeedback. Two to five sessions a patient were given over a period of 4 to 6 months. The number of sessions depended on whether the patient and therapist perceived that progress was being made.13

After a median of 14 months follow up (range 5–23), five patients expressed a benefit from biofeedback (table 1). Of the patients whose main complaint was constipation the main beneficial effect was on reduction in straining, as opposed to a change in bowel frequency. One patient stopped taking laxatives and two others reduced them substantially. Urgency and urge incontinence was initially reported in all patients with faecal incontinence and usually persisted after biofeedback or recurred at follow up. However, incontinence was usually less severe, as reflected in the use of pads by three patients before treatment and none on follow up.

Eight patients expressed no or only slight benefit from biofeedback. Two had a marked benefit immediately after treatment, which was not sustained at follow up, and one ultimately had an ileostomy created.

PREDICTORS OF OUTCOME

Patients who benefited from biofeedback were those with mild or moderate disability, with a quiescent or a non-relapsing pattern, who improved after a relapse and those with only minor changes in the natural history of their multiple sclerosis over the year before treatment. Patients failing to benefit from biofeedback were those with a severe disability, with worsening, deteriorating or progressing multiple sclerosis (table 2).

All patients who benefited from biofeedback had a raised EDSS and ISS for bowel function. At follow up the improvement in bowel symptoms was not reflected by changes in these scales, and no correlation was found between the scores and the response to biofeedback. Physiological studies and the presence of paradoxical puborectalis contraction did not predict the response to biofeedback.

Discussion

Biofeedback leads to symptomatic improvement in about two thirds of non-neurological patients with constipation13 and faecal incontinence.14 Although biofeedback and pelvic floor rehabilitation have proved to be efficient in some patients with multiple sclerosis with bladder dysfunction,16 this approach has not been previously reported in patients with multiple sclerosis complaining of bowel dysfunction. Biofeedback benefited patients with mild to moderate disability. Over a third considered themselves to have benefited in the medium term.

The assessment of patients with multiple sclerosis is difficult, as the natural history of the disease results in clinical deterioration and improvement over short periods of time. Although Kurtzke scales have gained international acceptance, we found that the imprecise terminology (for example, “retention of bowel”, “measures to evacuate stool”, “loss of bowel function”, “occasional incontinence”, “frequent soiling”) rendered the application of the EDSS or the ISS unhelpful in both assessing patients' dysfunction, and in assessing response to biofeedback. Kurtzke himself has criticised the EDSS since the separation between scores is narrow especially at the middle grades.17 The CAMBS has been shown to be a reliable outcome measure in patients with multiple sclerosis.18 We found that using the four component structures of the scoring system delivered a great deal of information in a simple way and that the assessment of disability, relapse, and progression all correlated with the response to biofeedback.

Constipation may be associated with either prolonged colonic transit time,8 or with pelvic floor dysfunction.8 19 20 Altered colonic compliance in patients with advanced multiple sclerosis21 may be a factor. Medications commonly prescribed to patients with multiple sclerosis, such as muscle relaxants or anticholinergic drugs, are also known to cause constipation. Finally, psychological factors or behavioural problems may also affect toileting.

Impaired faecal continence can be related to bowel or sphincter disturbance. The bowel can generate very high pressures during contraction, resulting in urgency and incontinence. If the anal sphincter is weak, the pressure in the anal canal is not maintained so that patients leak stool without being aware of it. Any or all of these mechanisms can occur. Factors linked with multiple sclerosis, such as fatigue, general muscle weakness, spasticity, poor mobility, and difficult access to the toilet can also contribute to incontinence.

Anorectal pathophysiological findings were consistent with previous studies.3 8 19 22 The reduced squeeze pressure (reflecting external anal sphincter dysfunction) may be related to multiple sclerosis in the same way that function of any striated muscle can be impaired. Whether the pelvic floor incoordination shown in some patients with multiple sclerosis20 23 should be regarded as a behavioural phenomenon, as in non-neurologically impaired patients, or as related to the multiple sclerosis, as in the multiple sclerosis related dyssynergia of striated urethral muscle,24 is as yet unknown. Impaired anorectal sensation was an infrequent finding in our patients, as reported by others.8 Impaired rectal or anal sensitivity to an electrical stimulus suggests that multiple sclerosis may be involved in the pathogenesis of the incontinence in some patients, as these tests are usually normal in non-neurological causes of incontinence. Due to the small size of the group no physiological test was predictive of the outcome.

Biofeedback aimed to condition patients to be more sensitive to a stimulus distending the rectum and to heighten the voluntary striated muscle sphincter response. Behavioural modification and improving pelvic floor function is the main goal. Bowel management in patients with multiple sclerosis involves counselling, health education, and biofeedback among other behavioural techniques. The main finding in this study was that patients with mild and moderate multiple sclerosis have a reversible component to their bowel dysfunction.