ELECTROMYOGRAPHIC ASSESSMENT OF BIOFEEDBACK TRAINING FOR FECAL INCONTINENCE AND CHRONIC CONSTIPATION

INTRODUCTION: Biofeedback: training is an effective modality for the t reatment of chronic constipation and fecal incontinence. In general, p atients express satisfaction and perceive functional improvement follo wing biofeedback therapy; however, quantifying these observations has been difficult. AIM: This study was undertaken to evaluate the physiol ogic benefits of biofeedback therapy as reflected by noninvasive elect romyography parameters. METHODS: Fifty-five patients who underwent com puterized electromyography-based biofeedback treatment at our institut ion between July 1993 and July 1995 were identified. Noninvasive elect romyographic testing was performed before, during (weekly), and at com pletion of training. Mean number of weekly sessions was seven (range, 5-11). Short-term and ten-second contractions (amplitude/mu V), sustai ned contractions (endurance, in seconds), and net strength (mu V) of t he external anal sphincter before and after biofeedback were compared for differences. RESULTS: There were 30 patients with chronic constipa tion, mean age, 65.3 (range, 33-86) years, composed of 24 women, and 2 5 patients with fecal incontinence, mean age 66 (range, 34-85) years, composed of 12 males. Statistically significant improvement in enduran ce and net strength following biofeedback training was noted in both t he constipated and the fecal incontinence groups. Fifty-three of 55 (9 6.4 percent) patients expressed 50 to 100 percent subjective satisfact ion after biofeedback therapy. Forty-six of 55 (83.6 percent) patients demonstrated individually improved endurance. CONCLUSIONS: Sphincter endurance and net strength, as measured by noninvasive electromyograph y, significantly improve following biofeedback therapy in both constip ated and fecal incontinence patients. These data suggest that enduranc e and net strength may be useful tools in assessing a benefit from bio feedback training in these patients.