Reflex Pelvic Floor Muscle Activities in Women with Urinary Incontinence (Ii)

Normal pelvic floor muscle function is defined as the ability to perform a normal or strong voluntary contraction and to present an involuntary (or reflex) contraction preceding or during increased intra-abdominal pressure, resulting in a circular closing of the levator hiatus and in a cranio-ventral or inward-upward movement of the perineum and pelvic floor structures. The voluntary or involuntary pelvic floor muscle contraction (PFMC) may prevent or limit the displacement of the pelvic floor, maintain normal positions of pelvic viscera, and assist urethral and anal closure. The ultrasonographic measures for reflex PFMC represented by anorectal lifts and inward clitoral movements during coughing have been proven valid and reliable. An anorectal lift is a direct exertion by levator ani muscle whereas an inward motion of the clitoris is an indirect action by the bulbocavernosus muscles. These two involuntary PFMC patterns appear to be involved in constricting genital hiatus and stabilizing pelvic floor structures. Our pilot study demonstrated a good reliability for assessing reflex PFMC using ultrasound, with Cohen’s k values ranging from 0.645 to 0.679 Nevertheless, the impact of reflex pelvic floor muscle contraction on female lower urinary tract symptoms, especially urinary incontinence, has not been well explored. This is the aim of this 4-year-period proposal. During the first-year-period observation, we did find that significant associations of reflex pelvic floor muscle contraction with incontinence severity and quality of life in the women who had urodynamic evidence of stress urinary incontinence. We believe this research project is practical and could provide valuable information regarding the pathophysiology of urinary incontinence.