Novel insight into the coordination between pelvic floor muscles and the glottis through ultrasound imaging: a pilot study

Introduction: Pelvic floor physical therapists have long utilized breathing cues with exercises and are beginning to incorporate vocalization tasks. To date, there have been no publications describing pelvic floor displacement during vocalization tasks. This study is a preliminary investigation into the changes in bladder shape distortion as a proxy for pelvic floor muscle displacement during respiratory and phonatory tasks. Methods: Bladders were imaged using two-dimensional ultrasound in standing position. Measurement consisted of a diagonal line from the most anterior–superior aspect of the bladder to the most inferior–posterior aspect of the bladder. Length was measured at baseline and maximum distortion for each task. The first two tasks cued pelvic floor muscles to contract and then strain. Subsequent tasks only cued glottis function. A linear regression tested correlation between bladder distortion response to glottis tasks and cued pelvic floor tasks. The hypothesis was that diagonal would shorten with contraction, lengthen with strain, and follow a similar pattern seen in respiration for phonation tasks. Results: Ten asymptomatic participants (5 men, 5 women) showed bladder diagonal shortening when cuing pelvic floor contraction for all participants and lengthening for 7 of the 10 participants when cued to strain the pelvic floor. The response of bladder length change was variable for glottis tasks, trending toward lengthening and significantly different in response to contraction. Conclusions: When cuing pelvic floor to contract, healthy individuals showed shortening of bladder length and most lengthened during strain. When cuing phonation and respiration tasks, there was a tendency toward bladder lengthening.