ICS 2022: A Short Story In Proprioceptive Facilitation To The Pelvic Floor – A Proof Of Concept Study Using INNOVO

(UroToday.com) Proprioception is fundamental to motor learning, and sensorimotor afferents may facilitate changes in motor control. Neuromuscular electrical stimulation (NMES) is used clinically as an adjuvant intervention to facilitate pelvic floor muscle (PFM) contractions. Neural imaging shows that NMES contractions activate similar cortical and subcortical structures to volitional ones. Consequently, these NMES elicited contractions may enhance proprioception and PFM function.

INNOVO shorts consist of 8 embedded electrodes, with a cumulative stimulating surface area of 1200cm2 with a maximum current density of 0.189 mA/cm2. The electrodes are positioned bilaterally around the pelvis, anterior and posterior thighs. INNOVO uses patented multipath stimulation delivered via a pulsed, symmetrical, rectangular biphasic waveform at 50Hz. A pulse duration of 620µs was delivered for 5 minutes (on:off time of 5sec:5sec), resulting in 30 elicited PFM contractions.

This proof of concept study of 10 healthy continent women (23 – 57 yrs) aimed to determine if NMES delivered in a pair of shorts (INNOVO) provided a proprioceptive stimulus to enhance PFM function in healthy women who were able to perform a PFM contraction. A bladder-filling protocol facilitated the delineation of structures during transabdominal ultrasound imaging (TAUS). The magnitude of bladder base displacement (BBD) was measured in centimeters (cm) under 3 conditions in standing: pre-NMES volitional contractions, INNOVO NMES contractions, and post-NMES volitional contractions with at least a 5-minute washout period between conditions. Participants were blinded to ultrasound imaging and verbally cued to perform volitional PFM contractions pre and post-INNOVO NMES. No verbal cues were given during INNOVO NMES, which was delivered at each participant's maximum tolerable amplitude (mA) to elicit a PFM contraction confirmed by a cranial displacement of the BBD observed with TAUS.

The findings suggest that a 5-minute bout using INNOVO NMES provided a proprioceptive sensorimotor stimulus that significantly enhanced pelvic floor function. All PFM contractions postNMES showed a greater magnitude of BBD when compared to baseline. Studies report that NMES elicited muscle contraction plays a role in proprioception by stimulating muscle spindles and Golgi tendon organs that send afferent information to the somatosensory cortex. High NMES amplitudes, which elicit a motor response, induce a cortical facilitation effect. In contrast, low amplitudes are associated with a cortical inhibitory effect, thus showing an amplitude-based dose effect. Consequently, the presence or lack of a contraction directly impacts the somatosensory cortex and, ultimately, cortical excitability as determined by motor evoked potentials (MEP). Since this improvement cannot be explained by increased strength, INNOVO may stimulate a large number of proprioceptive receptors and sensory afferents, which led to an immediate change in motor response.

Presented by: Ruth Maher, PT, PhD, DPT, Philadelphia College of Osteopathic Medicine, Suwanee, Georgia, USA

Written by: Diane Newman, DNP, CRNP, FAAN, BCB-PMD, Urologic Nurse Practitioner, Adjunct Professor of Urology in Surgery, Senior Research Investigator, Perelman School of Medicine, University of Pennsylvania during the International Continence Society Annual Meeting, September 7-10, 2022, Vienna, Austria.


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