Background and purpose: Stress urinary incontinence (SUI) is a common condition among
women, resulting in urine leakage during physical exertion, sneezing, or coughing. Due to
the risks associated with surgical and pharmacological treatments, women with SUI often
prefer conservative treatments, such as pelvic floor muscle (PFM) training (PFMT). PFMT
has been shown to provide increased beneficial effects when combined with
electromyography (EMG) biofeedback (referred to as conventional biofeedback [CB]) via
intravaginal probe than when performed alone. However, the CB device applied in clinical
practice is not preferred by women because it is invasive, and involves the insertion of
a probe into the vagina, causing pain/ discomfort. Therefore, we developed the
PelviSense, a non-invasive biofeedback device paired with wearable EMG sensors for use as
a PFMT adjunct.
The proposed study aims to (1) investigate the efficacy of PelviSense-assisted PFMT
compared with unassisted PFMT on SUI in women, and (2) identify the mechanisms underlying
the beneficial effects of PFMT for the treatment of SUI.
Hypotheses: (1) women assigned to the PelviSense-assisted PFMT group will report a
greater reduction in the severity of urine loss compared with women assigned to the
unassisted PFMT group; and (2) improvements in the severity of urine loss will be
mediated by increased PFM strength, causing an increase in bladder neck elevation and a
reduction in levator hiatus (LH) area during the Valsalva manoeuvre.
Methods: A two-arm, parallel-group RCT will be conducted using 132 non-pregnant women
with SUI, aged 18-60 years. The study participants will be randomised into two study
groups: PelviSense-assisted PFMT or unassisted PFMT. Women will be supervised in the
performance of PelviSense-assisted and unassisted PFMT on a 1:1 basis for 4 weeks and
instructed to perform unsupervised home exercises for 24 weeks after the completion of
supervised training.
Recruitment. Potential participants will be recruited using a non-probability convenience
sampling technique through public and university campus advertising.
Randomisation and blinding. An individual who will not be involved in study recruitment
will randomly assign participants to one of the two study groups (PelviSense assisted
PFMT or unassisted PFMT) at a 1:1 ratio. Another individual will assign treatments
according to a computer-generated random schedule in permuted blocks of two within age
strata. The allocation sequence will be concealed using sealed, opaque, sequentially
numbered envelopes containing the group name and a personal identification number. To
eliminate expectation effects and biases, a research assistant (RA) will complete the
assessment of primary outcomes, and intervention training and supervision at HK PolyU
will be conducted by a physiotherapy research postgraduate (RPg) student. Raw data will
be double entered into a spreadsheet by a student assistant. Data analysis will be
completed in a blinded manner, with code names (Groups A and B) used for each group, and
group identities will only be revealed after the analysis has been completed.
Procedure and baseline assessment. Potential participants will be invited to an in-person
visit at HK PolyU. On the first day of contact, the participants will complete a
screening questionnaire and a 1-h pad test to determine eligibility. Written informed
consent and body mass index (BMI) measurements will also be obtained. The 1-h pad test,
International Consultation on Incontinence Questionnaire, Short Form (ICIQ-SF), the
Incontinence Impact Questionnaire, Short Form (IIQ-7), and the MOS will be used to
establish baseline severity of urine loss, SUI symptoms severity, QoL, and PFM strength,
respectively. Participants will undergo a transabdominal ultrasound (TAU) to measure
baseline bladder neck elevation and LH area during a Valsalva manoeuvre (cough).
Following baseline assessments, participants will select an envelope containing treatment
allocation details.
Outcome measures: The primary outcome will be the severity of urine loss, as measured
using the one-hour pad test. Secondary outcomes will include quality of life, SUI
symptoms severity, and PFM strength, as measured using the incontinence impact
questionnaire, short-form, international consultation on incontinence questionnaire,
short-form, and modified Oxford scale, respectively. Mediator variables will include the
following: bladder neck elevation and levator hiatus area. Outcomes and mediator
variables will be assessed at baseline, 4, and 24 weeks. Statistical analysis: Treatment
and mediation effects will be evaluated using analysis of covariance and the Hayes'
PROCESS macro, respectively.
Statistical analysis. Hypothesis 1: Treatment effects on both primary and secondary
outcomes between T1, T2, and T3 and across the intervention groups will be evaluated
using analysis of covariance (ANCOVA).
Hypothesis 2: Mediation analyses will be conducted using the Hayes PROCESS SPSS macro
(v2.13), Model 4.