Repetitive Transcranial Magnetic Stimulation (rTMS) on Neurogenic Overactive Bladder in Stroke

Neurogenic overactive bladder (NOAB) presents with urgency incontinence. Existing NOAB management is expensive, lacks standardized regimens, or is invasive. Therefore, evaluating the effectiveness of non-invasive repetitive transcranial magnetic stimulation (rTMS) for NOAB management among stroke survivors remains crucial.

Objectives: Evaluate the effects of active-rTMS compared to sham-rTMS among stroke survivors with NOAB, the interventions' cost-effectiveness and explore their experiences qualitatively.

Summary Background: Neurogenic overactive bladder (NOAB) presents with urgency incontinence. Existing NOAB management is expensive, lacks standardized regimens, or is invasive. Therefore, evaluating the effectiveness of non-invasive repetitive transcranial magnetic stimulation (rTMS) for NOAB management among stroke survivors remains crucial.

Objectives: Evaluate the effects of active-rTMS compared to sham-rTMS among stroke survivors with NOAB, the interventions' cost-effectiveness and explore their experiences qualitatively.

Hypothesis: Active-rTMS will reduce NOAB symptom severity for stroke survivors, interventions' cost and assist in gaining insight into the NOAB patients' experiences.

Methods: This study will be a randomised-sham-controlled, double-blinded trial, with embedded qualitative and cost-effectiveness studies. Snowball-convenience sampling technique and computer-generated randomisation will be adopted to recruit 30 participants into active-rTMS and sham-rTMS groups each. Active-rTMS participants will receive a continuous 1 pulse per second 1200 pulses of low-frequency rTMS to the pelvic floor muscle representation in the contralesional primary motor cortex (M1) for 20 minutes thrice weekly. Sham-rTMS participants will receive the same parameters as the active-rTMS group, however, the coil will be rotated 90° away from the scalp. Fifteen active-rTMS participants will be invited for 45-60 minutes focus group discussions. The primary and secondary outcomes will be urinary incontinence severity and quality of life evaluated using the Overactive Bladder Symptom Score and Incontinence-Quality of life Questionnaire, respectively. Quality-adjusted life-years (QALY) will be the cost-effectiveness outcome. The EQ-5D-5L responses will estimate the gain or loss of QALY. A follow-up assessment will be conducted one-months post-intervention. The Client Service Receipt Inventory (CSRI) will be used to collect information on the whole range of services and support required by the study participants.

Statistical analysis: Normality will be evaluated using Shapiro-Wilk test. To determine active-rTMS and sham-rTMS group differences, between-groups analysis of covariance (ANCOVA) will be conducted using R software. Bonferroni correction will be applied for multiple comparisons. Thematic analysis will be used for analysing the qualitative data. For the cost-effectiveness analysis, the unadjusted mean costs and cost differences between active-rTMS and the sham-rTMS group will be calculated.

Eligibility Criteria:
Inclusion Criteria:

* Stroke survivors aged between 18-80 years diagnosed with NOAB
* Urodynamic findings confirming detrusor overactivity
* Experience moderate (OABSS scores: 6-11 points) to severe NOAB (OABSS scores: 12 points and above)
* Obtain a Mini-Mental State Examination (MMSE) score of ≥ 24
* Be willing to be randomized

Exclusion Criteria:

* Presence of metals in the cranium, intracardiac lines, increased intracranial pressure, heart diseases, or cardiac pacemaker, use of sacral neuro-modulation
* Pregnancy or less than six months postpartum stage
* Patients with a family history of epilepsy or seizures
* Patients taking tricyclic antidepressants or neuroepileptics
* Participation in any other research project related to urinary incontinence; contra-indicated to MRI, urologic cancer, prostatic pathology, severe pelvic pain, six weeks post-surgery and non-neurogenic bladder