Concurrent multi-session anodal trans-cranial direct current stimulation enhances pelvic floor muscle training effectiveness for female patients with multiple sclerosis suffering from urinary incontinence and pelvic floor dysfunction: a randomized clinical trial study

INTRODUCTION AND HYPOTHESIS: Urinary incontinence following a pelvic floor muscle (PFM) dysfunction is a common disorder in women with multiple sclerosis (MS). Concurrent anodal transcranial direct current stimulation (a-tDCS) of the primary motor cortex (M1) may prime the effects of PFM training (PFMT) in MS patients. This study was aimed at investigating the effects of M1 a-tDCS on the effectiveness of PFMT in the treatment of female MS patients with urinary incontinence and PFM dysfunctions. METHODS: In a randomized double-blinded, control trial study, 30 women with MS were divided into two groups (experimental group: concurrent active M1 a-tDCS and PFMT; control group: concurrent sham M1 a-tDCS and PFMT). Over the course of 8 weeks, these patients received 20-min interventions three times a week. As an indication of PFM function, the bladder base displacement was measured by ultrasonography before, during the 4th week, immediately, and 1 month after the intervention ended. Urinary incontinence was also measured by Incontinence Questionnaire-Urinary Incontinence Short Form (ICIQ-UISF) before, immediately, and 1 month after the intervention ended. RESULTS: A significant improvement in PFM function occurred in the 4th week of intervention and remained 1 month after the intervention in the experimental group when compared with the control group (p<0.05). Compared with baseline, both groups reported significant improvements in PFM function at 8 weeks (p<0.05). Also, both groups were found to have decreased ICIQ-UIS scores after the intervention and at 1-month follow-up (p<0.05). CONCLUSIONS: In MS patients, M1 a-tDCS can significantly enhance the effects of PFMT on the PFM function and urinary incontinence. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00192-022-05429-6