Noninvasive Spinal Cord Stimulation for Neurogenic and Idiopathic Overactive Bladder

Overactive bladder (OAB) affects 12-30% of the world's population. The accompanying urinary urgency, urinary frequency and incontinence can impair the ability to work, interact in social activities and can result in poor social functioning. Multiple treatment modalities are available for overactive bladder. However, each therapy has drawbacks that limit its application in certain patient populations. For example, oral medications have significant side effects and suffer from poor adherence. Botulinum toxin injection into the bladder wall is invasive, requires re-treatment on a regular basis and carries a risk of urinary retention. Current neuromodulatory techniques are invasive and require highly-specialized care. Therefore, a need exists for a non-invasive, well-tolerated and easily administered therapy for OAB. Transcutaneous spinal cord stimulation (TSCS) has been developed and tested in able bodied individuals to initiate locomotor function as well as in the SCI population for lower extremity and upper extremity function. More recently, we have tested this SCI patients to enable lower urinary tract function and decrease detrusor overactivity, resulting in improved continence.

Noninvasive spinal cord stimulation is a transcutaneous technique used to modulate the activity of the spinal cord. Subjects will undergo sham or actual stimulation 3-4 times a week for one hour at a time.

A voiding diary records the amount of fluid intake, the number of urinations and the number of incontinence episodes over 72 hours. The number of daily urinations and incontinence episodes will be compared at the beginning and the conclusion of the study. Changes in the number of daily urinations and incontinence episodes will be compared between participants in the stimulation and sham arms of the study.

Each participant will complete two validated questionnaires pertaining to overactive bladder: OAB-q and ICIQ-OAB. The OAB-q generates a total score ranging between 33 points (best) to 198 points (worst). The ICIQ-OAB generates a total score ranging between 0 points (best) to 58 points (worst). The questionnaires will be completed at the initiation and completion of the study. Change in questionnaire scores between initiation and completion of the study will be assessed. Changes in questionnaire scores will be compared between participants in the stimulation and sham arms of the study.

Urodynamic studies will be performed at the initiation and completion of the study. Urodynamic studies will be performed according to ICS (International Continence Society) criteria. Changes in cystometric capacity and number of detrusor overactivity episodes between initiation and completion of the study will be assessed. Changes in these parameters will be compared between participants in the stimulation and sham arms of the study.

Inclusion Criteria: Age between 18 and 80 years Known diagnosis of overactive bladder, confirmed by: presence of urinary frequency, urgency frequent small-volume voids on frequency-volume chart high score on ICIQ-OAB, ICIQ-OABQOL, and OAB-q questionnaires Exclusion Criteria: Younger than 18 years of age Older than 80 years of age Presence of lower urinary tract symptoms suggestive of urinary retention or obstruction Finding of an elevated post-void residual (>100 ml) on an ultrasonographic bladder scan History of spinal cord injury, spina bifida or other neurological disease affecting the spinal cord Acute or current urinary tract infection History of neuromodulation for overactive bladder (sacral nerve stimulation or peripheral tibial nerve stimulation) Current or planned pregnancy

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