After my first three treatments, I still was unsure what bladder spasms were, or how I would know I was having them. The nurse told me that other's have described them as very strong and sometimes painful urges to urinate, at times to the point that if you do NOT use the toilet you may wet yourself. Based on that definition, I have had spasms (frequent strong but mostly painless urges to urinate), but they have yet to cause me enough trouble that I take action. So far, they last only for the remainder of the day following my treatment.
My practice has been to avoid food and water for a few hours prior to the treatment, then to tank up on water following the treatment. Other than feeling strong flu-like symptoms, my treatments have been bearable. From the sounds of it, I may have more challenges with my maintenance treatments...I will let you know.