Objective: The aims of this study were to investigate whether detrusor overactivity can be influenced by a pelvic floor muscle contraction in multiple sclerosis-associated overactive bladder and idiopathic overactive bladder volunteers and to compare urodynamic findings between the two groups.

Design: Eighteen women with multiple sclerosis-associated overactive bladder and 17 women with overactive bladder responded the overactive bladder V8 questionnaire and performed urodynamic study with electromyography of pelvic floor muscle to confirm the presence of a 15-sec pelvic floor muscle contraction during a detrusor overactivity, when present. Variables were the following: overactive bladder-V8 questionnaire, maximum cystometric capacity, volume at first detrusor overactivity, maximum detrusor overactivity amplitude, and percentage of detrusor overactivity pressure reduction.

Results: All participants had a reduction in detrusor overactivity pressure when pelvic floor muscle contraction was requested. Multiple sclerosis-associated overactive bladder group showed significant higher detrusor overactivity amplitude than overactive bladder group (P = 0.02). Overactive bladder group had their detrusor overactivity pressure reduced in a greater extent when compared with multiple sclerosis-associated overactive bladder group (P = 0.01).

Conclusions: The results suggest that pelvic floor muscle contraction is able to reduce detrusor overactivity pressure in multiple sclerosis-associated overactive bladder and overactive bladder population.