Measuring the sensations of urge and bladder filling during cystometry in urge incontinence and the effects of neuromodulation.

AIMS: As urge and urgency contribute greatly to a patient's symptoms, it follows that sensory evaluation combined with noninvasive neuromodulation during urodynamics may provide new criteria for improving patient selection for an implantable stimulator. The purpose of this research was to develop and validate an objective measure of bladder sensations during filling cystometry and then to apply this technique to evaluate the effects of neuromodulation on the sensations of urge measured in this way. METHODS: In study 1 a new patient-activated keypad device was tested during urodynamics to measure bladder sensations according to a 0-4 scale and validated by using a technique adapted from a standard psychophysical sensory threshold testing method. In study 2 the effects of pudendal afferent nerve stimulation on measured sensations of urge were assessed during cystometry with patients as their own controls. Forty-three patients diagnosed with idiopathic detrusor instability were studied; 10 participated in study 1 and 35 in study 2. RESULTS: The new device gave reliable and repeatable measures of sensations with statistically significant differences in bladder volume at each of the urge levels tested (Wilcoxon matched pairs test). Neuromodulation suppressed urinary urge in 89% of the 35 patients. This effect was associated with a statistically significant increase in bladder volume at all urge levels. CONCLUSIONS: A new patient operated key-pad device provided a reliably objective measure of sensations of urge during urodynamics without the need for prompting. Neuromodulation using noninvasive pudendal afferent stimulation suppressed these sensations whilst increasing bladder volume.