AimsTo test the hypothesis that voiding in anesthetized rats is preceded by recurrent changes in the pattern of bladder pressure. To explore the use of frequency analysis as an analytical tool for automatically detecting these changes and to provide quantitative data on bladder pre-voiding activity. MethodsWe developed an algorithm, based on frequency analysis, to study bladder pressure during the filling phase in anesthetized rats. Two applications of the algorithm were tested: (i) as a predictor of a voiding contraction with alarms generated which would make conditional nerve stimulation to prevent incontinence possible; and (ii) as a new index to quantify rapid pressure transients in normal and overactive detrusor conditions (i.e., induced by acetic acid instillation into the bladder). ResultsThe results show that a very high percentage (approximate to 90%) of the alarms was generated by the algorithm within 100sec before voiding. The index of rapid transients and the bladder volume before voiding were respectively approximate to 13% less and approximate to 42% less in acetic acid. ConclusionsWe have shown that a simple algorithm, based on frequency analysis of bladder pressure, can be used to predict voiding and to provide quantitative data on non-voiding bladder activity and its changes due to pathology. Although the results refer to anesthetized rats, they are promising and warrant further urodynamic investigation to identify if similar patterns occur in non-anesthetized rats and in humans. Neurourol. Urodynam. 34:794-799, 2015. (c) 2014 Wiley Periodicals, Inc.