Detecting the onset of hyper-reflexive bladder contractions from pudendal nerve electrical activity

Individuals with spinal cord injury or neurological disorders may develop involuntary bladder contraction at low volumes (bladder hyper-reflexia), which can lead to significant health problems. Current devices can eliminate nascent contractions through continuous stimulation, but do not have a means to detect the onset of bladder contraction to stimulate conditionally. The objective of this study is to determine the relationship between the electrical activity of the pudendal nerve (PNT) and hyper-reflexive bladder contraction, and to use the relationship to develop an algorithm to detect the onset of a bladder contraction. Bladder pressure and PNT ENG were recorded in six intact male cats. There were bursts of neuronal activity in the PNT during bladder contractions. An algorithm was developed to detect the onset of a bladder contraction using the PNT ENG activity. The algorithm calculated the onset of bladder contraction on average 2.8 seconds after the contraction started with an average increase in pressure of 14.0 cmH2O. There existed a phasic relationship between the bladder and the PNT ENG, which enabled the algorithm to detect the onset of a bladder contraction. The PNT ENG can be used as a trigger to deliver conditional inhibitory stimulation of the bladder.