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. 2014 Jul 2;307(4):F485–F497. doi: 10.1152/ajprenal.00059.2014

Fig. 2.

Fig. 2.

Identification of micturition timing parameters in voids with different amounts of EUS bursting. A: void duration of a continuous urine bolus (top trace) is the time between the urine accumulation onset and offset (left and right vertical arrows, respectively). The sum of EUS EMG power at 2, 11–12, and 21–30 Hz (Ptrans) is calculated for identifying the transition from guarding to voiding in all voids (bottom trace; see Data Acquisition and Analysis in materials and methods for details). Void onset (long-dashed vertical arrow) is defined as the time of maximum rate of decrease in Ptrans before urine accumulation onset plus 0.62 s (to account for the minimum urine measurement delay). In this example, EUS EMG exhibits bursting during the void (second panel from the bottom), which is evident in the time-frequency spectrogram as a bright band at ∼7–9 Hz (second panel from top). Void EMG offset is defined as void EMG onset plus void duration. B: void duration with incomplete initial urine bolus (delayed drop indicated by arrowhead in top trace) is determined by the time between the urine accumulation onset and the estimated urine accumulation offset (left and right vertical arrows, respectively), calculated as the time of intersection of the extrapolated rate of urine accumulation (short-dashed diagonal line) and the final level of accumulated urine weight (horizontal arrow). Void EMG onset (vertical long-dashed line) is determined as in A as the time of maximum rate of decrease in Ptrans (bottom panel) before urine accumulation onset plus 0.62 s (long-dashed vertical arrow). Although the peak in Ptrans before voiding is smaller than that observed for the void in A, their configurations are similar, and are both capable of identifying the transition from continence to voiding. Although there is no bursting evident [i.e., no bright band between 3 and 10 Hz in the spectrogram (second trace from top)], the void size is similar to the example shown in A, which exhibited robust bursting. Void EMG offset is defined as void EMG onset plus void duration.