Comparison in Young Healthy Volunteers of 3 Different Parameters of Constant Current Stimulation Used to Determine Sensory Thresholds in the Lower Urinary Tract

Abstract

Purpose We compared different parameters of constant current stimulation used for evaluation of sensation in the lower urinary tract. Materials and Methods In 24 healthy male and 9 healthy female volunteers (mean age 24 years) sensory thresholds were determined at the same site on the bladder, urethra and skin with 3 different parameters of constant current stimulation (2.5, 20 and 95 Hz. at pulses 1, 1 and 0.5 msec., respectively) given at random. Results Thresholds were highly reproducible at all sites and with the 3 currents. Thresholds obtained with 2.5 Hz. were significantly greater than those obtained with 20 Hz. at all sites or 95 Hz. at the bladder and male urethra. No significant difference was found between thresholds in the bladder or urethra with 20 and 95 Hz. In 2 volunteers no bladder sensation was elicited with 2.5 Hz. even at 33 mA. A reproducible elevated threshold was found with 20 and 95 Hz. No intravesical pressure increase occurred during stimulation. Conclusions Absolute values of sensory thresholds vary in relation to the site of stimulus and stimulation parameters in healthy young subjects. Low frequency current (2.5 Hz.) is less easily perceived and, therefore, would seem less suitable for evaluation of electrical sensation in the lower urinary tract. Thresholds obtained with frequences of 20 and 95 Hz. were not statistically different.