Quantitative studies of perception of thermal stimuli in the normal and neurogenic urinary bladder

¹ Division of Urology, Department of Surgery, University of Washington School of Medicine, Seattle, Washington

Quantitative measurements of the ability of human beings to perceive temperature changes in the urinary bladder were made using copper-constantan thermocouples connected to a continuous recording electronic potentiometer. Ten different thermal changes were induced by irrigation of the bladder with cold or warm saline solution. Each stimulus was presented to each subject 10 times, according to a table of random numbers. The subjects were asked to indicate whether they felt warmer or colder. The stimulus was maintained for less than 3 seconds. In 40 normal volunteers, the mean warm response was 93°F. The mean cool response was 87.5°F. The neutrality point where the two curves intersected was 89.4°F. Statistical evaluation established the validity of the differences. The thermal sensation of seven patients with varying levels of spinal cord trauma seemed to indicate that the afferent pathway for thermal bladder sensation involved S_{2, 3, 4} cord segments.