To compare sensory thresholds in different nerve-fiber types in men with chronic pelvic pain syndrome (CPPS) and healthy controls, using thermal sensory testing and measuring current perception thresholds (CPT).

We enrolled 22 men with CPPS and 20 healthy control participants. We determined the thermal sensory perception thresholds of C and Aδ nerve fibers on the perineum and left posterior thigh. To test CPT, we used sine wave electrical stimulation at 5, 250, and 2000 Hz, resulting in the selective depolarization of small unmyelinated C fibers, small myelinated Aδ, and large myelinated Aβ fibers, respectively. We bilaterally tested the hypothenar surface of the palms, medial parts of soles, midshaft of penis, and 1 site in the midperineum, for a total of 7 sites.

The mean age of men with CPPS was similar to that of controls [42.8 (standard deviation, 9.4) and 40.4 (standard deviation, 13.2) years, respectively, P = .548]. There was no significant difference between the 2 groups for thermal perception thresholds in both the perineum and left thigh (P >.05). There was also no difference between the 2 groups for CPT values of all 3 frequencies of stimuli in each area tested (P >.05 for all comparisons).

The absence of sensory threshold differences between men with CPPS and controls, with either thermal stimulation of C and Aδ fiber afferents or electrical stimulation of C, Aδ, and Aβ fiber afferents, discounts the existence of a peripheral neuropathy as a cause for pain in men with CPPS.