Day-to-day reliability of pressure pain threshold and pain ratings in college-aged men.

Abstract

The purpose of this study was to examine the reliability of pressure pain threshold (PPT) and pain tolerance assessment in the finger over three testing days. PPT was assessed in the middle finger at the mid-point between the proximal and distal interphalangel joints in 49 college-aged men on three occasions (day 1, day 2, day 3) each separated by 48 h. The pressure evoking PPT was subsequently applied for up to 120 s to assess pain tolerance, whereas pain intensity was rated every 15 s. PPTs were reduced from day 1 to day 2 (P<0.001; intraclass correlation coefficient=0.63), but demonstrated excellent reliability from day 2 to day 3 (P=0.62; intraclass correlation coefficient=0.89). No differences were observed in pain tolerance. Ratings of pressure pain intensity rose over time during the 120 s test (P≤0.002) and were reduced on testing day 3 compared with day 1 (P=0.029). Our results suggest the use of least one familiarization session would lead to significantly improved day-to-day reliability of PPT assessment in the finger. In addition, the application of the force eliciting PPT was a poor discriminator of pain tolerance because of the fact the majority of participants (146 out of 147 sessions) could tolerate the stimulus for the entire 120 s.