title: Effects of stimulus duration on heat induced pain: the relationship between real-time and post-stimulus pain ratings.
abstract: Pain is a temporally dynamic experience. Yet, in most instances, pain ratings are acquired in a static fashion and frequently require subjects to retrospectively evaluate the pain experience that occurred in a preceding interval of time. In order to determine which components of the real-time experience of pain contribute to static pain ratings, we obtained real-time (dynamic) and post-stimulus (static) ratings using a visual analogue scale during various of durations (5-30 s) of noxious thermal stimulation (43-49 degrees C). For both pain-intensity and pain-unpleasantness, real-time ratings revealed that pain adapted when stimulus temperatures were low to moderate and summated when stimulus temperature was high. Regression analyses examining both pain-intensity and pain-unpleasantness revealed that the mean response and the peak response of real-time ratings significantly contributed to post-stimulus ratings, while temporal components such as perceived duration of pain contributed minimally. Additional regression analyses revealed that mean and peak responses of real-time intensity ratings accounted for much of the variability of post-stimulus unpleasantness ratings whereas real-time unpleasantness ratings accounted for somewhat less of the variability of post-stimulus intensity ratings. Taken together, the close relationship between real-time and post-stimulus ratings of pain across stimulus conditions evoking both adaptation and temporal summation further confirms that post-stimulus, retrospective ratings of pain are valid measures of the real-time experience of pain.
authors.affiliation: Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1010, USA Center for the Study of Pharmacologic Plasticity in the Presence of Pain, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1010, USA.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Koyama
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Koyama
authors.forename: Anna P
authors.initials: AP
authors.lastname: Kroncke
authors.forename: Robert C
authors.initials: RC
authors.lastname: Coghill
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006358:Hot Temperature / Q000009:adverse effects*; D006801:Humans; D008297:Male; D010146:Pain / Q000503:physiopathology*; D010147:Pain Measurement / Q000379:methods; D017288:Pain Threshold; D010812:Physical Stimulation; D012044:Regression Analysis; D012189:Retrospective Studies; D013997:Time Factors