Pain modulation profile (PMP) classification has been suggested as a predictor for pain onset and treatment outcomes. Conditioned pain modulation (CPM) and temporal summation (TS) assessment represent endogenous pain inhibition and facilitation respectively, and they are combined to construct PMPs. However, no validated protocol to define impaired CPM and/or facilitated TS responses is available. Our aim was to investigate methods to determine PMPs in temporomandibular disorder (TMD) patients and pain-free controls. Five female TMD patients (age [±SD]=47.3 years ±16.3) and five sex-matched pain-free controls (41.2 years ±15.6) were included. CPM response was calculated as percent change in face (masseter muscles) and hand (thenar) pressure pain thresholds before and during forearm noxious heat stimulation. TS response was determined in same locations by pinprick windup ratio (mean pain rating of 10-stimuli/single stimulus). Four methods classified CPM/TS responses to determine PMPs for face and hand: methods 1 and 2 used cut-points from literature, while cut-points for methods 3 and 4 were derived applying those methodologies using normative data and data from our sample. Four PMPs were constructed: I-Double pro-nociception (impaired CPM/facilitated TS), II-Inhibitory pro-nociception (impaired CPM/normal TS), III-Facilitatory pro-nociception (normal CPM/facilitated TS), and IV-Anti-nociception (normal CPM/normal TS). PMPs remained constant in hand and face across all methods in 7/10 participants. In the face, out of these seven participants 2/3 patients were classified as pro-nociceptive PMPs (I=1/II=1) and 2/4 controls as anti-nociceptive PMP, while in the hand 4/5 patients were classified as pro-nociceptive PMPs (I=3/II=1) and 1/2 controls as anti-nociceptive PMP. Out of all 10 participants, method 2 for hand classified 4/5 controls as anti-nociceptive PMP (lower CPM cut-point). Face and hand PMPs were concordant between-method in 2/5 patients (I=1/II=1) and 1/5 controls (IV=1). Within-method discordant PMPs for face and hand were frequent. PMP III was rare (only for method 2 in the face [1 control/1 patient]).
Bibliographical noteM1 - 4 (Supp)
Babiloni, A. H., Penteado Kapos, F., & Moana-Filho, E. (2017). Pain modulation profiles: initial investigation of classification methods: 36th Annual Scientific Meeting of the American Pain Society. Pittsburgh, PA. USA.: J Pain. https://doi.org/10.1016/j.jpain.2017.02.184