Associations among four modalities of experimental pain in women

The aim of this study was to investigate the associations among 4 measures of pain induction procedures in 244 healthy women. The procedures were (1) pressure pain threshold assessed over the temporalis muscles, masseter muscles, temporomandibular joints, and the wrists; (2) C fiber-mediated heat pain threshold/tolerance assessed on the skin over the forearm, cheek, and dorsal aspect of the foot; (3) temporal summation of C fiber-mediated heat pain; and (4) ischemic pain threshold/tolerance. Strong associations among pressure pain thresholds at the 4 sites examined (ρ = 0.7 to 0.8, P values ≤ .001) and among heat pain threshold/tolerance values at the 3 sites examined (ρ = 0.6 to 0.9, P values ≤ .001) were observed. Pressure pain threshold was moderately correlated with each of the heat pain threshold/tolerance values (ρ = 0.2 to 0.4, P values ≤ .001). Ischemic pain threshold/tolerance was moderately associated with each of the pressure and heat pain measures (ρ = 0.2 to 0.3, P values ≤ .05 to .001). Derived measures of the temporal summation of heat pain did not correlate strongly with threshold or tolerance measures of pressure, ischemic, or heat pain. We concluded (1) that for a specific pain modality, the correlation between threshold and tolerance values across anatomic sites is high, and (2) that measures of pressure, ischemic, and thermal pain threshold/tolerance are significantly correlated, although the strength of these associations is moderate. These findings demonstrate that a battery of pain-assessing procedures is required to determine an individual's pain sensitivity profile or phenotype.