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 (rho = 0.7 to 0.8, P values < or = .001) and among heat pain threshold/tolerance values at the 3 sites examined (rho = 0.6 to 0.9, P values < or = .001) were observed. Pressure pain threshold was moderately correlated with each of the heat pain threshold/tolerance values (rho = 0.2 to 0.4, P values < or = .001). Ischemic pain threshold/tolerance was moderately associated with each of the pressure and heat pain measures (rho = 0.2 to 0.3, P values < or = .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.

By investigating the relationship between pain sensitivity produced by different forms of stimuli, this study demonstrates that a battery of tests should be used to assess an individual's pain sensitivity and one should be careful in making inferences about an individual's sensitivity to pain by using only one pain modality.