Figure 1.
Choices of descriptors of the pain stimuli, summed across 20 subjects (Aδ selectivity more to the left, C fiber selectivity right).
The colored bars indicate the three discriminators found to provide a questionnaire that distinguishes between Aδ and C fiber mediated pain (blue = “pricking”, green = “pressing”, red = “dull”, as specified in Figure 2).
Figure 2.
Cumulative presentation of the selections of the three discriminators found to provide a questionnaire that distinguishes between Aδ and C fiber mediated pain.
Left: presentation separately for the four pain models and standardized at 100% of the ratings for each model. Right: presentation of the selections of the three discriminators, pooled for predominately Aδ fiber mediated pain sensations evoked with von Frey hair puntuate pressure stimuli or with laser heat stimuli and C fiber mediated pain sensations evoked with blunt pressure stimuli or with 5-Hz electrical stimuli.
Figure 3.
Odds ratios, calculated as (A · D)/(B · C), where A is the number of selections of the descriptor for C fiber pain, B the total number of presentations of C- fiber pain minus A, C the number of selection of the descriptor for Aδ fiber pain, and D the total number of presentations of Aδ pain minus C, and 95% confidence intervals, calculated as odds ratio±1.96 · (1/A+1/B+1/C+1/D)0.5, of the selections of the descriptors for C fiber mediated pain (pooled ratings of blunt mechanical pressure and 5-Hz electrical stimuli) and the number of selections of the descriptors for Aδ mediated pain (pooled ratings of punctate mechanical pressure and laser heat), sorted from top to bottom for decreasing selectivity for C fibers and increasing selectivity for Aδ fibers. The descriptors used in the questionnaire test (Figure 2) are marked in bold letters and thicker lines. Odds ratios and the corresponding p-values resulting from χ2 statistics are indicated at the right of the descriptors. Please note that the 10 descriptors that were never used are excluded and therefore, the total number of displayed descriptors is 67.