Table 2.
Generalized Estimating Equations (GEEs) to compare the cortical activation parameters induced by thermal stimulus (25 °C and 5 °C) on the bilateral PFC and MC between fibromyalgia patients and controls (n = 41).
| Fibromyalgia (n = 22) | Controls (n = 19) | Group effect | Temperature effect | Group * temperature interaction | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| 25 °C | 5 °C | 25 °C | 5 °C | |||||||
| Mean (SE) | Mean (SE) | Mean (SE) | Mean (SE) | Wald χ2 | P | Wald χ2 | P | Wald χ2 | P | |
| Oxyhemoglobin (HbO) peak latency | ||||||||||
| PFC left | 4.95 (0.51) | 6.33 (0.71) | 7.26 (0.79) | 6.71 (0.81) | 2.84 | 0.092 | 0.45 | 0.503 | 2.4 | 0.122 |
| PFC right | 5.73 (0.67) | 5.74 (0.66) | 7.08 (0.73) | 6.07 (0.71) | 1.08 | 0.298 | 0.82 | 0.365 | 0.84 | 0.359 |
| MC left | 5.61 (0.52) | 6.48 (0.62) | 8.09 (0.90) | 8.00 (0.73) | 5.39 | 0.020 | 0.63 | 0.427 | 0.95 | 0.331 |
| MC right | 5.36 (0.56) | 5.40 (0.78) | 6.98 (0.79) | 5.53 (0.83) | 1.00 | 0.317 | 1.41 | 0.235 | 1.56 | 0.212 |
| Delta value of oxyhemoglobin (mM) (ΔHbO)—from baseline to peak amplitude of the curve | ||||||||||
| PFC left | 0.35 (0.05) | 0.41 (0.05) | 0.39 (0.10) | 0.49 (0.10) | 0.42 | 0.519 | 2.6 | 0.107 | 0.14 | 0.712 |
| PFC right | 0.35 (0.07) | 0.44 (0.06) | 0.32 (0.05) | 0.44 (0.06) | 0.05 | 0.818 | 3.17 | 0.075 | 0.08 | 0.777 |
| MC left | 0.39 (0.06) | 0.57 (0.08) | 0.44 (0.06) | 0.72 (0.13) | 1.24 | 0.265 | 6.90 | 0.009 | 0.27 | 0.603 |
| MC right | 0.35 (0.05) | 0.45 (0.06) | 0.50 (0.07) | 0.44 (0.05) | 1.48 | 0.223 | 0.12 | 0.729 | 2.13 | 0.144 |
| Delta value of HbO concentration (mM) (ΔHbO*) [based on HbO concentration before thermal stimuli onset minus HbO concentration level 15 s after thermal stimuli end] at 5 °C and 25 °C | ||||||||||
| PFC left | 0.23 (0.03) | 0.34 (0.06) | 0.30 (0.05) | 0.53 (0.14) | 2.01 | 0.157 | 5.33 | 0.021 | 0.55 | 0.457 |
| PFC right | 0.22 (0.04) | 0.34 (0.07) | 0.25 (0.05) | 0.38 (0.08) | 0.3 | 0.581 | 5.07 | 0.024 | 0.02 | 0.889 |
| MC left | 0.17 (0.04) | 0.37 (0.06) | 0.28 (0.05) | 0.54 (0.11) | 3.05 | 0.081 | 13.15 | < 0.001 | 0.22 | 0.637 |
| MC right | 0.15 (0.03) | 0.24 (0.05) | 0.26 (0.05) | 0.35 (0.07) | 3.7 | 0.054 | 3.82 | 0.051 | < 0.01 | 0.952 |
Bold denotes data that actually had statistical difference and also the identification of each parameter - just in order to clarify data.
Data are presented as mean and standard error (SE) (n = 41).
SE standard error, PFC pre-frontal cortex area, MC motor cortex area, HbO oxyhemoglobin, mM millimolar.