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Table 4 Outcome of the multivariate correlation analysis (principal component analysis; PCA) in the trapezius myalgia group (NSP; n = 19)

From: An increased response to experimental muscle pain is related to psychological status in women with chronic non-traumatic neck-shoulder pain

  PC1 PC2 PC3 PC4
Clinical neck-shoulder pain     
  Current pain area size 0.20 -0.22 0.21 0.16
  Worst pain area size 0.08 -0.27 0.17 0.29
  Least pain area size 0.02 0.01 0.32 0.02
  Pain duration 0.18 0.21 0.02 0.08
  Neck pain intensity -0.13 0.30 -0.17 0.00
  Shoulder pain intensity 0.04 0.30 -0.19 -0.12
Pain after hypertonic saline infusion     
  Area under VAS curve 0.18 0.13 0.05 0.30
  Mean VAS 0.19 0.14 0.10 0.37
  Pain onset -0.09 -0.10 -0.40 0.09
  Peak VAS 0.14 0.22 0.12 0.36
  Time to peak 0.00 -0.26 -0.15 0.04
  Total pain area size 0.13 -0.18 0.04 0.27
  Referred pain area size 0.07 -0.28 0.01 0.20
Pressure pain thresholds     
  Mean PPT Trapezius right 0.05 -0.21 -0.30 0.00
  Mean PPT Trapezius left 0.08 -0.30 -0.17 0.00
  Tibialis right -0.10 -0.31 0.07 -0.15
  Tibialis left -0.15 -0.25 -0.03 -0.10
Psychological factors     
  KSQ-Aw -0.29 0.02 0.28 -0.02
  KSQ-Dst -0.27 0.02 0.23 -0.06
  KSQ-Si -0.26 0.09 0.14 0.02
  HADS-A -0.20 0.09 -0.28 0.30
  HADS-D -0.29 0.06 -0.07 0.24
  ASI -0.31 0.06 0.16 0.18
  PASS-20 -0.28 -0.12 0.10 0.19
  PCS -0.32 -0.14 -0.15 0.15
  PDI -0.20 0.12 -0.26 0.26
  FABQphysical -0.08 -0.10 0.13 0.18
  FABQwork -0.27 0.01 0.21 -0.13
Explained variance R 2 0.21 0.19 0.14 0.10
  1. Variable loadings upon the principal components (PC) in bold indicate variables of significant importance for the component. At the bottom line is given the explained variation (R2) of each significant component (PC1-4).
  2. Abbreviations: VAS = visual analogue scale, Abbreviations: KSQ = Karolinska sleep questionnaire, KSQ-Aw = KSQ- subscale "awakening problems", KSQ- Dst = KSQ- subscale "daytime sleepiness"(denoted), KSW-Sd = KSQ- subscale "sleep disturbances", HADS = hospital anxiety and depression scale; HADS-D = depression subscale of HADS, HADS-A = anxiety subscale of HADS, ASI = anxiety sensitivity index, PASS = pain anxiety symptoms scale, PCS = pain catastrophizing scale; FABQ = fear-avoidance beliefs questionnaire, FABQphysical = subscale fear-avoidance beliefs for physical activity of FABQ, FABQwork = subscale fear-avoidance beliefs for work of FABQ, PDI = pain disability index.