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Table 2 Item loadings in exploratory factor analysis with 2–factor solution and the internal consistency variables

From: Cross-cultural adaptation, reliability, and validity of the Vertigo symptom scale–short form in the central Kurdish dialect

  Kurdish Samplea Norwegian Sampleb
  n = 165 n = 509
  Internal consistency variables Polychoric Correlationsc Principal Axis Factoringd Maximum Likelihoode
  CI-TC in subscales AIID in subscales CI-TC in total scale AIID in total scale Factor 1
Vestibular
Factor 2
Anxiety
Factor 1
Vestibular
Factor 2
Anxiety
Factor 1
Vestibular
Factor 2
Anxiety
VSS–V   0.809  
 4- Vertigo (> 20 min) 0.56 0.783 0.49 0.862 0.91 −0.17 0.76 −0.15 0.84 − 0.18
 10- Unsteady (> 20 min) 0.63 0.768 0.58 0.857 0.85 −0.06 0.76 −0.05 0.80 −0.01
 13- Unsteady (< 20 min) 0.60 0.773 0.56 0.858 0.74 − 0.03 0.72 −0.04 0.58 0.14
 6- Dizziness (all day) 0.59 0.777 0.61 0.855 0.58 0.21 0.53 0.19 0.81 −0.10
 8- Difficult to stand or walk 0.45 0.800 0.41 0.865 0.54 −0.03 0.52 −0.03 0.67 0.07
 15- Dizziness (< 20 min) 0.55 0.784 0.55 0.858 0.54 0.18 0.47 0.19 0.60 0.10
 1- Vertigo (< 20 min) 0.44 0.801 0.43 0.864 0.52 0.04 0.46 0.05 0.61 0.09
VSS–AA   0.807  
 9- Difficulty in breathing 0.57 0.779 0.52 0.860 −0.05 0.78 −0.07 0.69 0.02 0.55
 14- Chest pain 0.46 0.794 0.40 0.865 −0.10 0.71 −0.14 0.63 0.05 0.45
 7-Headache 0.51 0.787 0.46 0.863 −0.09 0.69 −0.11 0.66 0.33 0.33
 11- Excessive sweating 0.55 0.781 0.53 0.860 0.06 0.59 0.06 0.56 0.09 0.82
 3- Nausea, vomiting 0.52 0.785 0.50 0.861 0.05 0.59 0.07 0.52 0.35 0.31
 2- spells of cold or hot 0.49 0.790 0.51 0.861 0.07 0.56 0.12 0.47 −0.02 0.81
 5- Heart fluttering 0.51 0.788 0.54 0.859 0.20 0.50 0.16 0.48 −0.04 0.56
 12- Feeling faint 0.55 0.781 0.62 0.855 0.33 0.45 0.30 0.43 0.43 0.32
VSS–T   0.868  
 AVE      0.47 0.38 0.38 0.32   
 IFC (IFC2)      0.63 (0.40) 0.65 (0.42) 0.56 (0.31)
 RhoC      0.86 0.83 0.80 0.78   
 RhoAf      0.82 0.82     
If item12 deletedg
 AVE      0.47 0.40 0.37 0.33   
 IFC (IFC2)      0.62 (0.38) 0.62 (0.39)   
 RhoC      0.85 0.82 0.80 0.77   
 AIC VSS–V = 0.38 VSS–AA = 0.34 VSS–T = 0.31
  1. Note: For convenience, symptoms shortened; Alphas of the subscales and total scale are in bold and in three decimal places, to be compared with resultant alpha when any item deleted; aPromax, Kappa = 4; bWilhelmsen K, Strand LI, Nordahl SHG, Eide GE, Ljunggren AE. Psychometric properties of the Vertigo symptom scale - Short form. BMC Ear Nose Throat Disord. 2008;8(1):2; cPolychoric algorithm by Diagonally Weighted Least Squares (DWLS); dPromax with Kaiser normalization in 3 iterations; eOblimin, Delta = 0; fValues provided by SmartPLS 3; gInflation of AVE and deflation of IFC2
  2. Abbreviations: VSS–V/AA/T Vertigo Symptom Scale–Vestibular/Autonomic-Anxiety/Total, CI-TC Corrected Item-Total Correlation, AIID Alpha If Item Deleted, AVE Average Variance Extracted, IFC Inter-Factor Correlation, IFC2 Square of IFC, RhoC Composite reliability, RhoA Reliability measure of the partial least squares, α Cronbach’s alpha, PLS Partial Least Squares, AIC Average Inter-item Correlation