PEA and SEA concentrations (nM) in microdialysis samples from patients with trapezius myalgia and controls.

Shown are median values with range in brackets. P values were determined by two-tailed Mann-Whitney U-test at each time point. For each series, there was no significant variation of the microdialysate concentrations over time (P>0.2, Kruskal-Wallis test). Non-parametric statistics were chosen since approximately half of the PEA data series and two of the SEA series (time points and pain conditions analysed separately) did not pass the D'Agostino and Pearson omnibus normality test.