Mean values of ACh peak measured in the whole population either with LDF or LSCI at day 1 (D1) and day 7 (D7) in protocols 1 and 2.

The inter-subject variability at a 7-day interval was evaluated by the coefficient of variations (inter-CV) calculated as the SD of CBF values of all subjects divide by the mean CBF of all subjects multiplied by 100. The parameters of the maximal ACh vasodilation measurement obtained after current application are presented in Table 1. Which every way the results were expressed for both techniques, no statistical difference was found between mean values of ACh measured at D1 and mean values of ACh measured at D7. Time to peak corresponds to the time after the end of the current stimulation until the maximal acetylcholine vasodilation is reached.