Skin conductance; validation of Skicon-200EX^® compared to the original model, Skicon-100^®

Background/purpose: Measurement of skin surface and stratum corneum (SC) hydration during experimental trials needs devices with acceptable precision under conditions ranging from decreased, and normal to high hydration. The aim of this study was to validate the recent model of a commonly used device for measurement of skin conductance (Skicon-200EX^®) vs. the original model (Skicon-100^®) introduced 20 years ago.

Methods: Twenty-six healthy Danish volunteers (16 women and 10 men, aged between 22 and 67, with a median age of 42 years) were studied using the Skicon-100^®and the Skicon-200EX^® mounted with three different probes. Normal skin of the cheek, forearm, antecubital fossa, palm, lower leg, and popliteal fossa was studied. The sorption–desorption test was performed on the forearm.

Result: The two instruments displayed closely correlated conductance levels. However, the Skicon-200EX^® displayed systematically 1.6-fold higher values than the Skicon-100^®. Different body sites showed different levels depending on anatomical regions. The three probes measured systematically different levels with the original probe measuring lower values. The sorption–desorption test showed high skin conductance values which peaked a few minutes after hydration, in accordance with the original experiments of Tagami.

Conclusion: The two Skicon^® instruments evaluated in this study correlated well, however, they displayed different levels depending on instrument main body and probes. Overall, the Skicon-200EX^® gave 1.6-fold higher value, and this instrument might be more sensitive than the original device, Skicon-100^®. In scientific reports, the type of instrument main body as well as probe shall be clearly specified.