Electrodermal activity (EDA) is a sensitive measure of the sympathetic nervous
system activity. It is used to describe changes in the skin electrical properties. This
chapter aimed to show advantages of simultaneous recordings of EDA parameters
at the same skin site over other recordings. The literature databases, Web of
Science and Google Scholar, were searched using terms like “electrodermal activity,”
“sequential recording,” “simultaneous recording,” “skin conductance,” “skin
potential,” and “skin susceptance.” Articles that include sequential and/or simultaneous
recording of EDA parameters were analyzed. The chapter presents a description
of the oldest and current methods used for recording EDA parameters and an
explanation of the newest techniques used in EDA researches. Although sequential
recordings are predominant and widely spreading, much effort has been made to
simultaneously record skin conductance (SC) and skin potential (SP), and recently
researchers realized the capability of simultaneously recording SC, SP, and skin
susceptance (SS) at the same skin site. The advantage of simultaneous over the
sequence measurements is that the latter must be manually time realigned when
measured by different instruments, which means it is time-consuming. Although
the simultaneous measurements are used exclusively for research purposes at this
stage, this may open horizons in the modern trends of psychophysiology applications
in the near future.