Detecting electroporation by assessing the time constants in the exponential response of human skin to voltage controlled impulse electrical stimulation.

We propose a new method for extracting the electrical properties of human skin based on the time constant analysis of its exponential response to impulse stimulation. As a result of this analysis an adjacent finding has arisen. We have found that stratum corneum electroporation can be detected using this analysis method. We have observed that a one time-constant model is appropriate for describing the electrical properties of human skin at low amplitude applied voltages (<30V), and a two time-constant model best describes skin electrical properties at higher amplitude applied voltages (>30V). Higher voltage amplitudes (>30V) have been proven to create pores in the skin's stratum corneum which offer a new, lower resistance, pathway for the passage of current through the skin. Our data shows that when pores are formed in the stratum corneum they can be detected, in-vivo, due to the fact that a second time constant describes current flow through them.

Identifying changes in human skin electrical properties due to long-term NeuroMuscular Electrical Stimulation.

The skin electrical properties are identified using a standard NeuroMuscular Electrical Stimulation (NMES) voltage pulse. The three component series equivalent electrical model was chosen to account for the skin electrical properties. The values of each of these three electrical components of the equivalent electrical model were identified and compared throughout 40 minute daily NMES sessions and over 5 days. Current measurements were performed during the NMES sessions in a non-invasive way, in order to assess changes occuring during each stimulation session and due to long-term NMES.