RELATIONSHIPS BETWEEN PARAMETERS DESCRIBING LOW-FREQUENCY ELECTRICAL ADMITTANCE LOCUS PLOT OF HUMAN PALMAR SKIN

Using a two-frequency three-electrode method, unipolar electrical admi ttance was measured in the palmar skin of 48 normal healthy humans. Ch aracteristics of and relationships between the phase angle pi alpha/2, the conductance extrapolated at zero frequency G(o) and ion relaxatio n time tau obtained from the Cole-Cole equation were examined in a low -frequency region (up to 354 Hz). At base-line resting values, the thr ee admittance parameters were interrelated according to the regression model; log tau(i) = A + B alpha(i) + D log G(oi) + epsilon(i) with R( 2) greater than or equal to 0.7434 (P less than or equal to 0.0001), w here ($) over cap A,($) over cap B and ($) over cap D determined from regression analysis showed inter- and intra-individual variation. Mult i-factor analyses of variance showed that a was greater in women than men (0.8025 versus 0.7545, p < 0.0023), and log G(o) decreased signifi cantly with age (covariate coefficient = -0.0058 log mu S cm(-2) per y ear, p < 0.04). For evoked responses, alpha showed a very small change (maximum < 5%), tau decreased while G(o) increased. With increasing f requency, conductance responses increased in absolute amplitudes but d ecreased in relative changes (amplitude change divided by static level ), Statistical analyses from clinical experimental materials (total 13 0 subjects) showed that the capacitive behaviour of admittance (due to alpha) presented significant variation between controls and patient g roups. This may shed new light on the nature of the skin electrical ad mittance/impedance.