THE RELATIONSHIP OF SWEAT GLAND COUNT TO ELECTRODERMAL ACTIVITY

This study assessed whether greater skin conductance activity at the d istal versus medial site (Scerbo, Freedman, Raine, Dawson, and Venable s, 1992) is attributable to a greater number of active (open) sweat gl ands at the distal site. The number of sweat glands was measured using the Palmar Sweat Index (PSI). Twenty-four subjects were exposed to 10 auditory stimuli. Electrodes were placed on the fore and middle finge rs of each hand, using distal sites on one hand and medial sites on th e other. The PSI was measured at the medial and distal phalanges adjac ent to the electrode placement sites. The distal site contained more o pen and total sweat glands. Open gland count had the strongest correla tions with skin conductance. Multivariate analyses of covariance revea led that site effects for nonspecific and orienting response frequency and trials to habituation were associated with site differences in op en glands. Skin conductance measures and the PSI reveal greater electr odermal activity at the distal site. In addition, the number of open g lands may be a useful measure related to electrodermal response freque ncy when polygraph measurement is unavailable.