Interpreting palmar sweat prints: A not-so-simple measure

Abstract

THE PLASTIC replica technique to obtain palmar sweat prints (PSP) is a simple, direct measure of sweating related to other electrodermal measures of arousal [l-7]. This technique is a direct measure of the number of active or open sweat pores in a given area. The advantage of PSP measures over other more commonly used electrodermal methods lies in its convenience for use in patient care settings in which fixed equipment may not be readily available or where electrode attachments may be perceived as interfering with treatment. For these reasons, PSP was selected as one method to be used to study reactions of dental patients to treatment in a dental emergency room. Although the technique is convenient, interpretation of results is far from simple. Changes in PSP can occur in both directions-an increase or a decrease from pretreatment in number of open pores. The direction of expected change is not clear. Johnson and Landon [3] for example, reported that subjects sitting quietly during a rest period had the lowest number of active sweat glands. In studies with surgical patients the number of active sweat glands showed a steady daily drop before surgery with a return increase in number of active sweat glands during recovery [2, 71. MacKinnon [6] found significant differences between normals and schizophrenics to the stress and fatigue of maintaining a raised leg. Normals inhibited sweating while chronic and acute schizophrenics showed a mixed raising and lowering of sweating as measured by number of open sweat pores. To further complicate the interpretation of results, Johnson and Dabbs [4] obtained prints from 12 females before, during, and after a statistics examination, before a regular class, and later while working on multiplication problems. A higher number of open sweat pores was obtained for the examination condition than for the other conditions. During the multiplication problems, a high number of open sweat pores was obtained at the start and at the end of the task, with a depression in the middle. Dabbs et al. [5] obtained PSP measures on subjects flying in a light aircraft. Increased number of open sweat pores was obtained prior to take-off and during the flight. These increases correlated with reported mood ratings of increases in arousal and happiness, and decreases in anger and depression. Johnson et al. [7] explained the increased number of open sweat pores to be associated with interacting with the environment while decreased number of open sweat pores was found to be associated with introspection and withdrawal from the environment. Such a withdrawal occurs days before surgery. MacKinnon [6] interprets increases in number of open sweat pores as a response to alerting stimuli of an anticipatory or apprehensive nature, while decreases in stimuli were associated with mental fatigue.