Printed in U.S.A. VOL. 29, NO. 8, AUGUST 2003
CLINICAL RESEARCH Objective Measurement of Patient’s Dental Anxiety by Galvanic Skin Reaction
H. John Caprara, DMD, Paul D. Eleazer, DDS, MS, Robert D. Barfield, DMD, and Scott Chavers, PhD
The purpose of this study was to determine if anxiety can be measuredobjectively by skin conductance of a weak electric current. Three measurements were taken. First, a standardized dentalanxiety questionnaire was given to determine anxiety. Second, galvanic skin conductance was measured. Third, polygraph responses were recorded to three key questions from the questionnaire. Questionnaire scores of these key questions were used to create two groups: anxious andnotanxious. The three key questions were subjected to polygraph verification. In the first analysis patients were excluded if the polygraph test disclosed lying on any of the three key questions. The second analysis excluded liars on a question-byquestion basis. The third analysis disregarded the polygraph. A statistically significant correlation was found between skin conductance and dental anxietyin all cases. Data seem to indicate that fear of injection is the most anxiety-producing aspect of modern dentistry.
To overcome these shortcomings, several investigators have used psychophysiological measurements such as galvanic skin resistance (GSR), as used in polygraph testing to quantitate levels of anxiety in patients (4 – 6). These measurements take advantage of the electrical changesinduced by minute amounts of fluid from epidermal sweat glands released secondary to anxiety. Sweat on the skin provides a low-resistance pathway for electric current. Lykken and Venables (4) have shown that galvanic skin reaction as measured by skin conductance is a more reliable method than skin resistance. Conductance measurement produced more reproducible values with narrower ranges (4). Suchmeasurement of skin conductance may result in a more linear relationship to the underlying psychophysiological aspects of anxiety. Also, skin conductance measurements require less complicated electronic circuitry than skin resistance measurements. Benjamins et al. (7) studied dental anxiety and found that skin conductance levels were significantly different and more reproducible than resistancemeasurements in dental patients, both at baseline and when stress-inducing stimuli were introduced. The purpose of this study was to determine if galvanic skin conductance (GSC) of endodontic patients correlated to anxiety levels as measured by a standard dental-anxiety questionnaire. Because we recognize that some patients will consciously or subconsciously deny anxiety on a questionnaire, weverified their answers with polygraph responses.
Dental anxiety and fear may result in avoidance of needed dental care by the apprehensive patient. This seems especially true in the patient who fears root canal therapy. A classic study has shown that approximately 50% of the general population has some degree of dental anxiety and that 6% to 20% of all dental patients have serious dental phobias(1). Identification of the nervous dental patient is not always easy. Presently the primary available means of quantifying dental anxiety are questionnaires such as the Kleinknecht’s dental-fear survey and the Corah dental-anxiety scale (1, 2). Schuurs and Hoogstraten (3) have shown that although the above scales provide valuable information to the treating practitioner concerning anxiety, thereliability of such scales is often questionable, falling in the 40% to 80% confidence level.
MATERIALS AND METHODS The 49 patients used for this study were adults who read, stated that they understood, and signed an informed consent approved by the university human studies committee (IRB). Three measurements were taken: a dental-anxiety questionnaire, GSC as measured by voltage, and polygraph...