Psychophysiological reactions in dental phobic patients during video stimulation.

Electromyography (EMG) reflecting forehead muscle tension, heart rate (HR) and skin conductance (SC) were continuously recorded in dental phobic subjects (n = 126) and controls (n = 25) during exposure of dental and neutral video scenes in order to explore the relationship between dental fear and psychophysiological responses. This relationship is far from well established, and the present investigation was performed to contribute to the understanding of the psychophysiology of dental fear. Dental phobics had a mean anxiety level of 17.3 as measured by Corah's Dental Anxiety Scale (DAS) and refused conventional dental treatment. Control subjects reported regular dental treatment and a DAS score below population average (DAS < 8). Psychophysiological data was reduced to level (mean) and reactivity (means of intraindividual variations). Results showed that physiologic reactions to fear-relevant conditions measured by HR and EMG reflected degree of dental fear, and that neutral conditions, when presented for the second and third time, induced lower psychophysiologic reactions in phobics than in controls. Recordings of SC indicated that dental phobics may differ from individuals suffering from other types of specific phobia by showing weakened autonomic responsiveness to threat.