Search

Vertex evoked potentials (40--500 ms) elicited by painful dental stimulation were compared with those elicited by innocuous auditory stimuli across three rates of stimulus repetition: one second, four seconds, and eight seconds. In both modalities peak amplitude of the major waveform components increased linearly over log rate as stimulus repetition was slowed, and latency of the latest positive component was increased. No changes in subjective stimulus intensity across rate of repetition were reported. These observations demonstrate that the normally close relationship between subjective pain report and EP amplitude is not variant, and they suggest that the development of EP methodology in human pain research should proceed conservatively.

The effect of low frequency electrical acupunctural stimulation on the perception of induced dental pain were compared in two cultural settings. Twenty Japanese and 20 American subjects (consisting of 10 Caucasians and 10 second or third generation Japanese) were tested in two functionally identical laboratories, one at Tottori University in Yonago, Japan and the other at the University of Washington. Each subject underwent a control and an acupuncture session on separate days wtih subjects counterbalanced for carry-over order effects. Sensory decision theory (SDT) analysis demonstrated a significant reduction in perceptual capability and an increased bias against reporting stimuli as painful following the acupuncture as treatment which was performed bilaterally at traditional facial points. No significant differences between groups in alteration of perceptual capability, bias or pain threshold were demonstrated, indicating that the cultural and racial differences studied did not influence responses to acupuncture in a laboratory setting.