CHANGES IN PAIN PERCEPTION AND PAIN-RELATED SOMATOSENSORY-EVOKED POTENTIALS IN HUMANS PRODUCED BY EXPOSURE TO OSCILLATING MAGNETIC-FIELDS

Nociception has been reported to be influenced by exposure to magnetic fields (MFs). The aim of this study was to investigate the effects of 2 h exposure to weak, oscillating MFs on pain perception thresholds a nd on pain-related somatosensory evoked potentials (SEPs). In 11 healt hy volunteers, pain perception thresholds and pain-related SEPs were a ssessed by intracutaneous electrical stimulation. After sham treatment , pain thresholds significantly increased, whereas after MFs a slight non-significant decrease in thresholds was found. After both treatment s pain-related SEP amplitude was reduced, but this decrease was more e vident and statistically significant only after MF exposure. The incre ase found in thresholds after sham exposure may be due to stress-induc ed analgesia (SIA) and the contrasting behaviour recorded after MF exp osure might indicate a suppression of SIA. The significant reduction i n pain-related SEP amplitude observed after MF exposure provides the f irst evidence that human SEPs are influenced by MFs. (C) 1997 Elsevier Science B.V.