Oscillating magnetic fields change in an opposite way pain-thresholds and pain-related evoked potentials.
摘要
It is well known that oscillating magnetic fields (MFs) modify stress-induced analgesia. Hitherto, to test these effects in man only psychophysical methods (pain-threshold) have been employed. In this study, MF effects have been assessed in 10 normal subjects (6 females and 4 males; age range 26-45 years), both with psychophysical (tactile and pain thresholds) and electrophysiological (pain-related evoked potentials, PEPs) methods. During two independent experimental sessions, they have been submitted to effective (ON) and shame (OFF) MFs, in a random way. Following OFF condition, tactile and pain thresholds showed a significant increase (stress induced hypoalgesia due to the experimental method itself). After ON condition, both thresholds were decreased; on the contrary, a significant N150 and P250 waves amplitude loss has been detected, not correlated with psychophysical data. In conclusion, MFs change in an opposite way to perception thresholds and PEPs, as a possible consequence of an independent effect on the nociceptive system and electroencephalographical activity.