Natural very-low-frequency sferics and headache

Very-low-frequency (VLF) atmospherics or sferics are pulse-shaped alternati ng electric and magnetic fields which originate from atmospheric discharges (lightning). The objective of the study was threefold: (i) to analyse nume rous parameters characterizing the sferics activity with regard to their su itability for field studies, (ii) to identify meteorological processes rela ted to the sferics activity and (iii) to investigate the possible associati on of sferics with pain processes in patients suffering from migraine- and tension-type headaches. Over a period of 6 months (July through December) t he sferics activity in the area of Giessen (Germany) was recorded. Three sf erics parameters were chosen. The number of sferics impulses per day, the v ariability of the impulse rate during a day and the variability in comparis on to the preceding day were correlated with weather processes (thunderstor m, temperature, vapour pressure, barometric pressure, humidity, wind veloci ty, warm sector). Significant correlations were obtained during the summer months (July, August) but not during the autumn months (October, November, December). During autumn, however, the sferics activity was correlated with the occurrence of migraine-type headaches (r=0.33, P <0.01) recorded by 37 women who had filled out a headache diary over a period of 6 months (July- December). While the thunderstorm activity was very intense during July and August, no relationship between sferics and migraine was found. In summer, tension-type headaches were associated with meteorological parameters such as temperature (r=0.42, P <0.01) and vapour pressure (r=0.28, P <0.05). Al though the sferics activity can explain a small percentage of the variation in migraine occurrence, a direct influence was more likely exerted by visi ble or otherwise perceptible weather conditions (thunderstorms, humidity, v apour pressure, warm sector, etc.) than by the sferics activity itself.