Is geomagnetic activity a risk factor for sudden unexplained death in epilepsies?

Objective: To test the hypothesis that sudden unexplained death (SUD) in ep ilepsy is related to geomagnetic activity. Background: Prior studies presum e that geomagnetic activity (with average amplitudes above 50 nanotesla [nT ]) is associated with SUD in epileptic human patients and in epileptic labo ratory rats. Methods: In a retrospective study, 46 epileptic patients with definite SUD were compared with 108 epileptic patients with known cause of death (KCD) who died between 1981 and 1992. A complete postmortem examinati on was performed in all cases. The time of the day and date of death, as we ll as two international geomagnetic indices concerning Bartels' planetary S -hour signs (Kp) and the mean planetary daily amplitudes (Ap) at time of de ath, were assessed. Results: Among 45 SUD individuals, the local time (37.8 %) and the universal time of death (35.6%) peaked within the critical perio d between 3 to 9 AM. However, the SUD and KCD group did not substantially d iffer in regard to the distribution of local or universal time of death (p > 0.2, Fisher test). Neither the Kp signs at death and 2 hours before death nor the Ap values showed considerable differences between the SUD and KCD series (p > 0.2, Mann-Whitney test). Merely 4.3% of SUD patients and 3.7% o f KCD patients were associated with Ap indices above 50 nT (p > 0.2, Fisher test). Conclusion: The results do not support the hypothesis that geomagne tic activity is related to occurrence of sudden unexplained death in epilep tic patients.