Correlation between convulsive seizure and geomagnetic activity.

The annual percentage of patients with convulsive seizure in the Neurological Department of the Bangur Institute of Neurology, Calcutta, is found to be significantly correlated with the annual values of sunspot numbers and geomagnetic activity indices for the period 1955--1971. For a particular geomagnetic activity index the correlation coefficient is significant at a 99% confidence level. The study shows that a proper choice of elements in the series is important in studies undertaken to establish the biological effects of solar activity.