VISUAL AND MOTOR CHANGES IN PATIENTS WITH MULTIPLE SCLEROSIS

Abstract

CLIMATE and temperature have been recognized as affecting the incidence of multiple sclerosis. Although sex and race appear not to be important factors in its occurrence, its geographical distribution seems to vary significantly with the distance of an area from the equator. According to one study of the mortality statistics in 14 countries,¹ there is '"an inverse and rather striking relationship between reported mortality due to multiple sclerosis and mean annual temperature. The colder the climate, the higher the crude death rates for multiple sclerosis." Other authors have been in agreement,² pointing out the commonness of multiple sclerosis in northern European countries, as well as Canada, the United States and Australia. In Canada, the United States and Italy, the areas with a higher death rate from multiple sclerosis seem to lie above the 60 degree isotherm of the mean annual temperature reduced to sea level. A definite statistical