Abstract

Neurol. 285 J. Neurosurg. Psychiat., 1959, 22, THE SEASONAL INCIDENCE OF ONSET AND IN EXACERBATIONS MULTIPLE SCLEROSIS BY KURT SCHAPIRA From the Department Royal Victoria Newcastle of Neurology, Infirmary, upon Tyne possible that new That the disease is significantly more common in symptoms may be caused by is one one the northern part of the northern hemisphere or two strategically situated lesions amongst about many simultaneously initiated or of the few epidemiological observations re-activated, and as reason- that some pathological exacerbations may multiple sclerosis which can be regarded even be for entirely ably well established. The cause this increased asymptomatic. However, both the onset of obscure: the incidence in colder climates remains entirely symptoms and, particularly identifiable acute infec- exacerbations of an increased prevalence of upper respiratory the disease, presumably indicate at under such con- the least a critical activation of tions or of vasospastic disorders the disease process- which a pathological as well as a clinical exacerbation. ditions are amongst the possible mechanisms the have been speculatively invoked, but there is no Quite often, progress of the disease is insidious throughout. Such cases were excluded from the reliable evidence in either direction. of interest to present series but