Epidemiology of motor neuron disease in two Italian provinces. Analysis of secular trend and geographic distribution.

Incidence and prevalence rates of motor neuron disease in two Italian provinces (Asti and Cuneo, Piedmont region) in the period 1971 through 1985 were estimated. The data were omogeneous in the investigated area, but an increasing incidence of the disease during the period studied was found, particularly in older age groups and in females. An increasing trend in mean age of onset of symptoms was also found.