• ALS
• epidemiology

The understanding of the cause of amyotrophic lateral sclerosis (ALS) remains elusive, despite the increase in the number of published papers on this disease in the two last decades. Epidemiological studies have given important insight into ALS frequency and clinical characteristics. It is now established that ALS is similarly distributed in industrialised countries, including Europe, USA and Japan; its incidence has not changed over the two last decades and its classification as an age-related disease (ie, the product of pathogenic noxae acting at specific ages) versus an ageing-related disease (ie, a selective impairment of specific neuronal systems/pathways …