Getting the diagnosis right: beyond El Escorial.

The development and endorsement of the 'El Escorial criteria' by the World Federation of Neurology (WFN) for the diagnosis of amyotrophic lateral sclerosis (ALS) in 1990 and subsequent revision of these guidelines in April 1998 has provided physicians with a much needed tool in the secure diagnosis of ALS. However, even today, over 100 years since ALS was first described by Charcot, when asked to define ALS most neurologists will answer that ALS remains an extremely difficult disease to diagnose early and therefore to manage optimally. Despite the WFN's admirable commitment to optimising the management of ALS the definition of the early stages of ALS is still not clear. To appreciate why this remains so, the development of our understanding of ALS as documented by case reports in the literature will be discussed in this paper.