Diagnostic dilemmas in amyotrophic lateral sclerosis.

The El Escorial criteria for the diagnosis of amyotrophic lateral sclerosis (ALS) were introduced in 1990 to provide a standardised and diagnostically reliable approach to the early recognition of this disease. It is still unclear, however, whether these are the best criteria available for the early diagnosis of ALS. We applied these criteria retrospectively to clinical material available from 34 cases of autopsy proven ALS in an attempt to validate their usefulness in a pathological series. The clinical material was reviewed and specific clinical signs and anatomical levels of involvement recorded. Only signs listed in the criteria were included in the analysis. The El Escorial criteria for clinically definite ALS demonstrated high sensitivity and accuracy when validated in this clinicopathological study. Neuroimaging and electromyography were important in shortening the time in which patients were given a diagnosis of clinically definite ALS. Other diagnostic dilemmas in ALS and the role of early diagnosis of this disease are discussed.