El Escorial revisited: Revised criteria for the diagnosis of amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder involving primarily motor neurons in the cerebral cortex, brainstem and spinal cord. The variability in clinical Žndings early in the course of ALS and the lack of any biological diagnostic marker make absolute diagnosis difŽcult and compromise the certainty of diagnosis in clinical practice, therapeutic trials and other research purposes. The El Escorial criteria for the diagnosis of ALS have been widely accepted, but it was felt that they should be revised in order to increase their sensititvity. The criteria described below represent the result of a three-day workshop, convened at Airlie Conference Center, Warrenton, Virginia on 2–4 April, 1998 by the World Federation of Neurology Research Committee on Motor Neuron Diseases. This consensus document, reviewed, amended and ultimately accepted by all workshop participants, has been placed on the WFN ALS website (www.wfnals.org) where additional clinicians, researchers involved in ALS research, as well as appropriate scientiŽc review bodies and concerned voluntary organizations, have reviewed it, prior to formal publication. Requirements for the diagnosis of ALS