Table 8.

Summary of the revised El Escorial Diagnostic criteria for ALS.

Diagnosis	Involved segments
Clinically possible ALS	UMN and LMN signs in one region; UMN signs in at least two regions; or UMN and LMN signs in two regions without UMN signs rostral to the LMN signs
Laboratory-supported probable ALS	UMN signs in one or more regions and LMN signs in at least two regions defined by electromyography
Clinically probable ALS	UMN and LMN signs in two regions with some UMN signs rostral to the LMN signs
Clinically definite ALS	UMN and LMN signs in three regions

UMN: upper motor neuron and LMN: lower motor neuron.