Table 1 Summary of Revised El Escorial Research Diagnostic Criteria for ALS (Brooks et al., 2000)

The diagnosis of ALS requires:

1 Evidence of LMN degeneration by clinical, electrophysiological or neuropathological examination;

2 Evidence of UMN degeneration by clinical examination, and

3 Progressive spread of symptoms or signs within a region or to other regions, as determined by history or examination,

Together with the absence of:

[1] Electrophysiological and pathological evidence of other disease that might explain the signs of LMN and/or UMN degeneration, and

[2] Neuroimaging evidence of other disease processes that might explain the observed clinical and electrophysiological signs

Categories of clinical diagnostic certainty on clinical criteria alone

Definite ALS

• UMN signs and LMN signs in 3 regions

Probable ALS

• UMN signs and LMN signs in 2 regions with at least some UMN signs rostral to LMN signs

Probable ALS – Laboratory supported

• UMN signs in 1 or more regions and LMN signs defined by EMG in at least 2 regions

Possible ALS

• UMN signs and LMN signs in 1 region (together), or

• UMN signs in 2 or more regions

• UMN and LMN signs in 2 regions with no UMN signs rostral to LMN signs