Revised Criteria for the Diagnosis of Amyatrophic Lateral Sclerosis

 In order to standardize the diagnosis of ALS the  El Escorial Criteria (EEC) have been developed in 1994 following the older Airlie-House-Criteria.

The EEC have been revised in 1998 (Brooks et al. 2000). The EEC are mainly clinical and form the gold standard of ALS diagnosis. They are, however, relatively rigid and are not suitable for early diagnosis.

They are important for scientific classification and so far for recruitment into clinical trials, but not for clinical praxis. According to the EEC, the diagnosis of ALS requires the presence of A-criteria and the absence of B-criteria:

A-criteria:

A1: Degeneration of the lower motor neuron approved by clinical, electrophysiological or neuropathological examination.

A2: Degeneration of the upper motor neuron approved by clinical examination.

A3: Progressive dissemination beyond typical nerve supply areas.

B-criteria:

B1: Electrophysiological or neuropathological findings typical for other diseases which could explain the degeneration of the upper and lower motor neuron.

B2: Findings in imaging studies which can explain the clinical symptoms.

The diagnosis ALS requires an extensive history and a thorough clinical and electrophysiological examination. The electrophysiological tests can demonstrate the involvement of the lower motor neuron in affected and frequently also in clinically not affected body regions. The EEC define four body regions to be evaluated:

• brain stem (bulbar),

• cervical (neck and upper extremities),

• thoracal (trunk, abdominal wall)

• lumbosacral (lumbar spine and lower extremities).

The classification according to the revised EEC distinguishes between:

Clinically definite ALS

Proof of both, lower and upper motor neuron signs in at least 3 body regions.

Clinically probable ALS

Proof of both, lower and upper motor neuron signs in at least 2 body regions. The upper motor neuron signs have to be demonstrated rostrally to the region of the lower motor neuron signs.

Clinically probable – laboratory supported ALS

Clinical signs of the lower and the upper motor neuron in 1 body region only. Additionally there are electromyographic signs of active and chronic degeneration in at least 2 extremities.

Possible ALS

Signs of lower and upper motor neuron in 1 body region only or upper motor neuron signs in 2 or more body regions.

The old version of the EEC additionally contained the category “clinically suspected ALS” which has been deleted in the revised version.