REQUIREMENTS FOR THE DIAGNOSIS OF
ALS
The diagnosis of Amyotrophic Lateral Sclerosis [
ALS] requires:
A - the presence of:
(A:1) evidence of lower motor neuron (LMN) degeneration
by clinical, electrophysiological or neuropathologic examination,
(A:2) evidence of upper motor neuron (UMN) degeneration
by clinical examination, and
(A:3) progressive spread of symptoms or signs within a region or to other regions,
as determined by history or examination,
together with
B - the absence of:
(B:1) electrophysiological and pathological evidence of other disease
processes that might explain the signs of LMN and/or UMN degeneration, and
(B:2) neuroimaging evidence of other disease processes that might explain the
observed clinical and electrophysiological signs.
CLINICAL STUDIES IN THE DIAGNOSIS OF
ALS
A careful history, physical and neurological examination must search for clinical evidence of UMN and LMN signs in four regions [brainstem, cervical, thoracic, or lumbosacral spinal cord] (see Table 1) of the central nervous system [CNS]. Ancillary tests should be reasonably applied, as clinically indicated, to exclude other disease processes. These should include electrodiagnostic, neurophysiological, neuroimaging and clinical laboratory studies.
Clinical evidence of LMN and UMN degeneration is required for the diagnosis of
ALS.
The clinical diagnosis of
ALS, without pathological confirmation, may be categorized into various levels of certainty by clinical assessment alone depending on the presence of UMN and LMN signs together in the same topographical anatomic region in either the brainstem [bulbar cranial motor neurons], cervical, thoracic, or lumbosacral spinal cord [anterior horn motor neurons]. The terms Clinical Definite
ALS and Clinically Probable
ALS are used to describe these categories of clinical diagnostic certainty on clinical criteria alone:
Clinically Definite
ALS
is defined on clinical evidence alone by the presence of UMN, as well as LMN signs, in three regions.
Clinically Probable
ALS
is defined on clinical evidence alone by UMN and LMN signs in at least two regions with some UMN signs necessarily rostral to (above) the LMN signs.
The terms Clinically Probable
ALS - Laboratory-supported and Clinically Possible
ALS are used to describe these categories of clinical certainty on clinical and criteria or only clinical criteria:
Clinically Probable - Laboratory-upported
ALS
is defined when clinical signs of UMN and LMN dysfunction are in only one region, or when UMN signs alone are present in one region, and LMN signs defined by EMG criteria are present in at least two limbs, with proper application of neuroimaging and clinical laboratory protocols to exclude other causes.
Clinically Possible
ALS
is defined when clinical signs of UMN and LMN dysfunction are found together in only one region or UMN signs are found alone in two or more regions; or LMN signs are found rostral to UMN signs and the diagnosis of Clinically Probable - Laboratory-supported
ALS cannot be proven by evidence on clinical grounds in conjunction with electrodiagnostic, neurophysiologic, neuroimaging or clinical laboratory studies. Other diagnoses must have been excluded to accept a diagnosis of Clinically possible
ALS.
Clinically Suspected
ALS
it is a pure LMN syndrome, wherein the diagnosis of
ALS could not be regarded as sufficiently certain to include the patient in a research study. Hence, this category is deleted from the revised El Escorial Criteria for the Diagnosis of
ALS.
. Requirements for ALS Diagnosis 
