Clinical features of amyotrophic lateral sclerosis and their prognostic value.

In classic amyotrophic lateral sclerosis (ALS), the relative degree of impairment of cortical vs spinal motor neurons serving the different body regions is highly variable. This means that an accurate, systematic assessment of the patient's clinical presentation is essential for both the diagnosis and prognosis. The patient's phenotype, rate of disease progression, time of onset (if early) of respiratory failure and nutritional status all have prognostic value, and should be specified in the nosological classification of the disease.