The emerging picture of ALS: a multisystem, not only a "motor neuron disease.

Amyotrophic lateral sclerosis (ALS) is traditionally considered a disease affecting exclusively motor neurons: compelling evidence points now towards additional involvement of extramotor functions. Beside the cognitive-behavioural disturbances, many ALS patients express extrapyramidal deficits: neuropathological findings fully support the multisystem brain degeneration. The therapeutical option to treat the multisystemic character of ALS represents an additional difficult task in absence of sensitive biomarkers or better understanding of the pathophysiological mechanisms of the disease. Future clinical trials need to identify subgroups of patients, representing the post-hoc analysis after a trial the extreme effort to define sensitive ALS patients to new treatments, as the edaravone story seems to demonstrate.