Autonomic impairment in amyotrophic lateral sclerosis

Purpose of review: Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by progressive, loss of motor neurones, but it is increasingly recognized to be a more disseminated disease. The autonomic nervous system may also be involved. Here we review the literature with specific emphasis on autonomic functions in ALS. Recent studies: Ample evidence exists for subclinical dysfunction of cardiovascular, sudomotor, gastrointestinal, salivary and lacrimal regulation, even in early ALS cases. Autonomic disturbances may lead to circulatory collapse or sudden death in respirator dependent patients. Several studies suggest the existence of sympathetic hyperactivity in ALS. We discuss some possible pathophysiological mechanisms of the subtle abnormalities and some clinical and treatment implications. Summary: The wide range of autonomic involvement, together with results suggesting cognitive and extrapyramidal dysfunction, supports the view that ALS is a multisystem degenerative disease.