Amyotrophic lateral sclerosis (ALS), also referred to as Lou Gehrig’s disease in American English and Motor Neurone Disease in British English, is a form of Motor Neuron Disease caused by the degeneration of upper and lower neurons, located in the ventral horn of the spinal cord and the cortical neurons that provide their efferent input. The condition is often called Lou Gehrig’s disease in North America, after the New York Yankees baseball player who was diagnosed with the disease in 1939. The disorder is characterized by rapidly progressive weakness, muscle atrophy and fasciculations, spasticity, dysarthria, dysphagia, and respiratory compromise. Sensory function generally is spared, as is autonomic and oculomotor activity. ALS is a progressive, fatal, neurodegenerative disease with most affected patients dying of respiratory compromise and pneumonia after 2 to 3 years; although some perish within a year from the onset of symptoms, and occasional individuals have a more indolent course and survive for many years.