<P> Descriptions of the disease date back to at least 1824 by Charles Bell . In 1869, the connection between the symptoms and the underlying neurological problems was first described by Jean - Martin Charcot, who in 1874 began using the term amyotrophic lateral sclerosis . It became well known in the United States in the 20th century when in 1939 it affected the baseball player Lou Gehrig and later worldwide when physicist Stephen Hawking, diagnosed in 1963 and expected to die within two years, became famous . In 2014, videos of the ice bucket challenge went viral on the internet and increased public awareness of the condition . </P> <P> ALS is a motor neuron disease, also spelled "motor neurone disease", which is a group of neurological disorders that selectively affect motor neurons, the cells that control voluntary muscles of the body, including amyotrophic lateral sclerosis (ALS), primary lateral sclerosis, progressive muscular atrophy, progressive bulbar palsy, pseudobulbar palsy, and spinal muscular atrophy . </P> <P> ALS itself can be classified a few different ways: by how fast the disease progresses (slow vs fast progressors), by whether it is inherited or sporadic, and by where it starts . Most commonly (~ 70% of the time) the limbs are affected first . In this case, neurons in the brain (upper motor neurons) and in the spinal cord (lower motor neurons) are dying and this form is called "limb onset". In about 25% of cases, muscles in the face, mouth, and throat are affected first because motor neurons in the part of the brain stem called the medulla oblongata (formerly called the "bulb") start to die first along with lower motor neurons . This form is called "bulbar onset". In about 5% of cases muscles in the trunk of the body are affected first . In all cases the disease spreads and affects other regions . The symptoms may also be limited to one spinal region . </P> <P> Those with leg amyotrophic diplegia and brachial amyotrophic diplegia have a longer survival compared to classic onset ALS . </P>

In most cases does als affect the brain