What are the types of amyotrophic lateral sclerosis (ALS)?

Doctors have identified five types of ALS (commonly known as Lou Gehrig's disease):

• Classical ALS - The most common form of this syndrome. The individual experiences a progressive deterioration of the nerve cells and experience loss of motor function in hands, feet, arms, and legs, in addition to difficulty chewing, speaking, and swallowing

• Primary Lateral Sclerosis (PLS) - The rarest form of this syndrome. The nerve damage is isolated to one type of nerve and symptoms are generally confined to loss of motor function in hands, feet, arms, and legs.

• Progressive Bulbar Palsy (PBP) - Affects about 25 percent of the people afflicted with ALS. Unlike most other forms, its symptoms are generally confined to difficulty speaking, chewing, or swallowing.

• Progressive Muscular Atrophy (PMA) - A type of ALS in which the nerve damage is confined to one area. In this case, it's the nerves and muscles that control the hands and lower body that become damaged.

• Familial - Used to classify patients who have one or more members of the family who has also been afflicted with this syndrome. This, however, is very rare and accounts for only between five and ten percent of ALS cases.