A progressive, degenerative disease in which the neurons in the brain and spinal cord that control muscles die off, resulting in inability to use the muscles. ALS is also called Lou Gehrig’s disease, so named after the famous baseball player whose diagnosis with and death of the disease gave it public prominence. In its early stages, ALS begins with mild muscle twitching, fatigue, and weakness and can be difficult to distinguish from other neuro degenerative disorders such as Parkinson’s disease without a careful neurologic exam. These conditions sometimes are mistaken for one another until symptoms progress. Diagnosis of ALS commonly hinges on electromyographic testing.
ALS progresses relatively rapidly once symptoms become apparent, however, making diagnosis fairly certain. In most people ALS progresses from initial symptoms to dependence on mechanical ventilation and death inside five years, although some people have survived as long as 20 years. There are no effective treatments for ALS, although a drug called riluzole provides some neuroprotec-tive effects that appear to extend the length of time a person with ALS can breathe without mechanical assistance for a few months if started early in the disease.
ALS interests researchers studying Parkinson’s disease because ALS, as do Parkinson’s and Alzheimer’s diseases, destroys motor neurons, depletes neurotransmitters, and has both familial (genetic) and idiopathic forms. ALS and Parkinson’s also can occur together, and ALS, an Alzheimer’s type of dementia, and parkinsonism frequently occur together in the native Chamorro population of Guam. Studies have identified a defective gene present in a small percentage of those diagnosed with ALS, although for most people the cause is unknown. Unlike Parkinson’s and Alzheimer’s, ALS does not have among its symptoms cognitive impairment or dementia. About 5,000 Americans are diagnosed with ALS each year.