Amyotrophic lateral sclerosis (ALS), sometimes called Lou Gehrig's disease, is a rapidly progressive, invariably fatal neurological disease that attacks the nerve cells (neurons) responsible for controlling voluntary muscles (muscle action we are able to control, such as those in the arms, legs, and face). The disease belongs to a group of disorders known as motor neuron diseases, which are characterized by the gradual degeneration and death of motor neurons.
Symptoms: The onset of ALS may be so subtle that the symptoms are overlooked. The earliest symptoms may include fasciculations, cramps, tight and stiff muscles (spasticity), muscle weakness affecting an arm or a leg, slurred and nasal speech, or difficulty chewing or swallowing.
In contrast to previous retrospective and mortality studies, the incidence rates were remarkably similar, ranging from 1.7 to 2.3 cases per 100,000 per year. This relative homogeneity is due to a confluence of factors inherent to registry design, a consensus diagnostic criteria for ALS had been established in 1990, which allowed standardization of the diagnosis of ALS across the different registers.