Of or pertaining to James the First, of England, or of his reign or times; especially, pertaining to a style of architecture and decoration popular in the time of James I.; as, Jacobean writers. Etymology: From L. Jacobus James.
ALS is a progressive, degenerative disease of the nervous system. It is one of a group of diseases, called motor neuron diseases (MND), in which specialized nerve cells that control movement of the voluntary muscles gradually cease functioning and die. Fasciculation is a sign of muscle irritability, as the normal action of the lower motor neuron on the muscle is impaired. 2  The sole involvement of lower motor neurons can be seen in a form of ALS called progressive muscular atrophy.
Muscle atrophy is a loss of muscle tissue due to disuse, disease or injury. A decrease in physical activity can lead to muscle loss in as little as 72 hours. Atrophy can occur more suddenly with illness or injury to the muscles or their nerves, and the muscles in the legs are among the first to weaken.