Amyotrophic lateral sclerosis (ALS), also referred to as Lou Gehrig’s disease, is a neurodegenerative disease that affects nerve cells in the brain and the spinal cord. Like Alzheimer’s and Parkinson’s, the disease worsens over time and the rate at which ALS progresses varies from person to person.
In healthy bodies, upper motor neurons in the brain send signals to lower motor neurons in the spinal cord and brainstem, which send signals to muscles—creating body movement. This sequence of signals allows you to reach for your glass, say hello to your neighbor and operate a vehicle. In ALS, both the upper motor neurons and the lower motor neurons degenerate or die, resulting in loss of muscle function with progression to severe impairment of mobility, speech and communication.
Early symptoms of ALS usually include muscle weakness or stiffness, and over time, all muscles under voluntary control are affected. As ALS progresses, individuals lose their strength and the ability to speak, eat, and move. Many will lose the muscular ability to maintain breathing, requiring permanent ventilatory support. Individuals with ALS usually retain their ability to perform higher mental processes such as reasoning, remembering, understanding, and problem solving, so they are entirely aware of their progressive loss of muscle function.