Amyotrophic lateral sclerosis, also known as motor neuron disease or Lou Gehrig’s disease, is an adult-onset neurodegenerative disease that targets motor neurons in the spinal cord, cortex and brain stem. Selective degeneration of corticospinal (upper) and spinal (lower) motor neurons manifests as a linear decline in muscular function, eventually resulting in paralysis, speech and swallowing deficits and death, usually from impaired respiratory function, over a time course of approximately 3-5 years.