Amyotrophic Lateral Sclerosis (ALS)

Amyotrophic lateral sclerosis, or ALS, is a disease in which the nerve cells that command your muscles slowly die off. These cells, called motor neurons, are like the wiring that carries every order from your brain to your muscles — telling your hand to grip, your legs to walk, your throat to swallow. In ALS, that wiring frays and breaks down a little more each month. The muscles, no longer receiving signals, stop being used, shrink, and grow weak. The name itself describes this: 'amyotrophic' means the muscles waste away from lack of nourishing signals, and 'lateral sclerosis' means the side regions of the spinal cord, where these nerve fibers run, harden and scar as the cells are lost.

ALS is progressive, meaning it keeps advancing — it usually begins with something small, like a weak grip, a stumble, or slurred speech, and over months to a few years spreads to more and more muscles, leading to paralysis (the loss of the ability to move). Crucially, ALS attacks movement but typically spares the senses and, in most people, the thinking mind: someone can become unable to walk, speak, or eventually breathe on their own while still seeing, hearing, feeling, and understanding everything around them. There is no cure yet, but care, breathing support, and a few medicines can ease symptoms and slow the decline. Scientists study ALS hard because it reveals, in stark form, how delicate and irreplaceable motor neurons are, and the hunt for treatments drives much of modern neuroscience.