What is ALS?

Over the last few weeks, many of us have seen video after video of friends and celebrities taking on the “Ice Bucket Challenge” to benefit ALS research. So, what is ALS? And why does it need to be researched?

In a sentence: Amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig’s disease, is a progressive neurodegenerative disease for which there is currently no cure.

What it looks like clinically, and what’s causing it to look that way:

–ALS is “neurodegenerative” because “motor neurons,” or nerve cells that control movement, are damaged. Motor neurons are damaged because they accumulate a build-up of “inclusions,” or clumps of dysfunctional proteins, which cause the cell harm. These damaged neurons then cannot signal muscles to contract and release as they normally would. As a result, patients with ALS develop muscle weakness and, eventually, paralysis.


–Loss of motor neurons eventually impairs the function of limbs, head and neck muscles, spinal muscles, and respiratory muscles. That means that, eventually, people with ALS will not be able to walk, speak, eat, or breathe.

–In ALS, the motor neurons in both the brain (“upper motor neurons”) and the brainstem and spinal cord (“lower motor neurons”) are affected. Signs of upper motor neuron involvement include increased reflexes, “spasticity” (increased muscle tone leading to muscle tightening), and lack of coordination. Signs of lower motor neuron include muscle atrophy and “fasciculations,” or muscle twitches.


–There are different variations of ALS where the initial symptoms and areas affected differ, and where additional symptoms such as dementia are present.

Who gets it? ALS most often affects people between ages 40 and 70, but can affect individuals in their 20s and 30s. Sometimes it runs in families, but most often people with ALS have no known affected family member. There are about 2 cases per 100,000 in the US population newly diagnosed each year (about 5,600 new cases per year). About 30,000 people in the US are currently living with ALS.


Left: baseball player Lou Gehrig (right) after whom the disease was named. Right: Professor Stephen Hawking, living with a form of ALS.

Is it life-threatening? Yes. Respiratory failure is the most common cause of death in ALS. The median survival from the time of diagnosis is three to five years.

What are the currently available treatment options? Though there is no cure, some treatment options modestly modify the disease. A drug called Riluzole which targets the pathway of the neurotransmitter glutamate is the only drug shown to impact survival, and even so only increases lifespan by months. Otherwise, patients must be given supportive care to assist them with functions of daily living.

What could we use in the future? There are several therapies being tested in animals and humans, and there are therapies that have been proposed for future trials including drugs, stem cell treatments, and gene therapy.

The aim of the ice bucket challenge is to raise money for ALS research by encouraging donations to the ALS organization.