When you decide to shake someone’s hand or wiggle your toes, your brain sends a signal that travels down your spinal cord to the muscles you want to move. The highway that allows this to happen is built from nerve cells called motor neurons.
These motor neurons help you turn thoughts into physical actions. But when they’re damaged, your brain can no longer make the muscles they’re connected to move. The highway is damaged, and the signal can’t travel very well.
This is the reality for people with amyotrophic lateral sclerosis (ALS). For reasons unknown, ALS causes motor neurons to degenerate over time. According to the ALS Association, as motor neurons die, people with ALS lose their ability to walk, talk, eat and eventually breathe.
Adding to this scary reality is that there’s no cure for ALS — yet. While some people live more than 10 years with ALS, the average life expectancy is just 2 to 5 years.
Famous people who faced ALS include baseball great Lou Gehrig, scientist and author Stephen Hawking and Sesame Street co-creator Jon Stone.
Fortunately, ALS is a rare condition. There are about 2 new cases per 100,000 Americans each year. “This leads to about 5,000 people in the U.S. having ALS at any one time,” says Robert Gordon Kalb, MD. He’s a neuromuscular medicine specialist at Northwestern Memorial Hospital in Chicago.
So if you experience any common ALS warning signs such as muscle weakness or issues with your speech, it’s best not to jump to conclusions. Here’s why — and what your symptoms could actually signal.
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Common ALS symptoms — and the other conditions they could suggest
ALS gradually gets worse over time. And its onset can be very subtle, making it easy to overlook symptoms, according to the National Institute of Neurological Disorders and Stroke (NINDS).
Early symptoms can include:
- Muscle twitches in the arms, legs, shoulder or tongue
- Muscle cramps
- Stiff or tight muscles
- Slurred speech
- Muscle weakness in your arms, legs, neck or diaphragm
Another key sign can be trouble with simple tasks, such as writing, buttoning a shirt or turning a key in a lock. “A person becomes progressively weak with ALS,” says Dr. Kalb. Feeling awkward when walking or stumbling more often can occur, too. “Over time, the nerve cells that connect to your diaphragm are affected so your breathing gets weak,” adds Dr. Kalb. “Swallowing becomes very difficult. It becomes progressively harder to get enough air and to eat or drink.”
But having some ALS symptoms doesn’t necessarily mean you have this disorder. These symptoms are also common in a whole host of other health conditions.
Let’s first dig into muscle twitches and spasms. They can be caused by things not related to an underlying condition or disease. These can include medication side effects, dehydration and even stress. (We cover muscle spasms in depth here.)
Likewise, muscle cramps are common after exercise. And many people experience cramps in their legs during the night. While they’re uncomfortable, they’re usually harmless, according to the Cleveland Clinic.
If you’re having weakness or a loss of feeling, it’s important to not panic, either. “There are much more common causes for these symptoms,” says Holli Horak, MD. She’s a neuromuscular specialist and professor at the University of Arizona College of Medicine in Tucson.
For example, weakness could be due to a pinched nerve in the neck or low back. Or it could be related to another condition such as peripheral neuropathy. According to the Mayo Clinic, this condition happens when nerves outside of your brain and spinal cord, such as in your feet or hands, are damaged. It can cause numbness, tingling, muscle weakness and pain.
“ALS does not cause sensory changes,” says Dr. Horak. “So any symptoms with numbness or tingling are not likely to be ALS.”
Dr. Horak adds that for some people, ALS begins with speech changes. These symptoms can be similar to some types of strokes. So doctors will often evaluate for strokes first before considering ALS. (Do you know the signs of a stroke? Catch up here.)
Other serious conditions can mimic ALS at first. But they still allow for a long, happy life. These include:
- Multiple sclerosis
- Parkinson’s disease
- Post-polio syndrome
- Certain infectious diseases
If you have a relative who had ALS, it’s natural to worry that you might get it, too. But this isn’t very likely. “If you have a grandparent who had a genetic form of the disease, it’s possible for another family member to have the same mutant gene,” says Dr. Kalb. “But everyone who has this gene will not necessarily develop the disease.”
