When you take a walk, talk to a friend, or chew a piece of food, motor neurons are behind these movements.
Just like other parts of your body, they can become damaged. You may have heard of amyotrophic lateral sclerosis (ALS), commonly known as Lou Gehrig’s disease. It’s one kind of motor neuron disease (MND), and there are several other lesser-known types.
What Are Motor Neurons?
Motor neurons are nerve cells that connect your brain and spinal cord to your muscles. They are responsible for all the movements you make — voluntary and involuntary. So when you take a walk, talk to a friend, or even breathe, motor neurons are behind these movements.
You have two main kinds of motor neurons:
- Upper motor neurons: Located in your brain, they send messages to the lower motor neurons in your spinal cord, telling your body which muscles to move.
- Lower motor neurons: They transmit the messages sent from your brain directly to your muscles so you can move them.
Just like other parts of your body, motor neurons can be damaged, leading to motor neuron disease (MND). As nerve cells die because of an MND, electrical messages can’t get from your brain to your muscles. Over time, your muscles waste away. You may hear a doctor or nurse call this “atrophy.” When this happens, you lose control over movements. It gets harder to walk, talk, swallow, and breathe.
Each kind of motor neuron disease affects different types of nerve cells or has a different cause.
What Causes Motor Neuron Diseases?
Researchers haven’t yet found what causes motor neuron diseases, but there are some theories. Even in the 10% of situations where a disease might run in families, there still needs to be a trigger that starts the disease. Researchers believe that these factors could have a role in that:
- Exposure to toxins and chemicals, such as heavy metals and pesticides
- Viruses
- Trauma to the cells
- Extreme exercise
Who’s most likely to get an MND?
Anyone can get a motor neuron disease, but some people do have a higher risk. MNDs tend to affect slightly more men than women, and more people over 40, with the highest risk age group being between 50 and 70. People of all ethnicities and races can develop an MND, but not in the same numbers. For example, amyotrophic lateral sclerosis (ALS) is less common among people of South and East Asian descent than among those who are White. It can run in families too, so if someone in your family has ALS, your risk goes up.
Researchers don’t know why, but where you live might also play a role in who gets an MND. New Zealand has the highest rate of this type of disease in the world.
What Are the Most Common Symptoms of Motor Neuron Disease?
Symptoms of the different MNDs are pretty similar because they result from the motor neurons not working properly and you can’t use your muscles like you did before. The symptoms may show up in different parts of the body but some things, such as twitches in your face, aren’t necessarily signs of such a serious disease.
“There are people that get twitches of their muscles, which is called fasciculations,” says Philip Blum, MD, a neurologist at Memorial Hermann in Houston, Texas. “They are certain that they have ALS as soon as they see those fasciculations. I would say that the number of people I see for fasciculations that aren’t due to motor neuron diseases is at least 20 times more common than those who do have [an MND].”
Some symptoms a person with an MND might experience include:
- Muscle weakness that could start anywhere. Some people with ALS notice they first have difficulty speaking or swallowing because of weakness in their tongue, while others have weakness in their arm or leg
- Breathlessness, shortness of breath when lying down
- Frequent chest infections
- Difficulty sleeping
- Poor concentration
- Confusion
- Morning headaches
- Fatigue
What Are the Types of Motor Neuron Disease?
Amyotrophic lateral sclerosis (ALS)
ALS is the most common type of MND, affecting about 4 to 6 out of every 100,000 people in the U.S. It affects both your upper and lower motor neurons. With ALS, you gradually lose control over the muscles that help you walk, talk, chew, swallow, and breathe. You may also have stiffness and twitches in your muscles. Over time, they weaken and waste away.
Most of the time, ALS is what doctors call “sporadic.” This means anyone can get it. Only about 10% of cases in the U.S. run in families.
ALS usually starts between the ages of 40 and 70, but the average age of diagnosis is 55 years. It can, however, start as early as the 20s and 30s. Most people with the disease live for three to five years after their symptoms start, yet some people can live for 10 years or longer.
Primary lateral sclerosis (PLS)
PLS is similar to ALS, but it’s rare and researchers don’t know exactly how often it occurs. The disease affects only upper motor neurons.
The symptoms usually start in your legs and then spread to other parts of your body. Early signs include a slower walking pace, poor coordination, and balance. Over time, speech may become slow and slurred, and chewing and swallowing become difficult.
Like ALS, it usually starts in people aged 40-60 years. The muscles get stiffer and weaker over time. But unlike ALS, most people don’t die from PLS.
Progressive bulbar palsy (PBP)
PBP is a form of ALS that involves the lower motor neurons in your brain stem. Many people with this condition will eventually develop ALS.
These motor neurons help you chew, swallow, and speak. With PBP, you might slur your words and have trouble chewing and swallowing. The muscle in your tongue also atrophies. The disease also makes it hard to control emotions, so you may laugh or cry without meaning to.
There’s a condition called pseudobulbar palsy that is similar to PBP, but it’s not a motor neuron disease. It’s a complication of other conditions that could be neurological (affecting your nerves) or cerebrovascular (affecting your brain). Pseudobulbar palsy can cause difficulty speaking and swallowing, and wild mood swings, just like PBP.
Spinal muscular atrophy (SMA)
Spinal muscular atrophy is an inherited condition that affects lower motor neurons. A defect in a gene called SMN1 causes spinal muscular atrophy. This gene makes a protein that protects your motor neurons. Without it, they die. This causes weakness in the upper legs and arms, as well as in the trunk.
SMA comes in different types based on when symptoms first appear:
Type 0. A very rare form of SMA, the symptoms begin before the baby is born and the infant is born with severe weakness and difficulty breathing and feeding.
Type 1 (also called Werdnig-Hoffmann disease). Type 1 starts around the age of 6 months. Children with this type can’t sit on their own or hold up their head. They have weak muscle tone, poor reflexes, and trouble swallowing and breathing.
Type 2. Type 2 starts between 6 and 18 months of age. Kids with this form can sit, but they can’t stand or walk alone. They may also have trouble breathing.
Type 3 (also called Kugelberg-Welander disease). Type 3 starts after 18 months. It affects how a child can walk, run, stand up, and climb stairs. Kids with this type may also have a curved spine or shortened muscles or tendons around their joints.
Type 4. Type 4 usually starts after age 18 years. People with this type may have muscle weakness, shaking, twitching, or breathing problems. It mainly affects muscles in the upper arms and legs.
Kennedy’s disease
Kennedy’s disease is another inherited MND. It affects only males. Females can be carriers but don’t get ill from it. A woman with the Kennedy’s disease gene has a 50% chance of passing it on to a son.
Males with Kennedy’s disease have shaking hands, muscle cramps and twitches, and weakness in their face, arms, and legs. They may have trouble swallowing and speaking. They can also have enlarged breasts and a low sperm count.
Post-polio syndrome (PPS)
Post-polio syndrome is a motor neuron disease that only affects people who had polio earlier in life. It can occur 10-40 years after the initial polio infection. Researchers estimate that about 30%-40% of people who have polio will develop PPS.
Muscle weakness in PPS depends on what muscles were weak when you had polio. If you had difficulty breathing or swallowing when you had polio, you might have problems with that again with PPS. Other symptoms include fatigue, joint pain, and muscle pain.
How Are Motor Neuron Diseases Treated?
Motor neuron diseases can’t be cured, so treatment focuses on managing symptoms and helping people keep their function as long as possible. There are some medications that might help delay the worsening of symptoms. For ALS, medications include:
Edaravone. This is a medication you can take by IV or by mouth. It might slow down the progress of symptoms. Side effects include bruising, headache, and difficulty walking.
Riluzole. This oral medication might extend life by about 25%, but it can have serious side effects, which can affect your liver and gastrointestinal system.
Equally important treatment for MNDs is supportive care such as speech, respiratory, occupational, and physical therapies to make everyday activities easier, helping you live as long as you can as comfortably as you can rather than just a medication that might extend your life, says Blum.
“The supportive care makes a huge difference,” he says. “Starting automatic positive airway pressure, particularly at night, as a support to patients earlier than later [is one way], because it’s very helpful with fatigue, and it appears to slow down the progress of the disease. That supportive intervention is worth more in terms of quality and quantity of life than all of the drugs so far.”
Occupational therapists (OTs) are well placed to help someone with a motor neuron disease, says Leigh Stephens, a licensed social worker and educational services and resources manager at ALS Quebec. “An OT will be able to assess where you are at any given point, the equipment or adaptations that might be needed at home, and so on. If they notice things outside their expertise, such as communication or swallowing, they’ll refer to other health care professionals as needed.”
Living With a Motor Neuron Disease
The outlook is different for each type of motor neuron disease. Some are milder and progress more slowly than others. Regardless of your MND diagnosis, there will be times you need help with your daily activities. It could be as simple as someone coming to your appointments to take notes or helping you with daily tasks.
Working and workplace accommodations when you have an MND
Employers in the U.S. are required by law to provide reasonable accommodations to their employees so they may work. So if you want to continue working, you need to speak with your employer to discuss what you are still able to do, and what is going to happen as the disease advances. Some jobs can’t be adapted, especially if they’re physical labor, but other jobs can be with proper equipment.
At-home accommodations
As the disease advances, you will need to make accommodations in your home so you can fit your wheelchair, access the bathroom, and do tasks, such as preparing a meal. If you have stairs, you may want to rearrange your living environment so everything is on the main floor or consider moving to a more accessible home. While ramps and elevators can help with mobility where there are stairs, Stephens doesn’t recommend installing a chair lift, which you put beside the stairs to help you go up and down. As your disease worsens, your neck muscles become weaker, and the lift stops being useful too quickly because you need to be able to sit up fairly independently on these.
Communication and speech aids
People with ALS and most other motor neuron diseases will end up having difficulty speaking or communicating in general. With ALS, that might be the first thing that affects someone, but it also could be the last thing. Regardless of when it occurs, communication is important. A speech or language therapist can work with you to find the best ways for you to use your voice, if you can. If you can no longer speak, there are communication and speech aids, ranging from image boards to advanced computer programs.
Help with eating and drinking
Chewing and swallowing will become difficult when the disease progresses to the muscles in your tongue and throat. This poses a choking risk, and it affects your overall health. You might lose weight, which can lead to malnourishment. But having trouble eating also affects your social life because so much of what we do surrounds eating and drinking with others.
Meeting with a dietitian might be helpful. A dietitian can give you tips on the best types of food to eat, as well as a meal plan and instructions on how to prepare the foods to reduce the need to chew and the risk of choking. An occupational therapist can provide you with tools and aids that will help you with managing your meals, and a speech or language therapist can work with you on helping you swallow safely.
Getting help with personal care
Personal care and toileting can be among the most difficult things to ask for, especially from a spouse or adult child. You might be able to manage well for a while with solid grab bars in your bathroom. “A lot of people opt for a bidet,” Stephens said. A bidet is a great way to clean yourself after using the bathroom. Stephens also pointed out that OTs can help you get tools like hooks that help you do up your pants.
You can also ask your medical provider, insurance company, and local ALS or other MND society for resources. You might qualify for extra help, someone coming in regularly to help bathe you, for example.
Mental health and emotional well-being
Having an MND affects your emotional well-being in two ways. The first comes with knowing you have a disease that will only get worse, but some MNDs also cause emotional outbursts or swings – and this could make it even harder for you. And there’s the change in your identity that comes with having such a disease. “Your spousal relationship becomes a patient/caregiver relationship, there’s a loss of physical autonomy, or financial security,” Stephens explains. “And when communication is affected, your ability to participate socially is affected.”
This is where it’s important to know you’re not alone. There are others who are going through the same things, and reaching out to them might be helpful. Professional help might be an option. “If you have a counselor, psychologist, therapist, or access to a counselor at an ALS Association, this can be very helpful,” Stephens says. Otherwise, there are groups you can join, both online and in person, so you can see how others are dealing with it and get the support you need.
How Can I Help My Loved One?
Disease-specific organizations such as the ALS Society have chapters across the country. They offer many resources to people who are learning about the disease and how to help their loved ones. Reaching out to these organizations and asking your loved one’s health care team about local support is a good first step.
It can be very difficult for someone to watch a loved one live with a motor neuron disease. You might be a spouse or a child who is now taking on the caregiving role, something you never expected to do. This can change how you see yourself and your own identity, and it can affect both your physical and mental health.
Stephens says that the best way you can help your loved one is by helping yourself. While it’s easier said than done, if you don’t take care of yourself, you can’t care for your loved one. Part of this means asking for help. Some associations and societies offer programs, such as respite care, which allow loved ones to take a break from a few nights to longer.
Takeaways
Motor neuron diseases are progressive diseases that affect your muscles. The most common one is ALS. Treatment for motor diseases focuses more on helping you be as comfortable as possible and as functional as possible as the disease progresses. Asking for help, particularly from resources such as occupational therapists and social workers, can help you maintain your independence for as long as possible. Look for local chapters of organizations such as the ALS Association or others for the disease that you have.
FAQs About Motor Neuron Diseases
What are the most common motor neuron diseases?
Amyotrophic lateral sclerosis (ALS) is the most common motor neuron disease. There are others, but they are rare.
What are the three types of motor neuron disease?
There are more than three types of motor neuron disease. The most common one is ALS, but others include spinal muscular atrophy, progressive bulbar palsy, progressive muscular atrophy, Kennedy’s disease, and post-polio syndrome.
What are the first signs of motor neuron disease?
Muscle weakness is usually the first sign of an MND, but which muscles are affected can be very different between people who have the disease. For some, it starts in the face and mouth, others it could be an arm or leg.
What are the three stages of MND?
There aren’t any official three stages of MND, but if it’s often described in three general phases: early, middle, and advanced. In the early stage, there are symptoms, but you can manage independently. The middle stage means the symptoms are getting worse and you need some help with your everyday activities. If you are at the advanced stage, it would mean that you need specialized care.
Can MND be cured?
No, there is no cure for MND.
Is MND painful?
MND itself isn’t painful, but some of the problems that MND causes might be. For example, you might get muscle or joint pain or you could develop pressure sores from a wheelchair or from staying in bed.
