What Is Progressive Muscular Atrophy?

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Progressive muscular atrophy (PMA) is a rare disease that affects lower motor neurons, which are brain cells that begin in the spinal cord and provide muscles and glands with the nerves needed to function correctly. People with this disease experience wasting and loss of muscle mass.

This article discusses the symptoms, causes, and treatment associated with PMA.

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Progressive Muscular Atrophy Symptoms

Symptoms that can occur in someone with PMA include:

  • Muscle weakness and wasting that affects the legs, arms, body, and hands
  • Inability to use the arms, a condition known as flail arm syndrome
  • Fatigue
  • Muscle pain and cramps
  • Muscle twitching
  • Difficulty with motor function leading to clumsiness
  • Weight loss
  • Difficulty breathing

What Is Muscle Wasting?

Muscle wasting occurs when lack of use or disease causes the shrinking, weakening, and loss of muscle.


Medical researchers aren’t clear on what causes PMA. It is considered a sporadic disease, meaning it suddenly occurs and isn’t predictable. That said, theories suggest that genetics and environmental factors play a role in its development.


ALS (amyotrophic lateral sclerosis) can cause some of the same symptoms found in PMA. It has been suggested that PMA may be a variation of ALS. However, research shows that not everyone with the motor neuron disease has ALS. One study found that as many as 84.6% of people with PMA also had clinical signs of ALS, but the remaining 15.4% did not.


No single test can diagnose a person with PMA. Because symptoms are similar to that of other motor neuron diseases, PMA is diagnosed through a process of elimination. Other conditions that are ruled out before reaching a PMA diagnosis include:

The diagnostic process begins by collecting symptoms, health history, and physical examination of the muscles. After that, specific tests may help determine a definitive diagnosis. Those tests can include:

  • Computed tomography (CT) and other scans to check for structural issues within the spinal cord and brain
  • Nerve conduction studies to measure the speed electrical impulses move through your nerves
  • Electromyography to assess the health of your muscles and the nerves controlling them
  • Lumbar puncture, which removes and tests spinal fluid

These tests are designed to gain a deeper understanding of what is happening in the body, specifically the nerves.

In some cases, people may have to go through other tests, such as magnetic resonance imaging (MRI) or blood tests if medical providers suspect another disease is to blame for the symptoms.

Misdiagnosing PMA

Since PMA presents like other diseases, including ALS, misdiagnosis can happen. When it does, treatment may be delayed, and problems with muscle wasting, movement, and mobility can all occur faster than they would if someone were undergoing proper treatment.


PMA is a progressive disease, which means that it will continue to worsen over time. Since there is no cure, treatment is designed to slow down the damage to maintain a good quality of life for as long as possible. Some treatment options include:

  • Occupational therapy to plan for the use of wheelchairs and other mobility aids
  • Physical therapy to increase flexibility and range of motion in the muscles
  • Riluzole, which is a medication typically used for ALS but has shown promise in helping to slow the progression of PMA


PMA is fatal. However, the length of time a person will live with the disease differs. One study examined the overall survival rates of people with PMA and found that the average survival time is 56 months.  The symptoms a person has are contributing factors to survival rates. According to research, people with bulbar symptoms, which affect swallowing and speech, are more likely to have a shorter survival rate than those who don’t.

Survival Rate Timeline for PMA
One year 100%
Three years 67%
Five years 45%
Nine years 30%

What Does Survival Rate Mean?

The one-, three-, five-, and nine-year survival rates refer to the percentage of people still alive during that time frame when participating in a treatment or study.


Coping with PMA isn’t easy. When you receive a fatal diagnosis, it can be hard to think about anything else. It’s essential to establish good coping practices while you undergo treatment so that you can maintain a good quality of life, such as:

  • Joining a support group with others that have PMA or similar diseases
  • Giving yourself the time to grieve your old life and feel any negative emotions
  • Focus on what you can do instead of what you can't
  • Practicing positive self-talk
  • Using stress-reduction techniques such as meditation
  • Monitoring any changes in your body and mind and inform your healthcare team so that they can be addressed promptly
  • Taking care of yourself by eating healthily, getting exercise where and when you can, and spending time with loved ones


Progressive muscular atrophy is a motor neuron disease that affects the muscles. People with PMA develop symptoms such as weakness, loss of muscle mass, and fatigue. The cause of the disease is unclear, and there is no cure.

Because of that, treatment options revolve around improving a person’s quality of life for their remaining years. While PMA is fatal, many people live with the disease for five or more years following their diagnosis.

A Word From Verywell

Being told you have a fatal disease such as PMA is one of the hardest things you could hear. If you have PMA, getting support from others and focusing on the positive aspects of your life can make it easier to cope. Taking care of yourself in whatever ways you can will ensure that your condition doesn’t rob you of your happiness.

Frequently Asked Questions

  • Is PMA the same as ALS?

    Both PMA and ALS are diseases of motor neurons. Some research suggests that PMA is an extension or type of ALS. However, not all people with PMA have ALS. Roughly 85% of people with PMA have the clinical manifestation of ALS.

  • How long can you live with PMA?

    There is no cure for PMA, and it is a fatal disease. Because of that, people who have it will eventually succumb to it. That said, many people can live for as many as five years or more following their diagnosis.

  • What causes PMA?

    There is no clinical evidence to support a definitive cause of PMA. Research continues to search for answers because if they find a cause, they may be able to develop better treatments. Genetics and environmental factors may play a role in its development.

6 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. Motor Neurone Disease Association. Progressive muscular atrophy (PMA).

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  4. Ha, J., Ringel, S.P. and Oskarsson, B. Progressive muscular atrophy. In International Neurology. 22 April 2016:447-448. doi:10.1002/9781118777329.ch105

  5. Visser J, van den Berg-Vos RM, Franssen H, van den Berg LH, Wokke JH, de Jong JM, Holman R, de Haan RJ, de Visser M. Disease course and prognostic factors of progressive muscular atrophy. Arch Neurol. 2007 Apr;64(4):522-8. doi:10.1001/archneur.64.4.522

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By Angelica Bottaro
Angelica Bottaro is a professional freelance writer with over 5 years of experience. She has been educated in both psychology and journalism, and her dual education has given her the research and writing skills needed to deliver sound and engaging content in the health space.