CMT and Respiratory Dysfunction

Updated October 10, 2026: Added a caveat that the 2015 family study tested each person once, so it shows a correlation between CMT severity and breathing strength but not how breathing changes over time; added a note on asking for an in-lab sleep study when breathing-muscle weakness is possible; corrected “AVAP” to “AVAPS”; and replaced an outdated Facebook link.

I ran across an interesting 2015 pulmonary (lung) study of a large family with CMT2 in their gene pool. Its results showed that:

…patients with CMT, in spite of not showing clinical signs of advanced respiratory impairment, may present subclinical respiratory changes. The respiratory comprise in the CMT disease can be silent and insidious without presenting characteristic clinical signals.

— Evaluation of Respiratory Muscle Strength and Pulmonary Function in Patients with Charcot-Marie-Tooth Disease Type 2

Eighteen of the people in this extended family network from ages 11 to 79 had been diagnosed with CMT2, but 20 others were also included in a battery of standard lung and breathing tests to measure how much air they could inhale and exhale.

The researchers were also taking note of the degree of disability of the people with CMT by using the CMT neuropathy score (CMTNS). CMTNS produces a score between 0 and 36 to indicate the level of physical impairment. This group had scores ranging from 6 to 26. (I’m not sure why CMTNS was used for a CMT2 family since it’s designed for CMT1A and best suited for moderate to severe cases, but it does work as a basic assessment.)

In the overall results, there were significant correlations between the CMTNS severity and a person’s inhale and exhale capacity. More advanced CMT = more impaired breathing. That’s a correlation within one family at a single point in time, though: each person was tested once, so the study doesn’t show how breathing changes over the years, or how common these changes are in CMT generally.¹

This study is quite interesting and important! Science is starting to confirm very wide ranging effects for the nerve damage CMT does, often slowly and over time so it may not be very noticeable for many years.

A brand new study of 39 people with hereditary neuropathies who’d had MRI scans found thickening or enhancement of the cranial nerves on imaging in about a fifth of them (21%), though these imaging findings didn’t consistently match clinical symptoms. Who knows what they will find next? Many people with CMT have long complained of respiratory issues. Several different nerve branches are involved with breathing, speaking, and swallowing.

CMT’s Impact on Breathing

Do you think CMT might be impairing your breathing?

If you think you may have problems with your lungs or breathing, here are some things other CMTers have suggested to help!

The following list is adapted from one supplied on the CMT and US Facebook group by its ever-helpful leader, Angela Graham. ❤️🙏🏻

Diagnostic Testing:

• Ask your doctor for Pulmonary Function Tests and request that your maximum inspiratory pressure (MIP) and maximum expiratory pressure (MEP) be tested twice — once while you are sitting and once while you are lying down. (Nerve damage impacting the diaphragm can make it harder to breathe when lying flat on your back, in a supine position.)
• Get a Sleep Study, and if you find you have sleep apnea, use a C-Pap, Bi-Pap, AVAPS, or Ventilator device, whichever is appropriate for you. If breathing-muscle weakness is a possibility, ask for an in-lab overnight sleep study (polysomnography); sleep-medicine guidelines recommend it over a home sleep apnea test in that situation.²
• If you have symptoms of hypercapnia/hypercarbia, ask your doctor for an Arterial Blood Gas test to see how much carbon dioxide is in your arteries as they leave the lungs.
• A chest x-ray can reveal a raised diaphragm due to weakness or paralysis.

Simple Life Changes:

• Sleep on an incline by using a wedge pillow or with the head of your bed elevated slightly.
• Eat smaller meals and stop eating well before sleeping.
• Learn techniques for better breathing and coughing.
• Breathing exercises (e.g. Bubble PEP therapy, Incentive Spirometer therapy, or playing a musical instrument like a harmonica, etc.)
• Do core strengthening exercises.
• Take CoQ10 supplements. (This is an anecdotal suggestion from the group, not an evidence-based treatment for breathing problems in CMT.)
• Be cautious with medications that can depress breathing, like opioids, benzodiazepines and other sedatives, and gabapentin — especially in combination. (See Health Canada’s warnings on gabapentin and serious breathing problems and on benzodiazepines taken with opioids.)
• Maintain a healthy weight.
• Stay as active as possible.

Please note that this is NOT a prescription or medical advice. This is just a list of ideas you may want to discuss with your doctor if you feel it’s appropriate for your situation. You or your healthcare providers may have other (better) ideas for your specific situation. If so, please share them with us. Please follow the advice of your physician.

Notes

1. Garcez et al., “Respiratory Muscle Strength.” ↩︎
2. Kapur et al., “Diagnostic Testing for Adult Obstructive Sleep Apnea.” ↩︎

Sources

• Garcez, Catarina Andrade, Eduardo Luis Aquino Neves, Saulo Maia D’Avila Melo, et al. “Evaluation of Respiratory Muscle Strength and Pulmonary Function in Patients with Charcot-Marie-Tooth Disease Type 2.” European Neurology 74, no. 5-6 (2015): 310–314. https://doi.org/10.1159/000442282.
• Kapur, Vishesh K., Dennis H. Auckley, Susmita Chowdhuri, et al. “Clinical Practice Guideline for Diagnostic Testing for Adult Obstructive Sleep Apnea: An American Academy of Sleep Medicine Clinical Practice Guideline.” Journal of Clinical Sleep Medicine 13, no. 3 (2017): 479–504. https://doi.org/10.5664/jcsm.6506.