Skip to content
Inciteful Med

Monitoring Progression and Staging

Last updated:

Charcot-Marie-Tooth disease type 1A (CMT1A) progresses very slowly, typically changing less than 1 point per year on clinical scales. Doctors monitor this progression using clinical exams like the CMTNS, along with MRIs to measure muscle fat fraction and ultrasounds to check nerve size.

Key Takeaways

  • • Doctors track CMT1A progression using specialized clinical scoring systems like the CMT Neuropathy Score (CMTNS) and CMTES-R.
  • • MRI muscle fat fraction and nerve ultrasounds provide objective ways to track disease changes, often before you notice a difference in your symptoms.
  • • CMT1A progresses slowly in adults, with average clinical scores changing by only 0.3 to 1 point per year.
  • • Metabolic conditions like type 2 diabetes can accelerate nerve damage and worsen CMT1A progression.
  • • A formal neurological check-up every 12 to 15 months is recommended to monitor your condition and adjust your care plan.

Because Charcot-Marie-Tooth disease type 1A (CMT1A) is a slowly progressive condition, doctors use specialized tools to “stage” the disease and monitor how it changes over years [1][2]. Understanding these scores and biomarkers can help you and your care team make informed decisions about physical therapy, bracing, and potential clinical trials.

Clinical Scoring Systems

The most common way doctors track CMT1A is through clinical scales that combine your symptoms with a physical exam.

  • CMT Neuropathy Score (CMTNS): This is the “gold standard” for measuring overall disability [3]. It looks at your strength, sensation (like vibration and pinprick), and even your nerve conduction speeds [4][5].
  • CMTES-R (Revised Examination Score): This is a newer, more sensitive version of the exam that focuses on how your symptoms progress over time [2]. It is particularly useful for tracking changes in patients with mild-to-moderate symptoms [6].
  • Scoring Severity: A score of 5 or 6 on the CMTNSv2 generally indicates a very mild case, while scores between 12 and 20 are more typical for “classical” CMT1A [7][8].

Objective “Biomarkers” of Progression

Beyond the physical exam, doctors are increasingly using imaging and lab tests to get a more “objective” look at how the nerves and muscles are faring.

  • MRI Muscle Composition (Fat Fraction): As muscles weaken over time due to nerve damage, their composition gradually changes, with healthy muscle tissue taking on more fatty infiltration [9]. An MRI can measure this “fat fraction,” which is one of the most sensitive ways to track if the disease is progressing, even before you notice a change in your walking [9][10].
  • Nerve Ultrasound: Doctors may use ultrasound to measure the Cross-Sectional Area (CSA) of your nerves [11]. In CMT1A, nerves are often significantly enlarged because of the body’s attempt to repair the myelin sheath [12].
  • Gait Analysis: Using specialized sensors, a “gait profile” can show subtle changes in how you walk—such as reduced ankle movement or shorter steps—long before they are obvious to the naked eye [13][14].

What to Expect: The Rate of Change

For most adults with CMT1A, the disease progresses very slowly. On the CMTES-R scale, the average change is approximately 0.3 to 1 point per year [2][1].

  • Age and Progression: While the rate of decline is usually steady, some research suggests that the physical impact may become more noticeable after age 50 [15].
  • Metabolic “Triggers”: It is important to remember that conditions like Type 2 Diabetes can act as an “accelerator,” causing the CMTNS score to rise much faster than it would otherwise [16][17].

Monitoring Schedule

While there is no “one-size-fits-all” schedule, many specialists recommend a formal neurological check-up every 12 to 15 months to update your clinical scores and screen for any new symptoms like neuropathic pain or increased fatigue [18][2]. Ideally, these assessments should be performed by a neurologist specializing in neuromuscular disorders or at a dedicated CMT clinic. Yearly assessments are especially relevant for tracking objective markers like muscle fat fraction or walking speed [19][9].

Frequently Asked Questions

How fast does CMT1A progress?
For most adults, CMT1A progresses very slowly. On standard clinical scales like the CMTES-R, patients typically see a change of only 0.3 to 1 point per year, though progression may become more noticeable after age 50.
What is a CMTNS score?
The CMT Neuropathy Score (CMTNS) is a standard tool doctors use to measure overall disability in CMT1A. It combines your symptoms, a physical exam of your strength and sensation, and nerve conduction test results to give an overall picture of your nerve health.
Why do doctors use MRI to track CMT1A?
As muscles weaken from nerve damage, healthy tissue is gradually replaced by fat. An MRI can measure this fat fraction, providing a highly sensitive way to track disease progression before you even notice changes in your daily activities or walking.
How often should I see a neurologist for CMT1A?
Many specialists recommend a comprehensive neurological check-up every 12 to 15 months. This yearly visit allows your doctor to update your clinical scores, track objective markers, and adjust treatments like bracing or physical therapy if needed.
Can other health conditions speed up CMT1A progression?
Yes, metabolic conditions like type 2 diabetes can act as an accelerator for nerve damage. Managing your blood sugar, weight, and overall health is an important part of managing your CMT1A and protecting your nerves.

Questions for Your Doctor

  • • What is my or my child’s current CMTNSv2 or CMTES-R score, and how does it compare to our previous visit?
  • • Are there specific trends in my 10-meter walk test time or grip strength that we should be tracking every 12 months?
  • • Given that calf muscle fat fraction (FF) on MRI is a responsive biomarker, should we consider a baseline scan to monitor my progression more objectively?
  • • Is my rate of progression—roughly 0.3 to 1 point per year on the CMTES-R—consistent with what you see in other patients of my age and severity?
  • • Are there any 'red flags' in my gait analysis, such as changes in hip or ankle movement, that suggest we need to adjust my bracing?

Questions for You

  • • Have I noticed any new difficulty with 'fine motor' tasks, like buttoning a shirt or using a key?
  • • Am I tripping or losing my balance more frequently than I was a year ago?
  • • Has my walking speed changed noticeably during my normal daily routine?
  • • Am I experiencing more fatigue or muscle cramping after a typical day of activity?
  • • How am I managing other health factors, like my blood sugar and weight, which can impact how fast my CMT1A progresses?

Want personalized information?

Type your question below to get evidence-based answers tailored to your situation.

References

  1. 1

    Rate of Changes in CMT Neuropathy and Examination Scores in Japanese Adult CMT1A Patients.

    Kitani-Morii F, Noto YI, Tsuji Y, et al.

    Frontiers in neurology 2020; (11()):626 doi:10.3389/fneur.2020.00626.

    PMID: 32765395
  2. 2

    A longitudinal study of CMT1A using Rasch analysis based CMT neuropathy and examination scores.

    Fridman V, Sillau S, Acsadi G, et al.

    Neurology 2020; (94(9)):e884-e896 doi:10.1212/WNL.0000000000009035.

    PMID: 32047073
  3. 3

    The impact of symptoms on daily life as perceived by patients with Charcot-Marie-Tooth type 1A disease.

    Tozza S, Bruzzese D, Severi D, et al.

    Neurological sciences : official journal of the Italian Neurological Society and of the Italian Society of Clinical Neurophysiology 2022; (43(1)):559-563 doi:10.1007/s10072-021-05254-7.

    PMID: 33899151
  4. 4

    Multidimensional evaluation of clinical and functional impairment in a large population of patients with Charcot-Marie-Tooth.

    Calafiore D, Marotta N, Curci C, et al.

    Neurological sciences : official journal of the Italian Neurological Society and of the Italian Society of Clinical Neurophysiology 2025; (46(12)):6795-6803 doi:10.1007/s10072-025-08489-w.

    PMID: 41100006
  5. 5

    Cost of illness in Charcot-Marie-Tooth neuropathy: Results from Germany.

    Schorling E, Thiele S, Gumbert L, et al.

    Neurology 2019; (92(17)):e2027-e2037 doi:10.1212/WNL.0000000000007376.

    PMID: 30918088
  6. 6

    Neuropathy due to bi-allelic SH3TC2 variants: genotype-phenotype correlation and natural history.

    Rehbein T, Wu TT, Treidler S, et al.

    Brain : a journal of neurology 2023; (146(9)):3826-3835 doi:10.1093/brain/awad095.

    PMID: 36947133
  7. 7

    Intermediate conduction velocity in two cases of Charcot-Marie-Tooth disease type 1A.

    Tomaselli PJ, Blake J, Polke JM, et al.

    European journal of neurology 2024; (31(5)):e16199 doi:10.1111/ene.16199.

    PMID: 38409938
  8. 8

    Paternal gender specificity and mild phenotypes in Charcot-Marie-Tooth type 1A patients with de novo 17p12 rearrangements.

    Lee AJ, Nam DE, Choi YJ, et al.

    Molecular genetics & genomic medicine 2020; (8(9)):e1380 doi:10.1002/mgg3.1380.

    PMID: 32648354
  9. 9

    Validation of MRC Centre MRI calf muscle fat fraction protocol as an outcome measure in CMT1A.

    Morrow JM, Evans MRB, Grider T, et al.

    Neurology 2018; (91(12)):e1125-e1129 doi:10.1212/WNL.0000000000006214.

    PMID: 30120135
  10. 10

    Magnetic resonance imaging-based lower limb muscle evaluation in Charcot-Marie-Tooth disease type 1A patients and its correlation with clinical data.

    Kim YJ, Kim HS, Lee JH, et al.

    Scientific reports 2022; (12(1)):16622 doi:10.1038/s41598-022-21112-8.

    PMID: 36198750
  11. 11

    Evidence of nerve hypertrophy in patients with inclusion body myositis on lower limb MRI.

    Elmansy M, Morrow JM, Shah S, et al.

    Muscle & nerve 2022; (66(6)):744-749 doi:10.1002/mus.27728.

    PMID: 36151728
  12. 12

    Intraepineurial fat quantification and cross-sectional area analysis of the sciatic nerve using MRI in Charcot-Marie-Tooth disease type 1A patients.

    Kim HS, Lee JH, Yoon YC, et al.

    Scientific reports 2021; (11(1)):21535 doi:10.1038/s41598-021-00819-0.

    PMID: 34728674
  13. 13

    Gait Pattern in Charcot-Marie-Tooth Disease Type 1A According to Disease Severity.

    Park J, Joo SY, Choi BO, et al.

    Journal of personalized medicine 2023; (13(10)) doi:10.3390/jpm13101473.

    PMID: 37888085
  14. 14

    Disease-specific wearable sensor algorithms for profiling activity, gait, and balance in individuals with Charcot-Marie-Tooth disease type 1A.

    Dinesh K, White N, Baker L, et al.

    Journal of the peripheral nervous system : JPNS 2023; (28(3)):368-381 doi:10.1111/jns.12562.

    PMID: 37209301
  15. 15

    Motor performance deterioration accelerates after 50 years of age in Charcot-Marie-Tooth type 1A patients.

    Tozza S, Bruzzese D, Pisciotta C, et al.

    European journal of neurology 2018; (25(2)):301-306 doi:10.1111/ene.13494.

    PMID: 29053907
  16. 16

    High glucose level as a modifier factor in CMT1A patients.

    Secchin JB, Leal RCC, Lourenço CM, et al.

    Journal of the peripheral nervous system : JPNS 2020; (25(2)):132-137 doi:10.1111/jns.12379.

    PMID: 32347995
  17. 17

    Coexistence of Charcot Marie Tooth disease type 1A and diabetes in Taiwan: A clinicopathological study.

    Chao HC, Chou CT, Lee YC, Lin KP

    Journal of the neurological sciences 2015; (358(1-2)):213-20.

    PMID: 26349404
  18. 18

    A double-blind, placebo-controlled, randomized trial of PXT3003 for the treatment of Charcot-Marie-Tooth type 1A.

    Attarian S, Young P, Brannagan TH, et al.

    Orphanet journal of rare diseases 2021; (16(1)):433 doi:10.1186/s13023-021-02040-8.

    PMID: 34656144
  19. 19

    High-density surface electromyography to assess motor unit firing rate in Charcot-Marie-Tooth disease type 1A patients.

    Noto YI, Watanabe K, Holobar A, et al.

    Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology 2021; (132(3)):812-818 doi:10.1016/j.clinph.2020.11.040.

    PMID: 33483296

This page provides educational information about tracking CMT1A progression. Always consult your neurologist to interpret your specific clinical scores and imaging results.

Stay up to date

Get notified when new research about Charcot-Marie-Tooth disease type 1A is published.

No spam. Unsubscribe anytime.