Symptoms of NDM
People with NDM can experience a range of symptoms, but the severity and triggers of symptoms may vary.1 The common symptom shared by all people with NDM is myotonia.
People with NDM may struggle to exercise or even carry out simple movements such as walking up the stairs.2
“I can no longer pick up my son or hold him when he is given to me.”— KT, Becker myotonia
Myotonia means that after a muscle is used (a muscle contraction), it does not relax as quickly as it should. For people with NDM, myotonia may feel like stiffness, cramps or as if their muscles “freeze” or have “locked up”. Depending on which muscles are most affected, myotonia symptoms may make some daily activities troublesome, from using stairs, chewing, releasing a fist, or getting up from a chair.1,3 NDM tends to only affect skeletal muscles.3
If you think you are experiencing myotonia, this does not necessarily mean you have NDM. NDM is a rare disease, and there are other conditions where myotonia is also a symptom. To get an accurate diagnosis you will need a thorough medical investigation and it may be necessary to see a doctor with additional training in conditions like NDM, at a specialist centre.
NDM is not a single disease, it is a group of disorders, which share similar symptoms. The areas of the body that are affected, symptom severity and triggers differ according to NDM type.
Some people with NDM find that their muscles get bigger, which is called muscle hypertrophy.3 Whereas, others may experience their muscles weakening, which is called myopathy. People with NDM can also feel pain in their muscles, although for some myotonia will be pain-free.4 Around half of people with NDM report feeling fatigue, which means excessive tiredness that may not be cured by rest.
If your symptoms are affecting your quality of life, or if you are experiencing pain, you should speak to your doctor about how this can be managed.4 It is important to remember that NDM is a rare disease, and many doctors will have never met or treated anyone with NDM before. Preparing for a visit to the doctor can help you to help them understand the challenges you face.
Symptoms of NDM can change from day to day, and people with NDM often describe their symptoms as unpredictable.1,5 Tracking your symptoms in a diary may help you see when they are better or worse, and help you unlock any patterns. This information may also be useful for your healthcare team to understand how NDM is affecting your quality of life, and to help them develop a care plan specifically for you.
- Hahn C, Salajegheh MK. Iran J Neurol 2016;15:46–53
- Diaz-Manera J. EMJ. 2021;6:37-46
- Matthews E, et al. Brain 2010:133; 9–22
- Vereb N. J Neurol. 2021; 268(5): 1708–1720
- Heatwole CR, et al. Muscle Nerve 2013;47:632-648