MMN
Welcome to our Multifocal Motor Neuropathy (MMN) Information Hub
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If you're here because you've been recently diagnosed - welcome. We know this is a scary and confusing time for you and your loved ones. Being diagnosed with any chronic condition is hard, but something so rare makes it that little bit tougher.
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Please know you're in the right place. On this page we'll breakdown what is happening to you, or a loved one, and hopefully make this time a little less confusing.
Our information is sourced from our Medical Advisory Board, medical texts, and recognised support providers. This means that some of the text can be a bit complicated or "high level". Where possible, we've taken steps to make this page as accessible to everyone as possible.
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If you have any questions after reading this that you feel haven’t been answered. Please get in touch with us, we will do our best to respond or point you to the right place or person.
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If you feel you need support with the emotional impact of this, please visit our Emotional Support section. We have a specialist rare condition support service available.
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What is Multifocal Motor Neuropathy (MMN)
"Multifocal Motor Neuropathy, or MMN is a rare disorder in which focal areas of multiple motor nerves are attacked by one’s own immune system."
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Or in easier terms, MMN is a rare condition in which specific groups of your motor nerves (the ones that control movement), are accidentally attacked by your immune system.
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It's Rare
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MMN is very rare. There are estimated to be just 0.6 cases in every 100,000 people which makes it even rarer that GBS - one of the other rare conditions we support here at Inflammatory Neuropathies UK.
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It's asymmetrical
Typically, MMN is slowly progressive, resulting in asymmetrical weakness of a patient’s limbs (meaning it affects the right and left sides of the body differently).
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It causes weakness
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Patients frequently develop weakness in their hand(s). This can lead to dropping items like cutlery, finding shirts hard or impossible to button, making locking or unlocking a door difficult, and even limiting the ability to give a simple thumbs up.
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It shouldn't cause pain
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The weakness associated with MMN can be recognised as fitting a specific nerve territory. There is essentially no numbness, tingling, or pain, as you may find in some other Inflammatory Neuropathies. If you have been diagnosed with MMN and do feel any numbness, tingling like pins-and-needles, or pain that you cannot explain (such as you've bashed your arm, or you've sat funny and your leg has fallen asleep), please talk to your Neurologist, Consultant, or GP.
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It can cause twitches
Patients with MMN can have other symptoms, including twitching or fasciculations. Fasciculations are basically small muscle spasms or twitches visible under your skin, caused by your motor nerves firing involuntarily. They shouldn't cause pain like a cramp, but may be irritating or distracting when you're at rest.
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It doesn't go away
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The clinical course of MMN is chronically progressive without remission. This means that without treatment, the symptoms and affects will not improve, reduce, or disappear. However, treatment such as IVIg does limit progression, improves function, and allows people to carry out day to day activities.
It's not fatal
MMN is chronic, which means you will have the condition for life, but it will not shorten your life expectancy. It mainly impacts muscle strength and does not progress to vital organs or impact breathing.
While not fatal, without treatment, it can lead to permanent weakness so it is important to maintain your care.
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It can be mistaken for CIDP
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During diagnosis, you may have heard CIDP mentioned. This is another Inflammatory Neuropathy (you can learn more here). MMN has many features similar to CIDP in that its onset is progressive over time, causing increased disability that reflects the greater number of nerve sites involved. However, unlike CIDP, MMN is asymmetric. This may be one of the key clues that tipped your Neurologist or health care team off about your condition.
What Causes MMN
We know it's frustrating to read - but the simplest answer is we don't know.
Experts are yet to discover the exact cause of MMN.
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They know you're not born with it.
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They know it's an autoimmune condition.
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In a similar condition like CIDP, or even GBS, we know that the autoimmune reaction is triggered by an infection or illness. Food poisoning is a good example of this. Undercooked chicken can contain the bacteria Campylobacter jejuni. When consumed, someone becomes ill with food poisoning, the illness triggers an immune response, and in the case of GBS - the response is to accidentally attack the nerves.
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In MMN, this is not thought to be the case.
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So what do we know?
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"MMN is associated with increased levels of specific antibodies to GM1, a ganglioside or sugar-containing lipid found in peripheral nerves. Antibodies normally protect individuals from viruses and bacteria, but may under certain circumstances bind to and facilitate an immune attack on the peripheral nerve. These antibodies have been detected with newer assays in almost all of MMN patients. Even if these antibodies do not cause the nerve damage, they may be an important marker for disease and facilitate diagnosis."
Let's break that down.
Antibodies: Proteins made by the immune system that normally help fight infections
GM1: A ganglioside - A naturally occurring fat-and-sugar molecule found on the surface of nerve cells that helps nerves function and communicate properly
Immune Attack: When the bodies defence system mistakenly treats its own nerves and tissues as a threat and damages them
Peripheral Nerve: The nerves outside of the brain and spine (the Central Nervous System). They carry messages that control movement and touch.
Assays: A lab test used to detect substances in the blood like antibodies
Marker: A sign that helps identify or confirm a condition, even if it's not the direct cause
In simpler terms then:
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MMN is linked to higher levels of certain antibodies in the blood. These antibodies mistakenly recognise GM1, a molecule that helps nerve function and communication, as a threat. The antibodies then attach to the GM1 coated nerves and trigger an immune response that damages and interferes with how the nerves work.
In recent testing, these antibodies can now be detected in most people with MMN. Even if they're not a direct cause, they're an important clue for doctors and can help confirm a diagnosis.
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So while we don't know what is the overall cause, we do have some clues. And with thanks to kind donors that support our work, we can invest in research into that cause to help the global push for understanding. ​​​
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How is MMN diagnosed?
If you've been diagnosed, you'll have likely been through the following. However, if you or your medical team only suspect MMN may be present - here is what you can expect.
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A clinical diagnosis of MMN depends on demonstrating the following:
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The patient has a purely motor disorder affecting individual nerves
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They need to show that you have a nerve condition that only affects muscle movement and strength, but does not impact sensation or feeling. It should involve individual nerves/locations rather than the whole body or significant portions of the body.
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The patient shows no UMN (upper motor neuron) signs such as brisk reflexes at the knees or ankles or spasticity in the limbs
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So your knee or ankle reflexes shouldn't be overly or unusually active, and your limbs as a whole should not be unusually stiff or tight.
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The patient has no difficulty speaking or swallowing
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You shouldn't struggle to speak, and those around you haven't noticed a change in your pitch, volume, or tone. You should be able to eat, and drink, as normal.
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The patient demonstrates no sensory deficits
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While you may feel weakness, you should not feel any difference in sensation. You can feel hot and cold, if someone touches, pokes, or tickles the impacted area you can feel sensation, pain, or an itch. You should not usually feel numb or a pins-and-needles sensation.
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Shows evidence of focal areas of nerve in which electrical impulses are slowed or blocked (conduction block) which can be detected on electrophysiology tests
You'll have specialist electrical nerve tests that show that, in certain spots, nerve signals are slowed or stopped altogether.
Common Misdiagnoses
These criteria are designed to differentiate MMN from other conditions. Chiefly:
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ALS, (Lou Gehrig’s disease)
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Lewis-Sumner Syndrome (a multifocal inflammatory nerve disease with motor and sensory symptoms)
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and vasculitis or inflammation of small blood vessels in the peripheral nerve.
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In the early stages of investigation, CIDP is sometimes mentioned. We've also heard of people being told, "you're just getting older" when discussing weakness. Remember, if you think something is wrong and you don't agree - you can always ask for a second opinion.
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What tests will be carried out to do this?
Along with patient history and a physical examination, a neurologist is usually needed to determine the diagnosis via specialist tests including (but not limited to):
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An electrodiagnostic study, which includes nerve conduction studies (NCS) and needle electromyography (EMG).
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Laboratory testing for IgM GM1 antibodies is also frequently done.
How is MMN treated?
While there is no current cure for MMN, there are treatments to help improve independence, and reduce/reverse symptoms.
The most medically significant and impactful of these treatments is called IVIg (or intravenous immunoglobulin).
What is IVIg?
IVIg stands for intravenous immunoglobulin. It’s a treatment made from donated human blood plasma that contains healthy antibodies. These antibodies help calm down an immune system that’s behaving abnormally, which is why IVIg is so popular across the conditions we support. It's ability to calm, or reduce, inflammation can save the lives of our GBS community, and give our chronic condition community back their movement, strength, and independence.
In 2025, UK plasma was finally cleared for use in IVIg. This means it's more important than ever for as many people to donate blood and plasma as possible. Plasma can be given directly at specialist centres. However, it's also taken as part of your standard blood donation. Around 50% of each blood donation is plasma, so by donating blood - you're creating this life changing IVIg.
How is it given?
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You'll visit a hospital or clinic close to you that can administer IVIg. You'll sit on a chair or a raised bed and a drip will be inserted into your arm. Over a course of several hours, the IVIg will be infused into your bloodstream. Depending on your dose, this can be one session, or may take a day or two. Your Doctors and Nurses will discuss that with you.
Most people can sit fairly comfortably during the session, you shouldn't feel pain or discomfort. So do bring something to entertain you - a book, your phone or laptop, a pair of headphones, or a friend to chat to. Your medical team will keep an eye on you throughout, so you may even be allowed to doze off for a while if you prefer.
It's worth taking a trip to the toilet first, usually the machine can be paused or you may have a drip on wheels - but it just makes life a little easier for everyone.
What will it do and how often?
Picture a child's drawing of the sea, there's waves that go up and down sharply. MMN, like CIDP and many other Inflammatory Neuropathies, has its symptoms come in 'dips' - the bottom of the wave: minimal symptoms, and 'spikes' - the top of the wave: symptoms worsening.
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The first time you receive treatment, you'll likely be in a spike phase.
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Once you receive your IVIg, you can expect to feel a degree of improved motor function. Some may only experience slight improvement, others may feel a significant improvement across strength, grip, and movement. In some rare cases you may even feel like you have no symptoms at all.
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You'll now be in a dip phase. You're feeling stronger. You're feeling less MMN symptoms.
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Slowly, perhaps over 2-5 weeks (everyone is a little different), you'll start to feel weaker as the MMN symptoms return.
You're now beginning to come out of a dip and into a spike. At this stage you'll be given treatment again. Treatment given shortly after symptoms begin to appear is always more effective than letting symptoms set in fully.
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Your care team will work out the pattern/frequency of treatment that is right for you. This may change over the years and months ahead as they fine tune it to give you the best quality of life possible.
What other treatments are there?
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IVIg is not a cure for MMN but currently no other therapy has proven to be widely effective. In a limited number of patients a cancer chemotherapy drug is temporarily effective. However, its use is limited by the toxic side-effects and risks that accrue with chronic use.
Other immunosuppressive treatments such as corticosteroids and plasma exchange are ineffective and can actually make the condition worse.
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Many investigators around the world are working towards a better understanding of MMN, we hope any research we fund can help this journey.
MMN
Advice for Carers
Diagnosis of a rare and chronic condition can bring mixed emotions.
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On one hand, it's quite normal to feel relieved to have an answer, especially when you find out the condition is not fatal or life-threatening. On the other, learning someone important to you has a life-long illness can be daunting. Especially if you will be acting in the role of carer.*
On this page we have some practical suggestions that can help you in this new role, and some help contact details and/or resources you may wish to access.
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Quick Fact: Informal/Unpaid Carer
The Department of Health and Social Care has described an informal/unpaid carer as: “… someone who provides unpaid help to a friend or family member needing support, perhaps due to illness, older age, disability, a mental health condition or an addiction”. This means, even if your loved one only needs a hand during a spike of their symptoms, or a lift to hospital for IVIg, you're acting in a care capacity.
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These options may not be applicable to your or your loved one, but it's useful to know that help is available.
Ask for a needs assessment for the person you’re caring for
You need this before the council can recommend services such as equipment, home adaptations, help from a paid carer, etc.
Get a carer's assessment
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This can be requested at the same time as a needs assessment, via social services at your local council.
Don’t be afraid to ask for help
Ask family and friends (shopping, respite, etc), and contact carers’ organisations or Citizens Advice for benefits advice and other support.
Look after yourself
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Eat a healthy diet, maintain a regular sleep pattern and make time for exercise, preferably in the fresh air or at your local gym or pool, away from the care setting.
Remember to rest
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Put some activities on hold. Take some time for yourself by arranging respite care from a friend or relative, or through social services.
Recognise limitations
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Both those of the person you’re caring for and your own. Let them try to do things for themselves if they are able, but bear in mind their safety and yours.
Look after your mental health​
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Talk to each other about your experiences and frustrations during illness and recovery. Talk to your GP if either of you is struggling.
Be mindful of risks​
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Be aware of risk of falls due to poor balance, and dropping or spilling things due to weakness.
Diet and exercise​
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MMN should not overly impact diet, however, some find increasing protein intake helpful to help maintain muscle mass. Ask the community physio about exercises to do between visits.
Don't lose sight of your relationship​
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Whatever your relationship is to the person you’re caring for, make time for it. Do things together that you both enjoy and that feel ‘normal’.
Get in touch with Inflammatory Neuropathies UK​
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We provide information and support, organise peer support via phone or video link, virtual group chats, and run an active and supportive Facebook group.
Other sources of support
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Looking after someone you love doesn’t have to mean struggling alone. There are organisations out there who offer advice and practical support to carers, so reach out and see what help is available to you.
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NHS advice
Carers UK
Carers Scotland
Carers Wales
Carers Northern Ireland
Family Carers Ireland
Carers Trust
Help for young carers
Citizens Advice UK
Citizens Information RoI
Find your local social services
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England
Scotland
Wales
Northern Ireland
Republic of Ireland
Mental Health, Well-Being, and Work following MMN diagnosis
This section will provide useful links and sources to help support your mental health during MMN. If you’re a carer or have experienced a loved one going through an illness it can also be a traumatic time, and these links may also help you.
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We also discuss getting back to work and how to communicate with your employer.
Click one of the headers below to access the information directly:
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Back To Work: After a Long Absence
Back To Work: Making Reasonable Adjustments
Back To Work: Pay During A Phased Return To Work
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Mental Health & Wellbeing
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With all the changes in your health it is not uncommon to feel anxious or angry, and this can even be helpful to a degree in providing the mental and physical energy that is needed to anticipate and tackle problems. An acute stress reaction is recognised as being a normal part of the process of adjusting to a life change, and it can often help to talk things through with a partner or close friend. However, please seek advice and help from your GP if you are finding it difficult to cope or to sleep, or if you are feeling overwhelmed emotionally.
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The impact of being severely affected by a sudden, frightening and potentially life-changing condition such as MMN can leave people with symptoms of PTSD (post-traumatic stress disorder). It can develop immediately, or many months or even years after a traumatic event. If you are concerned about low mood, irritability, panic attacks, anxiety, flashbacks, physical sensations such as trembling or sweating, poor concentration or sleeping problems, please talk to your GP about getting some counselling.
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We may be able to provide access to counselling - please click here for more
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Some other sources of support are shown below.
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Post-Traumatic Stress Disorder
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Sexual Relationships
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MMN and other chronic neuropathies can bring on problems in any relationship, and sexual relationships are not excluded. Dealing with a long-term illness or disability can put a great strain on a relationship, particularly when one partner is partially or totally dependent on the other. As well as coming to terms with a physical disability, the emotional upheaval can interfere with a couple’s sex life and this can be difficult to talk about. This can mean that the once close, intimate relationship can become distant and stressful for both partners. Help is available so speak to your GP or a relationship counsellor.
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Relate https://www.relate.org.uk/
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Getting Back To Work
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When someone is ready to return to work after an absence, the employer should have a procedure they follow, or an Occupational Health service. You can check your workplace’s absence policy for this. Your workplace might have a policy for meeting with employees after absences.
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Back To Work: After a Long Absence
If there’s been a long absence or the employee has an ongoing health condition, it’s a good idea for the employer and employee to meet and:
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Make sure the employee is ready to return to work.
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Talk about any work updates that happened while they were off.
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Look at any recommendations from the employee’s doctor.
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See if they need any support.
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If the employee has a disability, see if changes are needed in the workplace to remove or reduce any disadvantages (‘reasonable adjustments’).
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Consider a referral to a medical service such as occupational health.
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Discuss an employee assistance programme (EAP) if it’s available.
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Agree on a plan that suits you both, for example a phased return to work.
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Back To Work: Making Reasonable Adjustments
If an employee has a disability, by law their employer must consider making ‘reasonable adjustments’ if needed to help them return to work.
Reasonable adjustments could include making changes to the employee’s:
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Workstation or working equipment.
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Working hours.
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Duties or tasks.
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For the best course of action, the employer should take advice from:
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- The employee themself.
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The employee’s doctor.
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Their Occupational Health adviser.
This can help get people back to work quicker prevent any further problems.
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Back To Work: Phased Return
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A ‘phased return to work’ is when someone who’s been absent might need to come back to work on:
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Reduced hours.
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Lighter duties.
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Different duties.
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Long-term illness.
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Serious injury.
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Bereavement.
The employer or their HR manager and the employee should agree on a plan for how long this will be for.
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For example, they could agree to review how things are going after a month and then decide to increase the working hours or duties, or they might decide they need to stay reduced for longer.
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The employer or HR manager should continue to regularly review the employee’s health and wellbeing in the workplace and make new adjustments if necessary.
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Back To Work: Pay During A Phased Return To Work
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If the employee returns to their normal duties but on reduced hours, they should get their normal rate of pay for those hours they work.
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For the time they’re not able to work, they should get sick pay if they’re entitled to it.
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If the employee is doing lighter duties, it’s up to the employer and employee to agree on a rate of pay. It’s a good idea to make sure this agreement is put in writing.
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This information is provided by ACAS (the Advisory, Conciliation and Arbitration Service).
Further information regarding absence and returning to work is available on the ACAS website:
MMN - what happens next?
MMN - So what happens next?
What happens next? That’s a big question for a lot of people after diagnosis and/or leaving hospital. This section covers everything from rehab to hygiene to pain management.
To skip to the information directly, just hit a header below:
Support and Rehabilitation
Financial Help
General Prognosis
Pregnancy
Physiotherapy
Hygiene, Cleanliness and Teeth ​
Diet
Your Immune System
Exercise and Rest
Pain
Support and Rehabilitation
If you do need time in hospital, you may require some form of rehabilitation before returning home, to help you regain strength, dexterity and mobility. This could be within a rehabilitation unit in the hospital, or you may be transferred to a specialist rehab unit elsewhere.
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You may also be offered psychological support, as a potentially life-changing illness such as MMN or another chronic inflammatory neuropathy can also severely impact your mental wellbeing.
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Specialists who might support you through rehab:
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Physiotherapist: will help you with movement issues, re-building muscle, and learning to walk
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Occupational Therapist (OT): will identify potential problem areas and work out some solutions
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Speech and Language Therapist: While not common for MMN, if you experienced any communication and swallowing problems, the therapist can help you with that.
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Counsellor or Psychologist: someone you can discuss your problems with and help you find ways to cope emotionally
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Financial Help
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Financial concerns may be causing anxiety, especially if you are the main wage-earner and unable to work. If you are employed, stay in regular contact with employers and make sure you understand the absence and returning to work processes.
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Inflammatory Neuropathies UK may be able to help with the cost of frequent journeys to visit a family member in hospital. Get in touch and ask about our Personal Grants Scheme.
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Once you leave hospital, or if you are already receiving treatment as an outpatient, you could be entitled to benefits to help you support yourself and your family. The benefits system is complex and subject to change, but Citizens Advice has up-to-date information on their website, and they can even help you make an application for benefits such as Personal Independence Payment (PIP) or Universal Credit:
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Further information on benefits can be found at:
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If adaptations to your home are needed, such as installing a ramp or downstairs bathroom for example, it is worth contacting your local council to see if you are entitled to help via a Disabled Facilities Grant:
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If you are on a low income, or someone in your household is severely and permanently disabled, you may be entitled to a reduction in Council Tax. Further information is available an Carers UK.
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General Prognosis ​
IVIg treatment of MMN is usually very effective with about 80%-90% of patients responding positively (though this can vary from partial to substantial improvement). Unlike CIDP, MMN almost never goes into remission and instead ongoing IVIg is usually needed to maintain function. Your health care provider will discuss appointments with you.
Delay in diagnosis or the wrong treatment can lead to permanent weakness. However, with proper treatment, and as progression is slow, many patients can maintain a stable functional status for years.​​
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Pregnancy ​
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Neither IVIg nor plasma exchange is contraindicated during pregnancy. However, as plasma exchange requires additional considerations and monitoring, IVIg might be preferred.
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Physiotherapy
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If you have difficulty accessing physiotherapy, but feel it would benefit you, or if you find yourself on a lengthy waiting list, please contact the office at Inflammatory Neuropathies UK.
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Hygiene, Cleanliness and Teeth
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Personal cleanliness for those who cannot care for themselves fully can be a problem. Many returning home from hospital may have reduced use of their hands, usually temporarily, but sometimes permanently. Many will be unable to wash themselves, brush their hair, use the lavatory, wipe their bottoms, brush their teeth, cut their nails etc. It is important for both hygiene and self-esteem that these matters are attended to by a carer.
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Through no fault of their own, many people’s teeth are neglected during periods of serious illness. Once you have returned home, arrange an appointment with your dentist as soon as possible. If you have difficulty attending a dental practice, enquire about community dental services. Using an electric toothbrush can be helpful if you have residual weakness in your hands. More advice can be found on the British Society for Disability and Oral Health website.
Diet
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During illness, nutritional needs are at their peak, but it is not unusual for patients to lose their appetites or taste for food. Worry and fear often accompany illness and can also contribute to loss of appetite. Good nutrition can be a powerful ally in the process of recovery, so if you need advice, ask to speak to a nutritionist. If taste has been affected, this will usually improve with time. Plastic utensils can be used if bitter or metallic tastes are experienced whilst eating.
Sometimes taste changes can be related to medications, but drugs should not be discontinued without first consulting your GP. Try to eat a healthy, balanced diet and keep consumption of sugary and processed foods, and drinks that are high in caffeine or alcohol to a minimum. There is some excellent advice on nutrition on the NHS website:
Your Immune System
Although caused by your immune system malfunctioning, MMN does not weaken or damage your immune system, and having MMN does not mean that your immune system is compromised, unless you are being treated with steroids.
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Regular exercise and maintaining a healthy diet and sleep regime will all help during recovery. There is anecdotal evidence, and lots of hype surrounding supplements and alternative remedies, but very few are known to have real benefits. Most people are able to get the vitamins they need from their diet, but if you wish to take dietary supplements, your doctor (rather than Google!) will be able to advise you on anything that may help you during recovery.
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Exercise and Rest
Physiotherapy, occupational therapy (OT) and speech and language therapy play a vital role in maximizing functional ability.
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Exercise can help to improve your muscle strength and reduce your overall sense of fatigue. It can also aid sleep and support mood through the production of endorphins. Other benefits include helping your heart and lungs remain healthy and making you feel more positive about yourself. However, it may take weeks or even months before you feel some of the benefits, so it is important to pace yourself. You will find lots of exercises online, including seated exercises, or you could ask your GP or physiotherapist about how to start regular exercise and what exercises might be right for you.
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Visit the NHS website for advice on exercise: https://www.nhs.uk/live-well/exercise/
and also for advice on sleep: https://www.nhs.uk/live-well/sleep-and-tiredness/
Pain
​​Being in pain naturally impacts on mood and the ability to cope with everyday situations. MMN should not cause pain itself, but can lead to accident or injury via falls or drops. If you are experiencing pain, it is important to talk to your family and friends about this, so that they understand what you are going through and why you might be irritable and difficult to live with at times.
Other Sources of Support:
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Pain Concern https://painconcern.org.uk/
British Pain Society https://www.britishpainsociety.org/
Pain Association Scotland https://painassociation.co.uk/
Welsh Pain Society https://www.welshpainsociety.org.uk/
Pain Relief Foundation https://painrelieffoundation.org.uk/
Pain Relief Ireland https://painreliefireland.ie/