Motor neurone disease (MND) is a rare, serious and incurable condition where over time, the nerves in the brain and spine experience a progressive loss of function (neurodegeneration).
Specifically, nerve cells known as motor neurones are affected by MND.
What are motor neurones?
Motor neurones are specialised nerve cells that control important voluntary muscle activity, such as:
- breathing, and
Loss of motor neurone function can lead to weakness and wasting of the muscles, increasing loss of mobility in the limbs and difficulties with speech, swallowing and breathing.
How common is motor neurone disease?
MND is one of the rarest neurological conditions (conditions that affect the nervous system). For example, in England, it is estimated that there will be two new cases of MND each year for every 100,000 people.
MND mainly affects adults who are over 40 and most cases develop in people between 50 and 70 years of age. However, MND can affect adults under the age of 40.
Men account for 60% of all cases of MND, with women accounting for the remaining 40%.
The cause (or causes) of MND are unknown, but it seems likely that genes play a factor, at least in some people with the condition. This is because 10% of people who develop MND also have a close family relative with the condition.
Types of motor neurone disease
There are three main types of MND:
- amyotrophic lateral sclerosis (ALS) – is the most common form of MND and accounts for 60-70% of cases,
- progressive bulbar palsy (PBP) – accounts for 20% of MND cases, and
- progressive muscular atrophy (PMA) – accounts for 10% of cases.
The symptoms of all three forms of MND are similar, although there is a difference in how quickly each type progresses.
There is also a very rare form of MND known as primary lateral sclerosis.
In terms of survival rates, the outlook for MND is very poor. The facts are that:
- most people with ALS die withitwo to fivyears after the start of symptoms,
- most people with PBP die withisix months to threyears after the start of symptoms, and
- the outlook for PMA is slightly better, with an average survival rate of five to 10 years.
Although the outlook for most cases of MND is poor, a minority of people with the condition survive much longer than the timescales stated above. For example, the scientist Steven Hawkings has MND, and was diagnosed over 40 years ago.
In terms of quality of life, the outlook for people living with MND is not as bleak as many people imagine. While MND cannot be cured, its symptoms can be treated and some people with the condition are able to maintain a fairly independent lifestyle for a number of years.
A number of recent high-profile news stories have involved people with MND attempting to fight a legal battle in order to obtain the right to euthanasia or assisted suicide. This has led to a widespread misconception that people with MND face the prospect of a painful and traumatic death from choking, malnutrition or suffocation.
However, this is not the case. A recent study found that 98% of people in England with MND died peacefully in their sleep, and 50% of those people were able to die at home.
Symptoms of motor neurone disease
The symptoms of motor neurone disease (MND) usually follow a pattern that is marked by three stages:
- the initial stage,
- the advanced stage, and
- the end stage.
The initial symptoms of MND usually develop slowly and subtly over time. It can be easy to mistake early symptoms for those of a number of unrelated neurological conditions (conditions affecting the nervous system).
The initial symptoms of MND may include:
- a weakened grip, which can make it difficult to pick up or hold objects,
- a general feeling of tiredness,
- muscle pains and cramps,
- muscle twitches,
- slurred speech,
- weakness in the arms and/or legs, and
- a feeling that you have become much more clumsy than usual, such as always tripping over.
The advanced symptoms of MND are outlined below.
If you have MND, your limbs will become progressively weaker, and the muscles in your limbs will begin to shrink. As a result of this, you will find it increasingly difficult to move your affected limbs.
The twitching in your muscles will also get worse, and it is likely that you will experience muscle spasms (twinges). You may also notice that certain muscles in your limbs become unusually stiff. This type of muscle stiffness is known as spasticity.
The combination of muscle spasms and stiffness can lead to episodes of pain in your muscles and joints.
If you have MND, you will find it increasingly difficult to swallow, which may make eating and drinking problematic. Difficulty swallowing is known as dysphagia.
If you have MND, you may find that you have problems controlling the production of saliva and that you experience excessive and/or constant drooling of watery saliva.
Some people with MND find that they experience episodes of uncontrollable, excessive yawning, even when they are not tired. This can sometimes cause jaw pain.
As MND progresses, you may find it increasingly difficult to control the muscles of your throat and mouth, making it difficult for you to talk.
MND does not usually affect a person’s intelligence, but it can lead to changes in a person’s personality and emotional state.
One of the most common signs of this is known as emotional lability. Emotional lability is when a person experiences episodes of uncontrollable crying or laughter.
There is often no connection between these episodes and a person’s actual emotional state or their immediate environment. For example, someone with emotional lability may break into uncontrollable laughter when watching a news report about a serious incident, such as an air crash.
Cognitive changes and dementia
Occasionally, people with MND may experience difficulties with memory, learning, language and concentration. This is known as cognitive change. Some of these changes may be quite subtle, making it difficult to tell them apart from the normal ageing process.
A small number of people with MND may also be diagnosed with dementia at some time. It is important that help and advice is sought from healthcare professionals who are trained in the treatment of MND and dementia.
As the nerves and muscles that help control your lungs become progressively more damaged, you will find that your breathing becomes increasingly difficult.
This usually develops as a feeling of being very short of breath after carrying out everyday tasks, such as walking up the stairs. Over time, you may become very short of breath, even when you are resting.
This shortness of breath may be particularly troublesome at night. Some people find it difficult to breathe when they are lying down, while others find themselves waking suddenly in the night as a result of breathlessness.
As MND progresses, it is likely that you will need mechanical assistance with your breathing – for example, you may need to use an oxygen mask.
As MND progresses to its final phase, it is likely that you will experience:
- total body paralysis, and
- significant breathing difficulties.
Eventually, mechanical assistance, such as using an oxygen mask, will not be enough to compensate for the loss of normal lung function. At this stage, most people with MND become increasingly drowsy before falling into a deep sleep. They usually die peacefully in their sleep.
A number of people with MND will experience additional symptoms that are not directly caused by the condition, but are related to the stress and anxiety of living with MND.
These secondary symptoms include:
- insomnia, and
Causes of motor neurone disease
Motor neurone disease (MND) occurs when motor neurones progressively lose function.
Motor neurones are specialised nerve cells tharelay signals from your brain to your muscles and bones, allowing you to move them. They also help to regulate many of the body’s automatic processes, such as breathing and swallowing.
For the majority of cases, MND does not affect any other family member – this is called sporadic MND. In these cases, researchers believe the cause is a combination of subtle genetic, environmental and lifestyle factors that build up through life.
However, one in 10 people with MND will hava close family relative who has also developed the condition – this is called familial MND. In these cases, the cause is a problem with the genes (see below).
Familial (inherited) MND
The fact that MND can run in families suggests that certain genetic mutations (mistakes in the genes) that people inherit from their parents may play a role in the condition.
Currently, three genetic mutations have been identified. These have been found in genes called SOD1, TDP-43 and FUS.
Research into the genetic basis of MND is still ongoing.
Possible cellular causes of MND
In MND, it is still unclear exactly why the motor neurones begin to lose function. Most experts believe that the loss of function is caused by a combination of interrelated factors. Some of these factors are outlined below.
Disrupted chemical communications
Nerve cells use special ‘messenger chemicals’ called neurotransmitters to transmit information from one cell to another. One of the neurotransmitters is called glutamate.
There is some evidence to suggest that people with MND have an excess amount of glutamate. Excess glutamate may lead to a disruption in the chemical communication that is needed to maintain usual nerve function.
All cells contain transport systems that are designed to move nutrients and other chemical components into a cell while moving waste products out of the cell.
Research suggests that the transport systems in motor neurones become disrupted very early in the initial stages of MND, which may contribute to the loss of normal nerve function.
Aggregates are abnormal clumps of protein molecules that develop inside motor neurones and have been found in most cases of MND. The clumps may disrupt the normal functioning of the motor neurones.
Oxygen free radicals are a toxic waste product that is produced as a natural by-product of cell activity. In response to free radicals, the body produces a special substance, known as antioxidants, which are used to neutralise the free radicals and prevent them damaging cells.
Research suggests that in cases of MND, the motor neurones are not producing enough antioxidants.
Mitochondria are the ‘batteries’ of cells; they provide the energy that a cell needs to carry out its normal function. Research has shown that the mitochondria in the motor neurones of people with MND appear to be abnormal. This may be a result of excess glutamine (a building block of protein) or damage that is caused by free radicals.
Lack of nutrients
Like all living tissue, motor neurones need a regular supply of nutrients. Motor neurones receive nutrients from a group of proteins that are known as neurotrophic factors. There is some evidence that in cases of MND, neurotrophic factors are not produced in the correct way, which may make the motor neurones more vulnerable to damage and affect their function.
Glia cells surround and support nerve cells, such as motor neurones, and help to provide them with nutrients. Glia cells also help relay information from one nerve cell to another.
Some cases of motor neurone disease may be caused by underlying problems with the gila cells, which mean that the motor neurones no longer receive the support and nutrition that they require to function normally.
Diagnosing motor neurone disease
Diagnosing motor neurone disease (MND) can be difficult when the condition is in its initial stages.
This is because many of the initial symptoms can also be caused by other more common health conditions, such as multiple sclerosis (MS), tumours, a trapped nerve, or Parkinson’s disease (a condition that affects the way the brain coordinates body movements).
Ruling out other conditions
As there is no single diagnostic test for MND, your GP will refer you to a consultant neurologist (a specialist in conditions affecting the nervous system) so that other conditions can be ruled out. These tests include
- blood and urine tests,
- a liver function test,
- a magnetic resonance imaging (MRI) scan,
- electromyography (EMG) – a test where needles are used to measure the electrical activity in your muscles,
- a nerve conduction test – which is similar to an EMF, except the speed that your nerves are able conduct an electrical signal is measured, and
- transcranial magnetic stimulation (TMS) – where a specially designed magnetic coil is used to measure the electrical activity in your brain.
Confirming the diagnosis
As MND is a serious diagnosis for a neurologist to make, they will want to be sure that all other possible causes of your symptoms are eliminated before diagnosing the condition.
Sometimes, neurologists may ask to see the patient again, in three months time, before making a diagnosis.This is because they may wish to see how the symptoms have progressed during that time and to make sure that their diagnosis is correct.
Most health professionals use a type of diagnostic checklist that is known as the El Escorial criteria. It works by checking for distinctive symptoms, known as motor neurone signs. Examples of motor neurone signs include:
- muscle weakness,
- shrinking muscles,
- increase in muscle tone, and
- changes in normal muscle reflexes.
If motor neurone signs can be found in three or more regions of your body, a definite diagnosis of MND can be made.
Receiving the diagnosis
Being told that you have motor neurone disease (MND) can be an emotionally devastating experience and the news can be difficult to take in.Many people diagnosed with MND experience the classic stages of the grieving process:
- Denial. You may initially disbelieve the diagnosis and think that there is nothing wrong with you.
- Anger. You may feel angry towards friends, family or medical staff.
- Bargaining. Sometimes, people with terminal conditions try to ‘bargain’ with their doctors, asking for any sort of treatment that can prolong their life.
- Depression. You may lose all interest in life and feel that your situation is hopeless.
All of these feelings are perfectly normal.
In time, most people eventually accept the diagnosis.
If you have been diagnosed with MND, talking to a counsellor or psychiatrist may help combat feelings of depression and anxiety. Taking antidepressants or medicines to reduce anxiety may also help as you move through the stages of the grieving process. Your care team will be able to advise you about this.
The MND Association can give you practical advice, support and information about living with MND, as well as providing support on coping with the emotional impact of the condition.
Treating motor neurone disease
Your care team
If you are diagnosed with motor neurone disease (MND), you will be introduced to a team of health professionals who will be involved in your care. This type of team is often called a multidisciplinary team because it contains experts from many different health care disciplines. For more information, see box, left.
Many people with MND draw up an advanced directive. An advanced directive is where you make your treatment preferences known in advance in case you cannot communicate your decisions later because you are too ill.
Issues that can be covered by an advanced directive include:
- whether you want to be treated at home, in a hospice or in a hospital once you reach the final stages of MND,
- what type of painkillers you would be willing to take,
- whether you would be willing to use a feeding tube if you were no longer able to swallow food and liquid,
- whether you are willing to donate any of your organs once you die (the brain and spine of people with MND are particularly important for ongoing research), and
- if you experience respiratory failure (loss of lung function), whether you would be willing to be resuscitated by artificial means, such as having a breathing tube inserted into your neck.
You cannot request anything illegal in your advanced directive, such as assisted suicide. Your care team will be able to provide you with more information and advice about advanced directives.
Riluzole is the only medication that is available to treat MND directly. Riluzole reduces the amount of glutamate in the body, which can slow the progression of MND.
Riluzole can extend the survival rate of people with MND for about three months. It can also delay the need for artificial ventilation.
Side effects of riluzole include:
- rapid heartbeat (tachycardia),
- headaches, and
Very occasionally, riluzole has been known to damage the liver. Therefore, you will need to have regular liver function tests while taking riluzole. If you have a previous history of liver disease, riluzole may not be suitable for you.
There are a range of treatments that can relieve many of the symptoms of MND and improve your quality of life. These are described below.
Muscle cramps can be treated with two different medications:
- phenytoin, and
These medicines were originally designed to treat epilepsy and were called anti-epileptic drugs or AEDs, but they have also proved useful in preventing cramping.
Muscle cramps can also be treated with physiotherapy.
Muscle stiffness (spasticity) can be treated using medication to relax the muscles (muscle relaxants.)
If muscle relaxants are not effective, an injection of botulinum toxin (BTA) may be given. BTA works by blocking the signals from the brain to the affected muscles. The effects of the injection normally last for up to three months.
Another possible treatment for muscle stiffness is intrathecal baclofen therapy. This involves surgically implanting a small pump on the outside of the body, which is connected to the spinal cord. The pump delivers regular doses of a medicine called baclofen into the nervous system.
Baclofen blocks some of the nerve signals that cause muscle stiffness. It can also help control the symptoms of excessive yawning.
The symptoms of excessive drooling can be treated using a number of medications. One widely used medication is called hyoscine hydrobromide. This medication was originally designed to help treat motion sickness but has since proved useful in helping to control symptoms of drooling.
Side effects of hyoscine hydrobromide include:
- dizziness, and
- blurred vision.
If you experience any of the above side effects, you should not drive or operate complex or heavy machinery.
Glycopyrrolate is an alternative medication that can be used to control drooling. It is usually given as an injection. Side effects of glycopyrrolate include:
- difficulty urinating,
- rapid and/or irregular heartbeat, and
- blurred vision.
If your drooling fails to respond to either hyoscine hydrobromide or glycopyrrolate, a medication called atropine can be used.
Atropine works by blocking the normal functions of the saliva glands. It can either be given in tablet form or by injection.
The side effects of atropine include:
- dry mouth,
- dry skin,
- difficulties in passing urine,
- constipation, and
- changes in heartbeat (the heart can beat either slower, or faster, than usual).
Emotional lability (episodes of uncontrollable crying or laughter) can be treated using antidepressants. These can either be the newer type of antidepressant called selective serotonin reuptake inhibitors (SSRIs) or an older antidepressant called amitriptyline.
You may experience some side effects when you start taking SSRIs, including:
- sleep problems, and
These side effects usually improve over time.
Common side effects of amitriptyline include:
- dry mouth,
- problems passing urine,
- a slight blurring of vision, and
These side effects should ease in around seven to 10 days as your body gets used to the medication
Not everyone with MND will experience problems with their speech, but there is a lot of help for people who do experience speech problems. A speech and language therapist (SLT) can teach you a number of techniques to make the most of your speech function by making your voice as clear as possible.
As MND progresses, you may need some sort of assistive technology to help you communicate.A range of communication aids are available and your SLT will be able to advise you about the most effective communication aids for you.
As MND progresses, the symptoms of dysphagia (problems with swallowing) will become so severe that you will no longer be able to eat and drink in the normal way.
One widely used treatment for dysphagia is a feeding tube known as a percutaneous endoscopic gastrostomy (PEG) tube. A PEG tube is surgically implanted into your stomach (abdomen) through a small incision on the surface of the stomach.
PEG tubes are designed for long-term use and last for up to six months before they need replacing.
If you experience pain due to MND, the type of painkiller that will be recommended to help control symptoms will depend on how severe your pain is.
Mild to moderate pain can often be controlled using non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen. More severe pain can be treated using an opiate-based painkiller, such as morphine.
In some cases, a type of medication called gabapentin is used.
Originally, gabapentin was designed to treat epilepsy, but it has also been found to be useful in treating pain. The possible side effects of gabapentin include:
- tiredness, and
- loss of coordination.
If you are prescribed gabapentin, do not suddenly stop taking it as you will experience withdrawal symptoms. These could include anxiety, insomnia, nausea, pain and sweating.
If you wish to stop taking gabapentin, your GP will arrange for your dose to be gradually reduced over the course of a week. By reducing your dosage slowly in this way, you should not experience any withdrawal symptoms.
As MND progresses, respiratory muscle weakness will affect most people with the condition. Respiratory muscle weakness usually develops gradually, but it can also occur suddenly and, on very rare occasions, it may even be the first sign of MND.
It is important to discuss respiratory problems with your GP before they occur. They should be able to refer you to a respiratory specialist, and/or a palliative care specialist as appropriate.
Some people with MND use mechanical ventilation as a way of supporting their breathing. There are several systems that provide ventilatory support, which are known as non-invasive ventilation (NIV). In all cases of mechanical ventilation, air is sucked in, filtered and pumped into the lungs via a facemask or a nasal tube.
NIV may not be suitable for everyone living with MND. Your respiratory specialist, or a palliative care specialist, can discuss all of the options that are available to you.
Deciding what treatment options you want to use in the event of respiratory failure is an important part of drawing up a treatment plan and making an advanced directive (see above). This can obviously be a very difficult and upsetting decision, and you may wish to discuss it with your loved ones.
Your care team will be able to give you information and advice but the final decision will be yours.
Members of your multidisciplinary team may include:
- a neurologist (a specialist in treating conditions that affect the nervous system),
- a physiotherapist (a therapist who helps people improve their coordination and range of movement),
- a speech and language therapist,
- an occupational therapist (a therapist who helps people improve the skills and abilities they need for daily activities, such as washing or dressing),
- an incontinence adviser,
- a psychologist,
- a social worker,
- a palliative care specialist (a health professional who specialises in treating people with terminal conditions), and
- a specialist neurology nurse (who will usually be your first point of contact with the rest of the team).