A motor neuron disease (MND) is any of several neurodegenerative disorders that selectively affect motor neurons, the cells that control voluntary muscles of the body. MND basically affects the brain and nerves. These disorders are a rare but serious and incurable form of progressive neurodegeneration. Motor neurons are nerve cells that send electrical output signals to the muscles, affecting the muscles' ability to function.
Motor neuron disease (MND) can appear at any age, but most patients are over 40 years old at diagnosis. It affects men more than women.
MND is always fatal and can significantly shorten life expectancy, but some people live with it for many years. There’s no cure, but there are supportive treatments to help reduce the impact it has on one’s daily life.
There are several types of motor neuron disease. Each type does not describe a completely separate disease, just a different form. In other words, each type is a way of describing how the disease is likely to affect you.
Amyotrophic lateral sclerosis (ALS) also known as Lou Gehrig's disease, is the most common type, affecting muscles of the arms, legs, mouth, and respiratory system. Mean survival time is 3 to 5 years, but some people live 10 years or more beyond diagnosis with supportive care.
Progressive bulbar palsy (PBP) involves the brain stem. People with ALS often have PBP too. The condition causes frequent choking spells, difficulty speaking, eating, and swallowing.
Progressive muscular atrophy (PMA) slowly but progressively causes muscle wasting, especially in the arms, legs and mouth. It may be a variation of ALS.
Primary lateral sclerosis (PLS) is a rare form of MND that advances more slowly than ALS. It is not fatal, but it can affect the quality of life. In children, it is known as juvenile primary lateral sclerosis.
Spinal muscular atrophy (SMA) is sometimes included in the group by some neurologists but it is a different disease with clear genetic cause. It is an inherited MND that affects children. There are three types, all caused by an abnormal gene known as SMA1. It tends to affect the trunk, legs, and arms. Long-term outlook varies according to type.
The different types of MND share similar symptoms, but they progress at different speeds and vary in severity.
Signs and Symptoms
MND can affect how you walk, talk, eat, drink and breathe. Some people also experience changes to their thinking and behaviour. However, MND affects everyone differently. Not all symptoms will affect everyone, or in the same order.
Symptoms also progress at varying speeds, which makes the course of the disease difficult to predict.
MND symptoms can be divided into three stages, early, middle, and advanced.
Early stage signs and symptoms
Symptoms develop slowly and can be confused with symptoms of some other unrelated neurological conditions.
Early symptoms depend upon which body system is affected first. Typical symptoms begin in one of three areas: the arms and legs, the mouth (bulbar), or the respiratory system.
a weakening grip, making it hard to pick up and hold things
muscle pains, cramps, and twitches
slurred and sometimes garbled speech
weakness in the arms and legs
increased clumsiness and stumbling
trouble breathing or shortness of breath
Middle stage signs and symptoms
As the condition progresses, symptoms become more severe.
Muscle pain and weakness increase, and spasms and twinges worsen.
Limbs become progressively weaker.
Limb muscles start to shrink.
Movement in affected limbs becomes more difficult.
Limb muscles may become abnormally stiff.
Joint pain grows.
Eating, drinking, and swallowing become harder.
Drooling occurs, due to problems controlling saliva.
Yawning occurs, sometimes in uncontrollable bouts.
Jaw pain may result from excessive yawning.
Speech problems worsen, as muscles in the throat and mouth become weaker.
The person may show changes in personality and emotional state, with bouts of uncontrollable crying or laughing.
Previously, it was believed MND did not significantly affect brain function or memory, but studies have now shown that up to 50 percent of people with ALS have some type of brain function involvement.
This includes difficulties with memory, planning, language, behaviour, and spatial relationships. Up to 15 percent of people with ALS have a form of dementia known as frontotemporal dementia (FTD).
Breathing problems may occur as the diaphragm, the main breathing muscle, deteriorates. There may be a shortage of breath, even when sleeping or resting. Ultimately, breathing assistance will be necessary.
Secondary symptoms include insomnia, anxiety, and depression.
Advanced stage signs and symptoms
Eventually, the patient will be unable to move, eat, or breathe without assistance. Without supportive care, an individual will pass away. Despite the best of care currently available, complications of the respiratory system are the most common causes of death.
The senses are usually unaffected, so people can still see, hear, taste smell and feel sensations. Some people may experience changes to taste, skin hypersensitivity or problems with temperature regulation.
Bladder and bowels are not usually affected by MND, but it may be harder to get to the toilet in time if mobility is affected. Constipation can also be a problem if you become less mobile or get dehydrated.
Sexual function is not affected, but sexual expression may become more difficult if mobility and movement are restricted.
Motor neurons send signals from the brain to the muscles and bones, and this makes the muscles move. They are involved in both conscious movements and automatic movements.
Normally, messages from nerve cells in the brain (called upper motor neurons) are transmitted to nerve cells in the brain stem and spinal cord (called lower motor neurons) and from them to particular muscles. Upper motor neurons direct the lower motor neurons to produce movements such as walking or chewing. Lower motor neurons control movement in the arms, legs, chest, face, throat, and tongue. Spinal motor neurons are also called anterior horn cells. Upper motor neurons are also called corticospinal neurons.
When there are disruptions in the signals between the lowest motor neurons and the muscle, the muscles do not work properly; the muscles gradually weaken and may begin wasting away and develop uncontrollable twitching (called fasciculations). When there are disruptions in the signals between the upper motor neurons and the lower motor neurons, the limb muscles develop stiffness (called spasticity), movements become slow and effortful, and tendon reflexes such as knee and ankle jerks become overactive. Over time, the ability to control voluntary movement can be lost.
Some MNDs are inherited while others happen randomly. The exact causes are unclear, but the National Institute of Neurological Diseases and Stroke (NINDS) notes that genetic, toxic, viral, and other environmental factors likely play a role.
Here are some of the risk factors associated with MND.
Heredity: In the United States (U.S.), around 1 in every 10 cases of ALS is inherited. SMA is also known to be an inherited condition.
Age: After the age of 40 years, the risk rises significantly, although it is still very small. ALS is most likely to appear between the ages of 55 and 75 years.
Sex: Men are more likely to develop an MND than women.
Some experts have linked military experience to a higher chance of developing the disease.
In the early stage, MND can be hard to diagnose, because the signs and symptoms are common to other conditions, such as multiple sclerosis (MS), an inflamed nerve, or Parkinson's disease.
A primary care physician will normally refer the patient to a neurologist; a doctor specialized in the diagnosis and treatment of diseases and conditions of the nervous system.
The neurologist will start with a complete history and physical exam of the neurologic system.
To help rule out other conditions, other tests may be helpful, such as:
blood and urine tests
a scan of your brain and spine
tests to measure the electrical activity in your muscles and nerves
a lumbar puncture (also called a spinal tap) – when a thin needle is used to remove and test the fluid from within your spine
After tests, a doctor will normally monitor the patient for some time before confirming that he/she has MND.
There is no cure for MND, so treatments focus on slowing the progression and maximizing patient independence and comfort.
highly specialised clinics, typically involving a specialist nurse and occupational therapy to help make everyday tasks easier
physiotherapy and exercises to maintain strength and reduce stiffness
advice from a speech and language therapist or dietician about diet and eating
a medicine called riluzole that can slightly slow down the progression of the condition
medicines to relieve muscle stiffness and help make swallowing easier
emotional support for the patient and his/her carer
Treatment can also include the use of breathing, feeding, mobility and communication appliances and devices.
Prognosis of Motor Neuron Disease
MND is usually fatal. Depending on the type, most people will not survive longer than 5 years after symptoms appear, but some people live 10 years or even decades, depending on the extent and progression of their disease.
The United Kingdom's (U.K.) National Health Service (NHS) notes that living with an MND can be extremely challenging. However, they add that with community and other support, the patient's quality of life is often better than expected, and the advanced stage "isn't usually distressing." For most people, this comes at home, while sleeping.
As medical research continues, scientists hope to understand MNDs more fully. They are working towards finding new treatments.
....making effort to "STAY WELL"
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