Motor Neurone Disease
Motor neurone disease is a neurological condition that causes the progressive degeneration of specialised nerve cells, called motor neurons, in the brain and spinal cord. It has no known cause and is invariably fatal, with a likely life expectancy of 2-4 years from diagnosis.
Motor neurone disease can cause generalised muscle spasms, exaggerated reflexes and a progressive wasting and weakness of muscles responsible for speech, chewing and swallowing. As the condition progresses, sufferers may be unable to walk, speak, use their arms and hands or hold up their head.
General Information
Motor neurons in the brain and spinal cord convey electrical messages from the brain to the muscles to stimulate movement in the arms, legs, trunk, neck and head. As motor neurons degenerate, the muscles do not work properly and gradually weaken and waste away. This muscle weakness and wasting affects speech, swallowing, movement and breathing.
The three main forms of motor neurone disease are Amyotrophic Lateral Sclerosis (ALS), Progressive Muscular Atrophy (PMA) and Progressive Bulbar Palsy (PBP). Each form is named according to the pattern of symptoms it presents. The most common form is ALS, which affects about 75% of all motor neurone disease sufferers.
Most cases of motor neurone disease occur randomly, with no known cause. However, between five and ten per cent will have a family history of the disease.
Motor neurone disease generally starts between the age of 40 and 60 years, although symptoms can first appear as early as the 20s. In New Zealand about 200 to 250 people have motor neurone disease at any one time. Slightly more men than women develop the disease.
Usually the onset is gradual but younger patients may show a more rapid progression. The average life expectancy is two to four years from diagnosis but some people succumb within a matter of months, while others live up to 20 years. Motor neurone disease is not contagious.
Signs and Symptoms
Initial symptoms will depend on the form of the condition. However, the most common early sign is weakness in the arms and legs. This is often more pronounced on one side than the other. Other early signs of the condition include:
As the condition progresses, motor neurone disease sufferers may not be able to:
Pain is experienced by about 40% of cases. Musculoskeletal pain, pressure associated with immobility and muscle cramps are the most common causes of pain.
Motor neurone disease does not affect touch, sight, smell, hearing, or intellect. Additionally, the muscles that move the eyes are usually not affected.
Diagnosis
There is no specific test for motor neurone disease and it may be difficult to diagnose in the early stages.
Diagnosis relies on a complete medical history and physical examination, as well diagnostic tests. If motor neurone disease is suspected, a referral to a neurologist (a doctor who specialises in the treatment of diseases of the nervous system) will be recommended.
A common test used in the diagnostic process is an electromyogram (EMG). This is an electrical test of muscle function. Other tests that may be used to assist with the diagnosis and rule out other causes for the symptoms include:
Treatment
There is no cure for motor neurone disease and no treatment will significantly alter its course. Medications may be prescribed to control involuntary muscle twitching, muscle cramps and excess saliva. However, treatment essentially focuses on retaining function and quality of life, and providing comfort. Management of the condition will require input from a multi-disciplinary group of health professionals that may include:
The progressive nature of the condition means that most people will eventually require full time nursing care. When breathing becomes too difficult, a mechanical ventilator may be required to maintain breathing. While the use of a ventilator can prolong life and improve sleep, it will not alter the course of the condition, and many people with motor neurone disease therefore choose not to use ventilators for lengthy periods.
Motor neurone disease can cause generalised muscle spasms, exaggerated reflexes and a progressive wasting and weakness of muscles responsible for speech, chewing and swallowing. As the condition progresses, sufferers may be unable to walk, speak, use their arms and hands or hold up their head.
General Information
Motor neurons in the brain and spinal cord convey electrical messages from the brain to the muscles to stimulate movement in the arms, legs, trunk, neck and head. As motor neurons degenerate, the muscles do not work properly and gradually weaken and waste away. This muscle weakness and wasting affects speech, swallowing, movement and breathing.
The three main forms of motor neurone disease are Amyotrophic Lateral Sclerosis (ALS), Progressive Muscular Atrophy (PMA) and Progressive Bulbar Palsy (PBP). Each form is named according to the pattern of symptoms it presents. The most common form is ALS, which affects about 75% of all motor neurone disease sufferers.
Most cases of motor neurone disease occur randomly, with no known cause. However, between five and ten per cent will have a family history of the disease.
Motor neurone disease generally starts between the age of 40 and 60 years, although symptoms can first appear as early as the 20s. In New Zealand about 200 to 250 people have motor neurone disease at any one time. Slightly more men than women develop the disease.
Usually the onset is gradual but younger patients may show a more rapid progression. The average life expectancy is two to four years from diagnosis but some people succumb within a matter of months, while others live up to 20 years. Motor neurone disease is not contagious.
Signs and Symptoms
Initial symptoms will depend on the form of the condition. However, the most common early sign is weakness in the arms and legs. This is often more pronounced on one side than the other. Other early signs of the condition include:
- Muscle twitching
- Muscle wasting
- An increasingly stiff, clumsy walk
- General fatigue
- Difficulty with chewing, swallowing and speech.
As the condition progresses, motor neurone disease sufferers may not be able to:
- Walk
- Use their hands and arms
- Speak clearly, or at all
- Swallow
- Hold up their head.
Pain is experienced by about 40% of cases. Musculoskeletal pain, pressure associated with immobility and muscle cramps are the most common causes of pain.
Motor neurone disease does not affect touch, sight, smell, hearing, or intellect. Additionally, the muscles that move the eyes are usually not affected.
Diagnosis
There is no specific test for motor neurone disease and it may be difficult to diagnose in the early stages.
Diagnosis relies on a complete medical history and physical examination, as well diagnostic tests. If motor neurone disease is suspected, a referral to a neurologist (a doctor who specialises in the treatment of diseases of the nervous system) will be recommended.
A common test used in the diagnostic process is an electromyogram (EMG). This is an electrical test of muscle function. Other tests that may be used to assist with the diagnosis and rule out other causes for the symptoms include:
- Blood and urine tests
- X-rays
- CT or MRI scans
- Muscle biopsy – to determine the health of the muscle tissue.
Treatment
There is no cure for motor neurone disease and no treatment will significantly alter its course. Medications may be prescribed to control involuntary muscle twitching, muscle cramps and excess saliva. However, treatment essentially focuses on retaining function and quality of life, and providing comfort. Management of the condition will require input from a multi-disciplinary group of health professionals that may include:
- Family doctor and medical specialists (neurology, respiratory, sleep, gastroenterology)
- Physiotherapists
- Occupational therapists
- Speech and language therapists
- Nurse specialists and district nurses
- Dietitians
- Social workers
- Counsellors
- Palliative care specialists and hospice care
- Sleep technologists.
The progressive nature of the condition means that most people will eventually require full time nursing care. When breathing becomes too difficult, a mechanical ventilator may be required to maintain breathing. While the use of a ventilator can prolong life and improve sleep, it will not alter the course of the condition, and many people with motor neurone disease therefore choose not to use ventilators for lengthy periods.