Motor Neurone Disease Explained
by Dr John Rees
Motor Neurone Disease (MND) is a part of a wide range of disorders that affect the motor neurone, the nerve cell responsible for initiating movement. Dr Rees explains further.
MND occurs most often in an older age group (mean onset age 55), incidence about 1.2 :1000, but variants can occur at all ages, even in the new born. It has a progressive course resulting in death over 4-6 years on average. If the disease starts by affecting swallowing and or breathing muscles, then the duration of the illness is usually shorter. Some rare conditions also affecting the motor neurone have a much more benign course, for example the late Prof Stephen Hawking. About 10% of patients have a family history of MND and in some cases a dementia can occur, it is also called amyotrophic lateral sclerosis, and there are a number of less common variants with other names.
Typically, the illness presents when the patient notices unexplained, increasing weakness of a limb, difficulty walking or swallowing or that speech has changed and become rather nasal.
Diagnosis is made based on the history, finding weakness on examination and noting the presence of muscular twitching called fasciculation. In those patients who present with swallowing or speech problems, this fasciculation may be visible in the tongue. Fasciculation means that the tiny muscle fibres have become detached from their nerve supply, in this case because the important powerhouse of the nerve, the neurone itself has died. Diagnosis is usually confirmed by examining the electrical behaviour of the affected nerves and muscles (electromyography), which if positive will show characteristic abnormalities. A diagnosis of MND has grave implications, and so great care is taken to be accurate in making that diagnosis. Most neurologist use what are called the El Escorial criteria which were agreed internationally some years ago.
The cause of MND is not known with any certainty. It is thought that similar process may underlie cell death in Parkinson’s and Alzheimer’s diseases. We know that certain toxins and some chemicals produced by cancers can cause similar death of neurones so much research is directed along those lines.There are major research efforts worldwide to understand what causes MND and to find an effective treatment.
There is no cure for MND and currently, only one drug called Riluzole that has been available for some years, has been shown to have a very modest effect in slowing the pace of the disease.
The most important part of treatment to help patients with MND is to be on top of the increasing disability that most patients will have. This means that regular contact with the neurologist or more often these days, with the specialist MND nurse are essential, so that appropriate, often extensive physical aids can be supplied that will allow patients maximum help and independence for as long as possible. These needs will change as symptoms progress, so regular contact via clinic or phone with the MND clinic staff is essential. Regular assessment of breathing ability and also swallowing function will be necessary for most patients, assisted breathing at night may be helpful for some and patients who cannot swallow safely may need a feeding tube inserted into their stomach.
All neurological departments have consultant expertise in MND and specialist trained nurses to give ongoing help. The MND Association has been exemplary in funding practical help for patients locally and nationally and also important research.
For further information about MND please visit www.mndassociation.org