Motor Neurone Disease

Motor Neurone Disease (MND) is the name given to a group of related diseases affecting the motor neurones in the brain and spinal cord. Motor neurones are the nerve cells along which the brain sends instructions, in the form of electrical impulses, to the muscles. Degeneration of the motor neurones leads to weakness and wasting of muscles. This generally occurs in arms or legs initially, some groups of muscles being affected more than others. Some people may develop weakness and wasting in the muscles supplying the face and throat, causing problems with speech and difficulty chewing and swallowing.

The first evidence of the disease typically is insidiously developing asymmetric weakness, usually first evident distally in one of the limbs. Weakness caused by denervation is associated with progressive wasting and atrophy of muscles and, particularly early in the illness, spontaneous twitching of motor units, or fasciculations. When the initial denervation involves bulbar rather than limb muscles, the problem at onset is difficulty with chewing, swallowing, and movements of the face and tongue. Early involvement of the muscles of respiration may lead to death before the disease is far advanced elsewhere. The illness is relentlessly progressive, leading to death from respiratory paralysis; the median survival is from three to five years. There are very rare reports of stabilisation or even regression.

In the vast majority of cases, the intellect remains unaffected MND is generally a steadily progressive disease, but the rate of progression varies greatly from one person to another. The illness is not infectious and normally affects people over 40 years of age, most commonly between 50 and 80 years.

The incidence of motor neurone disease is around two cases per 100,000 population per year. About half of all patients with motor neuron disease die within two years of the diagnosis, but probably about 20% survive five years or more. Prevalence is about 6 per 100,000. Each general practitioner will see one or two new cases in a professional career of 40 years.

Scottish Motor Neurone Disease Association

Motor Neurone Disease - NHS Direct Information

Motor Neurone Disease Association