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Motor neurone disease

Steve Smith discusses motor neurone disease

Motor neurone disease is a degenerative condition with symptoms including weakening leg, arm and hand muscles, impaired speech and swallowing, cramp, twitches, weight loss and emotional lability, that tend to affect people in their 60s or 70s but can arise in much younger adults.

This condition doesn’t usually run in families but having a close relative with it does increase the risk (the risk is very low so an increased risk is still a low risk), and there seems to be an increased risk of this condition for people with a type of dementia affecting the frontal and temporal lobes of the brain (frontotemporal dementia). But the cause of the condition is not well understood.

The condition shortens life expectancy but some people do live for many years after diagnosis.

The effects of motor neurone disease (MND) vary between individuals, but four main ‘types’ have been identified.

Amyotrophic Lateral Sclerosis (ALS)

Amyotrophic Lateral Sclerosis (ALS) is the most common type. There is muscle wasting particularly in the limbs, stiffness and cramps, and from early on people tend to trip and drop things. Usually life expectancy after diagnosis is between 2 and 5 years though there are exceptions – some individuals live many years with ALS. Also known as Lou Gehring’s disease after a famous baseball player (1903-1941). ALS is one form of motor neuron disease. The long arm of motor neurons (the axon) that are bundled together to make a motor nerve, connecting the brain to muscles degenerate and die. The muscle receives no signal from the brain and so cannot be controlled. Over time the muscle deteriorates. About five in 100,000 people are affected. Symptoms – muscle cramps, trips and falls, inability to walk in time; slurred speech and eventually problems with breathing, tend to begin occurring over the age of 50 but can occur in younger people. About one fifth of people with ALS survive more than five years post diagnosis, more than 50% live more than three years, though many live for between two to three years after symptoms appear. Commonly death is due to breathing difficulties resulting when breathing muscles fail to receive signals from the brain.

Progressive Bulbar Palsy (PBP)

Progressive Bulbar Palsy (PBP) is rarer than ALS. The face, throat and tongue muscles in particular are affected. Speech and swallowing are impaired and life expectancy is between 3 to 5 years.

Progressive Muscular Atrophy (PMA)

Progressive Muscular Atrophy (PMA) is a particularly rare form of MND. People affected experience difficulty coordinating hand movement and lack strength early on. A majority live more than 5 years post diagnosis.

Primary Lateral Sclerosis- (PLS)

Another rare form of MND is Primary Lateral Sclerosis- (PLS). The lower limbs are most affected, but hand movement and speech can also be impaired. Progression of this disease is slow compared to other forms of MND and people can expect to live up to 20 years or more post diagnosis.

© University of East Anglia
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