Types of Motor Neurone Disease

MND is a neurological disease that affects the neurones (nerves) that provide the stimulus to our muscles through which we move, breathe, eat and drink. The disease is given different names depending upon how the symptoms present themselves. All forms of the disease are ultimately fatal.

The three main forms are: amyotrophic lateral sclerosis (ALS), progressive muscular atrophy (PMA) and progressive bulbar palsy (PBP).

Motor neurones are classified as upper and lower motor neurones. Upper motor neurones descend from the brain to the brain stem and the spinal cord; lower motor neurones extend from the brain stem and the spinal cord to the muscles.

When the upper motor neurones alone are affected the disease has two names: if limb involvement is predominant the disease is called progressive lateral sclerosis; if brain stem involvement is predominant the disease is called progressive pseudobulbar palsy. When lower motor neurones alone are affected the disease is called progressive muscular atrophy. When both upper and lower motor neurones are involved the disease is called amyotrophic lateral sclerosis. This is the commonest form.

Amyotrophic : -
Muscle wasting (A: - Without, Myo: - Muscle, Trophic: - Nourishment).

Amyotrophic lateral sclerosis : -
The form of the disease caused by deficits of upper and lower motor neurones.

Atrophy : -
Wasting away.

Bulbar: -
Pertaining to the brain stem or bulb (the region containing the lower motor neurones for the muscles of speech, swallowing and other functions).

Lateral : -
Refers to the lateral columns of the spinal chord through which the motor pathways descend from the brain to the motor neurones for the limbs and trunk.

Palsy : -
Paralysis.

Progressive: -
Continuing deterioration.

Progressive bulbar palsy: -
Progessive weakness of (mainly) speech and swallowing owing to lower motor neurone involvement
.
Pseudobulbar palsy : -
Progessive weakness of (mainly) speech and swallowing owing to upper motor neurone involvement.

Sclerosis : -
Fibrous tissue overgrowth following the loss of nerves and nerve pathways.