Motor neuron disease

This article is about a category of neurological disorders. It is not to be confused with motor neurone disease which is another name for amyotrophic lateral sclerosis.

Motor neuron disease
spinal diagram
Classification and external resources
Specialty	Neurology
ICD-10	G12.2
ICD-9-CM	335.2
DiseasesDB	8358
Patient UK	Motor neuron disease
MeSH	D016472

A motor neuron disease (MND) is any of five neurological disorders that selectively affect motor neurons, the cells that control voluntary muscles of the body. These five conditions are amyotrophic lateral sclerosis, primary lateral sclerosis, progressive muscular atrophy, progressive bulbar palsy and pseudobulbar palsy. They are neurodegenerative in nature and cause increasing disability and, eventually, death.

Terminology

Technically the term "motor neuron disease" includes five diseases: amyotrophic lateral sclerosis (ALS), primary lateral sclerosis, progressive muscular atrophy, progressive bulbar palsy and pseudobulbar palsy.

In the United States the term is often used interchangeably with ALS. In the United Kingdom "motor neurone disease" may be used to mean ALS.

While MND refers to a specific subset of similar diseases, there are numerous other diseases of motor neurons that are referred to collectively as "motor neuron disorders", for instance disease belonging to spinal muscular atrophies. However, they are not classified as "motor neuron diseases" by the tenth International Statistical Classification of Diseases and Related Health Problems (ICD-10) which is the definition followed in this article.

Classification

Motor neuron diseases affect either upper motor neurons (UMN) or lower motor neurons (LMN), or both:

Type	UMN degeneration	LMN degeneration
Amyotrophic lateral sclerosis (ALS)	Yes	Yes
Primary lateral sclerosis (PLS)	Yes	No
Progressive muscular atrophy (PMA)	No	Yes
Progressive bulbar palsy (PBP)	No	Yes, bulbar region
Pseudobulbar palsy	Yes, bulbar region	No

External links

• Motor neuron diseases at NINDS