What is motor neuron disease?
A motor neuron disease is a neurological disorder marked by the progressive function loss or destruction of motor neurons. Because this disease manifests itself in different ways, it’s broken down into various types. Let’s start with this discussion with what is a motor neuron.
A neuron is a cell that conducts electrochemical impulses. Basically, neurons are like messengers, carrying vital signals to and from your brain. There are essentially three types of neurons:
- motor
- sensory
- interneuron
Motor neurons transmit their impulses outwards from your central nervous system (brain and spinal cord) to the periphery, i.e. muscles and glands. Sensory neurons carry their signals to the brain from sensory receptor cells, which generally convey information regarding your environment. And interneurons is the communication channels between various neurons.
Nerve impulses transmitted through your motor neurons control muscle activity and glandular tissue. The destruction of motor type neurons can severely disrupt the voluntary control of your arms, legs, chest, face, throat and tongue. And motor neuron diseases can impact smooth, coordinated muscular movements that produce speech, chewing, swallowing, breathing and walking. Eventually, your ability to control them can be lost altogether.
Motor Neuron Disease Causes
The causes for why motor neuron diseases develop isn’t known. Some cases run in families, thus indicating inherited gene mutations might somehow be involved. Also, research reveals certain physiological differences that cause a negative affect on the function or destruction of motor neuron cell, including:
- problem with glia cells
- abnormal mitochondria
- clumps of protein molecules
- inadequate antioxidant production
- excess glutamate neurotransmitter
- improper production of neurotrophic factors
- disturbed transport system for cell metabolism
Various triggers are being investigated in an effort to find the cause for these changes to occur, such as toxins, viruses, genetics and cancers. And when motor neuron signalling is disrupted, then some of these muscle related symptoms may begin to arise and gradually worsen:
- spasms
- myalgia
- spasticity
- fasciculations
- slurred speech
- muscle cramps
- muscle atrophy
- muscle stiffness
- muscle weakness
Because there are different types of motor neuron diseases, symptoms will vary accordingly.
Types of Motor Neuron Diseases
Motor neuron diseases are typed based the primary site of degenerating neurons. Here’s a list of more common types of motor neuron diseases:
- pseudobulbar palsy
- post-polio syndrome
- spinal muscular atrophy
- primary lateral sclerosis
- progressive bulbar palsy
- amyotrophic lateral sclerosis
- progressive muscular atrophy
Not all motor neuron diseases are fatal, yet many eventually cause unpleasant effects on the quality of your life.