Motor Neuron Disorders

A motor neuron disease (MND) is any of several neurological disorders that selectively affect motor neurons, the cells that control voluntary muscles of the body. They include amyotrophic lateral sclerosis (ALS), primary lateral sclerosis (PLS), progressive muscular atrophy (PMA), progressive bulbar palsy (PBP) and pseudobulbar palsy; spinal muscular atrophies are also sometimes included in the group. They are neurodegenerative in nature and cause increasing disability. 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.

Symptoms may be mild and may include:

  • Stumbling due to weakness of the leg muscles

  • Difficulty holding objects caused by weakness of the hand muscles

  • Slurring of speech or swallowing difficulties due to weakness of the tongue and throat muscles

  • Cramps and muscle twitching.


As the disease progresses symptoms may include:

  • Breathing difficulties from decreased lung capacity caused by muscle weakness

  • Fatigue caused by muscle exhaustion, metabolic changes, weight loss and reduced food intake, decreased lung capacity

  • Insomnia caused by discomfort, pain from stiff joints and muscles, excessive saliva, dry mouth or breathing problems

  • Mild changes in cognitive skills and processes and/or behavioural change

  • Frontotemporal cognitive changes (a type of dementia)

  • Excessive laughing or crying due to damage to the upper motor neurones

  • Some pain or discomfort.


Motor neurone disorders can be difficult to diagnose because the initial symptoms can be similar to many other conditions. Neurologists will often use a series of tests called a Nerve Conduction Study to eliminate other conditions before making a definitive diagnosis.

Tests may include:

  • Blood tests to look for a rise in a creatine kinase, which is produced when muscle breaks down.

  • Nerve conduction studies (NCS)

  • Electromyography (EMG)

  • Magnetic Resonance Imagery (MRI) scans




If you or someone you know suffers or suspects they may have a motor neuron disorder and are looking for a specialist neurologist, please feel free to contact Synapse Neurology for a consultation 03) 8582 6945.



*Source: Deloitte Access Economics report Economic Analysis of MND in Australia