Motor Neuron Disease (MND) is a progressive neurodegenerative disease, which attacks the upper and lower motor neurons in the brain and spinal cord. Degeneration of the motor neurons means that messages sent through the nerves gradually stop reaching muscles, leading to loss of limb mobility, and difficulties with speech, swallowing and breathing. Some individuals experience cognitive changes, however the senses including vision, hearing and touch as well as the bladder and bowel remain unaffected. There are four main types of MND, and symptoms vary depending on the type and progression of the disease.
Amyotrophic lateral sclerosis (ALS)
ALS is the most common form of MND; both the upper and motor neurons are affected with ALS. ALS is characterised by muscle and limb weakness, stiffening and wasting, over-active reflexes and for some individuals, rapidly changing emotions. Common symptoms include tripping when walking or dropping objects. The average life expectancy for an individual with ALS is between 2-5 years post onset of symptoms.
Progressive bulbar palsy (PBP)
PBP makes up 25% of individuals with ALS; similarly, both the upper and lower motor neurons are affected. Some common symptoms include slurred speech and dysphagia (difficulties swallowing). The average life expectancy for individuals with PBP is between 6months and 3 years post onset of symptoms.
Progressive muscular atrophy (PMA)
PMA is rare and makes up only a small proportion of individuals with ALS and the damage is mainly present in the lower motor neurons. Symptoms present at onset include weakness or clumsiness often in the hands. The average life expectancy for most individuals with PMA is greater than 5 years.
Primary lateral sclerosis (PLS)
PLS is another rare form of MND that affects only the upper motor neurons. PLS causes weaknesses in the lower limbs, however individuals may also present with clumsiness in the hands, or speech difficulties. The average life span can be the same as individuals without the disease depending on whether disease progresses on to become ALS.
Although there is currently no cure, the symptoms can be managed through speech therapy and other medical and allied health interventions to improve quality of life.
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This article was written by our Speech Pathologist Ashleigh Fattah who is a Speech Pathology Australia member. If you have speech pathology related questions, make an appointment. We‘ll provide you with simple and effective therapy targeted to your concerns. Contact us today.