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Motor Neuron Disease

Motor neuron diseases (MNDs) are a group of progressive neurological disorders that destroy motor neurons, the cells that control essential voluntary muscle activity such as speaking, walking, breathing, and swallowing. Normally, messages from nerve cells in the brain (called upper motor neurons) are transmitted to nerve cells in the brain stem and spinal cord (called lower motor neurons) and from them to particular muscles. Upper motor neurons direct the lower motor neurons to produce movements such as walking or chewing. Lower motor neurons control movement in the arms, legs, chest, face, throat, and tongue. Spinal motor neurons are also called anterior horn cells. Upper motor neurons are also called corticospinal neurons.

Types of Motor Neuron Disease

There are several types of motor neuron diseases, including:

• Amyotrophic lateral sclerosis (ALS): Also known as Lou Gehrig's disease, it's the most common form of MND. It affects both upper and lower motor neurons and leads to muscle weakness and wasting.
• Progressive bulbar palsy (PBP): This affects the lower motor neurons of the brain stem, causing slurred speech and difficulty swallowing.
• Pseudobulbar palsy: This is caused by damage to the upper motor neurons of the brain stem.
• Primary lateral sclerosis (PLS): This rare form of MND affects only the upper motor neurons.
• Progressive muscular atrophy (PMA): This affects only the lower motor neurons in the spinal cord.

Symptoms

Symptoms of motor neuron diseases can include:

• Difficulty walking or performing daily activities
• Difficulty swallowing or breathing
• Slurred speech
• Muscle weakness and atrophy
• Muscle cramps and twitching

Diagnosis

Diagnosis of motor neuron diseases may involve a physical examination, blood and urine tests, MRI, Electromyography (EMG) and Nerve conduction velocity (NCV) test.

Treatment

There is no cure for motor neuron diseases. Treatment is aimed at relieving symptoms and improving quality of life. This can include physical therapy, occupational therapy, speech therapy, and medications to control symptoms.

See also

• Neurology
• Neurological disorder
• Neuromuscular disease

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