Motor Neuron Disease
Motor neuron disease is a neurological disorder characterized by gradual weakening of the muscles that control activities such as speaking, breathing, and walking. In some types of motor neuron disease, such as ALS, muscle weakness is progressive and eventually fatal. However, the prognosis for each motor neuron disease depends on the type and the age of the patient when the disease began.
Motor neuron disease is a group of progressive neurological disorders that destroy motor neurons. Motor neurons are the cells that control essential muscle activity, such as:
Characteristic symptoms of motor neuron disease include:
- Gradual weakening, wasting away, and uncontrollable twitching of the muscles
- Spasticity or stiffness in the arms and legs
- Overactive tendon reflexes.
Sensation, intellect, memory, and personality are not affected in motor neuron disease. In some types of motor neuron disease, such as amyotrophic lateral sclerosis (ALS, commonly called Lou Gehrig's disease), muscle weakness is progressive and eventually leads to death when the muscles that control breathing no longer work. Other types of motor neuron disease progress slowly and last a lifetime.
(Click ALS Symptoms for more information about the symptoms of amyotrophic lateral sclerosis.)
Motor neuron disease occurs in adults and children, and tends to be more common in men than in women. In adults, symptoms of motor neuron disease usually appear after age 40. Symptoms may be similar to those of other diseases, which makes diagnosis difficult. In children, particularly in inherited forms of motor neuron disease, symptoms are present from birth.