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Amyotrophic lateral sclerosis (ALS) is the disease of motor neurons.
The earliest signs of ALS usually include muscle weakness or stiffness (spasticity). ALS typically affects all muscles under voluntary control, and the person ultimately loses their strength and ability to eat, speak, grasp things, move, and even breathe. They find it difficult to perform routine tasks such as feeding themselves or getting dressed.
Many people with ALS notice the first signs of the disease in the hand or arm as they find it difficult to perform simple tasks such as turning a key in a lock, buttoning a shirt, combing their hair, or writing.
Some report initial symptoms in one of the legs causing difficulty or awkwardness when walking or running. They may also report that they are tripping or stumbling more often than before. If the initial symptoms affect the arms or the legs, it is called a ‘limb onset’ ALS.
Few people notice their first symptoms as difficulty in speech or swallowing, but these may rarely be the first signs of ALS. This is termed as ‘bulbar onset’ ALS.
Some of the early symptoms of ALS are:
- Muscle twitches or fasciculations in the arm, leg, shoulder, or tongue
- Muscle tightness or stiffness (spasticity)
- Muscle cramps
- A weakness of muscles affecting an arm, a leg, neck, or diaphragm (the muscular partition separating the chest from the abdomen).
- Slurred speech
- Nasal voice
- Difficulty in chewing or swallowing.
Whatever may be the initial symptom, most people with ALS eventually die from respiratory failure, usually within two to five years from when the symptoms first appear. About 10% of people with ALS, however, survive for 10 years or more after diagnosis.
What does ALS do to your body?
ALS belongs to a group of disorders known as motor neuron diseases (MND). The disease causes gradual damage to the nerve cells (motor neurons).
Motor neurons extend from the brain to the spinal cord and to muscles throughout the body. They are responsible for carrying messages between the brain, spinal cord, and the voluntary muscles that help you do various tasks such as grasping objects, talking, eating, dressing up, and moving around. In ALS, the death of these neurons stops the transfer of messages from the brain and spinal cord to the muscles.
The disease has a progressive and fatal course. In absence of the control from the nerves, the muscles stay unused and gradually weaken, twitch (fasciculations), and waste away (atrophy). It ultimately causes the brain to lose its ability to initiate and control voluntary movements. There is a progressive decline in the ability to talk, write, pick up or hold things, swallow, and breathe.
There is no cure for ALS. People with this disease have a shortened life expectancy and may die within a few years of diagnosis. ALS most commonly affects white people, males, and people over age 60.
How is ALS diagnosed?
The diagnosis of ALS is based on a detailed history of the symptoms and signs observed by a doctor during a physical examination, along with various tests to rule out other mimicking diseases.
Your doctor may request certain tests which include:
- Genetic testing (may point to a mutation in cases of familial ALS)
- Muscle and imaging tests including MRI, electromyography (EMG), and nerve conduction studies (NCS)
- Blood tests
- Urine examination
- Tests for other medical conditions such as multiple sclerosis, HIV, polio, and other viral infections