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Amyotrophic lateral sclerosis (ALS)

Author: Judy Zhu


Amyotrophic lateral sclerosis (ALS) is a nervous system disease that affects neurons in the brain and spinal cord, causing loss of muscle control because the motor neurons cannot send impulses to the muscles. ALS is commonly called Lou Gehrig's disease, named after one of the greatest baseball players who was diagnosed with it. Currently, there is no cure for ALS, and the cause of it is unknown. It occurs rarely and spontaneously.


Most people who develop ALS are between the ages of 40 and 70, although the disease can occur at a younger age. It is most common among individuals above 60.

It occurs throughout the world with no racial, ethnic or socioeconomic boundaries.



With current healthcare, about 50% of affected patients live at least three or more years after diagnosis; 20% live five years or more; and up to 10% will survive more than ten years.



The causes of ALS are unknown as nothing in the patients’ life styles offer a clue, and there is often a lack of an obvious genetic history. However, in about 5% to 10% of cases, ALS is inherited as autosomal dominant. There are theories on what causes ALS, and many of them focus on the interaction between genetic and environmental factors. Some environmental factors may include smoking, exposure to toxins, and military service. 


On a microscopic level, ALS causes motor neurons to gradually deteriorate and then die. Motor neurons extend from the brain to the spinal cord to muscles throughout the body. When motor neurons are damaged, they stop sending messages to the muscles, so the muscles cannot function. 



The symptoms of ALS usually start with muscle weakening in hands, feet or limbs and progressively gets worse. In most cases, ALS does not affect a person's sexual, bowel or bladder functions. However, there may be 

  • difficulty in walking or doing normal daily activities

  • weakness in legs, feet, hands or ankles

  • slurred speech

  • muscle cramps and twitching in your arms, shoulders and tongue

  • inappropriate crying, laughing or yawning

As the disease progresses, symptoms may include

  • shortness of breath

  • difficulty breathing

  • difficulty swallowing

  • paralysis



According to Johns Hopkins Medicine, in addition to a complete medical history and physical examination, diagnostic procedures for ALS may include:


  • laboratory tests - including blood and urine studies and thyroid functioning tests

  • muscle and/or nerve biopsy

  • cerebral spinal fluid analysis (spinal tap) - a procedure used to make an evaluation or diagnosis by examining the fluid withdrawn from the spinal column.

  • X-rays

  • magnetic resonance imaging (MRI) - a way to image soft tissues that's noninvasive and that doesn't involve X-rays. MRI produces a sharp, two-dimensional view of the brain and spinal cord.

  • electrodiagnostic tests (i.e., electromyography (EMG) and nerve conduction velocity, or NCV) - studies that evaluate and diagnose disorders of the muscles and motor neurons. Electrodes are inserted into the muscle, or placed on the skin overlying a muscle or muscle group, and electrical activity and muscle response are recorded.

“Amyotrophic Lateral Sclerosis (ALS) - Symptoms and Causes”. Mayo Clinic, 22 februari 2022,,who%20was%20diagnosed%20with%20it.


Heller, Laura. “ALS, Amyotrophic Lateral Sclerosis, Lou Gehrig’s Disease”. Johns Hopkins Medicine, 11 juni 2019,

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