What is amyotrophic lateral sclerosis (ALS)?
Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease that affects the nerve cells in both the brain and the spinal cord. Both of these organs are part of the central nervous system which is responsible for sending messages to the peripheral nervous system that controls the body's organs. This causes many muscles to not function properly due to motor neurons, which are responsible for sending instructions of voluntary muscle function, have degenerated.
ALS causes the upper motor neurons, present in the brain, and the lower motor neurons, present in the spinal cord, to degenerate. The degeneration of the upper motor neurons leads to spasticity which is a condition that causes certain muscles to be continuously contracted. This leads to muscles stiffness and tightness. It can also interfere with normal movement, speech or gait. On the other hand, the degeneration of the lower motor neurons causes muscular atrophy (the shrinking of muscles) which leads to muscle weakness and/or muscle twitching. When both the upper and lower motor neurons are lost at the same time, the condition is called ALS.
ALS causes the upper motor neurons, present in the brain, and the lower motor neurons, present in the spinal cord, to degenerate. The degeneration of the upper motor neurons leads to spasticity which is a condition that causes certain muscles to be continuously contracted. This leads to muscles stiffness and tightness. It can also interfere with normal movement, speech or gait. On the other hand, the degeneration of the lower motor neurons causes muscular atrophy (the shrinking of muscles) which leads to muscle weakness and/or muscle twitching. When both the upper and lower motor neurons are lost at the same time, the condition is called ALS.
Why is the disease called amyotrophic lateral sclerosis?
"Amyotrophic" comes from the Greek word "amyotrophia". In this word the "a" means no, "myo" means muscle, and trophia means "nourishment". Combined together, it means "no muscle nourishment" which describes the atrophy (shrinkage) of the patient's disused tissue. Lateral means that the disease occurs in the lateral or side parts of the spinal cord, where the nerve cells are located. The degeneration of motor neurons in this area causes hardening or scarring which is the meaning of "sclerosis". The name of the disease sounds difficult at first but when broken into pieces it makes a lot of sense!
Who does ALS affect?
ALS can affect people of any age. However, it mostly affects people from the ages of 40 to 70 with the average age of 55 at the time that ALS is diagnosed. In the United States, around 5600 people are diagnosed with ALS each year (15 new cases each day) with an estimated 30 000 Americans having ALS at any given time. Generally, people have a higher chance of getting ALS as they grow older since an aging brain is a major risk factor for most neurodegenerative disease, including ALS.
ALS can arise in people of any race. In the United States, ALS has mostly affected Caucasians, white-skinned or European people, with 93% of the patients in the ALS CARE Database being Caucasian. This may be due to the higher percentage of Caucasians in the population since around 77% of the U.S. population is Caucasian.
ALS can also affect both genders, male and female. However, the ALS CARE Database, in the U.S., shows that 60% of the patients within the database are male while 40% are female. This means statistically ALS is 20% more common in men than in women.
ALS can also affect both genders, male and female. However, the ALS CARE Database, in the U.S., shows that 60% of the patients within the database are male while 40% are female. This means statistically ALS is 20% more common in men than in women.