Despite its low incidence but high visibility, Amyotrophic Lateral Sclerosis is, along with many other neurodegenerative conditions, one of the greatest challenges faced by the scientific community. Although it was first described in 1869, very little is known about it.

Throughout this article we will talk about this disease, its main characteristics and the symptoms that distinguish it from other neuronal diseases. We will also describe its possible causes and the most effective treatment guidelines.

What is Amyotrophic Lateral Sclerosis or ALS?

Amyotrophic Lateral Sclerosis (ALS), also known as motor neuron disease , is one of the most well known neurodegenerative diseases worldwide. The reason is that famous people who suffer from it, such as scientist Stephen Hawking or baseball player Lou Gehrig, have given it great visibility.

Amyotrophic Lateral Sclerosis is distinguished by causing a gradual decrease in the activity of motor cells or motor neurons , which eventually stop working and die. These cells are in charge of controlling the movement of voluntary muscles. Therefore, when they die, they cause the weakening and atrophy of these muscles.

This disease is gradual and degenerative, meaning that muscle strength gradually declines until patients suffer total paralysis of the body coupled with a decline in inhibitory muscle control.

In most cases the patient is forced to remain in a wheelchair in a state of total dependence and the prognosis is usually fatal. However, despite this absolute loss of the ability to perform virtually any movement , ALS patients keep their sensory, cognitive and intellectual abilities intact , since any brain function not related to motor skills remains immune to this neurodegeneration. Similarly, eye movement control and sphincter muscle control are preserved until the end of the person’s days.


The incidence of Amyotrophic Lateral Sclerosis is about two cases per 100,000 people per year in the general population. In addition, it has been observed that ALS tends to affect certain groups of people to a greater extent, including football players or war veterans. However, the causes of this phenomenon have not yet been determined.

In terms of the characteristics of the population most likely to develop this disease, ALS tends to appear more frequently in people between the ages of 40 and 70, and with much more frequency in men than in women , although with nuances, as we shall see.

What are the symptoms?

The first symptoms of amyotrophic lateral sclerosis are usually involuntary muscle contractions, muscle weakness in a specific limb or alterations in the ability to speak which, with the development of the disease, also affect the ability to make movements, eat or breathe. Although these early symptoms may vary from person to person, over time, atrophy of the muscles results in a large loss of muscle mass and, consequently, body weight.

In addition, the development of the disease is not the same for all muscle groups. Sometimes the muscle degeneration of some parts of the body is very slow and can even stop and remain at a certain degree of disability.

As mentioned above, sensory, cognitive and intellectual abilities are fully preserved, as are sphincter control and sexual functions. However, some people affected by ALS may develop secondary psychological symptoms associated with the state they are in and of which they are fully aware, these symptoms are associated with alterations in affectivity such as emotional lability or depressive phases.

Although Amyotrophic Lateral Sclerosis is characterized by the development of the disease without causing any pain to the patient, the appearance of muscular spasms and the progressive decrease of mobility usually generate discomfort in the person. However, this discomfort can be alleviated with physical exercise and medication.


Although, at the moment, the causes of ALS have not been established with certainty, it is known that between 5 and 10% of cases are caused by a hereditary genetic alteration .

However, recent studies open up different possibilities when it comes to determining the possible causes of ALS:

1. Genetic alterations

According to the researchers, there are a number of genetic mutations that can lead to ALS, which cause the same symptoms as the non-hereditary versions of the disease .

2. Chemical imbalances

ALS patients tend to have abnormally high levels of glutamate , which can be toxic to certain types of nerve cells.

3. Alterations in immune responses

Another hypothesis relates ALS to a disorganized immune response . As a result, the person’s immune system attacks the body’s own cells and causes neuronal death.

4. Deficient protein administration

Abnormal formation of the proteins found inside the nerve cells could lead to the degradation and destruction of the nerve cells .

Risk factors

The risk factors traditionally associated with the development of amyotrophic lateral sclerosis are as follows.

Genetic inheritance

People with a parent with ALS are 50% more likely to develop the disease.


Before age 70, males are a higher risk factor for developing ALS. After age 70, this difference disappears.


The age range between 40 and 60 years is the most likely for the symptoms of this disease to appear.

Tobacco habits

Smoking is the most dangerous external risk factor for developing ALS. This risk increases in women from the age of 45-50 years.

Exposure to environmental toxins

Some studies link environmental toxins, such as lead or other toxic substances present in buildings and homes , to the development of ALS. However, this association has not yet been fully demonstrated.

Certain groups of people

As discussed at the beginning of this article, there are certain specific groups of people who are more likely to develop ALS. Although the reasons for this have not yet been established, people who serve in the military are at greater risk of ALS; it is speculated that this is due to exposure to certain metals, injuries and intense exertion .

Treatment and prognosis of ALS

No effective cure for amyotrophic lateral sclerosis has yet been developed. Therefore, although treatments cannot reverse the effects of ALS, they can delay the development of symptoms, prevent complications and improve the patient’s quality of life . Through intervention with groups of multidisciplinary specialists, a series of both physical and psychological treatments can be carried out.

By administering some specific medications such as riluzole or edaravone, the progression of the disease can be delayed, as well as reducing the deterioration in daily functions . Unfortunately, these medications do not work in all cases and still have numerous side effects.

As for the other consequences of Amyotrophic Lateral Sclerosis, the symptomatic treatment has proved to be highly effective in relieving symptoms such as depression, pain, feeling of tiredness, phlegm, constipation or sleep problems.

The types of interventions that can be performed on patients with amyotrophic lateral sclerosis are

  • Physical therapy .
  • Respiratory care.
  • Occupational therapy.
  • Speech therapy.
  • Psychological support .
  • Nutritional care.

Despite the types of treatments and interventions, the prognosis for ALS patients is quite guarded. With the development of the disease, patients lose the ability to be autonomous. Life expectancy is restricted to 3-5 years after diagnosis of the first symptoms.

However, about 1 in 4 people can survive much longer than 5 years , as is the case with Stephen Hawkins. In all these cases the patient requires a large number of devices to keep them alive.