Amyotrophic Lateral Sclerosis

Alternate Names: Lou Gehrig's Disease, ALS

Featuring content from MRI Clinic

  • The Facts

    Amyotrophic lateral sclerosis (ALS) – commonly known as Lou Gehrig's disease – is a motor neuron disease. It's caused when the motor neurons that send electric "messages" from the brain to the spinal cord (upper motor neurons) or from the spinal cord (lower motor neurons) to the muscles are slowly being destroyed. These neurons are responsible for muscle movement.




    The causes of ALS are starting to be understood. Multiple factors are at play, both genetic and environmental. At least 16 different genes are involved in ALS. No single environmental factor has been proven to cause it. ALS dose not appear to result from exposure to heavy metal or viral infection alone. Even blocking the neurotransmitter glutamate does not stop the disease.

    Genetic counselling and then possible genetic testing should be offered to all people diagnosed with ALS.

    Symptoms and Complications



    • impaired speech
    • difficulty swallowing
    • breathing problems caused by a weakened diaphragm

    In most patients, only motor neurons – and therefore only muscles – are affected with ALS. Eye muscles, as well as bladder and bowel muscles, aren't usually involved, and the disease doesn't affect a person's mind or any of the 5 senses. People remain alert, but often lose the ability to take care of themselves. It can even become impossible to breathe without the help of a respirator. In about 30% to 50% of patients, other parts of the brain are affected, which can lead to progressive cognitive decline, emotional instability, and even dementia.





    Making the Diagnosis

    When the muscles get progressively weaker, especially if a person's sensations aren't at all impaired, doctors will suspect ALS. The standard criteria for establishing the diagnosis of ALS are:

    • the presence of lower and upper motor neuron degeneration with documented progression of symptoms, either within the same body area or to other areas
    • the absence of electrodiagnostic (EMG) or pathologic (biopsy) evidence of another disease processes that could cause lower and/or upper motor neuron degeneration
    • the absence of neuroimaging (MRI) evidence of other disease processes that could explain the symptoms


    A magnetic resonance imaging (MRI) scan of the head or spine may be used to exclude other conditions that can damage or compress nerve cells such as cervical spondylosis, multiple sclerosis, and thyroid disorders.


    Treatment and Prevention

    Because the exact causes of the disease haven't been pinpointed, ALS cannot be prevented or cured. The treatment is focused on managing the symptoms and allowing the patient to have a good quality of life. Many health care specialists will be involved, including the family doctor, home nurses, a neurologist, respiratory therapist, physical therapists, occupational therapists, nutritionists, and social workers.




    To avoid choking or inhaling food and saliva into the lungs, a feeding tube might need to be placed into the stomach. People with difficulty breathing will eventually have to go on a respirator. Physical therapy can help people maintain strength in their muscles and control muscle contractions. Speech therapy can help people with speech and swallowing difficulties. Many will benefit from a motorized wheelchair and devices that allow communication through eye movements.


    End-of-life care is an essential component of the care for someone with ALS. The person should choose how they wish to be treated in the late phase of the disease. This is usually done by filling advance directives.

