Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease in which muscles waste away due to the death of the nerve cells that control them. The condition affects limb function and produces bulbar symptoms, such as difficulty speaking and swallowing, that originate in the brainstem.

The outlook for ALS is poor, with most patients dying of it, typically from respiratory failure. Statistics show that half of those with ALS live at least three years after diagnosis, 25 percent at least five years, and up to 10 percent 10 years or more.

Once ALS develops, patients’ physical condition begins deteriorating. Initially, a person has difficulty performing everyday tasks because of muscle weakness, stiffness, and paralysis. Some patients experience brief periods — weeks to months — without further loss of function, or even recover some function. But significant improvement lasting a year or more occurs in less than 1 percent of patients.

The speed at which symptoms worsen, affect breathing and become life-threatening varies from patient to patient.

Researchers have identified some of the factors accounting for the variability. For example, those with the bulbar onset form of the disease — ALS with initial bulbar symptoms — have a worse survival outlook than those with the spinal onset form that initially affects the limbs and trunk. The outlook for respiratory onset ALS, the form that initially affects the respiratory system, is particularly poor.

In addition to the form of ALS a patient has, a factor that worsens prognosis is developing the disease later in life. Those who develop it before they are 40 are apt to survive longer.

Another factor that impacts a patient’s prognosis is whether they inherited ALS. Those with an inherited disease caused by a gene mutation that affects a particular enzyme are likely to survive only 12 months. The mutation, A4V, impacts the SOD1 enzyme. Other mutations of the same gene result in a less aggressive disease course.

Neck muscle weakness can predict a more rapid deterioration in a person’s ability to perform daily tasks and a shorter life.

ALS experts are split on whether three other factors can impact the progression of the disease and patients’ survival. They are gender, the time it takes for a person experiencing symptoms to be diagnosed, and whether ALS manifests itself in the upper or lower limbs. The question of whether a delay in diagnosis impacts ALS’s progression and patients’ survival is complicated by the likelihood that those who go to a doctor later may have a disease that is progressing slower.

In addition to the movement problems associated with ALS, there has been increasing recognition that it affects thinking. Fourteen percent of ALS patients develop frontotemporal dementia, a condition associated with shorter survival. And up to half experience subtle cognitive impairment.

Although there is no cure for ALS, riluzole can extend a patient’s survival by three to six months. Radicava (edaravone), which obtained U.S. regulatory approval in May 2017, can slow patients’ deterioration in function, research has shown.

ALS News Today is strictly a news and information website about the disease. It does not provide medical advice, diagnosis or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.