Every case of amyotrophic lateral sclerosis (ALS) is unique. Factors like the part of the body where symptoms first appear, the speed of progression, and the presence of co-occurring cognitive disabilities can vary greatly from person to person. However, there are fundamental symptoms of the disease that everyone with ALS will experience—primarily, the progressive loss of the nervous system’s ability to control the muscles, leading to weakness and paralysis.

The earliest symptoms of ALS can vary, but early signs and symptoms may include:

  • muscle cramps and muscle twitching
  • weakness in hands, legs, feet, or ankles
  • difficulty speaking or swallowing

These symptoms will continue to progress, eventually causing paralysis. The senses, including hearing, sight, smell, taste, and touch, are not affected by ALS. In most—but not all—cases of ALS, memory and thinking are not affected.

The manner and speed at which the disease progresses throughout a person's body can vary greatly. Most people live about 3-5 years after first experiencing ALS symptoms, while one in ten people survive for 10 years or more. The variable rate of disease progression makes prognosis difficult to predict and therapies challenging to develop.

Diagnosing ALS

Receiving an ALS diagnosis can be a long and challenging process, taking months, or even years. No one test can determine whether someone does or does not have ALS. People with ALS-like symptoms will often undergo extensive testing to rule out other neurological diseases that can mimic the disease. Clinicians will then recommend electromyography (EMG) testing to observe electrical activity within the muscles and nervous system. Abnormalities in these tests may result in a diagnosis of ALS.

Early Signs of ALS

Most early ALS symptoms include muscle cramps, spasms, or twitching (fasciculations) in one’s arms or legs. Other signs include weakness in the hands and feet or loss of balance. This form of the disease is called limb-onset ALS.

About 25% of people with ALS first have trouble talking clearly and begin to experience slurred speech. This form of the disease is called bulbar-onset ALS.

Middle Stages of ALS

As the disease spreads, muscles throughout the body will continue to weaken and start to stiffen. Because of this, range of motion exercises will likely be recommended by physical therapists. These help to keep muscles loose and prevent the formation of contractures and muscle pain.

A person with ALS's breathing may become affected as the disease progresses. A doctor may recommend noninvasive ventilation, such as a BiPAP machine, to help support breathing, particularly during sleep. Clinicians may recommend a feeding tube to help meet nutritional needs if swallowing becomes difficult. They may also prescribe medications to help control pseudobulbar affect (uncontrolled laughing or crying) or to help reduce muscle spasms.

People with bulbar-onset ALS often work with a speech therapist to keep their ability to speak for longer. Those with limb-onset ALS may rely on a cane, walker, or wheelchair due to difficulties walking and maintaining balance.

Late Stages of ALS

As ALS progresses and a person's muscles become paralyzed, they may lose the ability to move and speak. Many people with ALS may require a powered wheelchair to get around. Some may communicate through assistive devices like an eye-tracking device or a letter board. Some people with ALS choose to undergo a tracheostomy, a procedure in which a tube is surgically inserted into the throat, to help them breathe. People with advanced ALS are often cared for at home or in hospice.

ALS and Frontotemporal Dementia

In most cases of ALS, cognitive function is not affected. However, over the past decade, there has been an increasing interest in investigating the overlap of ALS with Frontotemporal Dementia (FTD), another neurological disease characterized by a decline in cognitive function. It is believed that up to a third of those diagnosed with ALS may be affected by cognitive issues.

Monitoring ALS Symptoms

After receiving a diagnosis, people with ALS often schedule regular clinic visits every 3-4 months. During these visits, patients are monitored for changes in their functional abilities and ALS symptoms. Commonly used tests for monitoring ALS include:

  • Spirometry: This is a test that measures lung function. Breathing abilities are typically estimated based on the maximum amount of air that can be blown out either slowly (slow vital capacity - SVC) or quickly (forced vital capacity - FVC).
  • ALS Functional Rating Scale-Revised (ALSFRS-R): The ALSFRS-R is a questionnaire that measures changes in a person's abilities, including breathing, speaking, sleeping, swallowing, and walking. The score is based on answers to 12 questions using a 48-point scale. Individuals with ALS can track their disease at home using the ALSFRS-R scale, there are several websites that offer that service free of charge, such as PatientsLikeMe.
  • Clinic Visits: Following clinic visits, individuals with ALS should consider asking for access to the “data” obtained during the visit, such as the doctor's recorded ALSFRS-R and SVC or FVC scores. This information is used as enrollment criteria for most clinical trials. Having it on hand can allow people to quickly determine if they qualify for trial participation.
  • ALS Research Collaborative (ARC): Through the ALS Research Collaborative (ARC), researchers at ALS TDI partner with people with ALS around the world to share and gather data on medical histories, family histories, genetics, biomarkers, and patient cell biology to better understand the disease. Participants are provided with a secure online portal where their data is located and easily accessible. They can track their disease progression and follow how various interventions might impact their symptoms and progression.

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