Amyotrophic Lateral Sclerosis (ALS)

Overview

Amyotrophic lateral sclerosis (ALS) is a progressive disease in which the nerve cells that tell your muscles to move gradually stop working. These nerve cells act like messengers, carrying movement commands from the brain down to the muscles. When they are damaged, the muscles no longer receive those commands, begin to weaken, and eventually waste away.

ALS is also known as Lou Gehrig's disease, named after the famous American baseball player who was diagnosed with the condition in 1939.

One of the hardest things about ALS is that as the disease progresses and control of the muscles is gradually lost, thinking, memory, and feelings remain largely intact. Most people with ALS keep their full mental sharpness until the very end. Over time, the muscles that control speech, swallowing, and breathing are also affected.

In the majority of people with ALS, the disease develops without any family history. In roughly one in ten people, it is linked to a gene change passed down through the family.

There is currently no treatment that can fully stop or reverse ALS. However, some medications are now available that can slow its progression, and good care and support can meaningfully extend both the length and quality of life.

Symptoms

ALS symptoms vary depending on where in the body the disease begins. In some people it starts with weakness in a hand or foot; in others the first sign is a change in speech or difficulty swallowing.

ALS symptoms include the following:

• Muscle weakness. The most prominent feature of the disease. Weakness often begins on one side of the body. In the hands and fingers, gripping objects, doing up buttons, or holding a pen becomes increasingly difficult. In the legs, weakness shows up as tripping, stumbling, and difficulty keeping balance.
• Muscle twitches and cramps. Small, involuntary twitches visible or felt just under the skin, and painful muscle cramps that tend to occur at night, are common in the early stages.
• Changes in speech. As the muscles involved in speaking weaken, the voice gradually becomes slurred, nasal, or harder to understand. This is especially prominent when ALS begins in the mouth and throat area.
• Difficulty swallowing. When the swallowing muscles are affected, eating and drinking becomes harder. Frequent choking and coughing can develop. Food or liquid accidentally entering the airway (going down the wrong way) is a serious risk and can lead to significant weight loss.
• Shortness of breath. This develops as the breathing muscles weaken and is the most serious complication of ALS. At first it may only be noticed during activity, but over time it can occur at rest too. Struggling to breathe at night disrupts sleep and can cause morning headaches.
• Stiffness in the muscles. Stiffness and painful muscle spasms can develop in affected areas. When this occurs alongside weakness, it is a strong indicator of ALS.
• Uncontrollable laughing or crying. Some people with ALS experience sudden, involuntary bouts of laughing or crying that seem out of proportion to the situation. This is not a mood disorder — it happens because certain brain pathways are affected — and it can be managed with medication.
• Changes in thinking and behavior. Some people with ALS notice difficulty with decision-making, planning, or finding words. In a smaller number of patients, changes in memory and personality can also occur.

It is also worth knowing what ALS typically does not affect. Eye movements are usually preserved until the very late stages. Bladder and bowel function remains normal in most cases. The senses of touch, pain, and temperature are not impaired.

When to See a Doctor

In the early stages, ALS symptoms can easily be dismissed as ordinary tiredness or the effects of getting older. But the following signs are worth discussing with a neurologist promptly.

Schedule a medical evaluation if:

• You have unexplained muscle weakness, particularly weakness that has started on one side of the body
• Your speech has become noticeably more slurred or your voice has changed
• You are frequently choking or liquid is going down the wrong way when you swallow
• You have persistent, unexplained muscle twitches or cramps
• You have been tripping, stumbling, or experiencing worsening balance
• You are finding it harder to breathe, particularly when lying down or during sleep

Causes

Why does ALS happen? For the majority of people who develop it, there is no clear single answer. Research suggests that several things work together to cause the nerve cells to break down.

• Gene changes. In about one in ten people with ALS, the disease is linked to a gene change inherited from a parent, and other family members may also have been affected. Specific gene changes make nerve cells more vulnerable to damage over time. Gene changes associated with ALS can also be found in some people who have no family history of the disease.
• Protein buildup inside nerve cells. In ALS, abnormal clumps of protein accumulate inside the nerve cells. These clumps interfere with how the cells work and eventually lead to cell death. Why this process starts in some people and not others is still being studied.
• Nerve cells being over-stimulated. The chemical signals that nerve cells use to communicate can build up to toxic levels in ALS, essentially over-exciting the nerve cells and wearing them out. One of the main ALS medications — riluzole — works specifically by reducing this effect.
• Inflammation. Immune cells in the brain and spinal cord can contribute to nerve cell damage in ALS. This is an active area of research.

Risk Factors

The known risk factors for ALS include the following:

• Age. ALS most commonly begins between the ages of 40 and 70. Younger adults can also be affected, and the familial form tends to appear at an earlier age.
• Sex. ALS is somewhat more common in men than in women. This difference becomes smaller with increasing age.
• Family history. When ALS has occurred in a parent or sibling, the risk is higher. This applies to approximately one in ten people with the condition.
• Smoking. Some research suggests that smoking may increase the risk of ALS.
• Certain environmental exposures. Long-term occupational exposure to pesticides and heavy metals has been linked to ALS risk in some studies, though this relationship has not been conclusively proven.
• Military service. Some research has found a higher rate of ALS among certain veterans. The exact reason is not yet understood.

Diagnosis

Diagnosing ALS takes time. In the early stages, the symptoms resemble those of many other conditions, and no single test can confirm the diagnosis on its own. On average, it takes around 9 to 12 months from when symptoms first appear to reach a diagnosis. Reducing this delay is one of the main priorities in ALS research.

Diagnostic methods include the following:

• Neurological examination. The doctor carefully assesses your muscle strength, reflexes, any stiffness or twitching in your muscles, your speech, and your ability to swallow. Finding signs of nerve damage coming from both the brain and the spinal cord in the same person is the key indicator that points toward ALS.
• Muscle and nerve test (EMG). A thin needle is placed into different muscles to measure their electrical activity. This test looks for evidence of nerve damage and is one of the most important tools for confirming ALS. It is also used to check that the nerves carrying sensation (feeling) are working normally — something that helps rule out other nerve conditions.
• MRI scan (brain and spine). This is done to look for other possible explanations for the symptoms — such as a tumor, pressure on the spinal cord, or another brain condition — rather than to confirm ALS directly.
• Blood tests. Certain markers of muscle damage may be elevated. Thyroid function, inflammation markers, and other values are also checked to rule out other possible causes of the symptoms.
• Genetic test. If there is a family history of ALS or if the disease has appeared at a relatively young age, a genetic test may be recommended. This can support the diagnosis and help family members understand their own risk. Genetic counseling is an important part of this process.
• Breathing test. This measures how strong the breathing muscles are. Getting a baseline measurement early is important for tracking changes over time and for knowing when breathing support should be introduced.

Treatment

There is currently no treatment that can fully stop or reverse ALS. What is available focuses on slowing progression, managing symptoms, and preserving quality of life. Being followed by a team of specialists from different fields makes a real difference to how well ALS can be managed.

Treatment options include the following:

• Riluzole. The first medication approved specifically for ALS. It works by reducing the chemical over-stimulation that damages nerve cells. It slows the progression of the disease and contributes to a modest extension of survival. It is taken as a tablet.
• Edaravone. A medication that helps protect nerve cells from damage. It has been shown to slow functional decline in some patients — particularly those in the earlier stages of the disease or those whose condition is progressing rapidly.
• Tofersen. A newer treatment developed specifically for the form of familial ALS linked to a particular gene change. It works by reducing the production of the abnormal protein associated with that gene change. It is given as an injection into the spinal fluid.
• Breathing support. When the breathing muscles weaken, a mask-based breathing device (often called a BiPAP machine) can make breathing easier. This device reduces breathlessness, improves sleep, and can meaningfully extend life. In more advanced stages, a breathing tube through the throat connected to a ventilator is an option — a decision that is always made together with the patient, based on their own values and wishes.
• Feeding tube. When swallowing difficulties lead to weight loss or inadequate nutrition, a thin tube placed directly into the stomach can ensure the person receives enough food and fluid. This procedure is safest when done while breathing capacity is still good, so the timing matters.
• Physiotherapy and exercise. Gentle exercises to maintain joint movement and muscle function are recommended. Exhausting, high-intensity exercise is not advised as it can increase fatigue and potentially cause harm.
• Communication support. Recording your voice while speech is still clear, and getting familiar with communication devices early, is enormously valuable for later. Eye-tracking devices that allow someone to communicate by moving their eyes can be life-changing for those who have largely lost the ability to speak.
• Medications for individual symptoms. Muscle cramps, stiffness, excess saliva, uncontrollable laughing or crying, pain, and depression each have effective treatment options that can significantly improve day-to-day comfort.
• Clinical trials. Research into ALS is advancing rapidly, with gene therapies and new protective medications being tested in clinical studies. Ask your doctor whether there are any trials you might be eligible for.

Complications

As ALS progresses, a number of serious problems can develop:

• Respiratory failure. The most common cause of death in ALS. As the breathing muscles weaken, getting enough air in and out becomes progressively harder. Regular breathing tests and timely introduction of breathing support can delay this significantly.
• Lung infections. When food or liquid accidentally enters the airway, repeated chest infections can develop. This is both a significant cause of illness and an important cause of death in ALS.
• Weight loss and malnutrition. Swallowing difficulties, reduced appetite, and the body using more energy than usual combine to cause serious weight loss. This can accelerate how quickly the disease progresses.
• Depression and anxiety. The diagnosis of ALS and increasing physical limitations create a heavy emotional burden. Clinical depression develops in many people with ALS and affects both quality of life and engagement with treatment.
• Sleep problems. Breathing difficulty, muscle stiffness, and cramps can all seriously disrupt sleep quality at night.
• The burden on carers. As ALS advances, full-time care becomes necessary. This places an enormous physical and emotional strain on family members. Support for carers is just as important as care for the person with ALS.

Living with ALS

Many people feel a profound sense of helplessness when first diagnosed with ALS. This is completely understandable. But with the right support and planning, a meaningful and fulfilling life remains possible — even as the disease advances.

Protecting Your Ability to Communicate

Recording your voice while speech is still clear, and starting to explore communication aids early, pays enormous dividends later. Eye-tracking devices, tablet-based speaking apps, and brain-computer interfaces allow people who have largely lost speech to stay connected with the world. Working with a speech therapist from an early stage makes this transition far smoother.

Keep Up with Breathing Checks

Regular breathing tests and knowing the right time to start using breathing support directly affects both how long you live and how comfortable you feel. Monitoring oxygen levels overnight helps catch problems early.

Nutrition Matters

Getting enough calories and protein is one of the few things with clear evidence of a positive effect on the course of the disease. High-calorie, easy-to-swallow foods and timely placement of a feeding tube when needed are key. A dietitian should be involved from the beginning.

Get Psychological Support

Grief, uncertainty, and a search for meaning after diagnosis are entirely normal. Talking to a psychologist or counselor, and connecting with others through ALS support groups, can genuinely help. It is equally important that family members and carers receive support of their own.

Have the Important Conversations Early

Sharing your preferences about breathing machines, feeding tubes, and intensive care with your doctor and family while you are still able to express them clearly protects both you and your loved ones from having to make those decisions in a crisis. These conversations are easy to put off but among the most valuable you can have.

Specialist Team Follow-up

Being followed by a multidisciplinary team — a neurologist, respiratory specialist, dietitian, physiotherapist, speech therapist, psychologist, and social worker — has strong evidence behind it for extending both survival and quality of life. Specialist ALS centres provide this kind of coordinated care and are the recommended setting for ongoing management.

Preparing for Your Appointment

Coming to your appointment well prepared helps both you and your doctor make the most of the time available.

What you can do:

• Note when symptoms began, where they were first noticed, and how they have changed since
• Describe whether weakness started on one side of the body or has affected both sides
• Mention any difficulty with speech, swallowing, or breathing
• Mention any family history of ALS or other nerve or muscle disease
• List all current medications
• Consider bringing a family member or friend who can add their own observations
• Write down your questions in advance

Questions you may wish to ask your doctor:

• Is the diagnosis confirmed and have other conditions been ruled out?
• Where has the disease started and how far has it progressed?
• Which of the available medications would be right for me?
• Are there any clinical trials I might be able to join?
• Can you refer me to a specialist ALS centre?
• How often should I have my breathing checked?
• Should I have genetic testing, and what would the results mean for my family?
• How can I connect with an ALS support group?

Questions your doctor may ask:

• When did the first symptom appear and where did it start?
• Did the weakness begin on one side and has it spread since?
• Are you having any difficulty with speech, swallowing, or breathing?
• Are you experiencing muscle twitches or cramps?
• Is there a family history of ALS or other neurological disease?
• Do you smoke or have you smoked in the past?
• Are you still able to manage your daily activities independently?