Lou Gehrig’s disease, known medically as ALS (amyotrophic lateral sclerosis), typically begins with localized muscle weakness in an arm, leg, or the muscles controlling speech and swallowing. Symptoms most commonly appear between ages 55 and 75, though the disease can develop at any age. Because early signs can be subtle, many people don’t recognize them right away.
How ALS Typically Starts
ALS often starts in the hands, feet, arms, or legs. You might notice that your grip feels weaker, that you’re dropping things more often, or that buttoning a shirt has become oddly difficult. In the legs, early signs include stumbling, tripping, or feeling unsteady on stairs. These problems tend to begin on one side of the body and in one specific area before spreading.
Muscle twitching (called fasciculations) and cramping are also common early signs, particularly in the arms, shoulders, and tongue. On their own, muscle twitches are extremely common and usually harmless. What distinguishes ALS-related twitching is that it tends to appear alongside progressive weakness, not in isolation.
Fatigue and a general sense that your muscles aren’t responding the way they used to can accompany these early changes. Some people describe it as clumsiness that came on gradually, or a feeling of stiffness and tightness in the affected limb.
Limb Onset vs. Bulbar Onset
ALS shows up in one of two patterns at the beginning: limb onset or bulbar onset. Understanding which type is present helps explain why early symptoms can look so different from person to person.
Limb Onset
Limb onset is far more common. The first symptoms appear in the arms or legs. You might struggle to lift objects, have trouble raising your arms above your head, or notice that walking feels less stable. Daily tasks like climbing stairs, opening jars, or carrying groceries become progressively harder. Because the weakness often starts in the hands, it can initially be mistaken for carpal tunnel syndrome or a pinched nerve.
Bulbar Onset
Bulbar onset ALS begins in the muscles of the face and throat. Early signs include slurred speech, a hoarse voice, and difficulty chewing or swallowing. Some people choke or aspirate while eating. This form can be harder to manage early on because swallowing problems increase the risk of malnutrition, dehydration, and food entering the airway.
Symptoms as the Disease Progresses
ALS is progressive, meaning symptoms gradually spread from the area where they started to other parts of the body. Someone who initially had weakness in one hand will eventually notice it in the other hand, then the arms, then the legs, or vice versa. A person with bulbar onset will develop limb weakness over time, and someone with limb onset will eventually experience speech and swallowing difficulties.
As more motor neurons are lost, muscles shrink visibly (a process called atrophy). Stiffness and tightness in the muscles can coexist with weakness, making movement feel both difficult and rigid. Eventually, the ability to walk, dress, write, and eat independently is lost.
The most serious progression involves the breathing muscles. As the diaphragm and the muscles between the ribs weaken, breathing becomes shallow. Early respiratory signs include feeling short of breath during light activity, waking up frequently at night, morning headaches from poor oxygen exchange during sleep, and difficulty lying flat. Respiratory failure is the most common cause of death in ALS.
Cognitive and Behavioral Changes
ALS is often thought of as a purely physical disease, but it can also affect thinking and behavior. Some people with ALS develop changes associated with frontotemporal dementia, a condition that affects the front part of the brain responsible for personality, judgment, and language. When this overlap occurs, behavioral symptoms often appear first.
These changes can include:
- Acting impulsively or recklessly, such as excessive spending or making inappropriate comments to strangers
- Loss of interest in hobbies, work, or close relationships
- Neglecting personal hygiene
- Difficulty planning daily activities or managing finances
- Uncharacteristic aggression or frustration
- A lack of awareness about their own diagnosis or its severity
Language difficulties can also appear, such as trouble finding the right word or recalling the names of everyday objects. These cognitive and behavioral shifts can be among the most challenging aspects for families, especially when they precede the more recognizable physical symptoms of ALS.
Uncontrollable Laughing or Crying
A lesser-known but common symptom is pseudobulbar affect, a condition where you suddenly laugh or cry in a way that doesn’t match how you’re feeling. A mildly funny comment might trigger uncontrollable laughter, or a slightly sad scene in a movie might cause intense, prolonged sobbing. Sometimes laughter shifts into tears mid-episode. These outbursts can last several minutes and feel impossible to stop. Crying episodes are more common than laughing ones.
This isn’t an emotional disorder. It happens because ALS damages the brain pathways that regulate emotional expression. The person still feels emotions normally but loses the ability to control how those emotions are displayed. It can be distressing and socially isolating, but it is treatable.
What ALS Does Not Affect
Despite its devastating impact on movement, ALS generally spares certain functions. The senses of sight, hearing, touch, taste, and smell remain intact. Bladder and bowel control are typically preserved until very late in the disease, if they are affected at all. The muscles that move your eyes also tend to keep working, which is why many people with advanced ALS communicate using eye-tracking technology.
This is one of the key differences between ALS and conditions that may initially look similar. Multifocal motor neuropathy, for example, also causes muscle weakness but progresses much more slowly and typically does not affect the breathing or swallowing muscles the way ALS does.
Getting a Diagnosis
There is no single test for ALS. Diagnosis is based on the pattern of symptoms, a neurological exam, and a process of ruling out other conditions that can mimic it. Nerve conduction studies and electromyography (a test that measures electrical activity in muscles) help confirm that both upper and lower motor neurons are involved, which is a hallmark of the disease.
Diagnostic criteria were updated in 2020 to simplify the process and catch the disease earlier. Even so, the average time from first symptoms to diagnosis can stretch to a year or more, partly because early symptoms are easy to attribute to something less serious. Men are slightly more likely to develop ALS than women, though the gap narrows at older ages. White individuals, particularly non-Hispanic White individuals, have the highest rates, but ALS occurs across all races and ethnicities.