Amyotrophic lateral sclerosis (ALS) is a progressive neurological disease that affects nerve cells controlling voluntary muscle movement. Early symptoms can vary from person to person, and they are often subtle.
Common first symptoms include:
- Muscle weakness, often starting in one hand, arm, leg, or the muscles used for speech
- Twitching (fasciculations) in muscles, especially in the arms, legs, shoulders, or tongue
- Muscle cramps or stiffness
- Clumsiness or difficulty with fine movements (such as buttoning clothes, writing, or gripping objects)
- Tripping, stumbling, or difficulty walking
- Changes in speech, such as slurring, a softer voice, or trouble pronouncing words
- Difficulty swallowing (in some people, early on)
- Fatigue and reduced muscle endurance
Some early signs can overlap with many other, more common conditions. ALS typically causes progressive worsening of weakness, and it usually does not begin with sensory symptoms such as numbness, tingling, or loss of feeling.
A person with new or worsening muscle weakness, persistent twitching with weakness, speech changes, or trouble swallowing should be evaluated by a healthcare professional. A neurologist can perform an examination and tests (such as nerve studies and imaging when needed) to determine the cause.
