Signs and symptoms

Signs of amyotrophic lateral sclerosis are typically subtle at first. The disease commonly begins in one part of the body and progresses to other areas. Gradual death of nerve cells saps muscles of their control. Early signs and symptoms of ALS include:

•    Difficulty lifting the front part of your foot (footdrop)
•    Weakness in your leg, feet or ankles
•    Hand weakness or clumsiness
•    Slurring of speech or trouble swallowing
•    Muscle cramps and twitching in your arms, shoulders and tongue
•    Fatigue in combination with the above signs and symptoms
The disease frequently begins in your hands, feet or limbs, and then spreads to other parts of your body. It eventually affects chewing, swallowing, speaking and breathing — which are known as bulbar functions after the bulb-shaped part of the brainstem that houses nerve cells controlling these functions. Less commonly, ALS begins with these bulbar symptoms. As the disease advances, your muscles become progressively weaker until they're paralyzed.
Eventually, amyotrophic lateral sclerosis paralyzes the muscles needed to breathe. Most people with ALS die of respiratory failure, usually within three to five years after symptoms begin. Sometimes, people with amyotrophic lateral sclerosis develop pneumonia because they can't swallow and they inhale (aspirate) food and oral secretions into their lungs.

ALS usually leaves intellect intact and spares the senses of sight, hearing, smell, taste and touch. It doesn't affect involuntary muscles, such as the muscles that control heartbeat and bladder and bowel function.