What are the typical early symptoms of ALS?

ALS usually begins with subtle motor impairments. A common early symptom is a unilateral impairment of fine motor skills in the hand, which becomes noticeable during everyday movements: when handling utensils, turning a key, opening a bottle, or performing other manual tasks that require strength and dexterity. Another common early symptom is weakness in the foot’s lifting function: the foot can no longer be lifted effortlessly. This leads to “tripping over one’s own legs.”

In both scenarios—whether the disease begins in the hand or the foot—one side of the body is usually affected. Upon closer examination of the hand or lower leg, it becomes apparent that muscle mass is reduced (myatrophy). Myatrophy of the hand primarily affects the thenar eminence and the small hand muscles. When the disease begins in the foot, there is a narrowing of the muscles on the front of the lower leg—the edge of the shinbone becomes more prominent.

A third initial symptom, which occurs in 30–40% of cases, involves a speech disorder (dysarthria). Here, too, the changes are very subtle at first. Only certain sounds (so-called “S” and sibilant sounds) are affected. Fluctuations throughout the day are also typical. Upon examination of the tongue, “restlessness” of the muscles may be noticeable. Rare early symptoms include weakness of the shoulder muscles (flail arm variant), trunk instability, or labored breathing (axial form).