What is flail leg syndrome?

The name Flail-Leg Syndrome is derived from the English word “flail”, which means “to fling”. Flail leg syndrome is a particular form of ALS in which motor symptoms (paresis and myatrophy) begin and progress in the legs. The symptoms can remain limited to the legs over a longer period of time (up to several years). Symptoms in the trunk, arms and bulbar region appear with a long delay. The prognosis of Flail-Leg syndrome is characterized by slower progression and late involvement of the trunk (and associated respiratory effort) and delayed (or even absent) involvement of the bulbar region.

The main symptom is an early restriction of walking and standing and the need for mobility aids. Flail leg syndrome is quite rare and affects less than 10% of all people with ALS.