What is flail arm syndrome?

The English term “flail arm” can be translated as “flailing arm”. Flail arm syndrome is a special form of ALS in which muscle weakness (paresis) and muscle atrophy (myatrophy) develop and slowly progress in the shoulders, arms and hands. In fact, the severe paralysis of the arm causes the affected limb to hang limply from the body and “flinging” movements of the arm can be impressive when walking. In flail arm syndrome, the muscle groups of the shoulder can be primarily affected, while the hands function well. In this case, movements from the shoulder (working overhead) are restricted or no longer possible. In other patients, however, flail arm syndrome begins in the hand (with limited manual function), progresses to the shoulder of the first affected arm and, in a further step, affects the opposite arm.

Flail arm syndrome can be associated with high functional stress, as manual skills can be severely restricted even in the early stages of the disease (handling, dressing, opening doors, etc.). The spread of motor symptoms from the shoulder and arm region to the lower extremities and the bulbar region can be very delayed. The variability in the course of Flail arm syndrome is high (with individual patients experiencing a rapid spread of paresis), so that despite the generally better prognosis, an individual assessment of the prognosis is particularly important. Flail arm syndrome affects less than 10% of all people with ALS.