As the vertebrae press against each other, the nerves can get pinched, leading to chronic pain. Ultimately, sitting becomes impossible. Straightening the spine also improves appearance, and frees the arms of the need to support the upper body. A pneumobelt is a device worn around the waist. As it inflates, it pushes against the abdomen, causing exhalation without effort.
Inhalation then occurs more easily as the belt deflates.
But you can't use it if you have uncorrected scoliosis. Before spinal fusion became common in the late 1970s, many of those with neuromuscular disease-caused scoliosis were treated with braces that surrounded the chest and abdomen. In Duchenne, this approach did little good, because it didn't stop the spinal collapse that resulted from muscular weakness. You should never brace the spine of a Duchenne patient to prevent scoliosis. You are just postponing the real treatment until you miss your opportunity.