Patients with NMD can suffer from a range of respiratory problems due to respiratory muscle weakness. Cough muscle weakness worsens secretion clearance from the airways, and increases the risk of infection. As a result, these patients often require chest physiotherapy or are supported with devices to aid clearance (such as mechanical insufflation-exsufflation) to reduce the risk of infection. Although evidence supports the use of these devices, the optimal technique or settings on the device are not clear.