Evaluation of the Quality of Life of Patients With DBB With the Installation of OPEP

Inclusion Criteria: * Children (from 8 years of age) and adults over 18 years of age with DDB who doesn't use oscillating PEP. The study population will be clinically stable and will be seen in follow-up consultations. Exclusion Criteria: * Children under 8 years of age. * Patients who use an OPEP * Patients in the acute exacerbation phase of their DDB * Patients who are not under regular consultation * Patients with severe, uncontrolled co-morbidities * Patients with cognitive or psychiatric disorders preventing proper adherence to the study protocol * Patients taking part simultaneously in another clinical study that could interfere with the results of the OPEP study