Inclusion Criteria:  Children aged between 6 and 17 years old Adequate understanding of French or English Asthma diagnosis confirmed by a physician  Poor asthma control in the past 6 months, that is,  an acute exacerbation requiring oral corticosteroids, or an FEV1 <80% of predicted, FEV1/FVC ratio below the lower limit of normal, or significant (≥12%) reversibility in FEV1, or a total score <20 on the child Asthma Control Test (ACT) for children aged ≤11 years or on the ACT for those aged ≥12 years).  Exclusion Criteria:  Inability to produce a good seal around the mouthpiece when previously tested with spirometry Oscillometry or REOM, contra-indication to performing respiratory tests (e.g., facial trauma, chest pain, severe scoliosis) Other reason interfering with respiratory testing.